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Pathology and Genetics of Tumours of the Digestive System

World Health Organization Classification of Tumours
International Agency for Research on Cancer (IARC)
Pathology and Genetics of
Tumours of the Digestive System
Edited by
Stanley R. Hamilton
Lauri A. Aaltonen
IARCPress
Lyon, 2000
WHO OMS
Editors
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Stanley R. Hamilton, M.D.
Lauri A. Aaltonen, M.D., Ph.D.
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World Health Organization Classification of Tumours
Series Editors Paul Kleihues, M.D.
Leslie H. Sobin, M.D.
Pathology and Genetics of Tumours of the Digestive System
This volume was produced in collaboration with the
International Academy of Pathology (IAP)
and
with support from the
Swiss Federal Office of Public Health, Bern
The WHO Classification of Tumours of the Digestive System
presented in this book reflects the views of a
Working Group that convened for an
Editorial and Consensus Conference in
Lyon, France, November 6-9, 1999.
Members of the Working Group are indicated
in the List of Contributors on page 253.
IARC Library Cataloguing in Publication Data
Pathology and genetics of tumours of the digestive system / editors, S.R. Hamilton
and L.A. Aaltonen
(World Health Classification of tumours ; 2)
1. Digestive System Neoplasms I. Aaltonen, L.A. II. Hamilton, S.R.
III. Series
ISBN 92 832 2410 8 (NLM Classification: W1)
Format for bibliographic citations:
Hamilton S.R., Aaltonen L.A. (Eds.): World Health Organization Classification of
Tumours. Pathology and Genetics of Tumours of the Digestive System. IARC Press:
Lyon 2000
Published by IARC Press, International Agency for Research on Cancer,
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Diagnostic terms and definitions 8
1 Tumours of the oesophagus  9
WHO and TNM classifications 10
Squamous cell carcinoma 11
Adenocarcinoma 20
Endocrine tumours 26
Lymphoma 27
Mesenchymal tumours 28
Secondary tumours and melanoma 30
2 Tumours of the oesophagogastric junction
Adenocarcinoma 32
3 Tumours of the stomach 37
WHO and TNM classifications 38
Carcinoma 39
Endocrine tumours 53
Lymphoma 57
Mesenchymal tumours 62
Secondary tumours 66
4 Tumours of the small intestine 69
WHO and TNM classifications 70
Carcinoma 71
Peutz-Jeghers syndrome 74
Endocrine tumours 77
B-cell lymphoma 83
T-cell lymphoma 87
Mesenchymal tumours 90
Secondary tumours 91
5 Tumours of the appendix 93
WHO and TNM classifications 94
Adenocarcinoma 95
Endocrine tumours 99
Miscellaneous tumours 102
6 Tumours of the colon and rectum 103
WHO and TNM classifications 104
Carcinoma 105
Familial adenomatous polyposis  120
Hereditary nonpolyposis colorectal cancer 126
Juvenile polyposis 130
Cowden syndrome 132
Hyperplastic polyposis 135
Endocrine tumours 137
B-cell lymphoma 139
Mesenchymal tumours 142
7 Tumours of the anal canal  145
WHO and TNM classifications 146
Tumours of the anal canal 147
8 Tumours of the liver and
intrahepatic bile ducts
WHO and TNM classifications 158
Hepatocellular carcinoma 159
Intrahepatic cholangiocarcinoma 173
Combined hepatocellular and cholangiocarcinoma 181
Bile duct cystadenoma and cystadenocarcinoma 182
Hepatoblastoma 184
Lymphoma 190
Mesenchymal tumours 191
Secondary tumours  199
9 Tumours of the gallbladder and
extrahepatic bile ducts 203
WHO and TNM classifications 204
Carcinoma 206
Endocrine tumours 214
Neural and mesenchymal tumours 216
Lymphoma 217
Secondary tumours and melanoma 217
10 Tumours of the exocrine pancreas 219
WHO and TNM classifications 220
Ductal adenocarcinoma 221
Serous cystic neoplasms 231
Mucinous cystic neoplasms 234
Intraductal papillary-mucinous neoplasm 237
Acinar cell carcinoma 241
Pancreatoblastoma 244
Solid-pseudopapillary neoplasm 246
Miscellaneous carcinomas 249
Mesenchymal tumours 249
Lymphoma 250
Secondary tumours 250
Contributors 253
Source of charts and photographs 261
References 265
Subject index 307
Contents
157
31
Diagnostic terms and definitions1
Intraepithelial neoplasia2
.  A lesion cha-racterized by morphological changes
that include altered architecture and
abnormalities in cytology and differentia-tion. It results from clonal alterations in
genes and carries a predisposition for
progression to invasion and metastasis.
High-grade intraepithelial neoplasia.
A mucosal change with cytologic and
architectural features of malignancy but
without evidence of invasion into the stro-ma. It includes lesions termed severe
dysplasia and carcinoma in situ.
Polyp.  A generic term for any excres-cence or growth protruding above a
mucous membrane. Polyps can be
pedunculated or sessile, and are readily
seen by macroscopic examination or
conventional endoscopy.
Adenoma. A circumscribed benign
lesion composed of tubular and/or villous
structures showing intraepithelial neopla-sia. The neoplastic epithelial cells are
immature and typically have enlarged,
hyperbasophilic and stratified nuclei.
Tubular adenoma.  An adenoma in
which branching tubules surrounded by
lamina propria comprise at least 80% of
the tumour.
Villous adenoma.  An adenoma in which
leaf-like or finger-like processes of lami-na propria covered by dysplastic epithe-lium comprise at least 80% of the tumour.
Tubulovillous adenoma. An adenoma
composed of both tubular and villous
structures, each comprising more than
20% of the tumour.
Serrated adenoma. An adenoma com-posed of saw-toothed glands.
Intraepithelial neoplasia (dysplasia)
associated with chronic inflammatory
diseases. A neoplastic glandular
epithelial proliferation occurring in a
patient with a chronic inflammatory
bowel disease, but with macroscopic
and microscopic features that distin-guish it from an adenoma, e.g. patchy
distribution of dysplasia and poor cir-cumscription.
Peutz-Jeghers polyp.   A hamartoma-tous polyp composed of branching
bands of smooth muscle covered by nor-mal-appearing or hyperplastic glandular
mucosa indigenous to the site.
Juvenile polyp. A hamartomatous
polyp with a spherical head composed
of tubules and cysts, lined by normal
epithelium, embedded in an excess of
lamina propria. In juvenile polyposis, the
polyps are often multilobated with a pap-illary configuration and a higher ratio of
glands to lamina propria.
Adenocarcinoma. A malignant epithe-lial tumour with glandular differentiation.
Mucinous adenocarcinoma.  An ade-nocarcinoma containing extracellular
mucin comprising more than 50% of the
tumour. Note that ‘mucin producing’ is
not synonymous with mucinous in this
context.
Signet-ring cell carcinoma.  An adeno-carcinoma in which the predominant
component (more than 50%) is com-posed of isolated malignant cells con-taining intracytoplasmic mucin.
Squamous cell (epidermoid) carcino-ma.   A malignant epithelial tumour with
squamous cell differentiation.
Adenosquamous carcinoma. A malig-nant epithelial tumour with significant
components of both glandular and squa-mous differentiation.
Small cell carcinoma. A malignant
epithelial tumour similar in morphology,
immunophenotype and behaviour to
small cell carcinoma of the lung.
Medullary carcinoma. A malignant
epithelial tumour in which the cells form
solid sheets and have abundant
eosinophilic cytoplasm and large, vesic-ular nuclei with prominent nucleoli. An
intraepithelial infiltrate of lymphocytes is
characteristic.
Undifferentiated carcinoma.  A malig-nant epithelial tumour with no glandular
structures or other features to indicate
definite differentiation.
Carcinoid. A well differentiated neo-plasm of the diffuse endocrine system.
______________
1
This list of terms is proposed to be used for the entire digestive system and reflects the view of the Working Group convened in Lyon, 6 – 9 November,
1999. Terminology evolves with scientific progress; the terms listed here reflect current understanding of the process of malignant transformation in the
digestive tract. The Working Group anticipates a further convergence of diagnostic terms throughout the digestive system.
2
In an attempt to resolve confusion surrounding the terms ‘dysplasia’, ‘carcinoma in situ,’ and ‘atypia’, the Working Group adopted the term ‘intraepithe-lial neoplasia’ to indicate preinvasive neoplastic change of the epithelium. The diagnosis does not exclude the possibility of  coexisting carcinoma.
Intraepithelial neoplasia should not be used as a generic description of epithelial abnormalities due to reactive or regenerative changes.
CHAPTER 1
Tumours of the Oesophagus
Carcinomas of the oesophagus pose a considerable medical
and public health challenge in many parts of the world.
Morphologically and aetiologically, two major types are distin-guished:
Squamous cell carcinoma
In Western countries, oesophageal carcinomas with squa-mous cell differentiation typically arise after many years of
tobacco and alcohol abuse. They frequently carry G:C >T:A
mutations of the  TP53 gene. Other causes include chronic
mucosal injury through hot beverages and malnutrition, but the
very high incidence rates observed in Iran and some African
and Asian regions remain inexplicable.
Adenocarcinoma
Oesophageal carcinomas with glandular differentiation are
typically located in the distal oesophagus and occur predomi-nantly in white males of industrialized countries, with a marked
tendency for increasing incidence rates. The most important
aetiological factor is chronic gastro-oesophageal reflux lead-ing to Barrett type mucosal metaplasia, the most common pre-cursor lesion of adenocarcinoma.
10 Tumours of the oesophagus
Epithelial tumours
Squamous cell papilloma 8052/01
Intraepithelial neoplasia2
Squamous
Glandular (adenoma)
Carcinoma
Squamous cell carcinoma 8070/3
Verrucous (squamous) carcinoma 8051/3
Basaloid squamous cell carcinoma 8083/3
Spindle cell (squamous) carcinoma 8074/3
Adenocarcinoma 8140/3
Adenosquamous carcinoma 8560/3
Mucoepidermoid carcinoma 8430/3
Adenoid cystic carcinoma 8200/3
Small cell carcinoma 8041/3
Undifferentiated carcinoma 8020/3
Others
Carcinoid tumour 8240/3
Non-epithelial tumours
Leiomyoma 8890/0
Lipoma 8850/0
Granular cell tumour 9580/0
Gastrointestinal stromal tumour 8936/1
benign 8936/0
uncertain malignant potential 8936/1
malignant 8936/3
Leiomyosarcoma 8890/3
Rhabdomyosarcoma 8900/3
Kaposi sarcoma 9140/3
Malignant melanoma 8720/3
Others
Secondary tumours
WHO histological classification of oesophageal tumours
_____________
1
Morphology code of the International Classification of Diseases for Oncology (ICD-O) {542} and the Systematized Nomenclature of Medicine (http://snomed.org).
Behaviour is coded /0 for benign tumours, /1 for unspecified, borderline or uncertain behaviour, /2 for in situ carcinomas and grade III intraepithelial neoplasia, and /3 for
malignant tumours.
2
Intraepithelial neoplasia does not have a generic code in ICD-O. ICD-O codes are available only for lesions categorized as glandular intraepithelial neoplasia grade III
(8148/2), squamous intraepithelial neoplasia, grade III (8077/2), and squamous cell carcinoma in situ (8070/2).
_____________
1
{1, 66}. This classification applies only to carcinomas.
2
A help desk for specific questions about the TNM classification is available at http://tnm.uicc.org.
TNM classification1
T – Primary Tumour
TX Primary tumour cannot be assessed
T0 No evidence of primary tumour
Tis Carcinoma in situ
T1 Tumour invades lamina propria or submucosa
T2 Tumour invades muscularis propria
T3 Tumour invades adventitia
T4 Tumour invades adjacent structures
N – Regional Lymph Nodes
NX Regional lymph nodes cannot be assessed
N0 No regional lymph node metastasis
N1 Regional lymph node metastasis
M – Distant Metastasis
MX Distant metastasis cannot be assessed
M0 No distant metastasis
M1 Distant metastasis
For tumours of lower thoracic oesophagus
M1a Metastasis in coeliac lymph nodes
M1b Other distant metastasis
For tumours of upper thoracic oesophagus
M1a Metastasis in cervical lymph nodes
M1b Other distant metastasis
For tumours of mid-thoracic oesophagus
M1a Not applicable
M1b Non-regional lymph node
or other distant metastasis
Stage Grouping
Stage 0 Tis N0 M0
Stage I T1 N0 M0
Stage IIA T2 N0 M0
T3 N0 M0
Stage IIB T1 N1 M0
T2 N1 M0
Stage III T3 N1 M0
T4 Any N M0
Stage IVA Any T Any N M1a
Stage IVB Any T Any N M1b
TNM classification of oesophageal tumours
11Squamous cell carcinoma
Definition
Squamous cell carcinoma (SCC) of the
oesophagus is a malignant epithelial
tumour with squamous cell differentia-tion, microscopically characterised by
keratinocyte-like cells with intercellular
bridges and/or keratinization.
ICD-O Code 8070/3
Epidemiology
Squamous cell carcinoma of the oeso-phagus shows great geographical diver-sity in incidence, mortality and sex ratio.
In Western countries, the age-standar-dized annual incidence in most areas
does not exceed 5 per 100,000 popula-tion in males and 1 in females. There are,
however, several well-defined high-risk
areas, e.g. Normandy and Calvados in
North-West France, and Northern Italy,
where incidence may be as high as 30
per 100,000 population in males and 2 in
females {1020, 1331}. This type of can-cer is much more frequent in Eastern
countries and in many developing coun-tries. Regions with very high incidence
rates have been identified in Iran, Central
China, South Africa and Southern Brazil.
In the city of Zhengzhou, capital of
Henan province in China, the mortality
rate exceeds 100 per 100,000 population
in males and 50 in females {1116, 2191}.
In both high-risk and low-risk regions,
this cancer is exceedingly rare before
the age of 30 and the median age is
around 65 in both males and females.
Recent changes in the distribution pat-tern in France indicate that the rate of
SCC has increased steadily in low-risk
areas, particularly among females,
whereas there may be a slight decrease
in high-risk areas. In the United States, a
search in hospitalisation records of mili-tary veterans indicates that SCC is 2-3
times more frequent among blacks than
among Asians, Whites or Native
Americans {453}.
Aetiology
Tobacco and alcohol.   In Western coun-tries, nearly 90% of the risk of SCC can
be attributed to tobacco and alcohol.
Each of these factors influences the risk
of oesophageal cancer in a different way.
With regard to the consumption of tobac-co, a moderate intake during a long peri-od carries a higher risk than a high intake
during a shorter period, whereas the
reverse is true for alcohol. Both factors
combined show a multiplicative effect,
even at low alcohol intake. In high-risk
areas of North-West France and Northern
Italy, local drinking customs may partially
explain the excess incidence of SCC
{523, 1020}. In Japanese alcoholics, a
polymorphism in ALDH2, the gene
encoding aldehyde dehydrogenase 2,
has been shown to be significantly asso-ciated with several cancers of the upper
digestive tract, including squamous cell
cancer. This observation suggests a role
for acetaldehyde, one of the main car-cinogenic metabolites of alcohol in the
development of oesophageal carcinoma
{2177}.
Nutrition.  Risk factors other than tobac-co and alcohol play significant roles in
other regions of the world. In high-risk
areas of China, a deficiency in certain
trace elements and the consumption of
pickled or mouldy foods (which are
potential sources of nitrosamines) have
been suggested.
Hot beverages.   Worldwide, one of the
most common risk factors appears to be
the consumption of burning-hot bevera-ges (such as Mate tea in South America)
which cause thermal injury leading to
chronic oesophagitis and then to precan-cerous lesions {1116, 2191, 387}.
HPV.  Conflicting reports have proposed
a role for infectious agents, including
human papillomavirus (HPV) infection.
Although HPV DNA is consistently
detected in 20 to 40% of SCC in high-risk
areas of China, it is generally absent in
the cancers arising in Western countries
{954, 679}.
Squamous cell carcinoma
of the oesophagus
H.E. Gabbert Y. Nakamura
T. Shimoda J.K. Field
P. Hainaut H. Inoue
Fig. 1.02 Squamous cell carcinoma of the oesophagus. Age-standardized incidence
rates per 100,000 and proportions (%) due to alcohol and tobacco (dark-blue).
Fig. 1.01 Worldwide annual incidence (per 100,000) of oesophageal cancer in
males. Numbers on the map indicate regional average values.
5.2
7.8
19.3
11.9
51.6
4.611.0
< 2.2 < 3.8 < 5.8 < 9.5 < 51.7
China, Henan
Iran, North East
South Africa
India, Bombay
Urugay
China, Hong Kong
Italy, North East
USA, New York
France, Calvados
1%
70%
50%
50%
20%
90%
90%
70%
90%
0 50 100 150 200
12 Tumours of the oesophagus
Associations between achalasia, Plum-mer-Vinson syndrome, coeliac disease
and tylosis (focal nonepidermolytic pal-moplantar keratoderma) with oeso-phageal cancer have also been de-scribed.
Localization
Oesophageal SCC is located predomi-nantly in the middle and the lower third of
the oesophagus, only 10-15% being situ-ated in the upper third {1055}.
Clinical features
Symptoms and signs
The most common symptoms of ad-vanced oesophageal cancer are dys-phagia, weight loss, retrosternal or epi-gastric pain, and regurgitation caused
by narrowing of the oesophageal lumen
by tumour growth {606}. Superficial SCC
usually has no specific symptoms but
sometimes causes a tingling sensation,
and is, therefore, often detected inciden-tally during upper gastrointestinal
endoscopy {464, 1874}.
Endoscopy and vital staining
Superficial oesophageal cancer is com-monly observed as a slight elevation or
shallow depression on the mucosal
surface, which is a minor morphological
change compared to that of advanced
cancer. Macroscopically, three types can
be distinguished: flat, polypoid and ulcer-ated. Chromoendoscopy utilizing toluidine
blue or Lugol iodine spray may be of value
{465, 481}. Toluidine blue, a metachromat-ic stain from the thiazine group, has a par-ticular affinity for RNA and DNA, and
stains areas that are richer in nuclei than
the normal mucosa. Lugol solution reacts
specifically with glycogen in the normal
squamous epithelium, whereas precan-cerous and cancerous lesions, but also
inflamed areas and gastric heterotopia,
are not stained. However, the superficial
extension of carcinomas confined to the
mucosa can not be clearly recognized by
simple endoscopy.
Endoscopic ultrasonography
Endoscopic ultrasonography is used to
evaluate both depth of tumour infiltration
and para-oesophageal lymph node
involvement in early and advanced
stages of the disease {1509, 1935}. For
the evaluation of the depth of infiltration,
high frequency endoscopic ultrasono-graphy may be used {1302}. In general,
Fig. 1.03 Macroscopic images of squamous cell carcinoma (SCC) of the oesophagus. A Flat superficial type.
B Lugol iodine staining of the specimen illustrated in A. C Polypoid SCC. D Longitudinal sections of carcino-ma illustrated in C. E Deeply invasive polypoid SCC. F Longitudinal sections of carcinoma illustrated in E.
A
C
B
F
D
E
13Squamous cell carcinoma
oesophageal carcinoma presents on
endosonography as a circumscribed or
diffuse wall thickening with a predomi-nantly echo-poor or echo-inhomoge-neous pattern. As a result of tumour
penetration through the wall and into
surrounding structures, the endosono-graphic wall layers are destroyed.
Computed tomography (CT) and magnet-ic resonance imaging (MRI)
In advanced carcinomas, CT and MRI
give information on local and systemic
spread of SCC. Tumour growth is char-acterized as swelling of the oesophageal
wall, with or without direct invasion to
surrounding organs {1518}. Cervical,
abdominal and mediastinal node enlarg-ement is recorded. Three-dimensional
CT or MRI images may be presented as
virtual endoscopy, effectively demon-strating T2-T4 lesions, but not T1 lesions.
Macroscopy
The gross appearance varies according
to whether it is detected in an early or an
advanced stage of the disease. Among
early SCC, polypoid, plaque-like, de-pressed and occult lesions have been
described {161, 2183}. For the macro-scopic classification of advanced oeso-phageal SCC, Ming {1236} has proposed
three major patterns: fungating, ulcera-tive, and infiltrating. The fungating pattern
is characterized by a predominantly exo-phytic growth, whereas in the ulcerative
pattern, the tumour growth is predomi-nantly intramural, with a central ulceration
and elevated ulcer edges. The infiltrative
pattern, which is the least common one,
also shows a predominantly intramural
growth, but causes only a small mucosal
defect. Similar types of macroscopic
growth patterns have been defined in the
classification of the Japanese Society for
Esophageal Diseases {58}.
Tumour spread and staging
For the staging of SCC, the TNM system
(tumour, node, metastasis) established
by the International Union Against
Cancer (UICC) is the most widely used
system. Its usefulness in the planning of
treatment and in the prediction of prog-nosis has been validated {1104, 895, 66,
1, 772}.
Superficial oesophageal carcinoma.
When the tumour is confined to the
mucosa or the submucosa, the term
superficial oesophageal carcinoma is
used irrespective of the presence of
regional lymph node metastases {58,
161}. In China and in Japan, the term
early oesophageal carcinoma is often
used defining a carcinoma that invades
no deeper than the submucosa but has
not metastasised {609}. In several studies
from Japan, superficial carcinomas
accounted for 10-20% of all resected car-cinomas, whereas in Western countries
superficial carcinomas are much less fre-quently reported {543}. About 5% of
superficial carcinomas that have invaded
the lamina propria display lymph node
metastases, whereas in carcinomas that
invade the submucosa the risk of nodal
metastasis is about 35% {1055}. For
tumours that have infiltrated beyond the
submucosa, the term advanced oeso-phageal carcinoma is applied.
Intramural metastases.  A special feature
of oesophageal SCC is the occurrence of
intramural metastases, which have been
found in resected oesophageal speci-mens in 11-16% of cases {896, 987}.
These metastases are thought to result
from intramural lymphatic spread with the
establishment of secondary intramural
tumour deposits. Intramural metastases
are associated with an advanced stage
of disease and with shorter survival.
Second primary SCC. Additionally, the
occurrence of multiple independent SCC
has been described in between 14 and
31% of cases, the second cancers being
mainly carcinomas in situ and superficial
SCC {1154, 989, 1507}.
Treatment groups. Following the clinical
staging, patients are usually divided into
two treatment groups: those with locore-gional disease in whom the tumour is
potentially curable (e.g. by surgery,
radiotherapy, multimodal therapy), and
those with advanced disease (meta-stases outside the regional area or inva-sion of the airway) in whom only palliative
treatment is indicated {606}. Oeso-phageal SCC limited to the mucosa may
be treated by endoscopic mucosal
resection due to its low risk of nodal
metastasis. Endoscopic mucosal resec-tion is also indicated for high-grade
intraepithelial neoplasia. Tumours that
have invaded the submucosa or those in
more advanced tumour stages have
Fig. 1.06  Primary squamous cell carcinoma (CA) of
oesophagus with an intramural metastasis (M) near
the oesophagogastric junction.
Fig. 1.05  A Endoscopic view of a superficial squa-mous cell carcinoma presenting as a large nodule
(CA) in a zone of erosion.  B After spraying of 2%
iodine solution, the superficial extent of the tumour
becomes visible as unstained light yellow area (CA,
arrows).
A
B
Fig. 1.04 Catheter probe ultrasonograph of a squa-mous cell carcinoma, presenting as hypoechoic
lesion (arrow).
CA
CA
M
CA
more than 30% risk of lymph node
metastasis, and endoscopic therapy is
not indicated {465}. Additionally, clinical
staging is performed in order to deter-mine the success of treatment, e.g. fol-lowing radio- and/or chemotherapy.
Tumour spread
The most common sites of metastasis of
oesophageal SCC are the regional lymph
nodes. The risk of lymph node metasta-sis is about 5% in carcinomas confined
to the mucosa but over 30% in carcino-mas invading the submucosa and over
80% in carcinomas invading adjacent
organs or tissues {772}. Lesions of the
upper third of the oesophagus most fre-quently involve cervical and mediastinal
lymph nodes, whereas those of the mid-dle third metastasise to the mediastinal,
cervical and upper gastric lymph nodes.
Carcinomas of the lower third preferen-tially spread to the lower mediastinal and
the abdominal lymph nodes {28}. The
most common sites of haematogenous
metastases are the lung and the liver
{1153, 1789}. Less frequently affected
sites are the bones, adrenal glands, and
brain {1551}. Recently, disseminated
tumour cells were identified by means of
immunostaining in the bone marrow of
about 40% of patients with oesophageal
SCC {1933}. Recurrence of cancer fol-lowing oesophageal resection can be
locoregional or distant, both with approx-imately equal frequency {1185, 1027}.
Histopathology
Oesophageal SCC is defined as the pen-etration of neoplastic squamous epitheli-um through the epithelial basement mem-brane and extension into the lamina pro-pria or deeper tissue layers. Invasion
commonly starts from a carcinoma in situ
with the proliferation of rete-like projec-tions of neoplastic epithelium that push
into the lamina propria with subsequent
dissociation into small carcinomatous cell
clusters. Along with vertical tumour cell
infiltration, usually a horizontal growth
undermines the adjacent normal mucosa
at the tumour periphery. The carcinoma
may already invade intramural lymphatic
vessels and veins at an early stage of dis-ease. The frequency of lymphatic and
blood vessel invasion increases with
increasing depth of invasion {1662}.
Tumour cells in lymphatic vessels and in
blood vessels may be found progressive-ly several centimetres beyond the gross
tumour. The carcinoma invades  the mus-cular layers, enters the loose fibrous
adventitia and may extend beyond the
adventitia, with invasion of adjacent
organs or tissues, especially the trachea
and bronchi, eventually with the formation
of oesophagotracheal or oesophago-bronchial fistulae {1789}.
Oesophageal SCC displays different
microscopic patterns of invasion, which
are categorised as ‘expansive growth’ or
‘infiltrative growth’. The former pattern is
characterized by a broad and smooth
invasion front with little or no tumour cell
dissociation, whereas the infiltrative pat-tern shows an irregular invasion front and
a marked tumour cell dissociation.
The degree of desmoplastic or inflamma-tory stromal reaction, nuclear polymor-phism and keratinization is extremely
variable. Additionally, otherwise typical
oesophageal SCC may contain small foci
of glandular differentiation, indicated by
the formation of tubular glands or mucin-producing tumour cells {987}.
Verrucous carcinoma (ICD-O 8051/3)
This rare variant of squamous cell carci-noma {19} is histologically comparable to
verrucous carcinomas arising at other
sites {969}. On gross examination, its
appearance is exophytic, warty, cauli-flower-like or papillary. It can be found in
any part of the oesophagus. Histologi-cally, it is defined as a malignant papil-lary tumour composed of well differentia-ted and keratinized squamous epitheli-um with minimal cytological atypia, and
pushing rather than infiltrating margins
{2066}. Oesophageal verrucous carcino-ma grows slowly and invades locally, with
a very low metastasising potential.
Spindle cell carcinoma (ICD-O 8094/3)
This unusual malignancy is defined as a
squamous cell carcinoma with a variable
sarcomatoid spindle cell component. It is
also known by a variety of other terms,
including carcinosarcoma, pseudosarco-matous squamous cell carcinoma, poly-poid carcinoma, and squamous cell car-cinoma with a spindle cell component
{1055}. Macroscopically, the tumour is
characterized by a polypoid growth pat-tern. The spindle cells may be capable of
maturation, forming bone, cartilage and
skeletal muscle cells {662}. Alternatively,
they may be more pleomorphic, resem-bling malignant fibrous histiocytoma. In
the majority of cases a gradual transition
between carcinomatous and sarcomatous
components has been observed on the
light microscopic level. Immunohisto-chemical and electron microscopic stu-dies indicate that the sarcomatous spin-dle cells show various degrees of epithe-lial differentiation. Therefore, the sarcoma-14 Tumours of the oesophagus
Fig. 1.07 Squamous cell carcinoma with transmural
invasion. M, remaining intact mucosa.
Fig. 1.09 Verrucous carcinoma.  A Typical exo-phytic papillary growth. B High degree of differen-tiation.
B
Fig. 1.08 Squamous cell carcinoma invading thin-walled lymphatic vessels.
M
A
15Squamous cell carcinoma
tous component may be metaplastic.
However, a recent molecular analysis of a
single case of a spindle cell carcinoma
showed divergent genetic alterations in
the carcinomatous and in the sarcoma-tous tumour component suggesting two
independent malignant cell clones {823}.
Basaloid squamous cell carcinoma
(ICD-O 8083/3)
This rare but distinct variant of oeso-phageal SCC {1961} appears to be iden-tical to the basaloid squamous cell carci-nomas of the upper aerodigestive tract
{109}. Histologically, it is composed of
closely packed cells with hyperchromat-ic nuclei and scant basophilic cyto-plasm, which show a solid growth pat-tern, small gland-like spaces and foci of
comedo-type necrosis. Basaloid squa-mous cell carcinomas are associated
with intraepithelial neoplasia, invasive
SCC, or islands of squamous differentia-tion among the basaloid cells {2036}. The
proliferative activity is higher than in typi-cal SCC. However, basaloid squamous
cell carcinoma is also characterized by a
high rate of apoptosis and its prognosis
does not differ significantly from that of
the ordinary oesophageal SCC {1663}.
Precursor lesions
Most studies on precursor lesions of
oesophageal SCC have been carried out
in high-risk populations, especially in Iran
and Northern China, but there is no evi-dence that precursor lesions in low-risk
regions are substantially different. The
development of oesophageal SCC is
thought to be a multistage process which
progresses from the conversion of nor-mal squamous epithelium to that with
basal cell hyperplasia, intraepithelial
neoplasia (dysplasia and carcinoma in
situ), and, finally, invasive SCC {354,
1547, 377}.
Intraepithelial neoplasia.  This lesion is
about eight times more common in high
cancer-risk areas than in low-risk areas
{1547}, and is frequently found adjacent
to invasive SCC in oesophagectomy
specimens {1154, 988}. Morphological
features of intraepithelial neoplasia
include both architectural and cytological
abnormalities. The architectural abnor-mality is characterized by a disorganisa-tion of the epithelium and loss of normal
cell polarity. Cytologically, the cells exhibit
irregular and hyperchromatic nuclei, an
increase in nuclear/cytoplasmic ratio and
increased mitotic activity. Dysplasia is
usually graded as low or high-grade. In
low-grade dysplasia, the abnormalities
are often confined to the lower half of the
epithelium, whereas in high-grade dys-plasia the abnormal cells also occur in
the upper half and exhibit a greater
degree of atypia. In carcinoma in situ, the
atypical cells are present throughout the
epithelium without evidence of maturation
at the surface of the epithelium {1154}. In
a two-tier system, severe dysplasia and
carcinoma-in-situ are included under the
rubric of high-grade intraepithelial neo-plasia, and may have the same clinical
implications {1055}.
Epidemiological follow-up studies sug-gest an increased risk for the subse-quent development of invasive SCC for
patients with basal cell hyperplasia (rela-tive risk: 2.1), low-grade dysplasia (RR:
2.2), moderate-grade dysplasia (RR:
15.8), high-grade dysplasia (RR: 72.6)
and carcinoma in situ (RR: 62.5) {377}.
Fig. 1.10 Spindle cell carcinoma. A Typical polypoid appearance. B Transition between conventional and spindle cells areas. C Malignant fibrous histiocytoma-like
area in a spindle cell carcinoma.
B CA
Fig. 1.11  Basaloid squamous cell carcinoma. A Ty-pical comedo-type necrosis.  B Small gland-like
structures.
A
B
Fig. 1.12  Low-grade intraepithelial neoplasia with
an increase in basal cells, loss of polarity in the
deep epithelium and slight cytological atypia.
16 Tumours of the oesophagus
Basal cell hyperplasia
This lesion is histologically defined as an
otherwise normal squamous epithelium
with a basal zone thickness greater than
15% of total epithelial thickness, without
elongation of lamina propria papillae
{377}. In most cases, basal cell hyper-plasia is an epithelial proliferative lesion
in response to oesophagitis, which is fre-quently observed in high-risk populations
for oesophageal cancer {1547}.
Squamous cell papilloma (ICD-O 8052/0)
Squamous cell papilloma is rare and
usually causes no specific symptoms. It
is a benign tumour composed of hyper-plastic squamous epithelium covering
finger-like processes with cores derived
from the lamina propria. The polypoid
lesions are smooth, sharply demarcated,
and usually 5 mm or less in maximum
diameter {249, 1428}. Rarely, giant papil-lomas have been reported, with sizes up
to 5 cm {2037}. Most squamous cell
papillomas represent single isolated
lesions, typically located in the distal to
middle third of the oesophagus, but mul-tiple lesions occur.
Histologically, cores of fibrovascular tis-sue are covered by mature stratified
squamous epithelium. The aetiological
role of human papillomavirus (HPV)
infection has been investigated in seve-ral studies, but the results were inconclu-sive {248}. Malignant progression to SCC
is extremely rare.
In Japan, oesophageal squamous cell
carcinoma is diagnosed mainly based on
nuclear criteria, even in cases judged to
be non-invasive intraepithelial neoplasia
(dysplasia) in the West. This difference in
diagnostic practice may contribute to the
relatively high rate of incidence and good
prognosis of superficial squamous cell
carcinoma reported in Japan {1682}.
Grading
Grading of oesophageal SCC is tradition-ally based on the parameters of mitotic
activity, anisonucleosis and degree of
differentiation.
Well differentiated tumours have cytolo-gical and histological features similar to
those of the normal oesophageal squa-mous epithelium. In well differentiated
oesophageal SCC there is a high propor-tion of large, differentiated, keratinocyte-like squamous cells and a low proportion
of small basal-type cells, which are loca-ted in the periphery of the cancer cell
nests {1055}. The occurrence of kera-tinization has been interpreted as a sign
of differentiation, although the normal
oesophageal squamous epithelium does
not keratinize.
Poorly differentiated tumours predomi-nantly consist of basal-type cells, which
usually exhibit a high mitotic rate.
Moderately differentiated carcinomas,
between the well and poorly differentia-ted types, are the most common type,
accounting for about two-thirds of all
oesophageal SCC. However, since no
generally accepted criteria have been
identified to score the relative contribu-tion of the different grading parameters,
grading of SCC suffers from a great inter-observer variation.
Undifferentiated carcinomas are defined
by a lack of definite light microscopic
features of differentiation. However, ultra-structural or immunohistochemical inves-tigations may disclose features of squa-mous differentiation in a subset of light-microscopically undifferentiated carcino-mas {1881}.
Fig. 1.14 Squamous cell papilloma of distal oeso-phagus. This lesion was negative for human papilloma-virus by in situ hybridisation.
Fig. 1.13 High grade intraepithelial neoplasia of oesophageal squamous epithelium. Architectural disarray,
loss of polarity and cellular atypia are much greater than shown in Fig. 1.12. Changes in  D extend to the
parakeratotic layer of the luminal surface.
A B
C D
17Squamous cell carcinoma
Genetic susceptibility
Familial predisposition of oesophageal
cancer has been only poorly studied
except in its association with focal non-epidermolytic palmoplantar keratoderma
(NEPPK or tylosis) {1279, 1278, 752}.
This autosomal, dominantly inherited dis-order of the palmar and plantar surfaces
of the skin segregates together with
oesophageal cancer in three pedigrees,
two of which are extensive {456, 1834,
693}. The causative locus has been des-ignated the tylosis oesophageal cancer
(TOC) gene and maps to 17q25 between
the anonymous microsatellite markers
D17S1839 and D17S785 {1594, 899}.
The genetic defect is thought to be in a
molecule involved in the physical struc-ture of stratified squamous epithelia
whereby loss of function of the gene may
alter oesophageal integrity thereby mak-ing it more susceptible to environmental
mutagens.
Several structural candidate genes such
as envoplakin  (EVPL), integrin β4
(ITGB4) and plakoglobin have been
excluded as the TOC gene following inte-gration of the genetic and physical maps
of this region {1595}. The importance of
this gene in a larger population than
those afflicted with the familial disease is
indicated by the association of the
genomic region containing the TOC
gene with sporadic squamous cell
oesophageal carcinomas {2020, 823},
Barrett adenocarcinoma of the oesopha-gus {439}, and primary breast cancers
{549} using loss of heterozygosity stud-ies.
Genetics
Alterations in genes that encode
regulators of the G1 to S transition of cell
cycle are common in SCC. Mutation in
the TP53 gene (17p13) is thought to be
an early event, sometimes already
detectable in intraepithelial neoplasia.
The frequency and type of mutation
varies from one geographic area to the
other, suggesting that some  TP53 muta-tions may occur as the result of exposure
to region-specific, exogenous risk fac-tors. However, even in SCC from Western
Europe, the  TP53 mutation spectrum
does not show the same tobacco-associ-ated mutations as in lung cancers
{1266}. Amplification of cyclin D1
(11q13) occurs in 20-40% of SCC and is
frequently detected in cancers that retain
expression of the Rb protein, in agree-ment with the notion that these two fac-tors cooperate within the same signalling
cascade {859}. Inactivation of  CDKN2A
occurs essentially by homozygous dele-tion or de novo methylation and appears
to be associated with advanced cancer.
Other potentially important genetic alter-ations include transcriptional inactivation
of the FHIT gene (fragile histidine triad, a
presumptive tumour suppressor on
3p14) by methylation of 5’ CpG islands,
and deletion of the tylosis oesophageal
cancer gene on 17q25 {2020, 1264}.
Furthermore, analysis of clones on
3p21.3, where frequent LOH occurs in
oesophageal cancer {1274}, recently led
to identification of a novel gene termed
DLC1 (deleted in lung and oesophageal
cancer-1) {365}. Although the function of
the DLC1 gene remains to be clarified,
RT-PCR experiments indicated that 33%
of primary cancers of lung and oesopha-gus lacked DLC1 transcripts entirely or
contained increased levels of nonfunc-tional DLC1 mRNA. Recent evidence
suggests that LOH at a new, putative
tumour suppressor locus on 5p15 may
occur in a majority of SCC {1497}.
Amplification of several proto-oncogenes
has also been reported  (HST-1, HST-2,
EGFR, MYC) {1266}. How these various
genetic events correlate with phenotypic
Fig. 1.16  Location of  the tylosis oesophageal cancer gene on chromosome 17q.
A B C
Fig. 1.15 Squamous cell carcinoma. A Moderately differentiated. B Well differentiated with prominent lymphoid infiltrate. C Well differentiated areas (left) contrast
with immature basal-type cells of a poorly differentiated carcinoma (right).
Location of the tylosis
oesophageal cancer
gene by haplotype analy-sis
1cM/ 500 Kb
changes and co operate in the sequence
of events leading to SCC is still specula-tive.
Prognosis and prognostic factors
Overall, the prognosis of oesophageal
SCC is poor and the 5-year survival rates
in registries are around 10%. Cure is
foreseen only for superficial cancer. The
survival varies, depending upon tumour
stage at diagnosis, treatment received,
patient’s general health status, morpho-logical features and molecular features of
the tumour. In the past, studies on prog-nostic factors were largely focused on
patients who were treated by surgery,
whereas factors influencing survival of
patients treated by radiotherapy or by
multimodal therapy have been investi-gated only rarely.
Morphological factors
The extent of spread of the oesophageal
SCC is the most important factor for
prognosis, the TNM classification being
the most widely used staging system.
Staging. All studies indicate that the
depth of invasion and the presence of
nodal or distant metastases are inde-pendent predictors of survival {1104,
895, 772}. In particular, lymph node
involvement, regardless of the extent of
the primary tumour, indicates a poor
prognosis {1862, 912, 1873}. More
recently, the prognostic significance of
more sophisticated methods for the
determination of tumour spread have
been evaluated, including the ratio of
involved to resected lymph nodes
{1603}, immunohistochemically deter-mined lymph node micrometastases
{824, 1327} and micrometastases in the
bone marrow {1933}. However, current
data are still too limited to draw final con-clusions on the prognostic value.
Differentiation.  The prognostic impact of
tumour differentiation is equivocal, possi-bly due to the poor standardisation of the
grading system and to the high prognos-tic power of tumour stage. Although
some studies have shown a significant
influence of tumour grade on survival
{709, 772}, the majority of studies have
not {443, 1858, 1601, 1660}. Other
histopathological features associated
with a poor prognosis include the pres-ence of vascular and/or lymphatic inva-sion {772, 1662} and an infiltrative growth
pattern of the primary tumour {1660}.
Lymphocytic infiltration. Intense lympho-cytic response to the tumour has been
associated with a better prognosis
{1660, 443}.
Proliferation.  The cancer cell prolifera-tion index, determined immunohisto-chemically by antibodies such as PCNA
or Ki- 67 / MIB-1, have been studied
extensively. However, the proliferation
index does not appear to be an inde-pendent prognostic factor {2189, 1005,
1659, 779}.
DNA ploidy.   Aneuploidy of cancer cells,
as determined by flow cytometry or by
image analysis, has been identified in
55% to 95% of oesophageal SCC {935}.
Regarding the prognostic impact, patients
with diploid tumours usually survive longer
than those with aneuploid tumours.
However, a prognostic impact independ-ent of tumour stage has been shown only
in two studies {422, 1195}, whereas the
majority of studies have not verified this
0  10  20  30  40  50  60  70
SCC
ADC
G:C>A:T
G:C>A:T (CpG)
G:C>C:G
G:C>T:A
G:C>C:G
Deletions, insertions, complex mutations
G:C>A:T
G:C>A:T (CpG)
G:C>T:A
Deletions, insertions, complex mutations
18 Tumours of the oesophagus
Gene Location Tumor abnormality Function
TP53 17p13 Point mutation, LOH G1 arrest, apoptosis,
genetic stability
p16, p15, 9p22 Homozygous loss CDK inhibitor
ARF/CDKN2 Promoter methylation (cell cycle control)
Cyclin D1 11q13 Amplification Cell cycle control
EGFR 17p13 Amplification, overexpression Signal transduction
(membrane Tyr kinase)
c-myc 8q24.1 Amplification Transcription factor
Rb 13q14 LOH Cell cycle control
Absence of expression
TOC 17q25 LOH Tumour suppressor
FEZ1 8p22 Transcription shutdown Transcription factor
DLC1 3p21.3 Transcription shutdown Growth inhibition
Table 1.01
Genetic alterations in squamous cell carcinoma of the oesophagus.
Fig. 1.17 Spectrum of TP53 mutations in squamous cell carcinoma (SCC) and adenocarcinoma (ADC) of the
oesophagus.
19Squamous cell carcinoma
finding {935}. Therefore, the determination
of DNA ploidy is currently not considered
to improve the prognostic information pro-vided by the TNM system {1055}.
Extent of resection.  The frequency of
locoregional recurrence is negatively
correlated with the distance of the pri-mary tumour to the proximal resection
margin and possibly to preoperative
chemotherapy {1890, 1027}.
Molecular factors
The TP53 gene is mutated in 35% to 80%
of oesophageal SCC {1266}. Whereas
some studies indicated a negative prog-nostic influence of p53 protein accumula-tion in cancer cell nuclei {1743, 277}, oth-ers did not observe any prognostic value
of either immunoexpression or  TP53
mutation {2014, 1661, 1008, 779, 319}.
Other potential prognostic factors include
growth factors and their receptors {927},
oncogenes, including c-erbB-2 and int-2
{778}, cell cycle regulators {1748, 1297},
tumour suppressor genes {1886}, redox
defence system components, e.g., metal-lothionein and heat shock proteins {897},
and matrix proteinases {1303, 1947,
2155}. Alterations of these factors in
oesophageal SCC may enhance tumour
cell proliferation, invasiveness, and
metastatic potential, and thus may be
associated with survival. However, none
of the factors tested so far has entered
clinical practice.
Fig. 1.19  Immunoreactivity for epidermal growth
factor receptor (EGFR) in oesophageal squamous
cell carcinoma.
Fig. 1.20  Fluorescence in situ hybridisation demon-strating cyclin D1 in squamous carcinoma cells.
Fig. 1.18 TP53 immunoreactivity in squamous cell
carcinoma of the oesophagus.
Multiple LOH
Amplification of CMYC, EGFR, CYCLIND1, HST1…
Overexpression of CYCLIN D1
LOH at 3p21; LOH at 9p31
LOH 3p14 (FHIT); LOH 17q25 (TOC)
TP53 mutations
Normal oesophagus Oesophagitis Low-grade High-grade  Invasive SCC
intraepithelial neoplasia            intraepithelial neoplasia
Fig. 1.21 Putative sequence of genetic alterations in the development of squamous cell carcinoma of the oesophagus.
20 Tumours of the oesophagus
Definition
A malignant epithelial tumour of the
oesophagus with glandular differentia-tion arising predominantly from Barrett
mucosa in the lower third of the oeso-phagus. Infrequently, adenocarcinoma
originates from heterotopic gastric
mucosa in the upper oesophagus, or
from mucosal and submucosal glands.
ICD-O Code 8140/3
Epidemiology
In industrialized countries, the incidence
and prevalence of adenocarcinoma of
the oesophagus has risen dramatically
{1827}. Population based studies in the
U.S.A. and several European countries
indicate that the incidence of oeso-phageal adenocarcinoma has doubled
between the early 1970s to the late
1980s and continues to increase at a rate
of about 5% to 10% per year {152, 153,
370, 405, 1496}. This is paralleled by ris-ing rates of adenocarcinoma of the
gastric cardia and of subcardial gastric
carcinoma. It has been estimated that
the rate of increase of oesophageal and
oesophagogastric junction adenocarci-noma in the U.S.A. during the past
decade surpassed that of any other type
of cancer {152}. In the mid 1990s the
incidence of oesophageal adenocarcino-ma has been estimated between 1 and 4
per 100,000 per year in the U.S.A. and
several European countries and thus
approaches or exceeds that of squa-mous cell oesophageal cancer in these
regions. In Asia and Africa, adenocarci-noma of the oesophagus is an uncom-mon finding, but increasing rates are
also reported from these areas.
In addition to the rise in incidence, ade-nocarcinoma of the oesophagus and of
the oesophagogastric junction share
some epidemiological characteristics
that clearly distinguish them from squa-mous cell oesophageal carcinoma and
adenocarcinoma of the distal stomach.
These include a high preponderance for
the male sex (male:female ratio 7:1), a
higher incidence among whites and an
average age at the time of diagnosis of
around 65 years {1756}.
Aetiology
Barrett oesophagus
The epidemiological features of adeno-carcinoma of the distal oesophagus and
oesophagogastric junction match those
of patients with known intestinal metapla-sia in the distal oesophagus, i.e. Barrett
oesophagus {1605, 1827}, which has
been identified as the single most impor-tant precursor lesion and risk factor for
adenocarcinoma of the distal oesopha-gus, irrespective of the length of the seg-ment with intestinal metaplasia.
Intestinal metaplasia  of the oesophagus
develops when the normal squamous
oesophageal epithelium is replaced by
columnar epithelium during the process
of healing after repetitive injury to the
oesophageal mucosa, typically associat-ed with gastro-oesophageal reflux dis-ease {1798, 1799}.
Intestinal metaplasia can be detected in
more than 80% of patients with adenocar-cinoma of the distal  oesophagus. {1756,
1824}. A series of prospective endoscop-ic surveillance studies in patients with
known intestinal metaplasia of the distal
oesophagus has shown an incidence of
oesophageal adenocarcinoma in the
order of 1/100 years  of follow up  {1799}.
This translates into a life-time risk for
oesophageal adenocarcinoma of about
10% in these patients. The length of the
oesophageal segment with intestinal
metaplasia, and the presence of ulcera-tions and strictures have been implicated
as further risk factors for the development
of oesophageal adenocarcinoma by
some authors, but this has not been con-firmed by others {1799, 1797, 1827}.
The biological significance of so-called
ultrashort Barrett oesophagus or intestin-al metaplasia just beneath a normal Z
line has yet to be fully clarified {1325}.
Whether adenocarcinoma of the gastric
cardia or subcardial gastric cancer is
also related to foci of intestinal metapla-sia at or immediately below the gastric
cardia {715, 1797, 1722} is discussed in
the chapter on adenocarcinoma of the
oesophagogstric junction. Despite the
broad advocation of endoscopic surveil-lance in patients with known Barrett
oesophagus, more than 50% of patients
with oesophageal adenocarcinoma still
have locally advanced or metastatic dis-ease at the time of presentation {1826}.
Chronic gastro-oesophageal reflux is the
usual underlying cause of the repetitive
mucosal injury and also provides an
abnormal environment during the healing
process that predisposes to intestinal
metaplasia {1799}. Data from Sweden
have shown an odds ratio of 7.7 for oeso-phageal adenocarcinoma in persons
with recurrent reflux symptoms, as com-pared with persons without such symp-toms {1002, 1001}.
The more frequent, more severe, and
longer-lasting the symptoms of reflux, the
greater the risk. Among persons with
long-standing and severe symptoms of
reflux, the odds ratio for oesophageal
adenocarcinoma was 43.5. Based on
these data a strong and probably causal
relation between gastro-oesophageal
reflux, one of the most common benign
disorders of the digestive tract, and
oesophageal adenocarcinoma has been
postulated.
Factors predisposing for the development
of Barrett oesophagus and subsequent
adenocarcinoma in patients with gastro-oesophageal reflux disease include a
markedly increased oesophageal expo-sure time to refluxed gastric and duode-nal contents due to a defective barrier
function of the lower oesophageal sphinc-ter and ineffective clearance function of
the tubular oesophagus {1823, 1827}.
Experimental and clinical data indicate
that combined oesophageal exposure to
gastric acid and duodenal contents (bile
acids and pancreatic enzymes) appears
to be more detrimental than isolated
exposure to gastric juice or duodenal
contents alone {1241, 1825}. Combined
reflux is thought to increase cancer risk
M. Werner R. Lambert
J.F. Flejou G. Keller
P. Hainaut H.J. Stein
H. Höfler
Adenocarcinoma of the oesophagus
21Adenocarcinoma
by promoting cellular proliferation, and by
exposing the oesophageal epithelium to
potentially genotoxic gastric and intestin-al contents, e.g. nitrosamines {1825}.
Tobacco
Smoking has been identified as another
major risk factor for oesophageal adeno-carcinoma and may account for as much
as 40% of cases through an early stage
carcinogenic effect {562, 2204}.
Obesity
In a Swedish population-based case con-trol study, obesity was also associated
with an increased risk for oesophageal
adenocarcinoma. In this study the adjust-ed odds ratio was 7.6 among persons in
the highest body mass index (BMI) quar-tile compared with persons in the lowest.
Obese persons (BMI > 30 kg/m2
) had an
odds ratio of 16.2 as compared with the
leanest persons (persons with a BMI < 22
kg/m2
) {1002}. The pathogenetic basis of
the association with obesity remains to be
elucidated {310}.
Alcohol
In contrast to squamous cell oesopha-geal carcinoma, there is no strong rela-tion between alcohol consumption and
adenocarcinoma of the oesophagus.
Helicobacter pylori
This infection does not appear to be a
predisposing factor for the development
of intestinal metaplasia and adenocarci-noma in the distal oesophagus. Accor-ding to recent studies, gastric H. pylori
infection may even exert a protective
effect {309}.
Localization
Adenocarcinoma may occur anywhere in
a segment lined with columnar metaplas-tic mucosa (Barrett oesophagus) but
develops mostly in its proximal verge.
Adenocarcinoma in a short segment of
Barrett oesophagus is easily mistaken for
adenocarcinoma of the cardia. Since
adenocarcinoma originating from the dis-tal oesophagus may infiltrate the gastric
cardia and carcinoma of the gastric car-dia or subcardial region may grow into
the distal oesophagus these entities are
frequently difficult to discriminate (see
chapter on tumours of the oesopha-gogastric junction). As an exception, ade-nocarcinoma occurs also in the middle or
proximal third of the oesophagus, in the
latter usually from a congenital islet of het-erotopic columnar mucosa (that is pres-ent in up to 10% of the population).
Barrett oesophagus
Symptoms and signs
Barrett oesophagus as the precursor of
most adenocarcinomas is clinically silent
in up to 90% of cases. The symptomatol-ogy of Barrett oesophagus, when pres-ent, is that of gastro-oesophageal reflux
{1011}. This is the condition where the
early stages of neoplasia (intraepithelial
and intramucosal neoplasia) should be
sought.
Endoscopy
The endoscopic analysis of the squamo-columnar junction aims at the detection
of columnar metaplasia in the distal
oesophagus. At endoscopy, the squamo-columnar junction (Z-line) is in the thorax,
just above the narrowed passage across
the diaphragm. The anatomical land-marks in this area are treated in the
chapter on tumours of the oesophago-gastric junction.
If the length of the columnar lining in this
distal oesophageal segment is *3 cm, it
is termed a long type of Barrett metapla-sia. When the length is < 3 cm, it is a
short type. Single or multiple finger-like
(1-3 cm) protrusions of columnar mucosa
are classified as short type. In patients
with short segment (< 3 cm) Barrett
oesophagus the risk for developing ade-nocarcinoma is reported to be lower
compared to those with long segment
Barrett oesophagus {1720}.
As Barrett oesophagus is restricted to
cases with histologically confirmed intes-tinal metaplasia, adequate tissue sam-pling is required.
Histopathology
Barrett epithelium is characterized by two
different types of cells, i.e. goblet cells
and columnar cells, and has also been
termed ‘specialized’, ‘distinctive’ or
Barrett metaplasia. The goblet cells stain
positively with Alcian blue at low pH (2.5).
The metaplastic epithelium has a flat or
villiform surface, and is identical to gastric
intestinal metaplasia of the incomplete
type (type II or III). Rarely, foci of complete
intestinal metaplasia (type I) with absorp-tive cells and Paneth cells may be found.
The mucous glands beneath the surface
epithelium and pits may also contain
metaplastic epithelium. Recent studies
suggest that the columnar metaplasia
originates from multipotential cells located
in intrinsic oesophageal glands {1429}.
Intraepithelial neoplasia
in Barrett oesophagus
Macroscopy
Intraepithelial neoplasia generally has no
distinctive gross features, and is detected
by systematic sampling of a flat Barrett
mucosa {634, 1573}. The area involved is
variable, and the presence of multiple
dysplastic foci is common {226, 1197}.
In some cases, intraepithelial neoplasia
presents as one or several nodular
masses resembling sessile adenomas.
Rare dysplastic lesions have been con-sidered true adenomas, with an expand-ing but localised growth resulting in a
well demarcated interface with the sur-rounding tissue {1459}.
Microscopy
Epithelial atypia in Barrett mucosa is usu-ally assessed according to the system
Fig. 1.22 Endoscopic ultrasonograph of Barrett T1
adenocarcinoma. The hypoechoic tumour lies
between the first and second hyperechoic layers
(markers). The continuity of the second layer (sub-mucosa) is respected.
Table 1.02
Pattern of endoscopic ultrasound in oesophageal
cancer. There are three hyper- and two hypo-echoic layers; the tumour mass is hypoechoic.
T1 The 2nd hyperechoic layer
(submucosa) is continuous
T2 The 2nd hyperechoic layer
(submucosa) is interrupted
The 3rd hyperechoic layer
(adventitia) is continuous
T3 The 3rd hyperechoic layer
(aventitia) is interrupted
T4 The hypoechoic tumour is
continuous with adjacent structures
22 Tumours of the oesophagus
devised for atypia in ulcerative colitis,
namely: negative, positive or indefinite
for intraepithelial neoplasia. If intra-epithelial neoplasia is present, it should
be classified as low-grade (synonymous
with mild or moderate dysplasia) or high-grade (synonymous with severe dyspla-sia and carcinoma  in situ) {1582, 1685}.
The criteria used to grade intraepithelial
neoplasia comprise cytological and archi-tectural features {75}.
Negative for intraepithelial neoplasia
Usually, the lamina propria of Barrett
mucosa contains a mild accompanying
inflammatory infiltrate of mononuclear
cells. There may be mild reactive
changes with enlarged, hyperchromatic
nuclei, prominence of nucleoli, and
occasional mild stratification in the lower
portion of the glands. However, towards
the surface there is maturation of the
epithelium with few or no abnormalities.
These changes meet the criteria of atypia
negative for intraepithelial neoplasia, and
can usually be separated from low-grade
intraepithelial neoplasia.
Atypia indefinite for intraepithelial neo-plasia.   One of the major challenges for
the pathologist in Barrett oesophagus is
the differentiation of intraepithelial neo-plasia from reactive or regenerative
epithelial changes. This is particularly
difficult, sometimes even impossible, if
erosions or ulcerations are present
{1055}. In areas adjacent to erosions and
ulcerations, the metaplastic epithelium
may display villiform hyperplasia of the
surface foveolae with cytological atypia
and architectural disturbances. These
abnormalities are usually milder than
those observed in intraepithelial neopla-sia. There is a normal expansion of the
basal replication zone in regenerative
epithelium versus intraepithelial neopla-sia, where the proliferation shifts to more
superficial portions of the gland {738}. If
there is doubt as to whether reactive and
regenerative changes or intraepithelial
neoplasia is present in a biopsy, the cat-egory atypia indefinite for intraepithelial
neoplasia is appropriate and a repeat
biopsy after reflux control by medical
acid suppression or anti-reflux therapy is
indicated.
Low-grade and high-grade intraepithelial
neoplasia.   Intraepithelial neoplasia in
Barrett metaplastic mucosa is defined as
a neoplastic process limited to the
epithelium {1582}. Its prevalence in
Barrett mucosa is approximately 10%,
and it develops only in the intestinal type
metaplastic epithelium.
Cytological abnormalities typically extend
to the surface of the mucosa. In low-grade intraepithelial neoplasia, there is
decreased mucus secretion, nuclear
pseudostratification confined to the lower
half of the glandular epithelium, occa-sional mitosis, mild pleomorphism, and
minimal architectural changes.
High-grade intraepithelial neoplasia
shows marked pleomorphism and
decrease of mucus secretion, frequent
mitosis, nuclear stratification extending
Fig. 1.24 Barrett oesophagus with low-grade intraepithelial neoplasia on the left and high-grade on the right.
Note the numerous goblet cells showing a clear cytoplasmic mucous vacuole indenting the adjacent nucleus.
Fig. 1.23 Barrett oesophagus. A Haphazardly arranged glands (right) adjacent to hyperplastic squamous epithelium (left). B Goblet cells and columnar cells form vil-lus-like structures over chronically inflamed stroma. There is no intraepithelial neoplasia.
A B
23Adenocarcinoma
to the upper part of the cells and glands,
and marked architectural aberrations.
The most severe architectural changes
consist of a cribriform pattern that is a
feature of high-grade intraepithelial neo-plasia as long as the basement mem-brane of the neoplastic glands has not
been disrupted. The diagnostic repro-ducibility of intraepithelial neoplasia is far
from perfect; significant interobserver
variation exists {1572}.
Adenocarcinoma
Symptoms and signs
Dysphagia is often the first symptom of
advanced adenocarcinoma in the
oesophagus. This may be associated
with retrosternal or epigastric pain or
cachexia.
Endoscopy
The endoscopic pattern of the early
tumour stages may be that of a small
polypoid adenomatous-like lesion, but
more often it is flat, depressed, elevated
or occult {1011, 1009}. Areas with high
grade intraepithelial neoplasia are often
multicentric and occult. Therefore a
systematic tissue sampling has been
recommended when no abnormality is
evident macroscopically {483}. The usual
pattern of advanced adenocarcinoma at
endoscopy is that of an axial, and often
tight, stenosis in the distal third of the
oesophagus; with a polypoid tumour,
bleeding occurs at contact.
Radiology
This approach is still proposed in the pri-mary diagnosis of oesophageal cancer
when endoscopic access is not easily
available {1058}. Today, barium studies
are helpful mostly for the analysis of
stenotic segments; they are less efficient
than endoscopy for the detection of flat
abnormalities. Computerised tomogra-phy will detect distant thoracic and
abdominal metastases.
Endoscopic ultrasonography
At high frequency, some specificities in
the echoic pattern of the mucosa and
submucosa of the columnar lined oeso-phagus are displayed. However, the pro-cedure is only suitable for the staging of
tumours previously detected at endo-scopy; the tumour is hypoechoic. Lymph
nodes adjacent to the oesophageal wall
can also be visualised by this technique
{1614}.
Macroscopy
The majority of primary adenocarcino-mas of the oesophagus arise in the lower
third of the oesophagus within a segment
of Barrett mucosa {1055}. Adjacent to the
tumour, the typical salmon-pink mucosa
of Barrett oesophagus may be evident,
especially in early carcinomas. In the
early stages, the gross findings of Barrett
adenocarcinoma may be subtle with
irregular mucosal bumps or small
plaques. At the time of diagnosis, most
tumours are advanced with deep infiltra-tion of the oesophageal wall. The
advanced carcinomas are predominantly
flat and ulcerated with only one third
having a polypoid or fungating appear-ance. Occasionally, multifocal tumours
A B
Fig. 1.25  High-grade intraepithelial neoplasia in Barrett oesophagus. A Marked degree of stratification with nuclei being present throughout the thickness of the epithe-lium. Foci of cribriform, back-to-back glands. B Highly atypical cells lining tubular structures.
Fig. 1.27 Highly infiltrative adenocarcinoma in
Barrett oesophagus (pT3), with extension into the
cardia.
Fig. 1.26 Mucinous adenocarcinoma arising in
Barrett oesophagus. Large mucinous lakes extend
throughout the oesophageal wall.
24 Tumours of the oesophagus
may be present {1055, 1770}. The rare
adenocarcinomas arising independently
of Barrett oesophagus from ectopic gas-tric glands and oesophageal glands dis-play predominantly ulceration and poly-poid gross features, respectively. These
tumours are also found in the upper and
middle third of the oesophagus {265,
1204}, but are rare.
Histopathology
Adenocarcinomas arising in the setting
of Barrett oesophagus are typically papil-lary and/or tubular. A few tumours are of
the diffuse type and show rare glandular
formations, and sometimes signet ring
cells {1458, 1770}. Differentiation may
produce endocrine cells, Paneth cells
and squamous epithelium. Mucinous
adenocarcinomas, i.e. tumours with more
than 50% of the lesion consisting of
mucin, also occur.
Grading
Most adenocarcinomas arising from
Barrett mucosa are well or moderately
differentiated {1458}, and display well
formed tubular or papillary structures.
The well differentiated tumours may pose
a diagnostic problem in biopsy speci-mens because the infiltrating component
may be difficult to recognize as invasive
{1055} since Barrett mucosa often has
irregular dispersed glands. Glandular
structures are only slightly formed in
poorly differentiated adenocarcinomas
and absent in undifferentiated tumours.
Small cell carcinoma may show foci of
glandular differentiation. It is discussed
in the chapter on endocrine neoplasms
of the oesophagus.
Tumour spread and staging
Adenocarcinomas spread first locally and
infiltrate the oesophageal wall. Distal
spread to the stomach may occur.
Extension through the oesophageal wall
into adventitial tissue, and then into adja-cent organs or tissues is similar to squa-mous cell carcinoma. Common sites of
local spread comprise the mediastinum,
tracheobronchial tree, lung, aorta, peri-cardium, heart and spine {1055, 1789}.
Barrett associated adenocarcinoma
metastasizes to para-oesophageal and
paracardial lymph nodes, those of the
lesser curvature of the stomach and the
celiac nodes. Distant metastases occur
late. The TNM classification used for SCC
is applicable to Barrett adenocarcinoma
and provides prognostically significant
data {1945}.
Other carcinomas
Adenosquamous carcinoma
(ICD-O code: 8560/3)
This carcinoma has a significant squa-mous carcinomatous component that is
intermingled with a tubular adenocarci-noma.
Mucoepidermoid carcinoma
(ICD-O code: 8430/3)
This rare carcinoma shows an intimate
mixture of squamous cells, mucus secret-ing cells and cells of an intermediate
type.
Adenoid cystic carcinoma
(ICD-O code: 8200/3)
This neoplasm is also infrequent and
believed to arise, like the mucoepider-moid variant, from oesophageal glands
{265, 2066}. Both lesions tend to be of
salivary gland type, and small tumours
may be confined to the submucosa.
However, the ordinary oesophageal ade-nocarcinoma can also arise from ectopic
gastric glands, or oesophageal glands
{1204, 1055}.
Fig. 1.28 Adenocarcinoma, tubular type. A Well differentiated, B moderately differentiated and C poorly dif-ferentiated.
A
C
B
25Adenocarcinoma
Genetic susceptibility
Several lines of evidence suggest that
there is a genetic susceptibility to oeso-phageal adenocarcinoma arising from
Barrett oesophagus. The almost exclu-sive occurrence of Barrett oesophagus in
whites and its strong male predominance
hint at the involvement of genetic factors
{1605}. Several reports describe familial
clustering of Barrett oesophagus, adeno-carcinoma and reflux symptoms in up to
three generations, with some families
showing an autosomal dominant pattern
of inheritance with nearly complete pene-trance {470, 480, 482, 569, 861, 1537,
1610, 1959}. Although shared dietary or
environmental factors in these families
could play a role, the earlier age of onset
of Barrett in some families suggests the
influence of genetic factors {861}. The
molecular factors that determine this
genetic susceptibility are largely un-known and linkage analysis in families
has not been reported. Recently, an asso-ciation between a variant of the GSTP1
(glutathione S-transferase P1) gene and
Barrett oesophagus and adenocarcino-ma has been demonstrated {1994}. GSTs
are responsible for the detoxification of
various carcinogens, and inherited dif-ferences in carcinogen detoxification
capacity may contribute to the develop-ment of Barrett epithelium and adenocar-cinoma.
Genetics
In Barrett oesophagus a variety of mole-cular genetic changes has been correlat-ed with the metaplasia-dysplasia-carci-noma sequence (Fig. 1.21) {2091}.
Prospective follow-up of lesions biopsied
at endoscopy show that alterations in
TP53 and CDKN2A occur at early stages
{112, 1337}.
TP53. In high-grade intraepithelial neo-plasia a prevalence of TP53 mutations of
approximately 60% is found, similar to
adenocarcinoma {789}. Mutation in one
allele is often accompanied by loss of the
other (17p13.1). Mutations occur in
diploid cells and precede aneuploidy.
The pattern of mutations differs signifi-cantly from that in squamous cell carcino-mas. This is particularly evident for the
high frequency of G:C>A:T transition
mutations, which prevail in adenocarcino-mas but are infrequent in SCC (Fig. 1.17).
CDKN2A. Alterations of CDKN2A, a
locus on 9p21 encoding two distinct
tumour suppressors, p16 and p19arf
include hypermethylation of the p16 pro-motor and, more rarely, mutations and
LOH {948}.
FHIT.  Among other early changes in the
premalignant stages of metaplasia are
alterations of the transcripts of FHIT, a
presumptive tumour suppressor gene
spanning the common fragile site FRA3B
{1222}.
LOH and gene amplification. A number of
other loci are altered relatively late during
the development of adenocarcinoma,
with no obligate sequence of events.
Prevalent changes (> 50%) include LOH
on chromosomes 4 (long arm) and 5
(several loci including APC) and amplifi-cation of ERBB2 {1266, 1264}.
Phenotypic changes in Barrett oesopha-Fig. 1.29 Adenoid cystic carcinoma showing typical cribriform pattern resembling its salivary gland coun-terpart.
Table 1.03
Genes and proteins involved in carcinogenesis in Barrett oesophagus.
Factor Comment
Tumour suppressor genes
TP53 60% Mutation – high-grade intraepithelial neoplasia and carcinoma
APC Late in intraepithelial neoplasia-carcinoma sequence
FHIT Common, early abnormalities
CDKN2A (p16) Hypermethylation common in intraepithelial neoplasia
Growth factor receptors
CD95/APO/Fas Shift to cytoplasm in carcinoma
EGFR Expressed in 60% carcinomas, gene amplification
c-erbB2 Late in dysplasia-carcinoma sequence, gene amplification
Cell adhesion
E-cadherin Loss of expression in intraepithelial and invasive carcinoma
Catenins Similar loss of expression to E-cadherin
Proteases
UPA Prognostic factor in carcinoma
Proliferation
Ki-67 Abnormal distribution in high-grade intraepithelial neoplasia
Membrane trafficking
rab11 High expression in low-grade intraepithelial neoplasia
26 Tumours of the oesophagus
C. Capella
E. Solcia
L.H. Sobin
R. Arnold
Endocrine tumours of the oesophagus
Definition
Endocrine tumours of the oesophagus
are rare and include carcinoid (well dif-ferentiated endocrine neoplasm), small
cell carcinoma (poorly differentiated
endocrine carcinoma), and mixed
endocrine-exocrine carcinoma.
ICD-O codes
Carcinoid 8240/3
Small cell carcinoma 8041/3
Mixed endocrine-exocrine
carcinoma 8244/3
Epidemiology
In an analysis of 8305 carcinoid tumours
of different sites, only 3 (0.04%) carci-noids of the oesophagus were reported
{1251}. They represented 0.05% of all
gastrointestinal carcinoids reported in this
analysis and 0.02% of all oesophageal
cancers. All cases were in males and pre-sented at a mean age of 56 years {1251}.
Small cell carcinoma occurs mainly in the
sixth to seventh decade and is twice as
common in males as females {190, 421,
765, 1026}. The reported frequencies
among all oesophageal cancers were
between 0.05% to 7.6 % {190, 421, 765,
1026}.
The few mixed endocrine-exocrine carci-nomas were in males at the sixth decade
{256, 301}.
Aetiological factors
Patients with small cell carcinomas often
have a history of heavy smoking and one
reported case was associated with long
standing achalasia {93, 1539}. A case of
combined adenocarcinoma and carci-noid occurred in a patient with a Barrett
oesophagus {256}. Small cell carcinoma
has also been associated with Barrett
oesophagus {1678, 1813}.
Localization
Carcinoid tumours are typically located
in the lower third of the oesophagus
{1329, 1567, 1754}. Almost all small cell
carcinomas occur in the distal half of the
oesophagus {190, 421}.
Clinical features
Dysphagia, severe weight loss and
sometimes chest pain are the main symp-toms of endocrine tumours of the oesoph-agus. Patients with small cell carcinomas
often present at an advanced stage {765,
1026}. Inappropriate antidiuretic hor-mone syndrome and hypercalcemia have
been reported {421}. In addition, a case
of watery diarrhoea, hypokalaemia-achlor-hydria (WDHA) syndrome, due to
ectopic production of VIP by a mixed-cell
(squamous-small cell) carcinoma of the
oesophagus has been described {2070}.
Fig. 1.30 Small cell carcinoma of the oesophagus.
gus include expansion of the Ki-67 prolif-eration compartment correlating with the
degree of intraepithelial neoplasia {738}.
Molecules involved in membrane traffick-ing such as rab11 have been reported to
be specific for the loss of polarity seen in
low-grade intraepithelial neoplasia
{1566}. In invasive carcinoma, reduced
expression of cadherin/catenin complex
and increased expression of various pro-teases are detectable. Non-neoplastic
Barrett oesophagus expresses the
MUC2 but not the MUC1 mucin gene
product, whereas neither is expressed in
intraepithelial neoplasia in Barrett
oesophagus {298}. Invasive lesions
exhibit variable expression of MUC1 and
MUC2.
Prognostic factors
The major prognostic factors in adeno-carcinoma of the oesophagus are the
depth of mural invasion and the pres-ence or absence of lymph node or dis-tant metastasis {734, 1049, 1458, 1945}.
Gross features and histological differenti-ation do not influence prognosis. The
overall 5-year survival rate after surgery
is less than 20% in most series including
a majority of advanced carcinomas. The
survival rates are better in superficial
(pT1) adenocarcinoma, ranging from
65% to 80% in different series {735,
1219}.
Since the stage at the time of diagnosis
is the most important factor affecting out-come, endoscopic surveillance of Barrett
patients with early detection of their ade-nocarcinomas, results in better progno-sis in most cases {1995}.
27Lymphoma
Macroscopy
All reported oesophageal carcinoids
were of large size (from 4 to 7 cm in diam-eter) and infiltrated deeply the oeso-phageal wall {1329, 1567, 1754}. Small
cell carcinomas usually appear as fun-gating or ulcerated masses of large size,
measuring from 4 to 14 cm in greatest
diameter.
Histopathology
Carcinoid (well differentiated endocrine
neoplasm)
All carcinoids so far reported in the litera-ture have been described as deeply infil-trative tumours, with high mitotic rate and
metastases {1329, 1567, 1754}.
Microscopically, they are composed of
solid nests of tumour cells that show pos-itive stain for Grimelius and neuron-spe-cific enolase {1567}, and characteristic
membrane-bound neurosecretory gran-ules at ultrastructural examination {1754}.
Small cell carcinoma (poorly differentiat-ed endocrine carcinoma)
Small cell carcinoma of the oesophagus
is indistinguishable from its counterpart
in the lung according to histological and
immunohistochemical features as well as
clinical behaviour. The cells may be
small with dark nuclei of round or oval
shape and scanty cytoplasm, or be larg-er with more cytoplasm (intermediate
cells) forming solid sheets and nests.
There may be foci of squamous carcino-ma, adenocarcinoma, and/or mucoepi-dermoid carcinoma, a finding that raises
the possibility of an origin of tumour cells
from pluripotent cells present in the
squamous epithelium or ducts of the
submucosal glands {190, 1887}. Argyro-phylic granules can be demonstrated by
Grimelius stain, and small dense-core
granules are always detected by elec-tron microscopy {781}.
Immunohistochemical reactions for neu-ron-specific enolase, synaptophysin,
chromogranin and leu7 usually are posi-tive and represent useful diagnostic
markers {723}. Some cases have been
associated with calcitonin and ACTH
production {1272}.
Mixed endocrine-exocrine carcinoma
In the few reported cases {256, 301}, the
tumours combined a gastrointestinal-type adenocarcinoma with the trabecu-lar-acinar component of a carcinoid. In
one case the carcinoid component was
positive for Grimelius stain, Fontana
argentaffin reaction and formaldehyde
induced fluorescence for amines {301}.
Prognostic factors
Two of three oesophageal carcinoids
from the analysis of 8305 cases of carci-noid tumours {1251} were associated
with distant metastases and one {1567}
of the three reported cases {1329, 1567,
1754} died 29 months after surgery.
The prognosis of small cell carcinoma of
the oesophagus is poor, even when the
primary growth is limited {190, 421}. The
survival period is usually less than 6
months {816 and thus similar to that of
patients with small cell carcinoma of the
colon {765, 1026}. Multidrug chemother-apy may offer temporary remission {765,
816, 1026, 1678}.
Definition
Primary lymphoma of the oesophagus is
defined as an extranodal lymphoma aris-ing in the oesophagus with the bulk of
the disease localized to this site {796}.
Contiguous lymph node involvement and
distant spread may be seen but the pri-mary clinical presentation is in the
oesophagus with therapy directed at this
site.
Clinical features
The oesophagus is the least common
site of involvement with lymphoma in the
digestive tract, accounting for less than
1% of lymphoma patients {1399}. Oeso-phageal involvement is usually second-ary either from the mediastinum, from
nodal disease or from a primary gastric
location. Patients are frequently male and
usually over 50 years old. Tumours
involving the distal portion of the oesoph-agus may cause dysphagia {644}.
Histopathology
Primary oesophageal lymphomas may
be of the large B-cell type or may be low-grade B-cell MALT lymphomas {1794}.
MALT lymphomas show morphological
and cytological features common to
MALT lymphomas found elsewhere in the
digestive tract. Lymphoid follicles are
surrounded by a diffuse infiltrate of cen-trocyte-like (CCL) cells showing a vari-able degree of plasma cell differentia-tion. Infiltration of these cells into the
overlying epithelium is usually seen.
Characteristically the CCL cells express
pan-B-cell markers CD20 and CD79a
and they are negative for CD5 and CD10.
They express bcl-2 protein and may be
positive with antibodies to CD43. Due to
the rarity of these lesions, molecular
genetics data are not available.
In common with other sites in the diges-tive tract, secondary involvement of the
oesophagus may occur in dissemination
of any type of lymphoma.
Primary oesophageal T-cell lymphoma
has been described but is exceedingly
rare {547}.
A. Wotherspoon
A. Chott
R.D. Gascoyne
H.K. Müller-Hermelink
Lymphoma of the oesophagus
28 Tumours of the oesophagus
Definition
A variety of rare benign and malignant
mesenchymal tumours that arise in the
oesophagus. Among these, tumours of
smooth muscle or ‘stromal’ type are most
common.
ICD-O codes
Leiomyoma 8890/0
Leiomyosarcoma 8890/3
Gastrointestinal
stromal tumour (GIST) 8936/3
Granular cell tumour  9580/0
Rhabdomyosarcoma 8900/3
Kaposi sarcoma  9190/3
Classification
The morphological definitions of these
lesions follow the WHO histological clas-sification of soft tissue tumours {2086}.
Stromal tumours are described in detail
in the chapter on gastric mesenchymal
tumours.
Epidemiology
Leiomyoma is the most common mes-enchymal tumour of the oesophagus. It
occurs in males at twice the frequency
as females and has a median age distri-bution between 30 and 35 years {1712,
1228}. Sarcomas of the oesophagus
accounted for 0.2% of malignant oeso-phageal tumours in SEER data from the
United States from 1973 to 1987. Males
were more frequently affected than
females by nearly 2:1 {1928}. Adults
between the 6th and 8th decades are
primarily affected. Oesophageal stromal
tumours show demographics similar to
those of sarcomas {1228}.
Localization
Leiomyomas and stromal tumours are
most frequent in the lower oesophagus
and begin as intramural lesions. The
larger tumours can extend to medi-astinum and form a predominantly medi-astinal mass.  Leiomyomatosis forms
worm-like intramural structures that may
extend into the upper portion of the
stomach.
Clinical features
Dysphagia is the usual complaint, but
many leiomyomas and a small proportion
of stromal tumours are asymptomatic
and are incidentally detected by X-ray as
mediastinal masses. Since most sarco-mas project into the lumen, they are rela-tively easy to diagnose by endoscopy or
imaging studies. The endoscopic pattern
is that of a submucosal tumour with a
swelling of a normal mucosa. Endo-scopic ultrasound helps in determining
the actual size of the tumour, its position
in the oesophageal wall and its eventual
position in the mediastinum. A CT scan
of the mediastinum is then a useful com-pliment. Most tumours less than 3 cm in
diameter are benign. Endoscopic tissue
sampling (large biopsy or fine needle
aspiration) is difficult and not very reli-able for the assessment of malignancy.
Macroscopy
Leiomyomas vary in size from a few mil-limeters up to 10 cm in diameter (aver-age 2-3 cm). They may be spherical, or
when larger they can form sausage-like
masses with a large longitudinal dimen-sion or dumb-bell shaped masses with
circular involvement {1712, 1228}. Large
leiomyomas (over 0.5 kg) have been
described {968}.  Sarcomas, most of
them representing malignant gastroin-testinal stromal tumours (GISTs), are typi-cally multinodular or less commonly
plaque-like masses resembling sarco-mas of the soft tissues. Many oeso-phageal sarcomas protrude into the
mediastinum.
Histopathology
Leiomyoma is composed of bland spin-dle cells and shows low or moderate cel-lularity and slight if any mitotic activity.
There may be focal nuclear atypia. The
cells have eosinophilic, fibrillary, often
clumped cytoplasm. Eosinophilic granu-locytes and spherical calcifications are
sometimes present. Leiomyomas are
typically globally positive for desmin and
smooth muscle actin, and are negative
for CD34 and CD117 (KIT) {1228}.
M. Miettinen
J.Y. Blay
L.H. Sobin
Mesenchymal tumours
of the oesophagus
Fig. 1.31 Leiomyoma of oesophagus.  A Haema-toxylin and eosin stain.  B Immunoreactivity for
desmin.
Fig. 1.32 Stromal tumour of the oesophagus, involv-ing the oesophageal muscle layer beneath a normal
mucosa.
A
B
29Mesenchymal tumours
Leiomyosarcoma, a malignant tumour
featuring differentiated smooth muscle
cells, is rare in the oesophagus. In a
recent series, such tumours comprised
4% of all combined smooth muscle and
stromal tumours. They were large
tumours that presented in older adults,
and all patients died of disease.
Diagnosis is based on demonstration of
smooth muscle differentiation by  α-smooth muscle actin, desmin or both,
and lack of KIT expression {1228}.
Stromal tumours (GISTs) are rare in the
oesophagus, and comprise 20-30% of
the combined cases of smooth muscle
and stromal tumours. Like elsewhere in
the digestive system, they predominantly
occur in older adults between the 6th
and 8th decades; oesophageal stromal
tumours may have a male predomi-nance. Most oesophageal examples are
spindle cell tumours, and a minority are
epithelioid. Oesophageal GISTs are iden-tical with their gastric counterparts by
their positivity for KIT and CD34, variable
reactivity for smooth muscle actin and
general negativity for desmin. Most are
clinically malignant, and commonly
develop liver metastases. The oeso-phageal tumours analyzed to date have
shown similar  c-kit mutations (exon 11)
as observed in gastric and intestinal
GISTs {1228}. The pathological features
are described with gastric GISTs.
Granular cell tumours are usually detect-ed endoscopically as nodules or small
sessile polyps predominantly in the distal
oesophagus {1216, 7}. Benign behaviour
is the rule, but a case of malignant
oesophageal granular cell tumour has
been reported. The tumours are usually
small, up to 1-2 cm in diameter, and are
grossly yellow, firm nodules. Histologi-cally they are composed of sheets of oval
to polygonal cells with a small central
nucleus and abundant granular slightly
basophilic cytoplasm. This is due to
extensive accumulation of lysosomes
filled with lamellar material. Granular cell
tumours are typically PAS- and S100-pro-tein positive and negative for desmin,
actin, CD34 and KIT. Tumours that
encroach upon the mucosa may elicit a
pseudocarcinomatous squamous hyper-plasia {862, 1710}.
Rhabdomyosarcoma has been reported
in older adult patients in distal oesopha-gus. A few well-documented cases have
shown features similar to embryonal
rhabdomyosarcoma {2002}. Demonstra-tion of skeletal muscle differentiation by
the presence of cross-striations, electron
microscopy, or immunohistochemistry is
required for the diagnosis.
Synovial sarcoma has been reported in
children and in older adults. These
tumours usually present as polypoid
masses in the proximal oesophagus
{168, 149}.
Kaposi sarcoma may appear as a
mucosal or less commonly more exten-sive mural lesion, usually in HIV-positive
patients. Histologically typical are spin-dle cells with vascular slit formations and
scattered PAS-positive globules. The
tumour cells are positive for CD31 and
CD34.
Grading
Histological grading follows the systems
commonly used for soft tissue tumours.
Mitotic activity is the main criterion for
grading stromal sarcomas and
leiomyosarcomas, namely those tumours
with over 10 mitoses per 10 HPF are con-sidered high-grade.
Genetics
Somatic deletions and gene rearrange-ments involving the genes encoding
alpha5 and 6 chains of collagen type IV
have been described in oesophageal
leiomyomatosis associated with Alport
syndrome {1704, 1982} and in sporadic
leiomyoma {683}, whereas these tumours
do not have  c-kit gene mutations com-monly found in GISTs {1018}. Compar-ative genomic hybridization studies have
shown that oesophageal leiomyomas do
not have losses of chromosome 14, as
often seen in GIST, but instead have
gains in chromosome 5 {450, 1664}.
Oesophageal stromal tumours show simi-lar c-kit mutations as observed in gastric
and intestinal GISTs (see stomach mes-enchymal tumours) {1228}.
Kaposi sarcoma is positive for human
herpesvirus 8 by PCR.
Prognosis
The prognosis of oesophageal sarcomas,
like carcinomas, is largely dependent on
the size, depth of invasion, and presence
or absence of metastasis.
Fig. 1.33 Granular cell tumour of oesophagus. Fig. 1.34 Kaposi sarcoma in a patient with acquired
immunodeficiency syndrome.
1 cm
30 Tumours of the oesophagus
Secondary tumours
Definition
Tumours of the oesophagus that originate
from but are discontinuous with a primary
tumour elsewhere in the oesophagus or
an extra-oesophageal neoplasm.
Incidence
Metastatic spread to the oesophagus is
uncommon. An unusually high frequency
(6.1% of autopsy cases) was reported
from Japan {1249}.
Origin of metastases
The concept of intramural metastasis in
oesophageal squamous cell carcinoma
is discussed in the chapter on squamous
cell carcinoma of the oesophagus.
Neoplasms of neighbouring organs such
as pharynx or gastric cardia {714} can
spread to the oesophagus via lymphat-ics. Haematogenous metastases from
any primary localization may occur.
Reported primary sites include thyroid
{335}, lung {1416, 1249}, breast {2143,
1249, 545}, skin {1569, 1203}, kidney
{1956}, prostate {1318} and ovary {1249}.
Localization
The most common site of involvement is
the middle third of the oesophagus.
Clinical features
The leading symptom is dysphagia,
whereas achalasia and upper gastroin-testinal bleeding with anemia are unusu-al {545}. Barium swallow examination,
endoscopy, computed tomography and
magnetic resonance imaging demon-strate in most cases a submucosal
tumour, but any aspect resembling a pri-mary oesophageal carcinoma may be
observed {545, 1318, 714}.
Histopathology and predictive factors
Submucosal localization without invasion
of the mucosa is characteristic for a
metastasis. Early metastases of gastric
and oesophageal tumours into the
oesophagus may be local indicators of
systemic spread {896, 714}. The pres-ence of metastasis in the oesophagus is
a sign of poor prognosis, but the outcome
is much better when the primary tumour
growth rate is slow, and when other
metastases are excluded {1416, 1249}.
Melanoma
ICD-O Code 8720/3
Malignant melanoma in the oesophagus
is much more commonly metastatic than
primary. Primary oesophageal mela-nomas are usually polypoid and are clini-cally aggressive lesions {400, 353}. They
are believed to arise from a zone of atyp-ical junctional proliferation of melano-cytes and such a proliferation is often
present adjacent to the invasive tumour,
although it may not be observed in
advanced disease. The histology of the
invasive component is indistinguishable
from cutaneous melanoma {409}. Growth
is typically expansile rather than infiltra-tive.
G. Ilyés
A. Kádár
N.J. Carr
Secondary tumours and melanoma
of the oesophagus
Fig. 1.35  Primary melanoma of the oesophagus (ME). The gastro-oesophageal
junction is on the left (arrows).
Fig. 1.36 Primary malignant melanoma of the distal oesophagus. Zone of atypi-cal junctional proliferation of melanocytes located adjacent to the invasive
tumour. This supports the diagnosis of a primary melanoma.
ME

Definition
Adenocarcinomas that straddle the junc-tion of the oesophagus and stomach are
called tumours of the oesophagogastric
(OG) junction. This definition includes
many tumours formerly called cancers of
the gastric cardia.
Squamous cell carcinomas that occur at
the OG junction are considered carcino-mas of the distal oesophagus, even if they
cross the OG junction.
ICD-O code 8140/3
Definition of the
oesophagogastric junction
The OG junction is the anatomical region
where the tubular oesophagus joins the
stomach. The squamo-columnar (SC)
epithelial junction may occur at or above
the OG junction. The gastric cardia has
been defined conceptually as the region
of the stomach that adjoins the oesopha-gus {1568}. The gastric cardia begins at
the OG junction, but its distal extent is
poorly defined.
Figure 2.01 shows endoscopically recog-nizable landmarks that can be used to
identify structures at the OG junction. The
squamocolumnar junction (SCJ or Z-line)
is the visible line formed by the juxtaposi-tion of squamous and columnar epithelia.
The OG junction is the imaginary line at
which the oesophagus ends and the
stomach begins anatomically. The OG
junction is defined endoscopically as the
level of the most proximal extent of the
gastric folds {1200}. In normal individuals,
the proximal extent of the gastric folds
generally corresponds to the point at
which the tubular oesophagus flares to
become the sack-shaped stomach at the
distal border of the lower oesophageal
sphincter. In patients with hiatus hernias,
in whom there may be no clear-cut flare at
the OG junction, the proximal margin of
the gastric folds is determined when the
distal oesophagus is minimally inflated
with air because over-inflation obscures
this landmark {1271}. Whenever the
squamocolumnar junction is located
above the OG junction, there is a colum-nar-lined segment of oesophagus. When
the squamocolumnar junction and the OG
junction coincide, the entire oesophagus
is lined by squamous epithelium (i.e. there
is no columnar-lined oesophagus). By
definition, the gastric cardia starts at the
OG junction, but there are no endoscopic
landmarks that define the distal extent of
the gastric cardia.
A potential source of confusion is the his-tological terminology used to describe
the most proximal part of the stomach.
Cardiac mucosa is characterized by tor-tuous, tubular glands that are comprised
almost exclusively of mucus-secreting
cells with few or no parietal (oxyntic)
cells. The histological finding of cardiac
mucosa does not establish that the spec-imen has been obtained from the cardia
of the stomach, for the following reasons:
(1) Cardiac mucosa can be found in the
distal oesophagus {1479, 678}.
(2) Cardiac mucosa rarely extends more
than 2 to 3 mm below the SC epithelial
junction in the distal oesophagus {1430,
911}. Therefore it will not line the larger
anatomical area often called cardia.
(3) Recent studies have shown that the
proximal stomach is lined predominantly,
if not exclusively, by oxyntic epithelium
{272, 1388}. Therefore, even a tumour that
is unquestionably located at the cardia
may not have arisen from cardiac epithe-lium. Conversely, a tumour that clearly is
located in the distal oesophagus could
have arisen from oesophageal cardiac
epithelium.
Some investigators actually contend that
cardiac mucosa is not a normal mucosa
at all, but one that is acquired as a conse-quence of chronic inflammation in the dis-tal oesophagus {272, 1388}.
Diagnostic criteria
Various criteria have been used to cate-gorize tumours in the region of the OG
junction as cancers of the gastric cardia
{1240, 314, 877, 1271, 638, 767, 684}. In
most of these classification systems, the
anatomic location of the epicenter or pre-dominant mass of the tumour is used to
determine whether the neoplasm is
oesophageal or gastric in origin. Due to
the use of divergent classification sys-tems, the patient populations in studies
on cancers of the gastric cardia are het-erogeneous, and often include patients
with gastric tumours and others with
tumours of oesophageal origin. The fol-lowing guidelines are based on the defi-nition of the OG junction described
above:
(1) Adenocarcinomas that cross the
oesophagogastric junction are called
adenocarcinomas of the OG junction,
regardless of where the bulk of the tumour
lies.
(2) Adenocarcinomas located entirely
above the oesophagogastric junction as
defined above are considered oeso-phageal carcinomas.
(3) Adenocarcinomas located entirely
below the oesophagogastric junction are
considered gastric in origin. The use of
the ambiguous and often misleading term
‘carcinoma of the gastric cardia’ is dis-couraged; depending on their size , these
should be called carcinoma of the proxi-mal stomach or carcinoma of the body of
the stomach.
Epidemiology
Reliable data on the incidence of
tumours of the OG junction are not avali-S.J. Spechler P. Hainaut
M.F. Dixon R. Lambert
R. Genta R. Siewert
Adenocarcinoma of the oesophago-gastric junction
32 Adenocarcinoma of the oesophagogastric junction
Fig. 2.01  Topography of the oesophagogastric junc-tion and cardia {1797}.
33Adenocarcinoma of the oesophagogastric junction
able at this time. Tumour registries typi-cally distinguish only the adenocarcino-ma in Barrett oesophagus and the carci-noma of the cardia.
Adenocarcinomas of the OG junction
and ‘cardia’ share similar epidemiologic
characteristics. At both sites, there is a
strong predilection for middle-aged and
older white males {1133, 2205, 1473},
with a marked increase in incidence in
recent years. This is in contrast to the
worldwide decline of adenocarcinoma of
the gastric body and antrum (Fig. 2.02).
Despite the increasing incidence, the
cumulative rates at the OG junction and
the cardia are still much lower than those
observed in the ‘non cardia’ stomach. In
the Norwegian cancer registry data for
the period 1991/92 {664}, the age adjust-ed incidence rate for the combined ade-nocarcinoma of the distal third of the
oesophagus and proximal stomach was
3.0 for males and 0.8 for females, while
the incidence for all subsites of the stom-ach was 13.8 in males and 6.5 in
females.
Aetiology
The most consistent association des-cribed for carcinoma at the OG junction is
with gastro-oesophageal reflux. In con-trast with the aetiological factors involved
in ‘non cardia’ gastric cancer, there is no
consistent association with diet (salty food
in excess and lack of fruits and vitamins)
nor Helicobacter pylori infection, while in
the body and antrum of the stomach,
intestinal metaplasia occurs in relation to
chronic gastritis due to H. pylori infection
{1829, 88, 343}.
Intestinal metaplasia is judged to be the
precursor of adenocarcinoma both in the
oesophagus and in the stomach {1797}.
However, there appear to be significant
differences in the pathogenetic, morpho-logical and histochemical characteristics,
as well as in the clinical importance of
intestinal metaplasia in the two organs
(Fig. 2.03).
In the oesophagus, gastro-oesophageal
reflux disease (GERD) is accepted as the
cause of intestinal metaplasia (Barrett
oesophagus); chronic reflux oesophagitis
is a strong risk factor for adenocarcinoma
of the oesophagus {1001}. The cancer
risk for patients with intestinal metaplasia
in the oesophagus appears to be sub-stantially higher than for patients with
intestinal metaplasia in the stomach
{1797} In contrast to the stomach, infec-tion with H. pylori does not appear to play
a direct role in the pathogenesis of
oesophageal inflammation and metapla-sia {1381, 1076, 1617, 1889, 501, 1087, 6,
1579}. Indeed, recent reports suggest
that gastric infection with H. pylori may
actually protect the oesophagus from
cancer by preventing the development of
reflux oesophagitis and Barrett oesopha-gus {2090, 998, 2094, 309, 2012, 615,
350, 504, 1948, 2213, 837, 1957}. In biop-sies from the SC epithelial junction of
patients with Barrett oesophagus, a pecu-liar hybrid cell type has been observed
that has both microvilli (a feature of
columnar cells) and intercellular bridges
(a feature of squamous cells) on its sur-face {1740, 1651, 155}.
The relationship between intestinal meta-plasia in the proximal stomach and in the
oesophagus is disputed {1797}. Intestinal
metaplasia has been found in the proxi-mal stomach (gastric cardia) of only a
minority of patients with Barrett oesopha-gus {1498}.
Recent studies indicate that specialized
intestinal metaplasia at a normal-looking
OG junction carries a much lower rate of
malignancy than in Barrett oesophagus
{715}. Indeed, intestinal metaplasia at the
oesophagogastric junction has been
found with similar frequencies in Cau-casians with GERD (a high risk group for
adenocarcinoma at the junction) and in
African Americans without GERD (a low
risk group) {269}.
Cancers of the gastric cardia resemble
oesophageal adenocarcinomas in terms
of their association with GERD {1133,
2205, 1473}.
Fig. 2.02 Incidence of adenocarcinoma of the stomach (left) compared to adenocarcinoma of the distal
oesophagus and oesophagogastric junction (right). Rate per 10,000 hospitalisations from North America.
Intestinal Metaplasia
Dysplasia
Adenocarcinoma
H. Pylori
Gastritis
GERD
Reflux Oesophagitis
Oesophagus Stomach
Fig. 2.03 Pathogenetic pathways operative in the evolution of oesophageal and gastric carcinoma. Intesti-nal metaplasia is a common precursor lesion that may result from gastro-oesophageal reflux disease (GERD)
or chronic H. pylori infection.
Clinical features
Common presenting symptoms for
patients with adenocarcinomas of the
oesophagogastric junction include dys-phagia, weight loss, and abdominal pain.
Early cancers, and the metaplastic and
dysplastic lesions that spawn them, usual-ly cause no symptoms. Consequently,
symptomatic patients usually have ad-vanced, incurable disease. Oesophago-gastric junction tumours are discovered at
an early stage during endoscopic surveil-lance in patients known to have Barrett
oesophagus.
Endoscopy and imaging
The diagnosis of cancer at the oesopha-gogastric junction is typically established
by endoscopic examination with biopsy.
Endoscopy. The distal oesophagus
should be examined carefully for evi-dence of intestinal metaplasia (Barrett
oesophagus), and biopsy specimens of
the metaplastic epithelium should be
taken to determine whether the tumour is
oesophageal in origin. The finding of
intestinal metaplasia with dysplastic fea-tures above an OG junction tumour is
strong evidence that the cancer began in
the oesophagus. The location of the
tumour in reference to the landmarks
shown in Figure 2.01 should be noted.
The proximal stomach is examined care-fully, preferably by retroversion of the
endoscope, to determine the gastric
extent of the tumour. Early tumours may
be polypoid, but flat lesions are more fre-quent. These flat lesions may appear
depressed, elevated, or completely flush
with the surrounding mucosa {1010}.
Mucosal hyperplasia immediately distal to
the squamo-columnar junction, occurs in
carditis and can, without biopsy sam-pling, be mistaken for an elevated neo-plastic lesion. In advanced adenocarci-noma, the tumour is often polypoid and
circumferential. Tight stenoses can be dif-ficult to explore endoscopically and dan-gerous to dilate, especially when there is
tortuosity.
Endoscopic ultrasonography is the
modality of choice for tumour staging,
and accuracy can be improved even fur-ther by using high frequency (20 or 30
MHz) miniprobes {669}. Endosonogra-phy accurately identifies the depth of
tumour invasion and regional lymph
node involvement in approximately 77%
and 78% of cases, respectively {1301}.
Endosonography is also useful in
assessing the proximal extent of submu-cosal tumour invasion in the oesopha-gus. Endosonographic study of the wall
of the oesophagus reveals 3 hyperechoic
layers that are separated by 2 hypo-echoic layers. The inner (1st) and exter-nal (3rd) hyperechoic layers correspond
to the interfaces of the wall with the gut
lumen and surrounding tissues, respec-tively. The intermediate (2nd) hypere-choic layer corresponds to the submu-cosa. The inner (1st) and outer (2nd)
hypoechoic layers represent part of the
muscularis mucosae and the muscularis
propria, respectively.
Computed tomography is necessary to
detect distant thoracic and abdominal
metastases.
Barium swallow has a limited role as a
diagnostic test for cancer at the oeso-phagogastric junction {1058, 1180} but
may be helpful in the analysis of malig-nant stenoses that are too narrow to be
traversed by the endoscope.
Tumour spread and staging
According to TNM, in this junction area,
carcinomas that are mainly on the gastric
side should be classified according to
the TNM for gastric tumours, while those
predominantly on the oesophageal side
should be staged according to the TNM
for oesophageal carcinomas {698}.
Adenocarcinomas at the oesophago-gastric junction exhibit a great propensi-ty for upward lymphatic spread mainly in
the submucosa of the oesophagus. For
this reason, intraoperative frozen-section
examination of the proximal oesophageal
resection margin is recommended. Up-ward spread can also involve lower
mediastinal nodes. Lymphatic spread
from the cardia frequently extends down-wards to nodes in the oesophagogastric
angles and around the left gastric artery,
and may involve para-coeliac and para-aortic lymph nodes {26, 949}.
There are differences in the criteria for
stage grouping oesophageal and gastric
malignancies, and the pathological stag-ing recommended by the AJCC {1} for
lymph node involvement by gastric can-cers is not easily adapted for use by
endosonographers. Involvement of the
coeliac lymph nodes is usually deemed
regional disease for gastric cancers,
whereas coeliac node involvement is
considered distant metastatic disease
(M1) for cancers of the thoracic oeso-phagus. The regional nodes of the OG
junction are not well enough defined to
stage OG junction cancers properly.
Histopathology
Adenocarcinoma
The vast majority of cancers arising at
the cardia are adenocarcinomas {1790}.
Histologically, four types are usually dis-tinguished in the WHO classification:
papillary, tubular, mucinous, and signet-ring cell adenocarcinoma. The latter two
types are uncommon. The signet-ring
34
Fig. 2.04 Endoscopic ultrasonograph demonstrating
adenocarcinoma at the oesophagogastric junction
(CA) with deep infiltration and several lymph node
metastases (arrows).
Table 2.01
Features of intestinal metaplasia in the oesophagus and stomach.
Stomach Oesophagus
H. pylori association Yes No
GERD association No Yes
Usual type of metaplasia Complete Incomplete
Barrett cytokeratin pattern No Yes
Cancer risk Lower Higher
Adenocarcinoma of the oesophagogastric junction
35
type is much less common in the proxi-mal than in the distal stomach, and usu-ally not accompanied by atrophic gastri-tis {2045}. Well differentiated tubular
adenocarcinomas can present consider-able diagnostic difficulty as the neoplas-tic tubules may have a deceptively regu-lar appearance and can be readily
mistaken for low-grade dysplasia or even
hyperplastic glands.
Pylorocardiac carcinoma. Mulligan and
Rember {1847} termed lesions resem-bling normal pyloric glands as ‘pyloro-cardiac carcinomas’. They predominate
in the cardiac region and typically have
tall epithelial cells with clear or pale cyto-plasm and nuclei in a basal or central
position. However, this pattern is difficult
to distinguish reliably from other gland-forming adenocarcinomas {1847}.
Adenosquamous carcinoma
Of the less common forms of cancers in
the oesophagogastric junction region,
adenosquamous carcinoma is the one
most likely to be encountered. The diag-nosis rests on the finding of a mixture of
glandular and squamous elements and
not merely on the presence of small
squamoid foci in an otherwise typical ade-nocarcinoma. The latter is a frequent find-ing in tumours at this site. Such compos-ite tumours should also be distinguished
from the rare mucoepidermoid carcinoma
of the oesophagus, which arises from
mucous glands and is similar to the sali-vary gland tumour of that name. Although
the term mucoepidermoid has been used
synonymously for adenosquamous carci-nomas {1476}, the latter are distinguished
by increased nuclear pleomorphism,
occasional keratin pearls, and the separa-tion of the two components with some
areas of purely glandular epithelium and
mucin. While in the past there were claims
that adenosquamous carcinoma repre-sented a ‘collision tumour’, it is now gen-erally accepted that this malignancy
results from dual differentiation and that it
is analogous to other cancers arising at
junctional sites in the body (e.g. uterine
cervix and anal canal).
Small cell carcinoma can occur at this site.
Grading
Adenocarcinomas in the oesophago-gastric junction region can be graded as
well, moderately, or poorly differentiated.
However, agreement on tumour grading
is notoriously poor. Blomjous et al. {151}
reported that 3.6% of gastric cardiac
cancers were well differentiated, 31%
moderately differentiated, and 43% poor-ly differentiated, but others consider a
greater proportion well differentiated,
particularly when early carcinomas are
included {1271, 1903, 1363}.
Precursor lesions
Intraepithelial neoplasia
Interobserver agreement on the grading
of intraepithelial neoplasia in the
absence of invasion of the lamina propria
is poor, particularly in the identification of
low-grade changes, and different terms
have been applied to identical appear-ances {1683}. Such differences in
nomenclature have been reduced by the
widespread acceptance of a new classi-fication that embraces the previously dis-cordant terminology in a unified scheme
{1637}.
Intramucosal non-invasive neoplasia can
be classified as flat (synonymous with
dysplasia) or elevated (synonymous with
adenoma); lesions can be low grade or
high grade, the latter including lesions
previously designated as intraglandular
carcinoma.
Intestinal metaplasia
Putative precancerous lesions other than
intraepithelial neoplasia are controversial.
Fig. 2.05 Adenocarcinoma of the proximal stomach (‘pylorocardiac type’). A Macroscopic appearance resembles other adenocarcinmomas. B Glands with tall cells,
pale cytoplasm, and basal or central nuclei.
Fig. 2.06 Adenocarcinoma of the oesophagogastric
junction. pT2 lesion.
Adenocarcinoma of the oesophagogastric junction
Intestinal metaplasia is widely regarded
as carrying an increased risk of malig-nant change, but the frequency at which
it is found in the OG junction region (5.3%
to 23% of dyspeptic patients) limits its
value as a criterion for surveillance {716,
1960, 1800, 2028, 1269}. Some of the
variability in the reported prevalence of
intestinal metaplasia can be attributed to
differences in diagnostic criteria. Some
authors accept the finding of columnar
cells containing acidic glycoproteins
(‘columnar blues’ in Alcian blue / PAS
stained sections) as  evidence for intes-tinal metaplasia {1398}. This staining pat-tern reflects immature, regenerative cells
and is a common finding in biopsy spec-imens of the cardia in children with
GERD. This finding alone is not sufficient
to identify intestinal metaplasia; intestinal
metaplasia should only be diagnosed if
goblet cells are present.
Genetic changes
The best characterized somatic alteration
found in tumours of this region are muta-tions of  TP53 which are present in up to
60% of carcinomas of the oesophagogas-tric junction. In 5 patients who had ade-nocarcinomas at the junction associated
with Barrett oesophagus, the same muta-tion was detected in the tumour and in the
surrounding oesophageal intestinal meta-plasia, indicating an oesophageal origin.
No association has been found between
p53 status and tumour stage or subtype.
The TP53 alterations noted in tumours at
the oesophagogastric junction show a
predominance of transition mutations at
CpG sites, similar to the pattern seen in
adenocarcinomas in Barrett oesophagus
{585}. Transitions at CpG dinucleotides in
TP53 are generally assumed to result
from endogenous mutational mechanism
(deamination of 5-methylcytosine) which
may be enhanced by oxidative or
nitrosative stress. In colon cancers that
frequently exhibit CpG mutations, excess
nitric oxide production resulting from nitric
oxide synthase-2 expression may con-tribute to the transition from adenoma to
carcinoma {51}.
In a study of cancers at the oesopha-gogastric junction that did not show evi-dence of associated Barrett oesopha-gus, the prevalence of  TP53 mutations
was only 30% {1641}. Overexpression of
the MDM2 gene was found frequently in
these tumours, suggesting that  TP53
may be inactivated either by mutation or
by overexpression of the MDM2 gene.
Comparative genomic hybridization has
been used to compare tumours of the
‘gastric cardia’ and tumours in Barrett
oesophagus. Gains and losses of genet-ic material were identified at a number of
common regions in cancers from both
sites {1718}. Common altered regions
included chromosome 4q (loci not yet
identified), 3p14 (FHIT, RCA1), 5q 14-21
(APC, MCC), 9p21 (MTS1/CDKN2),
14q31-32.1 (TSHR), 16q23, 18q21
(DCC, p15), and 21q21. Minimal overlap-ping amplified sites were seen at 5p14
(MLV12), 6p12-21.1 (NRASL3), 7p12
(EGFR), 8123-24.1 (MYC), 15q25
(IGF1R), 17q12-21 (ERBB2/HER2-neu),
19q13.1 (TGFB1, BCL3, AKT2), 20p12
(PCNA), and 20q12-13 (MYBL2, PTPN1).
The distribution of these imbalances was
similar in both groups. However, loss of
14q31-32.1 (TSHR) was significantly
more frequent in Barrett-related adeno-carcinomas than in cardiac cancers.
Overall, the available genetic data sug-gests that within cancers of the oesoph-agogastric junction, a subset of tumours
is genetically similar to adenocarcinomas
in Barrett oesophagus, whereas another
subset is genetically distinct from adeno-carcinomas of both the oesophagus and
distal stomach {314, 1133}.
Prognosis and predictive factors
There is a significant relationship between
grade and prognosis by univariate analy-sis. For example, Blomjous et al. found
that 31% of patients with well or moder-ately differentiated cardia tumours sur-vived 5 years, whereas the survival for
patients with poorly or undifferentiated
tumours was only 17% {151}. When T, N,
and M status were included in the analy-sis, however, grade was significantly relat-ed to survival only in those patients with
negative lymph nodes (53% 5-year sur-vival for well and moderate compared to
21% for poor and undifferentiated
tumours).
36 Adenocarcinoma of the oesophagogastric junction
CHAPTER 3
Tumours of the Stomach
The incidence of adenocarcinoma of the stomach is declining
worldwide. In some Western countries, rates have been
reduced to less than one third within just one generation. In
countries with a traditionally high incidence, e.g. Japan and
Korea, the reduction is also significant but it will take more
time to diminish the still significant disease burden. The main
reasons for these good news is a change in nutrition, in par-ticular the avoidance of salt for meat and fish preservation, the
lowering of salt intake from other sources, and the availability
in many countries of fresh fruits and vegetables throughout
the year. Mortality has been further dercreased by significant
advances in the early detection of stomach cancer.
Infection with Helicobacter pylori appears to play an important
additional aetiological role since it leads to chronic atrophic
gastritis with intestinal metaplasia as an important precursor
lesion.
The stomach is the main gastrointestinal site for lymphomas
and most of these are also pathogenetically linked to H. pylori
infection. Regression of such tumours often follows  H. pylori
eradication.
WHO histological classification of gastric tumours1
TNM classification1
T – Primary Tumour
TX Primary tumour cannot be assessed
T0 No evidence of primary tumour
Tis  Carcinoma in situ: intraepithelial tumour
without invasion of the lamina propria
T1 Tumour invades lamina propria or submucosa
T2 Tumour invades muscularis propria or subserosa2
T3 Tumour penetrates serosa (visceral peritoneum)
without invasion of adjacent structures2,3,4,5
T4 Tumour invades adjacent structures2,3,4,5
N – Regional Lymph Nodes
NX Regional lymph nodes cannot be assessed
N0 No regional lymph node metastasis
N1 Metastasis in 1 to 6 regional lymph nodes
N2 Metastasis in 7 to 15 regional lymph nodes
N3  Metastasis in more than 15 regional lymph nodes
M – Distant Metastasis
MX Distant metastasis cannot be assessed
M0 No distant metastasis
M1 Distant metastasis
Stage Grouping
Stage 0 Tis N0 M0
Stage IA T1 N0 M0
Stage IB T1 N1 M0
T2 N0 M0
Stage II T1 N2 M0
T2 N1 M0
T3 N0 M0
Stage IIIA T2 N2 M0
T3 N1 M0
T4 N0 M0
Stage IIIB T3 N2 M0
Stage IV T4 N1, N2, N3 M0
T1, T2, T3 N3 M0
Any T Any N M1
TNM classification of gastric tumours
38 Tumours of the stomach
Epithelial tumours
Intraepithelial neoplasia – Adenoma 8140/02
Carcinoma
Adenocarcinoma 8140/3
intestinal type 8144/3
diffuse type 8145/3
Papillary adenocarcinoma 8260/3
Tubular adenocarcinoma 8211/3
Mucinous adenocarcinoma 8480/3
Signet-ring cell carcinoma 8490/3
Adenosquamous carcinoma 8560/3
Squamous cell carcinoma 8070/3
Small cell carcinoma 8041/3
Undifferentiated carcinoma 8020/3
Others
Carcinoid (well differentiated endocrine neoplasm) 8240/3
Non-epithelial tumours
Leiomyoma 8890/0
Schwannoma 9560/0
Granular cell tumour 9580/0
Glomus tumour 8711/0
Leiomyosarcoma 8890/3
GI stromal tumour 8936/1
benign 8936/0
uncertain malignant potential 8936/1
malignant 8936/3
Kaposi sarcoma 9140/3
Others
Malignant lymphomas
Marginal zone B-cell lymphoma of MALT-type 9699/3
Mantle cell lymphoma 9673/3
Diffuse large B-cell lymphoma 9680/3
Others
Secondary tumours
____________
1
{1, 66}. This classification applies only to carcinomas.
2
A help desk for specific questions about the TNM classification is available at http://tnm.uicc.org.
3
A tumour may penetrate muscularis propria with extension into the gastrocolic or gastrohepatic ligaments or the greater and lesser omentum without perforation of the visceral peri-toneum covering these structures. In this case, the tumour is classified as T2. If there is perforation of the visceral peritoneum covering the gastric ligaments or omenta, the tumour
is classified as T3.
4
The adjacent structures of the stomach are the spleen, transverse colon, liver, diaphragm, pancreas, abdominal wall, adrenal gland, kidney, small intestine, and retroperitoneum.
5
Intramural extension to the duodenum or oesophagus is classified by the depth of greatest invasion in any of these sites including stomach.
_____________
1
The classification is modified from the previous WHO histological classification of tumours {2066} taking into account changes in our understanding of these lesions. In the case of
endocrine neoplasms, the classification is based on the recent WHO clinicopathological classification {1784}, but has been simplified to be of more practical utility in morphological
classification.
2
Morphology code of the International Classification of Diseases for Oncology (ICD-O) {542} and the Systematized Nomenclature of Medicine (http://snomed.org). Behaviour is coded
/0 for benign tumours, /3 for malignant tumours, and /1 for unspecified, borderline or uncertain behaviour. Intraepithelial neoplasia does not have a generic code in ICD-O. ICD-O codes
are available only for lesions categorized as glandular intraepithelial neoplaia grade III (8148/2), and adenocarcinoma in situ (8140/2).
39Gastric carcinoma
Gastric carcinoma
Fig. 3.01 Worldwide annual incidence (per 100,000) of stomach cancer in males.
Numbers on the map indicate regional average values.
C. Fenoglio-Preiser N. Muñoz
F. Carneiro S.M. Powell
P. Correa M. Rugge
P. Guilford M. Sasako
R. Lambert M. Stolte
F. Megraud H. Watanabe
Fig. 3.02 The mortality of stomach cancer is decreasing worldwide, including
countries with a high disease burden.
7.4
45.5
77.9
49.1
10.8
7.4
18.0
7.4
25.9
< 6.7 < 11.6 < 17.1 < 25.0 < 77.9
Definition
A malignant epithelial tumour of the
stomach mucosa with glandular differen-tiation. Its aetiology is multifactorial; most
commonly it develops after a long period
of atrophic gastritis.
Tumours of the oesophagogastric junc-tion are dealt with in the preceding
chapter.
ICD-O codes
Adenocarcinoma 8140/3
Intestinal type 8144/3
Diffuse type 8145/3
Papillary adenocarcinoma 8260/3
Tubular adenocarcinoma 8211/3
Mucinous adenocarcinoma 8480/3
Signet-ring cell carcinoma 8490/3
Epidemiology
Geographical distribution
Gastric cancer was the second common-est cancer in the world in 1990, with an
estimated 800,000 new cases and
650,000 deaths per year; 60% of them
occurred in developing countries {1469}.
The areas with the highest incidence
rates (> 40/100,000 in males) are in
Eastern Asia, the Andean regions of
South America and Eastern Europe. Low
rates (< 15/100,000) are found in North
America, Northern Europe, and most
countries in Africa and in Southeastern
Asia {1471}. There is about a 20-fold dif-ference in the incidence rates when com-paring the rates in Japan with those of
some white populations from the US and
those of some African countries. A pre-dominance of the intestinal type of ade-nocarcinoma occurs in high-risk areas,
while the diffuse type is relatively more
common in low-risk areas {1296}.
Time trends
A steady decline in the incidence and
mortality rates of gastric carcinoma has
been observed worldwide over the past
several decades, but the absolute num-ber of new cases per year is increasing
mainly because of the aging of the pop-ulation {1296}. Analysis of time trends by
histological types indicates that the inci-dence decline results from a decline in
the intestinal type of carcinoma {1296}.
Age and sex distribution
Gastric carcinoma is extremely rare
below the age of 30; thereafter it increas-es rapidly and steadily to reach the high-est rates in the oldest age groups, both in
males and females. The intestinal type
rises faster with age than the diffuse
type; it is more frequent in males than in
females.
Diffuse carcinoma tends to affect
younger individuals, mainly females; it
frequently has hereditary characteristics,
perhaps modulated by environmental
influences {1738, 1633}.
Aetiology
Diet
Epidemiological studies in different pop-ulations show that the most consistent
association is diet. This is especially true
of intestinal type carcinomas. An ade-quate intake of fresh fruits and vegeta-bles lowers the risk {1450}, due to their
antioxidant effects. Ascorbic acid,
carotenoids, folates and tocopherols are
considered active ingredients. Salt intake
strongly associates with the risk of gas-tric carcinoma and its precursor lesions
{869}.
Other foods associated with high risk in
some populations include smoked or
cured meats or fish, pickled vegetables
and chili peppers.
Alcohol, tobacco and occupational
exposures to nitrosamines and inorganic
dusts have been studied in several pop-ulations, but the results have been incon-sistent.
Bile reflux
The risk of gastric carcinoma increases
5-10 years after gastric surgery, espe-cially when the Bilroth II operation, which
increases bile reflux, was performed.
40 Tumours of the stomach
Helicobacter pylori infection
The most important development in the
epidemiology of adenocarcinoma is the
recognition of its association with
Helicobacter pylori infection. Strong epi-demiological evidence came from three
independent prospective cohort studies
reporting a significantly increased risk in
subjects who 10 or more years before the
cancer diagnosis had anti-H. pylori anti-bodies, demonstrable in stored serum
samples {1371, 1473, 519}. At the patho-logical level, H. pylori has been shown to
induce the phenotypic changes leading
up to the development of adenocarcino-ma (i.e. mucosal atrophy, intestinal meta-plasia and dysplasia) in both humans
and in experimental animals {1635, 350,
2069}.
A prolonged precancerous process, last-ing decades, precedes most gastric
cancers. It includes the following
sequential steps: chronic gastritis, multi-focal atrophy, intestinal metaplasia, and
intraepithelial neoplasia {342}. Gastritis
and atrophy alter gastric acid secretion,
elevating gastric pH, changing the flora
and allowing anaerobic bacteria to colo-nize the stomach. These bacteria pro-duce active reductases that transform
food nitrate into nitrite, an active mole-cule capable of reacting with amines,
amides and ureas to produce carcino-genic N-nitroso compounds {2167}.
H. pylori acts as a gastric pathogen and
it is important in several steps in the car-cinogenic cascade. H. pylori is the most
frequent cause of chronic gastritis. It
decreases acid-pepsin secretion and
interferes with anti-oxidant functions by
decreasing intragastric ascorbic acid
(AA) concentrations. The organisms pre-dominantly occur in the mucus layer
overlying normal gastric epithelium. They
are absent in areas overlying intestinal
metaplasia where neoplasia originates.
Thus, H. pylori’s carcinogenic influences
are exerted from a distance, via soluble
bacterial products or the inflammatory
response generated by the infection.
H. pylori genome.  H. pylori is genetically
heterogeneous, and all strains may not
play the same role in the development of
malignancy. Strains containing a group
of genes named cag pathogenicity
island {264} induce a greater degree of
inflammation than strains lacking these
genes. The mechanism involves epithe-lial production of interleukin 8 via a
nuclear factor KappaB pathway. There is
an association between an infection with
a cag positive H. pylori strain and the
development of gastric carcinoma
{1549}.
The determination of the complete DNA
sequence of two H. pylori strains has
shown other similar ‘islands’ are also
present in the H. pylori genome. Re-search is ongoing to determine whether
strain-specific genes located in one of
these islands named the plasticity zone,
or outside on the rest of the chromo-some, could be associated with gastric
carcinogenesis. H. pylori can also pro-duce a vacuolating cytotoxin named
VacA. This cytotoxin, responsible for
epithelial cell damage, also associates
with gastric carcinogenesis {1771}. The
aetiological role of H. pylori in gastric
carcinogenesis was confirmed when
inoculation of a cag and VacA positive
strain was able to induce intestinal meta-plasia and gastric carcinoma in
Mongolian gerbils {2069}.
Excessive cell proliferation.  Cell replica-tion, a requisite of carcinogenesis, poten-tiates action of carcinogens targeting
DNA. The higher the replication rate, the
greater the chance that replication errors
become fixed and expressed in subse-quent cell generations. Spontaneous
mutations lead to subsequent neoplastic
transformation, but whether or not they
cause epidemic increases in cancer
rates is debatable. The latter is better
explained by the presence of external or
endogenous carcinogens. Proliferation is
higher in H. pylori infected than in non-infected stomachs; it declines signifi-cantly after infection eradication {187}
supporting the mitogenic influence of
H. pylori on gastric epithelium. Ammonia,
a substance stimulating cell replication,
is abundantly liberated by the potent ure-ase activity of H. pylori in the immediate
vicinity of gastric epithelium.
Oxidative stress.   Gastritis is associated
with increased production of oxidants
and reactive nitrogen intermediates,
including nitric oxide (NO). There is an
increased expression of the inducible
isoform of nitric oxide synthase in gastri-tis {1157}. This isoform causes continu-ous production of large amounts of NO.
NO can also be generated in the gastric
lumen from non-enzymatic sources.
Acidification of nitrite to NO produces the
reactive nitrogen species dinitrogen tri-oxide (N2O3), a potent nitrosating agent
that forms nitrosothiols and nitrosamines
{628}. Nitrosated compounds are recog-nized gastric carcinogens in the experi-mental setting.
Interference with antioxidant functions.
Ascorbic acid (AA), an antioxidant, is
actively transported from blood to the
gastric lumen by unknown mechanisms.
Its putative anti-carcinogenic role is by
preventing oxidative DNA damage.
H. pylori infected individuals have lower
AA intragastric concentrations than non-infected subjects. Following H. pylori
Fig. 3.03 Pathogenetic scheme of carcinogenesis in the stomach.
Gastritis
iNOS Gene Expression
NO
ONOOH
Nitrate Reductase
Nitrite
N2O3
Cell Damage
(DNA, lipids, mitochondria…)
Apoptosis Repair Mutation
CANCER
Ascorbic Acid
Antimicrobial
Nitrosamines
Acid (HCI)
Atrophic gastritis
β-Carotene
Diet. Saliva
H. Pylori Infection
41Gastric carcinoma
treatment, intragastric AA concentrations
increase to levels resembling those of
non-infected individuals {1613}.
DNA damage.  Free radicals, oxidants
and reactive nitrogen species all cause
DNA damage {344}. These usually gener-ate point mutations, the commonest being
G:C→A:T, the commonest type of trans-formation in cancer with a strong link to
chemical carcinogenesis. Peroxynitrite
forms nitro-guanine adducts that induce
DNA damage, generating either DNA
repair or apoptosis. The latter process
removes cells containing damaged DNA
from the pool of replicating cells in order
to avoid introduction of mutations into the
genome and an associated heightened
cancer risk. NO impairs DNA repair by
compromising the activity of Fpg, a DNA
repair protein. Thus, NO not only causes
DNA damage but it also impairs repair
mechanisms designed to prevent the for-mation of genetic mutations.
As noted, cell proliferation increases in
H. pylori infection. This increased replica-tion is balanced by increased cell death.
It is likely that the increased mitoses are a
response to increased epithelial loss.
However, the replicative rate exceeds
apoptotic rates in patients infected with
the virulent cagA vacA s1a  H. pylori
{1481} suggesting that cell loss also
occurs via desquamation in patients
infected by toxigenic  H. pylori strains.
Antitoxin derived from  H. pylori also
induces apoptosis. In patients with
H. pylori gastritis, treatment with anti-oxi-dants attenuates the degree of apoptosis
and peroxynitrite formation {1481}.
It seems more than coincidental that
dietary nitrite, nitrosamines and H. pylori-induced gastritis share so much chem-istry and their association with cancer. As
this process is chronic, the opportunity
for random hits to the genome to occur at
critical sites increases dramatically.
Localization
The most frequent site of sub-cardial
stomach cancer is the distal stomach,
i.e. the antro-pyloric region. Carcinomas
in the body or the corpus of the stomach
are typically located along the greater or
lesser curvature.
Clinical features
Symptoms and signs
Early gastric cancer often causes no
symptoms, although up to 50% of
patients may have nonspecific gastroin-testinal complaints such as dyspepsia.
Among patients in Western countries who
have endoscopic evaluations for dyspep-sia, however, gastric carcinoma is found
in only 1-2% of cases (mostly in men over
the age of 50). Symptoms of advanced
carcinoma include abdominal pain that is
often persistent and unrelieved by eating.
Ulcerated tumours may cause bleeding
and haematemesis, and tumours that
obstruct the gastric outlet may cause
vomiting. Systemic symptoms such as
anorexia and weight loss suggest dis-seminated disease.
The lack of early symptoms often delays
the diagnosis of gastric cancer.
Consequently, 80- 90% of Western
patients with gastric cancers present to
the physician with advanced tumours that
have poor rates of curability. In Japan,
where gastric cancer is common, the
government has encouraged mass
screening of the adult population for this
tumour. Approximately 80% of gastric
malignancies detected by such screen-ing programs are early gastric cancers.
However, many individuals do not choose
to participate in these screening pro-grams, and consequently only approxi-mately 50% of all gastric cancers in
Japan are diagnosed in an early stage.
Imaging and endoscopy
Endoscopy is widely regarded as the
most sensitive and specific diagnostic
test for gastric cancer. With high resolu-tion endoscopy, it is possible to detect
slight changes in colour, relief, and archi-tecture of the mucosal surface that sug-gest early gastric cancer. Endoscopic
detection of these early lesions can be
improved with chromoendoscopy (e.g.
using indigo carmine solution at 0.4 %).
Even with these procedures, a substan-tial number of early gastric cancers can
be missed {745A}.
Gastric cancers can be classified endo-scopically according to the growth pat-tern {1298, 63} The patterns I. II and III of
superficial cancer (Fig. 3.03) reflect the
gross morphology of the operative speci-men. The risk of deep and multifocal pen-etration into the submucosa and the risk
of lymphatic invasion is higher in type IIc,
the depressed variant of type II. Infiltration
of the gastric wall (linitis plastica) may not
be apparent endoscopically. This lesion
may be suspected if there is limited flexi-bility of the gastric wall. Diagnosis may
require multiple, jumbo biopsies. The
depth of invasion of the tumour is staged
with endoscopic ultrasound. A 5-layer
image is obtained at 7.5/12 MHz: in
superficial (T1) cancer the second hyper-echoic layer is not interrupted.
Radiology with barium meal is still used
in mass screening protocols in Japan,
followed by endoscopy if an abnormality
has been detected. For established gas-Fig. 3.05 Endoscopic views of early, well differentiated adenocarcinoma. A Polypoid type. B Elevated type.
A B
Fig. 3.04 Growth features of early gastric carcinoma.
Type I
Protruded
Type IIa
Elevated
Type IIb
Flat
Type IIc
Depressed
Type III
Excavated
42 Tumours of the stomach
tric cancers, radiology usually is not nec-essary, but may complement endoscop-ic findings in some cases. Tumour stag-ing prior to treatment decision involves
percutaneous ultrasound or computer-ized tomography to detect liver metas-tases and distant lymph node metas-tases. Laparoscopic staging may be the
only way to exclude peritoneal seeding in
the absence of ascites.
Macroscopy
Dysplasia may present as a flat lesion
(difficult to detect on conventional endo-scopy, but apparent on dye-staining
endoscopy) or polypoid growth. Appear-ances intermediate between them
include a depressed or reddish or discol-ored mucosa. The macroscopic type of
early gastric carcinoma is classified using
critera similar to those in endoscopy (Fig.
3.03) {1298, 63}. The gross appearance
of advanced carcinoma forms the basis
of the Borrmann classification (Fig. 3.06)
{63, 175}.
Ulcerating types II or III are common.
Diffuse (infiltrative) tumours (type IV)
spread superficially in the mucosa and
submucosa, producing flat, plaque-like
lesions, with or without shallow ulcera-tions. With extensive infiltration, a linitis
plastica or ‘leather bottle’ stomach results.
Mucinous adenocarcinomas appear gela-tinous with a glistening cut surface.
Tumour spread and staging
Gastric carcinomas spread by direct
extension, metastasis or peritoneal dis-semination. Direct tumour extension
involves adjacent organs. Tumours inva-ding the duodenum are most often of the
diffuse type and the frequency of seros-al, lymphatic, and vascular invasion and
lymph node metastases in these lesions
is high. Duodenal invasion may occur
through the submucosa or subserosa or
via the submucosal lymphatics.
Duodenal invasion occurs more fre-quently than expected based on gross
examination. Therefore, resection mar-gins should be monitored by intraopera-tive consultation.
Intestinal carcinomas preferentially meta-stasize haematogenously to the liver,
whereas diffuse carcinomas preferentially
metastasize to peritoneal surfaces {1273,
245}. An equal incidence of lymph node
metastases occurs in both types of
tumours with T2 or higher lesions. Mixed
tumours exhibit the metastatic patterns of
both intestinal and diffuse types. When
carcinoma penetrates the serosa, peri-toneal implants flourish. Bilateral massive
ovarian involvement (Krukenberg tumour)
can result from transperitoneal or haema-togenous spread.
The principal value of nodal dissection is
the detection and removal of metastatic
disease and appropriate tumour staging.
The accuracy of pathological staging is
proportional to the number of regional
lymph nodes examined and their loca-tion. When only nodes close to the
tumour are assessed, many cancers are
classified incorrectly.
Histopathology
Gastric adenocarcinomas are either
gland-forming malignancies composed
Fig. 3.08 Gastric adenocarcinoma of  (A) polypoid
and (B) diffusely infiltrative type.
A
B
Fig. 3.06 Endoscopic views of gastric cancer (A, C) and corresponding images with dye enhancement (B, D).
A, B Depressed early gastric cancer. C, D Deep ulcer scar surrounded by superficial early gastric cancer infil-trating the mucosa and submucosa.
A B
C D
Fig. 3.07  Borrmann classification of advanced gas-tric carcinoma.
Type I Type II
Polypoid Fungating
Type III Type IV
Ulcerated Infiltrative
43Gastric carcinoma
of tubular, acinar or papillary structures,
or they consist of a complex mixture of
discohesive, isolated cells with variable
morphologies, sometimes in combination
with glandular, trabecular or alveolar solid
structures {243}. Several classification
systems have been proposed, including
Ming, Carniero, and Goseki {1623}, but
the most commonly used are those of
WHO and Laurén {419, 87}.
WHO classification
Despite their histological variability, usu-ally one of four patterns predominates.
The diagnosis is based on the predomi-nant histological pattern.
Tubular adenocarcinomas
These contain prominent dilated or slit-like and branching tubules varying in
their diameter; acinar structures may be
present. Individual tumour cells are
columnar, cuboidal, or flattened by intra-luminal mucin. Clear cells may also be
present. The degree of cytological atypia
varies from low to high-grade {466,
1362}. A poorly differentiated variant is
sometimes called  solid carcinoma.
Tumours with a prominent lymphoid stro-ma are sometimes called medullary car-cinomas or carcinomas with lymphoid
stroma {2063}. The degree of desmopla-sia varies and may be conspicuous.
Papillary adenocarcinomas
These are well-differentiated exophytic
carcinomas with elongated finger-like
processes lined by cylindrical or
cuboidal cells supported by fibrovascu-lar connective tissue cores. The cells
tend to maintain their polarity. Some
tumours show tubular differentiation
(papillotubular). Rarely, a micropapillary
architecture is present. The degree of
cellular atypia and mitotic index vary;
there may be severe nuclear atypia. The
invading tumour edge is usually sharply
demarcated from surrounding structures;
the tumour may be infiltrated by acute
and chronic inflammatory cells.
Mucinous adenocarcinomas
By definition, > 50% of the tumour con-tains extracellular mucinous pools. The
two major growth patterns are (1) glands
lined by a columnar mucous-secreting
epithelium together with interstitial mucin
and (2) chains or irregular cell clusters
floating freely in mucinous lakes. There
may also be mucin in the interglandular
stroma. Scattered signet-ring cells, when
present, do not dominate the histological
picture. Grading mucinous adenocarci-Fig. 3.09 A Depressed adenocarcinoma. B Depressed signet ring cell carcinoma. C Gastric cancer, dye sprayed (pale area). D, E, F Advanced gastric carcinoma
with varying degrees of infiltration.
A
D
C
E
Fig. 3.10  Features of tubular adenocarcinoma. A Well differentiated tumour with invasion into the muscularis propria. B Solid variant. C Clear cell variant.
A B C
B
F
44 Tumours of the stomach
nomas is unreliable in tumours containing
only a few cells. The term ‘mucin-produ-cing’ is not synonymous with mucinous in
this context.
Signet-ring cell carcinomas
More than 50% of the tumour consists of
isolated or small groups of malignant
cells containing intracytoplasmic mucin.
Superficially, cells lie scattered in the lam-ina propria, widening the distances
between the pits and glands. The tumour
cells have five morphologies: (1) Nuclei
push against cell membranes creating a
classical signet ring cell appearance due
to an expanded, globoid, optically clear
cytoplasm. These contain acid mucin
and stain with Alcian blue at pH 2.5; (2)
other diffuse carcinomas contain cells
with central nuclei resembling histiocytes,
and show little or no mitotic activity; (3)
small, deeply eosinophilic cells with
prominent, but minute, cytoplasmic gran-ules containing neutral mucin; (4) small
cells with little or no mucin, and (5)
anaplastic cells with little or no mucin.
These cell types intermingle with one
another and constitute varying tumour
proportions. Signet-ring cell tumours may
also form lacy or delicate trabecular glan-dular patterns and they may display a
zonal or solid arrangement.
Signet-ring cell carcinomas are infiltra-tive; the number of malignant cells is
comparatively small and desmoplasia
may be prominent. Special stains,
including mucin stains (PAS, muci-carmine, or Alcian blue) or immunohisto-chemical staining with antibodies to
cytokeratin, help detect sparsely dis-persed tumour cells in the stroma. Cyto-keratin immunostains detect a greater
percentage of neoplastic cells than do
mucin stains. Several conditions mimic
signet-ring cell carcinoma including
signet-ring lymphoma, lamina propria
muciphages, xanthomas and detached
or dying cells associated with gastritis.
Laurén classification
The Laurén classification {1021} has
proven useful in evaluating the natural
history of gastric carcinoma, especially
with regard to its association with envi-ronmental factors, incidence trends and
its precursors. Lesions are classified into
one of two major types: intestinal or dif-fuse. Tumours that contain approximately
equal quantities of intestinal and diffuse
components are called  mixed carcino-mas. Carcinomas too undifferentiated to
fit neatly into either category are placed
in the indeterminate category.
Intestinal carcinomas
These form recognizable glands that
range from well differentiated to moder-ately differentiated tumours, sometimes
with poorly differentiated tumour at the
advancing margin. They typically arise
on a background of intestinal metaplasia.
The mucinous phenotype of these can-cers is intestinal, gastric and gastro-intestinal.
Diffuse carcinomas
They consist of poorly cohesive cells dif-fusely infiltrating the gastric wall with little
Fig. 3.13 Signet-ring cell carcinomas.  A Overview showing Infiltration of the lamina propria.  B Dispersed
signet-ring cells. C Accumulation of neoplastic signet ring cells in the mucosa. D Alcian green positive
signet-ring cells expanding the lamina propria in this Movat stain.
Fig. 3.12 A Papillary adenocarcinoma. B Well differentiated mucinous adenocarcinoma.
B
C D
Fig. 3.11 A, B Tubular adenocarcinoma.
A B
A B
A
45Gastric carcinoma
or no gland formation. The cells usually
appear round and small, either arranged
as single cells or clustered in abortive,
lacy gland-like or reticular formations.
These tumours resemble those classified
as signet-ring cell tumours in the WHO
classification. The mitotic rate is lower in
diffuse carcinomas than in intestinal
tumours. Small amounts of interstitial
mucin may be present. Desmoplasia is
more pronounced and associated inflam-mation is less evident in diffuse cancers
than in the intestinal carcinomas.
Rare variants
Several other carcinomas exist that are
not an integral part of the Laurén or WHO
classifications.
Adenosquamous carcinoma
This lesion combines an adenocarcino-ma and squamous cell carcinoma; nei-ther quantitatively prevails. Transitions
exist between both components. A
tumour with a distinct boundary between
the two components may represent a
collision tumour. Tumours containing dis-crete foci of benign-appearing squa-mous metaplasia are termed adenocarci-nomas with  squamous differentiation
(synonymous with adenoacanthoma).
Squamous cell carcinoma
Pure squamous cell carcinomas develop
rarely in the stomach; they resemble
squamous cell carcinomas arising else-where in the body.
Undifferentiated carcinoma
These lesions lack any differentiated fea-tures beyond an epithelial phenotype
(e.g. cytokeratin expression). They fall
into the indeterminate group of Laurén’s
scheme. Further analysis of this heteroge-neous group using histochemical meth-ods may allow their separation into other
types.
Other rare tumours include mixed adeno-carcinoma-carcinoid (mixed exocrine-endocrine carcinoma), small cell
carcinoma, parietal cell carcinoma, cho-riocarcinoma, endodermal sinus tumour,
embryonal carcinoma, Paneth cell rich-adenocarcinoma and hepatoid adenocar-cinoma.
Early gastric cancer
Early gastric cancer (EGC) is a carcino-ma limited to the mucosa or the mucosa
and submucosa, regardless of nodal sta-tus. Countries in which asymptomatic
patients are screened have a high inci-dence of EGCs ranging from 30-50%
{1410, 908, 718}, contrasting with a
smaller fraction of 16-24% {620, 253,
627} in Western countries. The follow-up
of dysplastic lesions does appear to
increase the prevalence of EGC. The
cost effectiveness of such an integrated
Fig. 3.14 Undifferentiated gastric carcinoma.
B
Fig. 3.15 Hepatoid variant of gastric carcinoma.
Fig. 3.17 A, B Adenocarcinoma, poorly differentiated. These two lesions show both intestinal and diffuse
components (Laurén classification).
A B
Fig. 3.16 Gastric choriocarcinoma composed of syncytiotrophoblastic and cytotrophoblastic cells next to
thin-walled vascular structures.  A Papillary carcinoma component is adjacent to the choriocarcinoma.
B High magnification of the choriocarcinoma.
46 Tumours of the stomach
endoscopic/biopsy approach remains to
be evaluated {1634, 1638}. Histological-ly, most subtypes of carcinoma occur in
EGC in either pure or mixed forms.
Elevated carcinomas with papillary, gran-ular or nodular patterns and a red colour
are more often well or moderately differ-entiated, tubular or papillary tumours
with intestinal features; sometimes a pre-existing adenoma is recognizable. Flat,
depressed, poorly differentiated carcino-mas may contain residual or regenerative
mucosal islands. Ulcerated lesions are
either intestinal or diffuse cancers.
Adenocarcinoma limited to the mucosal
thickness has also been divided into
small mucosal (< 4cm=SM) and superfi-cial (> 4cm=SUPER) {950}. Both of them
may be strictly confined at the mucosal
level (small mucosal M and superficial M)
or focally infiltrate the sub-mucosa (small
mucosal SM and superficial SM). In the
penetrating variant, (including two sub-categories: PenA and PenB) the invasion
of the submucosa is more extensive than
in the two above-mentioned variants.
PenA is defined by a pushing margin,
and is less frequent than PenB, which
penetrates muscularis mucosae at multi-ple sites.
The prognosis is worse in PenA carcino-mas (in contrast to adenocarcinomas of
the colon, where a pushing margin is
associated with a better prognosis). The
coexistence of more than one of the
described patterns results in the mixed
variant {950}.
Stromal reactions
The four common stromal responses to
gastric carcinoma are marked desmo-plasia, lymphocytic infiltrates, stromal
eosinophilia and a granulomatous res-ponse. The granulomatous reaction is
characterized by the presence of single
and confluent small sarcoid-like granulo-mas, often accompanied by a moderate-ly intense mononuclear cell infiltrate. The
lymphoid response is associated with an
improved survival.
Grading
Well differentiated: An adenocarcinoma
with well-formed glands, often resem-bling metaplastic intestinal epithelium.
Moderately differentiated: An adenocar-cinoma intermediate between well differ-entiated and poorly differentiated.
Poorly differentiated: An adenocarcino-ma composed of highly irregular glands
that are recognized with difficulty, or sin-gle cells that remain isolated or are
arranged in small or large clusters with
mucin secretions or acinar structures.
They may also be graded as  low-grade
(well and moderately differentiated) or
high-grade (poorly differentiated). Note
that this grading system applies primari-ly to tubular carcinomas. Other types of
gastric carcinoma are not graded.
Precursor lesions
Gastritis and intestinal metaplasia
Chronic atrophic gastritis and intestinal
metaplasia commonly precede and/or
accompany intestinal type adenocarci-noma, particularly in high-incidence
areas {780}. H. pylori associated gastritis
is the commonest gastric precursor
lesion.
However, autoimmune gastritis also
associates with an increased carcinoma
risk. If gastritis persists, gastric atrophy
occurs followed by intestinal metaplasia,
beginning a series of changes that may
result in neoplasia, especially of intestin-al type cancers. In contrast, diffuse gas-tric cancers often arise in a stomach
lacking atrophic gastritis with intestinal
metaplasia.
Fig. 3.18 Tubular adenocarcinoma. A Well differentiated; intramucosal invasion. B Moderately differentiated. C Poorly differentiated.
Fig. 3.19 A, B Tubular adenocarcinoma, well differ-entiated.
A
B Fig. 3.20  Intestinal metaplasia. The two glands on
the left exhibit complete intestinal metaplasia,
others show the incomplete type.
A B C
47
There are two main types of intestinal
metaplasia: ‘complete’ (also designated
as ‘small intestinal type’ or type I), and
‘incomplete’ (types II and III) {843}.
Different mucin expression patterns char-acterize the metaplasias: complete shows
decreased expression of ‘gastric’ (MUC1,
MUC5AC and MUC6) mucins and
expression of MUC2, an intestinal mucin.
In incomplete intestinal metaplasia, ‘gas-tric’ mucins are co-expressed with MUC2
mucin. These findings show that incom-plete intestinal metaplasia has a mixed
gastric and intestinal phenotype reflect-ing an aberrant differentiation program
not reproducing any normal adult gas-trointestinal epithelial phenotype {1574}.
Intraepithelial neoplasia
Intraepithelial neoplasia (dysplasia) arises
in either the native gastric or of intestinal-ized gastric epithelia.  Pyloric gland ade-noma is a form of intraepithelial neoplasia
arising in the native mucosa {2066, 1885}.
In the multi-stage theory of gastric onco-genesis, intraepithelial neoplasia lies
between atrophic metaplastic lesions
and invasive cancer (Table 3.01).
Problems associated with diagnosing
gastric intraepithelial neoplasia include
the distinction from reactive or regenera-tive changes associated with active
inflammation, and the distinction between
intraepithelial and invasive carcinoma
{1683, 1025}. Several proposals have
been made for the terminology of the
morphological spectrum of lesions that lie
between non-neoplastic changes and
early invasive cancer, including the
recent international Padova classification
{1636}.
Indefinite for intraepithelial neoplasia
Sometimes, doubts arise as to whether a
lesion is neoplastic or non-neoplastic (i.e.
reactive or regenerative), particularly in
small biopsies. In such cases, the dilem-ma is usually solved by cutting deeper
levels of the block, by obtaining addition-al biopsies, or after removing possible
sources of cellular hyperproliferation. One
important source of a potentially alarming
lesion is the regeneration associated with
NSAID-induced injury or superficial ero-sion/ulceration caused by gastric acid.
Cases lacking all the attributes required
for a definitive diagnosis of intraepithelial
neoplasia may be placed into the catego-ry ‘indefinite for intraepithelial neoplasia’.
In native gastric mucosa, foveolar hyper-proliferation may be indefinite for dyspla-sia, showing irregular and tortuous tubular
structures with epithelial mucus depletion,
a high nuclear-cytoplasmic ratio and loss
of cellular polarity. Large, oval/round,
hyperchromatic nuclei associate with
prominent mitoses, usually located near
the proliferative zone in the mucous neck
region.
In intestinal metaplasia, areas indefinite
for intraepithelial neoplasia exhibit a
hyperproliferative metaplastic epithelium.
The glands may appear closely packed,
lined by cells with large, hyperchromatic,
rounded or elongated, basally located
nuclei. Nucleoli are an inconsistent find-ing. The cyto-architectural alterations tend
to decrease from the base of the glands to
their superficial portion.
Intraepithelial neoplasia
It has flat, polypoid, or slightly depressed
growth patterns; the flat pattern may lack
any endoscopic changes on convention-al endoscopy, but shows an irregular
appearance on dye endoscopy. In
Western countries, the term adenoma is
applied when the proliferation produces
a macroscopic, usually discrete, protrud-ing lesion. However, in Japan, adenomas
include all gross types (i.e. flat, elevated
and depressed). Gastric adenomas are
less common than hyperplastic polyps;
overall, they account for approximately
10% of gastric polyps {1843}. They tend
to arise in the antrum or mid stomach in
areas of intestinal metaplasia.
Morphologically, adenomas can be
described as tubular (the most com-mon), tubulovillous, or villous; the latter
two have also been called papillotubular
and papillary. Most have epithelium of
intestinal type, but some have gastric
foveolar features.
Low-grade intraepithelial neoplasia
This lesion shows a slightly modified
mucosal architecture, including the pres-ence of tubular structures with budding
and branching, papillary enfolding, crypt
lengthening with serration, and cystic
changes. Glands are lined by enlarged
columnar cells with minimal or no mucin.
Homogeneously blue vesicular, rounded
or ovoid nuclei are usually pseudostrati-fied in the proliferation zone located at
the superficial portion of the dysplastic
tubules.
High-grade intraepithelial neoplasia
There is increasing architectural distortion
with glandular crowding and prominent
cellular atypia. Tubules can be irregular in
shape, with frequent branching and fold-Fig. 3.21 Reactive gastritis with marked foveolar
hyperplasia.
Fig. 3.22 Tubular adenoma of gastric antrum.
Uninvolved pyloric glands below the lesion show
cystic dilatation.
Gastric carinoma
48 Tumours of the stomach
ing; there is no stromal invasion. Mucin
secretion is absent or minimal. The pleo-morphic, hyperchromatic, usually pseu-dostratified nuclei often are cigar-shaped.
Prominent amphophilic nucleoli are com-mon. Increased proliferative activity is
present throughout the epithelium.
Progression of intraepithelial neoplasia to
carcinoma
Carcinoma is diagnosed when the tumour
invades into the lamina propria (intramu-cosal carcinoma) or through the muscu-laris mucosae. Some gastric biopsies
contain areas suggestive of true invasion
(such as isolated cells, gland-like struc-tures, or papillary projections). The term
‘suspicious for invasion’ is appropriate
when the histological criteria for an inva-sive malignancy are equivocal.
Up to 80% of intraepithelial neoplasias
may progress to invasion. Indeed, inva-sive cancer already may be present in
patients found to have high-grade intra-epithelial neoplasia with no obvious
tumour mass. The extent of intestinal
metaplasia associated with intraepithelial
neoplasia, together with a sulphomucin-secreting phenotype of the intestinalized
mucosa (type III intestinal metaplasia),
correlate with an increased risk of carci-noma development.
Adenomas
Adenomas are circumscribed, benign
lesions, composed of tubular and/or vil-lous structures showing intraepithelial
neoplasia. The frequency of malignant
transformation depends on size and his-tological grade. It occurs in approximate-ly 2% of lesions measuring < 2 cm and in
40-50% of lesions > 2 cm. Flat adenomas
may have a greater tendency to progress
to carcinoma.
Polyps
Hyperplastic polyps
Hyperplastic polyps are one of the com-monest gastric polyps. They are sessile
or pedunculated lesions, usually < 2.0
cm in diameter, typically arising in the
antrum on a background of H. pylori gas-tritis. They contain a proliferation of sur-face foveolar cells lining elongated, dis-torted pits extending deep into the
stroma. They may contain pyloric glands,
chief cells and parietal cells. The surface
often erodes. In a minority of cases, car-cinoma develops within the polyps in
areas of intestinal metaplasia and dys-plasia.
Fundic gland polyps
Fundic gland polyps are the commonest
gastric polyp seen in Western popula-tions. They occur sporadically, without a
relationship to  H. pylori gastritis. They
also affect patients on long-term proton
pump inhibitors or patients with familial
adenomatous polyposis (FAP), who may
have hundreds of fundic gland polyps
{2064, 2065}.
The lesions consist of a localized hyper-plasia of the deep epithelial compart-ment of the oxyntic mucosa, particularly
of mucous neck cells, with variable
degrees of cystic dilatation. Sporadic
fundic gland polyps have no malignant
potential. Exceptionally, patients with
attentuated FAP may develop dysplasia
and carcinoma in their fundic gland
polyps {2214, 1204}
Polyposis syndromes
Peutz-Jeghers polyps, juvenile polyps,
and Cowden polyps generally do not
occur spontaneously, but rather as part
of hereditary polyposis syndromes. In the
stomach, Peutz-Jeghers polyps are char-acterized histologically by branching
bands of smooth muscle derived from
Fig. 3.23  A, B Examples of low-grade intraepithelial neoplasia of flat gastric mucosa. The atypia extends to
the surface.
A B
Fig. 3.24 High-grade intraepithelial neoplasia in flat gastric mucosa (flat adenoma). A Architectal distortion of the gastric glands. B High degree of cellular atypia.
C Papillary pattern.
A B C
49
muscularis mucosae, and hyperplasia,
elongation and cystic change of foveolar
epithelium; the deeper glandular compo-nents tend to show atrophy.
Genetic susceptibility
Most gastric carcinomas occur sporadi-cally; only about 8-10% have an inherited
familial component {996}. Familial clus-tering occurs in 12 to 25% with a domi-nant inheritance pattern {597, 864}.
Case-control studies also suggest a
small but consistent increased risk in
first-degree relatives of gastric carcino-ma patients {2200}.
Gastric carcinoma occasionally devel-ops in families with germline mutations in
ATM5, TP53 (Li Fraumeni syndrome)
{2001, 743, 1652}, and BRCA2 {1934}.
Rare site-specific gastric carcinoma pre-disposition traits have been reported in
several families {1147, 2130}, including
that of Napoleon.
Hereditary diffuse gastric carcinoma
Germline mutations in the gene encoding
the cell adhesion protein E-cadherin
(CDH1) lead to an autosomal dominant
predisposition to gastric carcinoma,
referred to as hereditary diffuse gastric
carcinoma (HDGC) {640, 568}. Predis-posing germline CDH1 mutations gener-ally resulting in truncated proteins are
spread throughout the gene with no
apparent hotspots {641, 640, 568, 1581}.
HDGC has an age of onset ranging
upwards from 14 years and a penetrance
of approximately 70% {641, 568}.
Histologically, HDGC tumours are dif-fuse, poorly differentiated infiltrative ade-nocarcinomas with occasional signet-ring cells {641, 640, 568}.
HNPCC
Gastric carcinomas can develop as part
of the hereditary nonpolyposis colon
cancer (HNPCC) syndrome {1130, 922}.
They are intestinal type cancers, without
an association with H. pylori infection;
most exhibit microsatellite instability
(MSI) {4} with a trend that is opposite to
that found in tumours arising in young
patients {1739}.
Gastrointestional polyposis syndromes
Gastric carcinomas also occur in
patients with gastrointestinal polyposis
syndromes including FAP and Peutz-Jeghers syndrome.
Overall, gastric carcinoma is rare in
these settings, and the exact contribution
of the polyposis and underlying germline
alterations of APC and LKB1/STK11 to
cancer development is unclear.
Blood group A
The blood group A phenotype associ-ates with gastric carcinomas {27, 649}.
H. pylori adhere to the Lewisb
blood
group antigen and the latter may be an
important host factor facilitating this
chronic infection {244} and subsequent
cancer risk.
Molecular genetics
Loss of heterozygosity studies and com-parative genomic hybridization (CGH)
analyses have identified several loci with
significant allelic loss, indicating possi-ble tumour suppressor genes important
in gastric carcinoma. Common target(s)
of loss or gain include chromosomal
regions 3p, 4, 5q, (30 to 40% at or near
APC’s locus) {1656, 1577}, 6q {255}, 9p,
17p (over 60 percent at TP53’s locus)
{1656}, 18q (over 60 percent at DCC’s
locus) {1981}, and 20q {1287, 449,
2192}. Similar LOH losses at 11p15
occur in proximal and distal carcinomas,
suggesting common paths of develop-Gastric carcinoma
Fig. 3.25 A Large hyperplastic polyp of the stomach. B, C Typical histology of gastric hyperplastic polyp. D
Hyperplastic polyp with florid epithelial hyperplasia.
A B
DC
Table 3.01
Histological follow-up studies of gastric intraepithelial neoplasia. Proportion progressing to carcinoma and
mean interval.
Reports Low-grade dysplasia High-grade dysplasia
Saraga, 1987 {2355} 2% (1/64) 4 yr. 81% (17/21) 4 mos.
Lansdown, 1990 {2356} 0 (0/7) 85% (11/13) 5 mos.
Rugge, 1991 {2008} 17% (12/69) 1yr. 75% (6/8) 4 mos.
Fertitta, 1993 {2357} 23% (7/30) 10 mos. 81% (25/31) 5 mos.
Di Gregorio, 1993 {2358} 7% (6/89) 2 yr. 60% (6/10) 11 mos.
Rugge, 1994 {2009} 14% (13/90) 2 yr. 78% (14/18) 9 mos.
Kokkola, 1996 {2359} 0% (0/96) 67% (2/3) 1.5 yr.
50 Tumours of the stomach
ment {1288}. Loss of a locus on 7q
(D7S95) associates with peritoneal
metastasis.
The frequency of MSI in sporadic gastric
carcinoma ranges from 13% to 44%
{1713}. MSI+ tumours tend to be
advanced intestinal-type cancers. The
degree of genome-wide instability varies
with more significant instability (e.g.,
MSI-H: > 33% abnormal loci) occurring
in only 16% of gastric carcinoma, usually
of the subcardial intestinal or mixed type,
with less frequent lymph node or vessel
invasion, prominent lymphoid infiltration,
and better prognosis {430}. Loss of either
hMLH1 or hMSH2 protein expression
affects all MSI-H cases {654} suggesting
inactivation of both alleles by mecha-nisms such as hypermethylation {1050,
510}.
Genes with simple tandem repeat
sequences within their coding regions
that are altered in MSI+ tumours include
the TGF-β II receptor,  BAX, IGFRII,
hMSH3, hMSH6, and E2F-4. A study of
gastric cancers displaying the MSI-H
phenotype reveal that a majority contain
mutated TGF-β type II receptors in a
polyadenine tract {1420, 1462}. Altered
TGF-β II receptor genes can also be
found in MSI-lesions.
Allelic loss of  TP53 occurs in > 60% of
cases and mutations are identified in
approximately 30-50% of cases depend-ing on the mutational screening method
and sample sizes {729, 1937}.  TP53
mutations are identifiable in some intes-tinal metaplasias; {497} most alterations
affect advanced tumours.  TP53 muta-tions in gastric lesions resemble those
seen in other cancers with a predomi-nance of base transitions, especially at
CpG dinucleotides. Immunohistochemi-cal analyses to detect TP53 overexpres-sion can indirectly identify  TP53 muta-tions but do not have consistent
prognostic value in gastric carcinoma
patients {557, 766}. Finally, with respect
to TP53, there is a polymorphism in
codon 72 encoding a proline rather than
an arginine that strongly associates with
antral cancers {1735}.
Sporadic gastric carcinomas, especially
diffuse carcinomas, exhibit reduced or
abnormal E-cadherin expression {1196,
1135}, and genetic abnormalities of the
E-cadherin gene and its transcripts.
Reduced E-cadherin expression is asso-ciated with reduced survival {848}.
E-cadherin splice site alterations pro-duce exon deletion and skipping. Large
deletions including allelic loss and mis-sense point mutations also occur; some
tumours exhibit alterations in both alleles
{135}. Somatic E-cadherin gene alter-ations also affect the diffuse component
of mixed tumours {1136}. Alpha-catenin,
which binds to the intracellular domain of
E-cadherin and links it to actin-based
cytoskeletal elements, shows reduced
immunohistochemical expression in
many tumours and correlates with infiltra-tive growth and poor differentiation
{1189}. Beta catenin may also be abnor-mal in gastric carcinoma.
There is evidence of a tumour suppres-sor locus on chromosome 3p in gastric
carcinomas {893, 1688}. This area
encodes the FHIT gene. Gastric carcino-mas develop abnormal transcripts, delet-ed exons {1411}, a somatic missense
mutation in exon 6 and loss of FHIT pro-tein expression {102}.
Somatic APC mutations, mostly mis-sense in nature and low in frequency,
affect Japanese patients with in situ and
invasive neoplasia {1309}. Significant
allelic loss (30%) at the APC loci suggest
that there is a tumour suppressor gene
important in gastric tumourigenesis near-by. Indeed, alternative loci have been
mapped to commonly deleted regions in
gastric carcinomas {1891}.
Amplification and overexpression of the
c-met gene encoding a tyrosine kinase
receptor for the hepatocyte growth factor
occurs in gastric carcinoma {976}. Other
growth factor and receptor signal systems
that may be involved include epidermal
growth factor, TGF-alpha, interleukin-1-a,
cripto, amphiregulin, platelet-derived
Fig. 3.26 A, B Fundic gland polyp. Cystic glands are typical.
AB
Fig. 3.27 Peutz-Jeghers polyp with hyperplastic
glands.
51Gastric carcinoma
growth factor, and K-sam {1879}. Ampli-fication of  c-erbB-2, a transmembrane
tyrosine kinase receptor oncogene,
occurs in approximately 10% of lesions
and overexpression associates with a
poor prognosis {375}. Telomerase activity
has been detected by a PCR-based
assay frequently in the late stages of gas-tric tumours and observed to be associat-ed with a poor prognosis {719}.
Prognosis and predictive factors
Early gastric cancer
In early gastric cancers, small mucosal
(< 4 cm), superficial (> 4 cm) and Pen B
lesions have a low incidence of vessel
invasion and lymph node metastasis and
a good prognosis after surgery (about
90% of patients survive 10 years). In con-trast, penetrating lesions of the Pen A
type are characterized by a relatively
high incidence of vessel invasion and
lymph node metastasis and a poor prog-nosis after surgery (64.8% 5-year sur-vival).
Advanced gastric cancer
Staging.   The TNM staging system for
gastric cancer is widely used and it pro-vides important prognostic information.
Lymphatic and vascular invasion carries
a poor prognosis and is often seen in
advanced cases. Lymph node status,
which is part of the TNM system, is also
an important prognostic indicator. The 5th
edition of the UICC TNM Classification of
Malignant Tumours {66} and the AJCC
Manual for the Staging of Cancer {1} pub-lished in 1997, have a number-based
classification scheme for reporting nodal
involvement in gastric cancer.
Roder et al recently published data sup-porting the value of this reporting sys-tem. These authors found that for
patients who had nodal involvement in
1-6 lymph nodes (pN1), the 5-year sur-Fig. 3.29 CGH analysis of a poorly differentiated gastric adenocarcinoma: copy number gains at chromo-somes 3q21, 7p15, 8q, 10p12-15, 11q13, 12q24, 13q13-14, 15q23-25, 17q24, 20 and 21q21. Copy number losses
at chromosomes 4q12-28 and 5.
Fig. 3.28 E-cadherin expression in gastric adenocarcinoma. A Intestinal type of adenocarcinoma showing a normal pattern of membranous staining. B Diffuse type
of adenocarcinoma with reduced E-cadherin expression. Normal expression can be seen in the non-neoplastic gastric epithelium overlying the tumour. C Undiffer-entiated gastric carcinoma with highly reduced membranous expression and dot-like cytoplasmic expression.
AB C
52 Tumours of the stomach
vival rate was 44% compared with a 30%
survival rate in patients with 7-15 lymph
nodes involved with tumour (pN2).
Patients with more than 15 lymph nodes
involved by metastatic tumour (pN3) had
an even worse 5-year survival of 11%
{1602}. Gastric carcinoma with obvious
invasion beyond the pyloric ring, those
with invasion up to the pyloric ring, and
those without evidence of duodenal inva-sion have 5-year survival rates of 8%,
22%, and 58%, respectively {671}.
Patients with T1 cancers limited to the
mucosa and submucosa have a 5-year
survival of approximately 95%. Tumours
that invade the muscularis propria have a
60-80% 5-year survival, whereas tumours
invading the subserosa have a 50%
5-year survival {2181}. Unfortunately,
most patients with advanced carcinoma
already have lymph node metastases at
the time of diagnosis.
Histological features.  The value of the his-tological type of tumour in predicting
tumour prognosis is more controversial.
This relates in part to the classification
scheme that is used to diagnose the can-cers. Using the Laurén classification,
some believe that diffuse lesions general-ly carry a worse prognosis than intestinal
carcinomas. The prognosis is particularly
bad in children and young adults, in
whom the diagnosis is often delayed
{1986, 1554} and likely fit into the catego-ry of HDGC. However, others have not
found the Laurén classification to predict
prognosis {1788, 1177}. One study found
that only the Goseki classification {610}
added additional prognostic information
to the TNM stage {610}. 5-year survival of
patients with mucus rich (Goseki II and
IV) T3 tumours was significantly worse
than that of patients with mucus poor
(Goseki I and III) T3 tumours (18% vs.
53% p<0.003) {1177}. A second study
validated these findings  {1788}. Another
classification scheme for gastric carcino-ma was proposed by Carneiro et al that
may also have prognostic value {610}.
The recognition of mixed carcinoma may
be important since patients harbouring
this type of carcinoma may also have a
poor outcome {610}.
Some patients with medullary carcino-mas with circumscribed, pushing growth
margins and a marked stromal inflamma-tory reaction exhibit a better prognosis
than those with other histological tumour
types {430}. Some of these patients are
in HNPCC kindreds who have MSI-H, a
feature associated with better survival.
However, not all studies agree that stro-mal response and pushing margins pre-dict a better prognosis {1788, 1177}.
In summary, gastric carcinoma is a hete-rogeneous disease biologically and
genetically, and a clear working model of
gastric tumourigenesis has yet to be for-mulated. More tumours appear to be
related to environmental than to genetic
causes, although both may play a role in
individual cases. Characterization of the
various pathways should afford multiple
opportunities to design more specific
and therefore more effective therapies.
Fig. 3.30 TP53 mutations in gastric carcinoma. The
mutations are shown by both single-strand confor-mation polymorphisms (SSCP) as well as direct
sequencing. There is a G to A substitution indicated
by the right hand panel.
53Endocrine tumours
Definition
Most endocrine tumours of the stomach
are well differentiated, nonfunctioning
enterochromaffin-like (ECL) cell carci-noids arising from oxyntic mucosa in the
corpus or fundus. Three distinct types
have are recognized: (1) Type I, associ-ated with autoimmune chronic atrophic
gastritis (A-CAG); (2) type II, associated
with muliple endocrine neoplasia type 1
(MEN-1) and Zollinger-Ellison syndrome
(ZES); type III, sporadic, i.e. not associ-ated with hypergastrinaemia or A-CAG.
ICD-O Code
Carcinoid 8240/3
Small cell carcinoma 8041/3
Epidemiology
In the past, carcinoid tumours of the
stomach have been reported to occur
with an incidence of 0.002-0.1 per
100,000 population per year and to
account for 2-3 % of all gastrointestinal
carcinoids {587} and 0.3 percent of gas-tric neoplasms {1132}. More recent stud-ies, however, based on endoscopic tech-niques and increased awareness of such
lesions, have shown a much higher inci-dence of gastric carcinoids, which may
now account for 11-41% of all gastroin-testinal carcinoids {1588, 1764, 1782}.
The incidence of gastric carcinoids is
higher in Japan, where they re-present
30% of all gastrointestinal carcinoids,
which may be due to the high incidence
of chronic atrophic gastritis in this country
{1277}.
Age and sex distribution
Type I gastric ECL-cell carcinoids have
been reported to represent 74% of gas-tric endocrine tumours and to occur most
often in females (M:F ratio, 1:2.5). The
mean age at biopsy is 63 years (range
15-88 years). Type II ECL-cell carcinoids
represent 6% of all gastric endocrine
tumours and show no gender predilec-tion (M:F ratio, 1:1) at a mean age of 50
years (range 28-67 years) {1590}. Type
III ECL-cell carcinoids constitute 13% of
all gastric endocrine tumours and are
observed mainly in male patients (M:F
ratio, 2.8:1) at a mean age of 55 years
(range 21-38 years) {1590}.
Small cell carcinoma (poorly differentiat-ed endocrine carcinoma) accounts for
6% of gastric endocrine tumours and pre-vails in men (M:F ratio, 2:1) at a mean age
of 63 years (range 41-61 years) {1590}.
Gastrin cell tumours represent less than
1% of gastric endocrine tumours {1590}
and are reported in adults (age range
55-77).
Aetiology
Gastrin has a trophic effect on ECL-cells
both in humans and experimental ani-mals {172, 652}. Hypergastrinaemic
states, resulting either from unregulated
hormone release by a gastrinoma or from
a secondary response of antral G cells to
achlorhydria, are consistently associated
with ECL-cell hyperplasia {172}.
Autoimmune chronic atrophic gastritis
(A-CAG)
This disease is caused by antibodies to
parietal cells of the oxyntic mucosa. It
leads to chronic atrophic gastritis (with or
without pernicious anaemia) which leads
to an increase in gastrin production.
Zollinger-Ellison syndrome
This disease results from hypergastri-naemia due to gastrin-producing neo-plasms that are preferentially located in
the small intestine and pancreas. ECL-cell proliferation is usually limited to
hyperplastic lesions of the simple linear
type {1042, 1777}.
MEN-1
This inherited tumour syndrome causes a
variety of endocrine neoplasms, includ-ing gastrinomas. In patients with MEN-1
associated ZES (MEN-1/ZES), ECL-cell
lesions are usually dysplastic or overtly
carcinoid in nature {1779}. In the MEN-1
syndrome, the mutation or deletion of the
suppressor MEN-1 oncogene in 11q13
may be involved {394} as an additional
pathogenetic factor. In A-CAG, achlorhy-dria or associated mucosal changes may
contribute to tumourigenesis {1785}.
Several growth factors, including trans-forming growth factor-α (TGFα) and
basic fibroblast growth factor (bFGF)
seem to be involved in tumour develop-ment and progression as well as stromal
and vascular proliferation of ECL-cell
carcinoids {171}.
Localization
Type I, II, and III ECL-cell carcinoids are
all located in the mucosa of the body-fundus of the stomach, whereas the rare
G-cell tumours are located in the antro-pyloric region. Small cell carcinomas
prevail in the body/fundus, but some are
located in the antrum {1590}.
Clinical features
The three distinct types of ECL-cell car-cinoids are well differentiated growths
but with variable and poorly predictable
behaviour.
Type I ECL-cell carcinoids
These are associated with A-CAG involv-ing the corpus and fundus mucosa.
Clinical signs include achlorhydria and,
less frequently, pernicious anemia.
Hypergastrinaemia or evidence of antral
gastrin-cell hyperplasia is observed in all
cases of A-CAG. In patients with a carci-noid, ECL-cell hyperplastic changes are
a constant feature and dysplastic
growths are frequently observed {1590}.
A-CAG associated carcinoids are typi-cally small (usually less than 1 cm), mul-C. Capella
E. Solcia
L.H. Sobin
R. Arnold
Endocrine tumours of the stomach
Fig. 3.31 Chromogranin A immunostain demon-strates hyperplasia of endocrine cells at the base of
glandular tubules.
54 Tumours of the stomach
tiple and multicentric. Of 152 cases stud-ied by endoscopy, 57% had more than
two growths {1561}.
Type II ECL-cell carcinoids
Hypertrophic, hypersecretory gastropa-thy and high levels of circulating gastrin
are critical diagnostic findings. In all
cases, ECL-cell hyperplasia and/or dys-plasia were noted in the fundic peritu-moural mucosa {1590}. These gastric
carcinoids are usually multiple and small-er than 1.5 cm in size in the majority of
cases {1590}.
Type III (sporadic) ECL-cell carcinoids
These lesions are not associated with
hypergastinaemia or A-CAG. They are
generally solitary growths, and arise in the
setting of gastric mucosa devoid of
ECL-cell hyperplasia/dysplasia and of
significant pathologic lesions except for
gastritis (other than A-CAG). Rare multi-ple tumours have been observed {1590}.
Clinically, type III tumours present (1) as a
mass lesion with no evidence of endo-crine symptoms (nonfunctioning carci-noid) and with clinical findings similar to
those of adenocarcinoma, including gas-tric haemorrhage, obstruction and metas-tasis, or (2) with endocrine symptoms of
an ‘atypical carcinoid syndrome’ with red
cutaneous flushing and absence of diar-rhoea, usually coupled with liver metas-tases and production of histamine and
5-hydroxytryptophan {1386, 1598}.
Non ECL-cell gastric carcinoids.
These uncommon tumours may present
with ZES due to their gastrin production
(which is more frequently found in duo-denal gastrinomas) or with Cushing syn-drome due to secretion of adrenocorti-cotrophic hormone (ACTH) {711, 1791}.
Macroscopy
Type I ECL-cell carcinoids are multiple in
57% of cases {1590}, usually appearing
as small tan nodules or polyps that are
circumscribed in the mucosa or, more
often, to the submucosa. Most tumours
(77%) are < 1 cm in maximum diameter
and 97% of tumours are < 1.5 cm. The
muscularis propria is involved in only a
minority of cases (7%) {1590}.
The stomachs with type II tumours are
enlarged and show a thickened gastric
wall (0.6-4.5 cm) due to severe hyper-trophic-hypersecretory gastropathy and
multiple mucosal-submucosal nodules
which, though larger than those of type I,
are generally smaller than 1.5 cm in size
in 75% of cases {1590}.
Type III ECL-cell tumours are usually sin-gle and in 33% of the cases larger than 2
cm in diameter. Infiltration of the muscu-laris propria is found in 76%, and of the
serosa in 53% of cases {1590}.
Histopathology
The histopathological categorization of
endocrine tumours of the stomach
described here, is a modification of the
WHO classification of endocrine tumours
{1784}.
Carcinoid tumour
A carcinoid is defined morphologically
as a well differentiated neoplasm of the
diffuse endocrine system.
ECL-cell carcinoid
The majority of type I and type II
ECL-cell carcinoids are characterized
by small, microlobular-trabecular aggre-gates formed by regularly distributed,
often aligned cells (mosaic-like pattern),
with regular, monomorphic nuclei, usual-ly inapparent nucleoli, rather abundant,
fairly eosinophilic cytoplasm, almost
absent mitoses, and infrequent angioin-vasion.
Tumours with these features (grade 1
according to Rindi et al {1589}) are gen-erally limited to mucosa or submucosa
{1589} and can be considered as
tumours with benign behaviour. The ECL
nature of the tumours is confirmed by
strong argyrophilia by Grimelius or
Sevier Munger techniques and positive
immunoreactivity for chromogranin A, in
the absence of reactivity for the
argentaffin or diazonium tests for sero-tonin, and no or only occasional
immunoreactivity for hormonal products
{1591}. Minor cell sub-populations ex-pressing serotonin, gastrin, somato-statin, pancreatic polypeptide (PP), or
α-hCG have been detected in a minority
of tumours {1591}. A few ECL-cell
tumours produce histamine and
5-hydroxy-tryptophan; these lesions,
when they metastasize, can produce
‘atypical’ carcinoid syndrome {1591}
Vesicular monoamine transporter type 2
(VMAT-2) is a suitable and specific marker
for ECL-cell tumours {1592} while hista-mine or histidine decarboxylase immuno-histochemical analysis, although specific,
is less suitable for routinely processed
specimens {1865}. The ECL-cell nature of
argyrophil tumours is ultimately assessed
by demonstrating ECL-type granules by
electron microscopy {232, 1591}.
Sporadic ECL-cell carcinoids are usually
more aggressive than those associated
with A-CAG or MEN-1. Histopathologi-cally, these tumours show a prevalence
of solid cellular aggregates and large tra-beculae, crowding, and irregular distri-bution of round to spindle and polyhedral
tumour cells, fairly large vesicular nuclei
with prominent eosinophilic nucleoli, or
smaller, hyperchromatic nuclei with irreg-ular chromatin clumps and small nucle-oli, considerable mitotic activity, some-times with atypical mitotic figures and
scarce necrosis.
Tumours with these histological features
or grade 2 features {1589} show a higher
mitotic rate (mean of 9 per 10 HPF), a fre-quent expression of p53 (60%), a higher
Fig. 3.32 Sporadic (type III) ECL-cell carcinoid of the
gastric body. The surrounding mucosa is normal.
1. Carcinoid –
well differentiated endocrine neoplasm
1.1 ECL-cell carcinoid
1.2 EC-cell, serotonin-producing
carcinoid
1.3 G-cell, gastrin-producing tumour
1.4 Others
2. Small cell carcinoma –
poorly differentiated endocrine neoplasm
3. Tumour-like lesions
Hyperplasia
Dysplasia
1
Benign behaviour of ECL-cell carcinoid is associated
with the following: tumour confined to mucosa-sub-mucosa, nonangioinvasive, < 1cm in size, nonfunc-tioning; occurring in CAG or MEN-1/ ZES. Aggressive
behaviour of ECL-cell carcinoid is associated with the
following: tumour invades muscularis propria or
beyond, > 1cm in size, angioinvasive, functioning, and
sporadic occurrence.
Table 3.02.
Histological classification of endocrine neoplasms
of the stomach1
55Endocrine tumours
Ki67 labelling index (above 1000 per 10
HPF) and more frequent lymphatic and
vascular invasion than well differentiated
ECL-cell carcinoids {1589}. In addition,
deeply invasive tumours are associated
with local and/or distant metastases in
most cases.
EC-cell, serotonin-producing carcinoid
This is a very rare tumour in the stomach
{1591}. It is formed by rounded nests of
closely packed small tumour cells, often
with peripheral palisading, reminiscent of
the typical type A histologic pattern of
the argentaffin EC-cell carcinoid of the
midgut. The tumour cells are argentaffin,
intensely argyrophilic and reactive with
chromogranin A and anti-serotonin anti-bodies. Electron microscopic examina-tion confirms the EC-cell nature by
detecting characteristic pleomorphic,
intensely osmiophilic granules similar to
those of normal gastric EC-cells.
Gastrin-cell tumours
Most well differentiated gastrin-cell
tumours are small mucosal-submucosal
nodules, found incidentally at endoscopy
or in a gastrectomy specimen. They may
show a characteristic thin trabecular-gyriform pattern or a solid nest pattern.
The cells are uniform with scanty cyto-plasm and show predominant immunore-activity for gastrin.
Small cell carcinoma (poorly differentiat-ed endocrine neoplasm)
These are identical to small cell carcino-mas of the lung. They correspond to
grade 3 tumours according to Rindi et al.
{1589}, and are particularly aggressive,
malignant tumours {1591}.
Large cell neuroendocrine carcinoma  is a
malignant neoplasm composed of large
cells having organoid, nesting, trabecular,
rosette-like and palisading patterns that
suggest endocrine differentiation, and in
which the last can be confirmed by
immunohistochemistry and electron
microscopy. In contrast to small cell carci-noma, cytoplasm is more abundant,
nuclei are more vesicular and nucleoli are
prominent {1954}. These tumours have
not been well described in the gastroin-testinal tract because of their apparent
low frequency {1188}.
Mixed exocrine-endocrine carcinomas
These consist of neoplastic endocrine
cells composing more than 30% of the
whole tumour cell population. They are
relatively rare in the stomach, despite the
frequent occurrence of minor endocrine
components inside the ordinary adeno-carcinoma. They should generally be
classified as adenocarcinomas.
Precursor lesions
ECL-cell carcinoids arising in hypergas-trinaemic conditions (types I and II)
develop through a sequence of hyperpla-sia-dysplasia-neoplasia that has been
well documented in histopathological
studies {1777}. The successive stages of
hyperplasia are termed simple, linear,
micronodular, and adenomatoid. Dyspla-sia is characterized by relatively atypical
cells with features of enlarging or fusing
micronodules, micro-invasion or newly
formed stroma. When the nodules
increase in size to > 0.5 mm or invade
into the submucosa, the lesion is classi-fied as a carcinoid. The entire spectrum
of ECL-cell growth, from hyperplasia to
dysplasia and neoplasia has been
observed in MEN-1/ZES and autoimmune
chronic atrophic gastritis (A-CAG). A sim-ilar sequence of lesions has been shown
in experimental models of the disease,
mostly based on hypergastrinaemia sec-ondary to pharmacological inhibition of
acid secretion in rodents {1896}.
Genetic susceptibility
ECL-cell carcinoids are integral compo-nents of the MEN-1 syndrome {1042}. In
patients with familial MEN-1/ZES, type II
gastric carcinoids arise in 13-30% of
cases {854, 1042}. However, patients
Fig. 3.33 A Type I ECL-cell carcinoid in a patient with pernicious anaemia. B Type II ECL-cell carcinoid in a patient with MEN1 and ZES.
Fig. 3.34  ECL-cell carcinoid showing immunoex-pression of chromogranin A.
AB
56 Tumours of the stomach
with sporadic ZES rarely develop gastric
carcinoids despite serum gastrin levels,
which persist 10 fold above normal for a
prolonged time.
Diagnostic criteria of MEN-1
This rare dominantly inherited disorder is
characterized by the synchronous or
metachronous development of multiple
endocrine tumours in different endocrine
organs by the third decade of life. The
parathyroid glands are involved in
90-97%, endocrine pancreas in 30-82%,
duodenal gastrinomas in 25%, pituitary
adenomas in more than 60%, and foregut
carcinoids (stomach, lung, thymus) in
5-9% of cases {394}. Other, so-called
non-classical MEN-1 tumours, such as
cutaneous and visceral lipomas, thyroid
and adrenal adenomas, and skin angiofi-bromas, may occur {394, 1444}.
MEN-1 gene
MEN-1 has been mapped to chromo-some 11q13 {107, 1015}. It encodes for a
610 amino acid nuclear protein, termed
‘menin’, whose suppressor function
involves direct binding to JunD and inhi-bition of JunD activated transcription
{271, 18}. The tumour suppressor function
of the gene has been proposed based on
the results of combined tumour deletion
and pedigree analysis {107, 271, 394}.
High rates of loss of heterozygosity (LOH)
at the  MEN-1 gene locus have been
reported in classic tumours of the MEN-1,
such as endocrine pancreatic, pituitary
and parathyroid neoplasms {1553, 1923}.
LOH at 11q13 of type II gastric carcinoids
was found in 9 of 10 MEN-1 patients
investigated {123, 173, 219, 394}.
These findings support the concept that
these gastric tumours are integral com-ponents of the MEN-1 phenotype, shar-ing with parathyroid and islet cell
tumours the highest frequency of LOH at
11q13. In multiple carcinoids from the
same stomach, the deletion size in the
wild-type allele differed from one tumour
to another, suggesting a multiclonal ori-gin {394}. One of the type II tumours
showing LOH at 11q13 was in a patient
who had neither ZES nor hypergastri-naemia {173}, suggesting that inactiva-tion of the MEN-1 gene alone is capable
of causing ECL-cell tumours without
requiring the promoting effect of hyper-gastrinaemia.
The role of MEN-1 in non MEN-associat-ed gastric carcinoids is more controver-sial. Analysing six type I gastric carci-noids, Debelenko et al. {394} found
11q13 LOH in one tumour while D’Adda
et al. {363} detected 11q13 LOH in 12
out of 25 cases (48%). Large deletions in
both the 11q13 and 11q14 regions were
observed in two poorly differentiated
endocrine carcinomas {363}.
Prognosis and predictive factors
The prognosis of carcinoids is highly
variable, ranging from slowly growing
benign lesions to malignant tumours with
extensive metastatic spread.
Benign behaviour of ECL-cell carcinoids
is associated with the following: tumour
confined to mucosa-submucosa, nonan-gioinvasive, < 1 cm in size, nonfunction-ing; occurring in CAG or MEN-1/ ZES.
Type I, A-CAG associated tumours, have
an excellent prognosis, as do most type
II MEN-1/ZES tumours.
Aggressive behaviour of ECL-cell carci-noid is associated with the following:
tumour invades muscularis propria or
beyond, is > 1 cm in size, angioinvasive,
functioning, with high mitotic activity and
sporadic occurrence {1591, 1590, 1589}.
Metastasis. Lymph node metastases are
detected in 5% of type I and 30% of type
II cases, while distant (liver) metastases
are found respectively in 2.5% and 10%
of cases. No tumour-related or only
exceptional death was observed among
patients with type I carcinoid, while only
1/10 patients died of type II carcinoid. On
Fig. 3.36  Gastrin cell tumour (gastrinoma) of the
pylorus with trabecular growth pattern.
Fig. 3.35  Sporadic (type III) ECL carcinoid. A Tumour extends from mucosa into submucosa with well delineated inferior border. B The carcinoid (left) has round,
regular, isomorphic nuclei.
AB
57Lymphoma
the other hand, lymph node metastases
are found in 71% and distant metastases
in 69% of patients with type III tumours;
death from the tumour occurs in 27% of
patients with a mean survival of 28
months {1590}.
Therapy
Polypoid type I carcinoids < 1cm, fewer
than 3-5 in number, associated with
A-CAG can be endoscopically excised
and have an excellent prognosis. If larg-er than 1 cm or more than 3-5 lesions are
present, antrectomy and local excision of
all accessible fundic lesions is recom-mended.
In type II carcinoids the clinical evolution
depends on the behaviour of associated
pancreatic and duodenal gastrinomas
more than on the behaviour of gastric
tumours, although some aggressive
ECL-cell carcinomas may be fatal {173}.
In such patients, careful search for asso-ciated pancreatic, duodenal, parathyroid,
or other tumours and family investigation
for the MEN-1 gene mutation are needed.
Type III (sporadic) ECL-cell carcinoids
> 1 cm generally require surgical resec-tion even when they are histologically
well differentiated.
Definition
Primary gastric lymphomas are defined
as lymphomas originating from the stom-ach and contiguous lymph nodes.
Lymphomas at this site are considered
primary if the main bulk of disease is
located in the stomach. The majority of
gastric lymphomas are high-grade B-cell
lymphomas, some of which have devel-oped through progression from
low-grade lymphomas of mucosa associ-ated lymphoid tissue (MALT). The low-grade lesions are almost exclusively
B-cell MALT lymphomas.
Historical annotation
Classically, primary gastric lymphomas
have been considered to be lymphomas
that are confined to the stomach and the
contiguous lymph nodes {378}. While
this excludes cases of secondary
involvement of the stomach by nodal-type lymphomas – which may occur in
up to 25% of nodal lymphomas {508} –
this definition is excessively restrictive
and excludes more disseminated, higher
stage lymphomas arising within the
stomach as well as those with bone mar-row involvement. Today, stomach lym-phomas are considered primary if the
main bulk of disease is present in the
stomach. Recognition of morphological
features characteristic of primary extra-nodal lymphomas of mucosa-associated
lymphoid tissue-type helps in defining
these lesions as primary to the stomach
irrespective of the degree of dissemina-tion.
Epidemiology
Approximately 40% of all non-Hodgkin
lymphomas arise at extranodal sites
{1438, 527}, with the gastrointestinal tract
as the commonest extranodal site,
accounting for about 4-18% of all
non-Hodgkin lymphomas in Western
countries and up to 25% of cases in the
Middle East. Within the gastrointestinal
tract, the stomach is the most frequent
site of involvement in Western countries
while the small intestine is most frequent-ly affected in Middle Eastern countries.
Lymphoma constitutes up to 10% of all
gastric malignancies; its incidence
appears to be increasing but this may, at
least in part, be due to the recognition of
the neoplastic nature of lesions previous-ly termed ‘pseudolymphoma’ {677}.
Gastric lymphoma has a worldwide dis-tribution; somewhat higher incidences
have been reported for some Western
communities with a high prevalence of
Helicobacter pylori infection {420}.
Primary Hodgkin disease is very rare in
the gastrointestinal tract.
Age and sex distribution
Incidence rates are similar in men and
women. The age range is wide but the
majority of patients are over 50 years at
presentation.
Aetiology
Helicobacter pylori infection
Initial studies of low-grade MALT lym-phoma suggested that the tumour was
associated with  H. pylori in 92-98% of
cases {447, 2135}; subsequent studies
have suggested an association in
62-77% {1316, 583, 2146, 890, 178}.
H. pylori infection is seen less frequently
in high-grade lymphomas with a low-grade component (52-71%) and in pure
high-grade lymphomas (25-38%) {583,
A. Wotherspoon
A. Chott
R.D. Gascoyne
H.K. Müller-Hermelink
Lymphoma of the stomach
Fig. 3.37 Small cell carcinoma of the stomach.
890, 178}. The organism has been shown
to be present in 90% of cases limited to
the mucosa and submucosa, falling to
76% when deep submucosa is involved,
and is present in only 48% of cases with
extension beyond the submucosa
{1316}. It has been shown that the infec-tion by  H. pylori precedes the develop-ment of lymphoma, both by sequential
serological studies {1474} and by retro-spective studies of archival gastric biop-sy material {2211, 1314}.
There is some controversy surrounding
the role of the organism’s genetic fea-tures and the risk of lymphoma develop-ment. Studies of the association between
MALT lymphoma and cagA bearing
H. pylori strains have produced conflict-ing results, ranging from a lack of asso-ciation between cagA and lymphoma
{1492, 384} to a strong association {441}.
One study claimed no association with
low-grade lymphoma but a high frequen-cy of cagA strains in high-grade lesions
{1492}. Recently, a truncated form of an
H. pylori associated protein, fldA, has
been shown to be closely associated
with gastric MALT lymphoma. All strains
of H. pylori associated with MALT lym-phoma showed a nucleotide G insertion
at position 481 of the  fldA gene, com-pared to 6/17 stains unassociated with
lymphoma. This mutation causes a short
truncation in the protein and antibodies
to this truncated protein could be detect-ed in 70% of the patients studied with
MALT lymphoma, compared to 17% of
control patients {274}.
Immunosuppression
Lymphomas may arise or involve the
stomach in patients with both congenital
and acquired immunodeficiencies. In
general, the incidence, clinical features
and the histology of the lesions is indis-tinguishable from those that develop out-side the stomach. Up to 23% of gastroin-testinal tract non-Hodgkin lymphomas
arising in HIV infected patients occur in
the stomach and the vast majority of
these are large B-cell or Burkitt/Burkitt-like lymphomas, {122} although occa-sional low-grade MALT lymphomas are
described {2132}.
Clinical features
Symptoms and signs
Patients with low-grade lymphomas often
present with a long history of non-specif-ic symptoms, including dyspepsia, nau-sea and vomiting. High-grade lesions
may appear as a palpable mass in the
epigastrium and can cause severe
symptoms, including weight loss.
Imaging
Low-grade MALT lymphomas present as
intragastric nodularity with preferential
location in the antrum {2180}. A more
precise assessment is obtained with spi-ral CT, particularly if this is used in con-junction with distension of the stomach
by water. This technique can identify up
to 88% of cases, most of which have
nodularity or enlarged rugal folds, and it
can assess the submucosal extent of the
tumour {1493}. High-grade lymphomas
are usually larger and more frequently
associated with the presence of a mass
and with ulceration. In some cases, the
radiological features may mimic diffuse
adenocarcinoma {1059}. Endoscopic
ultrasound is emerging as the investiga-tion of choice in the assessment of the
extent of lymphoma infiltration through
the gastric wall. Local lymph node
involvement can also be assessed by
this technique.
Endoscopy
Some cases show enlarged gastric folds,
gastritis, superficial erosions or ulcera-tion. In these cases the surrounding nor-mal appearing gastric mucosa may har-bour lymphoma, and accurate mapping
of the lesion requires multiple biopsies
from all sites including areas appearing
macroscopically normal. In a proportion
of cases, endoscopic examination shows
very minor changes such as hyperaemia
and in a few cases random biopsies of
apparently entirely normal mucosa may
reveal lymphoma. High-grade lymphoma
is usually associated with more florid
lesions, ulcers and masses. It is often
impossible to distinguish lymphoma from
carcinoma endoscopically.
MALT lymphomas
Pathogenesis
The normal gastric mucosa contains
scattered lymphocytes and plasma cells
but is devoid of organised lymphoid tis-sue. The initial step in the development of
primary gastric lymphoma is the acquisi-tion of organised lymphoid tissue from
within which the lymphoma can develop.
In most cases, this is associated with
infection by  H. pylori {572}, although it
has also been seen following infection by
Helicobacter heilmannii {1842} and in
association with coeliac disease {227}.
This organised lymphoid tissue shows all
the features of MALT, including the infil-tration of the epithelium by B-lympho-cytes reminiscent of the lymphoepitheli-um seen in Peyer patches {2135}.
The cellular basis of the interaction
between H. pylori and MALT lymphoma
cells has been studied in detail. When
unseparated cells isolated from low-grade gastric MALT lymphomas are incu-bated in vitro with heat treated whole cell
preparations from  H. pylori, the tumour
cells proliferate while those cultured in
the absence of the organism or stimulat-ing chemical mitogen rapidly die {768}.
The proliferative response appeared to
be strain specific for individual tumours
but varied between tumours from differ-ent patients {768}. When T-cells were
removed from the culture system the pro-liferative response was not seen and this
could not be induced if the T-cells were
replaced by supernatant from other cul-tures containing unseparated tumour
derived cells {769}. Together these stud-ies show that the proliferation of the
MALT lymphoma is driven by the pres-ence of the H. pylori but that this, rather
than being a direct effect on the tumour
58 Tumours of the stomach
Fig. 3.38  Multifocal malignant lymphoma of the
stomach. The two larger lesions are centrally ulcer-ated.
Fig. 3.39 Low-grade B-cell MALT lymphoma.
Perifollicular distribution of centrocyte-like cells
with a predominant monocytoid morphology.
59Lymphoma
cells, is due to a mechanism mediated
via T-cells and that this help is contact
dependant. Further studies have shown
that the T-cells responsible for the prolif-erative drive are specifically those found
within the tumour and their function can-not be replaced by T-cells derived from
elsewhere (e.g. the spleen) in the same
patient {769}.
Histopathology
The organisation of the lymphoma mim-ics that of normal MALT and the cellular
morphology and immunophenotype is
essentially that of the marginal zone
B-cell. The neoplastic cells infiltrate
between pre-existing lymphoid follicles,
initially loca-lised outside the follicular
mantle zone in a marginal zone pattern.
As the lesion progresses, the neoplastic
cells erode, colonize and eventually
overrun the lymphoid follicles resulting in
a vague nodularity to an otherwise dif-fuse lymphomatous infiltrate {800}. The
morphology of the neoplastic cell can be
variable even within a single case.
Characteristically, the cell is of intermedi-ate size with pale cytoplasm and an
irregular nucleus. The resemblance of
these cells to the centrocyte of the follicle
centre has led to the term ‘centrocyte-like
(CCL)’ cell being applied to the neoplas-tic component of MALT lymphomas. In
some cases, the CCL cell may be more
reminiscent of a mature small B lympho-cyte while in other cases, the cell may
have a monocytoid appearance with
more abundant, pale cytoplasm and a
well defined cell border. Plasma cell dif-ferentiation is typical and may be very
prominent. Dutcher bodies may be iden-tified. The CCL cells infiltrate and destroy
adjacent gastric glands to form lym-phoepithelial lesions. Lympho-epithelial
lesions typical for MALT lymphoma are
defined as infiltration of the glandular
epithelium by clusters of neoplastic lym-phoid cells with associated destruction
of gland architecture and morphological
changes within the epithelial cells,
including increased eosinophilia.
Immunohistochemistry
The immunophenotype of the CCL cell is
similar to that of the marginal zone B-cell.
There is expression of pan-B-cell anti-gens such as CD20 and CD79a and the
more mature B-cell markers CD21 and
CD35. The cells do not express CD10.
They are usually positive for bcl-2 protein
and may express CD43 but do not
express CD5 or CD23. They express sur-face and, to a lesser extent, cytoplasmic
immunoglobulin (usually IgM or IgA,
rarely IgG) and show light chain restric-tion. Immunostaining with anti-cytoker-atin antibodies is useful in demonstrating
lymphoepithelial lesions. Immunostaining
with antibodies that highlight follicular
dendritic cells (anti-CD21, anti-CD23 or
anti-CD35) help to demonstrate underly-ing follicular dendritic cell networks in
those cases in which the lymphoid folli-cles have been completely overrun by
the lymphoma.
Differential diagnosis
The distinction between florid gastritis
and low-grade MALT lymphoma may be
difficult. In such cases it is essential to
have sufficient biopsy material (up to
eight biopsies from endoscopically sus-picious areas) with good preservation of
morphology and correct orientation of
the biopsy specimen. For the distinction
between reactive and neoplastic infil-trates, histological evaluation remains the
gold standard, but accessory studies
may be helpful. In both reactive and neo-plastic cases, lymphoid follicles are pres-ent and these may be associated with
active inflammation, crypt abscesses
and reactive epithelial changes. In gas-tritis, the infiltrate surrounding the lym-phoid follicles in the lamina propria is
plasma cell predominant while in MALT
lymphoma the infiltrate contains a domi-nant population of lymphocytes with CCL
cell morphology, infiltrating through the
lamina propria and around glands.
Prominent lymphoepithelial lesions,
Dutcher bodies and moderate cytologi-cal atypia are associated only with lym-phoma. All of these features may not be
present in biopsy material from a single
case. In some cases it is justifiable to
make the diagnosis of low-grade MALT
lymphoma in the absence of one or more
of these features if the overall histological
appearances are those of lymphoma.
Rare or questionable lymphoepithelial
lesions, dense lymphoid infiltration, mild
cytological atypia and muscularis muco-sae invasion are features more often
associated with, but not limited to, lym-phoma {2212}.
In some cases it will not be possible to
make a definite distinction between reac-tive infiltrates and lymphoma and in
these cases a diagnosis of ‘atypical lym-phoid infiltrate of uncertain nature’ is
appropriate.
Effect of H. pylori eradication
The histological appearances of gastric
biopsies from patients showing complete
regression of lymphoma after  H. pylori
Fig. 3.40 Low-grade B-cell MALT lymphoma. Small
lymphoid cells form a diffuse infiltrate extending
into the submucosa.
Fig. 3.41 Low-grade B-cell MALT lymphoma. The
centrocyte-like cells show prominent plasma cell
differentiation with  (A) extracellular immunoglobu-lin deposition, and (B) prominent Dutcher bodies.
A
B
eradication are characteristic. The lami-na propria appears ‘empty’ with gland
loss. Scattered lymphocytes and plasma
cells are seen within the lamina propria
and there are usually focal nodular col-lections of small lymphocytes. These col-lections frequently contain a mixture of
B- and T-cells and may be based on fol-licular dendritic cell networks.
In most cases, the appearances are
insufficient for a diagnosis of residual
lymphoma. The significance of these
lymphoid nodules remains uncertain. In
cases showing partial regression or no
change following  H. pylori eradication,
the lamina propria contains an infiltrate
morphologically indistinguishable from
that seen at diagnosis, but in these treat-ed cases lymphoepithelial lesions may
be very scanty or absent. In some cases
of partial regression and in cases with
relapsed low-grade MALT lymphoma fol-lowing H. pylori eradication, the lymph-oma may be largely confined to the sub-mucosa with only minimal involvement of
the mucosa.
PCR based diagnosis
The role of genetic analyses in the diag-nosis and follow up of low-grade MALT
lymphoma remains controversial. Up to
10% of well characterized cases of MALT
lymphoma identified as clonal through
demonstration of rearrangement of the
immunoglobulin heavy chain gene by
Southern blot fail to show a clonal pattern
when examined for immunoglobulin
heavy chain gene rearrangement by PCR
using fresh frozen tissue {418}. This false
negative rate increases if paraffin embed-ded material is studied {417}. Several
studies have revealed by PCR the pres-ence of clonal B-cell populations in biop-sies from patients with uncomplicated
chronic gastritis and no morphological
evidence of lymphoma {1677, 225, 388}.
In conjunction with histological assess-ment, PCR studies may be useful in mon-itoring regression of MALT lymphomas
following conservative therapy {25}.
However, PCR detected clonal B-cell
populations may still be detected in
cases showing complete histological
regression. Some, but no all of these will
eventually show molecular regression but
there may be a prolonged time lag
between histological and molecular
regression {1677}. In the absence of his-tological evidence of residual lymphoma,
the clinical significance of a persistent
clonal population remains uncertain.
Progression to high-grade lymphoma
The emergence of clusters of large trans-formed ‘blastic’ B-cells reflects transfor-mation to high-grade lymphoma {383}.
Eventually, these areas become conflu-ent to form sheets of cells indistinguish-able from the cells of a diffuse large
B-cell lymphoma. As long as a low-grade
component remains, these tumours may
be termed high-grade MALT lymphomas
but during further progression, all traces
of the pre-existing low-grade lymphoma
are lost, making it impossible to distin-guish the lesion from a diffuse large
B-cell lymphoma of unspecified type. In
cases with both low- and high-grade
components, genetic studies have con-60 Tumours of the stomach
Fig. 3.42  A, B, C Low-grade B-cell MALT lymphoma. A, B Lymphoepithelial lesions. C Immunostaining for cytokeratin highlights lymphoepithelial lesions. D Diffuse
large B-cell lymphoma; the neoplastic cells focally infiltrate glandular epithelium to form structures reminiscent of lymphoepithelial lesions.
AB
CD
61Lymphoma
firmed the transformation of low-grade to
high-grade lymphoma in the majority of
cases {1263} while in other cases both
components appear clonally unrelated,
suggesting the development of a second
primary lymphoma {1184, 1491}.
Molecular genetics of MALT lymphomas
Early studies confirmed the presence of
immunoglobulin gene rearrangement in
each case {1803} and suggested that
there was no involvement of the bcl-1 or
bcl-2 oncogenes {2136}. The transloca-tion t(11;18)(q21;q21) has been identified
in a significant number of low-grade
MALT lymphomas and may be the sole
genetic alteration in these cases. How-ever, this translocation appears to be less
common in high-grade lesions {1435, 95}.
Trisomy 3 has been detected in up to 60%
of cases in some studies using both
metaphase and interphase techniques
{2134, 2137}, but this finding has not
been confirmed by other studies {1434}.
The translocation t(1;14) (p22; q32) has
also been described in a small proportion
of cases {2138} and this is associated
with increased survival of tumour cells in
unstimulated cell culture. Cloning of the
breakpoint involved in this translocation
has led to the discovery of a novel gene,
bcl-10, on chromosome 1 that may be
significant in determining the behaviour of
MALT lymphomas {2116}.
Studies of the immunoglobulin gene of
MALT lymphoma  cells has shown the
sequential accumulation of somatic
mutations, consistent with an ongoing,
antigen driven selection and proliferation
{279, 434, 1546}. Study of the third com-plementary determining region of the
immunoglobulin heavy chain gene shows
a pattern of changes associated with the
generation of antibody diversity and
increased antigen binding affinity {131}.
Transformation of low-grade MALT lym-phoma to a high-grade lesion has been
associated with several genetic alter-ations. While the t(11;18) chromosomal
translocation is not seen in high-grade
MALT lymphoma and may be protective
against transformation, alterations in the
genes coding for p53, p16, c-myc and
trisomy 12 have all been identified in
high-grade lesions {1489, 1490, 1341,
270, 435, 1992}. Bcl-6 protein has also
been described in high-grade lym-phomas while being absent from low-grade lesions {1425}. Some studies have
shown a high level of bcl-6 gene hyper-mutations in diffuse large B-cell lym-phomas independent of a rearrangement
of the gene {1070}. Epstein-Barr virus is
not associated with low-grade lym-phomas and has only been seen in some
high-grade lymphomas {1038, 1437}.
Mantle cell lymphoma
Mantle cell lymphoma of the stomach is
typically a component of multiple lym-phomatous polyposis of the gastrointesti-nal tract and infrequently encountered
outside this clinical context {1380}.
Morphologically and immunophenotypi-cally, the lymphoma is indistinguishable
from mantle cell lymphomas of lymph
nodes, with a diffuse and monotonous
infiltrate of cells with scanty cytoplasm
and irregular nuclei that express B-cell
markers together with CD5 and cyclinD1.
Other low-grade B-cell lymphomas
Although the lymphoid tissue in the stom-ach contains all the B-cell populations
encountered in nodal lymphoid tissue,
other low-grade B-cell lymphomas, such
as follicle centre cell lymphomas, are
very rare and usually indistinguishable
from their nodal counterparts.
Diffuse large B-cell lymphoma
These lymphomas are morphologically
indistinguishable from diffuse large B-cell
lymphomas that arise within lymph
nodes. There is complete destruction of
the gastric glandular architecture by
large cells with vesicular nuclei and
prominent nucleoli. Variants of large B-cell lymphoma (e.g. plasmablastic lym-phoma) may also be encountered {1541}.
Burkitt lymphoma
Although rare, classical Burkitt lym-phomas may be encountered in the
stomach {55}. The morphology is identi-cal to that of Burkitt lymphoma encoun-tered elsewhere, with diffuse sheets of
medium sized cells with scanty cyto-plasm and round/oval nuclei containing
small nucleoli. Within the sheets there are
numerous macrophages, giving a ‘starry-sky’ appearance. Mitoses are frequent
and apoptotic debris abundant. The
cells express CD10 in addition to
pan-B-cell markers. Close to 100% of
nuclei are immunoreactive for Ki-67.
T-cell lymphoma
Primary gastric T-cell lymphomas are
rare. Most have been reported from
areas of endemic HTLV-1 infection and
probably represent gastric manifesta-tions of adult T-cell leukemia/lymphoma
(ATLL). In these regions, T-cell lymphoma
may represent up to 7% of gastric lym-phomas {1741}. Most of the remainder
are similar to peripheral T-cell lym-phomas encountered in lymph nodes but
occasionally, gastric NK cell lymphomas
are also seen {1741}. It has recently
been demonstrated that some gastric
T-cell lymphomas display features of
intraepithelial T lymphocyte differentia-tion (e.g. expression of the human
mucosal lymphocyte 1 antigen, CD103),
similar to those seen in intestinal T-cell
lymphomas {520}.
Hodgkin disease
Hodgkin disease may involve the gas-trointestinal tract but this is usually sec-ondary to nodal disease. Primary gastric
Hodgkin disease is very rare {2210}.
Prognosis and predictive factors
Studies on the regression of low-grade
MALT lymphoma through H. pylori eradi-cation have shown remission in 67-84%
of cases {1926, 1520, 2133}, but this
applies only to low-grade lesions and is
most effective for lesions showing super-ficial involvement of the gastric wall.
Although remission following  H. pylori
eradication has occasionally been seen
in advanced tumours, the highest suc-cess rate of 90-100% is seen in tumours
confined to the mucosa and superficial
submucosa. The time taken to achieve
remission in these patients varies from
4-6 weeks to 18 months. The stability of
these remissions remains to be deter-mined; one study has reported a relapse
in 10% of patients after a mean follow-up
period of 24 months {1338} while others
have found sustained remissions for up
to six years {801}.
Surgical resection is associated with pro-longed survival {552} in many cases.
Involvement of the resection margins and
advanced stage are poor prognostic fea-tures, but not with the addition of
chemotherapy {1262}. Irrespective of
treatment modality, the only significant
independent prognostic variables are
stage and tumour-grade {260, 1653,
1262, 320, 383}.
Definition
Most gastrointestinal mesenchymal neo-plasms are gastrointestinal stromal
tumours (GIST) or smooth muscle types.
They are predominantly located in the
stomach. The definitions of other mes-enchymal lesions follow the WHO histo-logical classification of soft tissue
tumours {2086}.
Terminology
The designation GIST was originally intro-duced as a neutral term for tumours that
were neither leiomyomas nor schwanno-mas. The term GIST is now used for a
specific group of tumours comprising the
majority of all gastrointestinal mesenchy-mal tumours. These tumours encompass
most gastric and intestinal mesenchymal
tumours earlier designated as leiomyoma,
cellular leiomyoma, leiomyoblastoma and
leiomyosarcoma {80, 76, 78, 79, 1227}.
Currently, the terms leiomyoma and
leiomyosarcoma are reserved for those
tumours that show smooth muscle differ-entiation, histologically or by immunohis-tochemistry, e.g. with strong and diffuse
actin and desmin positivity. Most tumours
historically called leiomyosarcoma {31,
1559, 1750} are now classified as GISTs;
hence the old literature on gastric (and
intestinal) leiomyosarcomas largely
reflects GISTs.
Epidemiology
GIST accounts for 2.2% of malignant gas-tric tumours in SEER data. There is no gen-der preference (M:F, 1.1:1), in contrast to
carcinomas which have a M:F of 2:1
{1928}. Adults between the 6th and 8th
decade are primarily affected. The ratio of
the age-adjusted incidence rates for
Blacks and Whites is greater for sarcomas
(3 to 1) than for carcinomas (2 to 1). Black
women are affected six times more fre-quently than white women (0.6 versus 0.1
per 100,000 per year, analogous to the
ratio for uterine leiomyosarcomas) {1584}.
Localization
GISTs occur at every level of the tubular
gastrointestinal tract and additionally
may be primary in the omentum and
mesentery. They are most common in the
stomach (60-70%), followed by small
intestine (20-30%), colorectum and
oesophagus (together < 10%) {1227}.
Clinical features
GISTs present a spectrum from clinically
benign, small to medium-sized tumours,
to frank sarcomas. According to our esti-mate, approximately 30% of GISTs are
clinically malignant, and a substantial
number of patients with apparent radical
surgery will relapse {1344, 462}. Typical
of the malignant GISTs at all locations is
intra-abdominal spread as multiple
tumour nodules, and distant metastases
most commonly to liver followed by lung
and bone in decreasing frequency
{478A, 1984, 1855}. Vague abdominal
discomfort is the usual complaint in
symptomatic tumours. Both benign and
sarcomatous GISTs that project into the
lumen may ulcerate and be a source of
bleeding {80, 78, 79}.
Macroscopy
Small gastric GISTs appear as serosal,
submucosal or intramural nodules that
are usually incidental findings during
abdominal surgery or endoscopy. Some
tumours may ulcerate, especially the
epithelioid stromal tumours. The larger
tumours protrude intraluminally or to the
serosal side, and may have a massive
extragastric component that masks the
gastric origin. Intraluminal tumours are
often lined by intact mucosa, but ulcera-tion occurs in 20-30% of cases. Infiltra-tion by direct extension to the pancreas
or liver occurs. On sectioning GISTs vary
from slightly firm to soft, tan, often with
foci of haemorrhage. Larger tumours
may undergo massive haemorrhagic
necrosis and cyst formation leaving only
a narrow rim of peripheral viable tissue;
malignant tumours may form complex
cystic masses. Multinodular peritoneal
seeding is typical of malignant GISTs.
Histopathology
Typically GISTs are immunohistochemi-cally positive for KIT tyrosine kinase
receptor (stem cell factor receptor),
which is perhaps their single best defin-ing feature {920, 713, 1665, 1762}.
The c-kit positivity of GISTs parallels that
seen in the interstitial cells of Cajal, the
pacemaker cells regulating autonomic
motor activity {1139, 1654}. Based on
this, and on the expression of an embry-onic form of smooth muscle myosin
heavy chain in GISTs and Cajal cells
{1648} the origin from Cajal cells has
been proposed {920, 1762}. However,
considering the origin of Cajal cells and
smooth muscle from a common precur-sor cell {1035, 2186}, the hybrid Cajal
cell and smooth muscle differentiation
seen in many GISTs, and the occurrence
of GISTs in the omentum and mesentery
{1225}, their origin from such a precursor
cell pool with differentiation towards a
Cajal cell phenotype is more likely.
Electron microscopic observations show-ing hybrid autonomic nerve and smooth
muscle features in many GISTs are also
consistent with origin from a multipoten-tial precursor cell {474, 1227}.
Morphology.  GISTs may resemble
smooth muscle tumours histologically as
well as grossly. The majority of gastric
GISTs are spindle cell tumours that show
a variety of histological patterns {1866}.
Some, including many of the smaller
ones, are collagen-rich and paucicellular.
A perinuclear vacuolization pattern is
common. Tumours with moderate cellu-larity and focal nuclear palisading can
resemble nerve sheath tumours. Peri-M. Miettinen
J.Y. Blay
L.H. Sobin
Mesenchymal tumours of the stomach
Fig. 3.43  Cajal cells immunoexpress KIT antigen
(CD117) in fetal small intestine.
62 Tumours of the stomach
63Mesenchymal tumours
vascular hyalinization can accompany
myxoid change. The epithelioid pattern
occurs in approximately one-third of gas-tric GISTs and corresponds to tumours
previously designated as leio-myoblas-toma or epithelioid leiomyosarcoma.
Some of the epithelioid tumours show
mild pleomorphism. Marked pleomor-phism is rare.
Immunohistochemistry.  Most GISTs are
positive for KIT (CD117), which may show
membrane, diffuse cytoplasmic or a perin-uclear accentuation pattern. Approxi-mately 70-80% of GISTs are positive for
CD34 (typically membrane pattern).
30-40% are focally or diffusely positive for
α-smooth muscle actin, very few show
reactivity for desmin (< 5%), and very few
for S100-protein (< 5%, usually weak reac-tivity) {526, 1229, 1260, 1991, 1227, 1232}.
Assessment of malignancy and grading.
Histological assessment of malignancy is
essentially based on mitotic counts and
size of the lesion. Tumours less than 5 cm
are usually benign. Different limits have
been applied for low-grade malignant
tumours. This designation has been used
for tumours showing mitotic counts
greater than 5 per 50 HPF, or tumours
showing as many as 5 mitoses per 10
HPF. Tumours over 5 cm, but with fewer
than 5 mitoses per 50hpf, are often
assigned to the category of ‘uncertain
malignant potential’. However, large
tumours (especially over 10 cm) with no
detected mitotic activity may develop
late recurrences and even metastases.
DNA-aneuploidy, high proliferative index
(over > 10%) by proliferation markers
(especially Ki67 analogs, such as MIB1)
may reflect higher malignant potential
{338, 362, 929, 525, 1048, 1632, 461,
462}.
Histological grading follows the systems
commonly used for soft tissue sarcomas.
Mitotic activity is the main criterion,
namely those tumours with over 10
mitoses per 10 hpf are considered high-grade. Lower mitotic activity (over 1-5
mitoses/10 HPH) is considered low-grade.
Genetics
Both benign and malignant GISTs com-monly show losses in chromosomes 14
and 22 in cytogenetic studies and by
comparative genomic hybridization. Los-ses in 1p and chromosome 15 have been
shown less frequently. Gains and high
level amplifications occur in malignant
GISTs in 3q, 8q, 5p and Xp {450, 451}.
A proportion of GISTs, more commonly
the malignant examples, show mutations
in the regulatory juxtamembrane domain
(exon 11) of the c-kit gene. A family with
germline KIT mutations and GISTs has
also been described. These  c-kit
mutations have been shown to represent
gain-of-function mutations leading to lig-and-independent activation (autophos-Fig. 3.44 Radiograph demonstrating mass defect in
stomach due to a stromal tumour.
Fig. 3.45  Gastrointestinal stromal tumour. A Ulceration is present at the summit of the lesion. B Cut surface showing transmural extension.
Fig. 3.46 Benign stromal tumours. A Vague palisa-ding pattern reminiscent of a nerve sheath tumour.
B Spindle cells with prominent cytoplasmic vacuo-lation. C An epithelioid pattern corresponding to the
previous designation of leiomyoblastoma.
A
B
C
AB
phorylation) of the tyrosine kinase and
further the phosphorylation cascade that
leads into mitogenic activation {928, 713,
1310, 1356}. The most common muta-tions appear to be in-frame deletions of
3-21 base pairs, followed by point muta-tions and occasionally described inser-tions {475, 713, 1018, 1289}. Association
of neurofibromatosis type I has been
described in rare cases; these tumours
represent phenotypical GISTs, but
molecular genetic studies are not avail-able {1681A}. The rare combination of
pulmonary chondroma, gastric epithe-lioid GIST and paraganglioma in the
Carney triad has probably a common yet
unknown genetic link {246}.
Prognosis and predictive factors
The prognosis of GISTs is largely
dependent on the mitotic rate, size,
depth of invasion, and presence or
absence of metastasis {462}. Although
race and gender did not play a role in
survival rates in the SEER data for gastric
carcinomas, the 5-year survival rates for
sarcomas varied considerably, e.g. 49%
5-year survival for males versus 74% for
females; 37% for Blacks versus 66% for
Whites {1928}.
Other mesenchymal tumours
Gastrointestinal autonomic nerve tumour
(GANT)
Gastrointestinal autonomic nerve tumour
(GANT), or the previous designation plex-osarcoma, has been applied to mes-enchymal tumours that have shown ultra-structural features of autonomic neurons:
64 Tumours of the stomach
Fig. 3.48 Malignant gastrointestinal stromal tumours. A Tumour cells form perivascular collars surrounded by necrosis. B Numerous mitotic figures are present.
Fig. 3.47 Examples of mutations of the exon 11 of the c-kit gene in gastrointestinal stromal tumours. A Nucleotide sequence of the c-kit gene. B Predicted amino
acid sequences of the mutant KIT. The top line in each figure represents the germline  I and the wild type KIT protein, respectively. Each line below them re-pres-ents one case. The codons are indicated by numbers. The shaded areas correspond to deletions (black) or point mutations (gray). Courtesy of Dr. J. Lasota,
Washington D.C.
AB
65Mesenchymal tumours
cell processes with neurosecretory type
dense core granules and arrays of micro-tubules {702, 701, 1023, 2038}. Histologi-cally, such tumours have shown a variety
of spindle cell and epithelioid patterns
similar to those seen in GISTs; at least
some of these tumours are positive for
KIT. It therefore appears that GANT and
GIST groups overlap, and may even
merge. Because electron microscopy is
currently applied less widely for tumour
diagnosis than before, GAN-type differen-tiation in gastrointestinal tumours is prob-ably underestimated. Correlative light
microscopic, ultrastructural, immuno-histochemical and molecular genetic
studies are needed to resolve the ques-tion of the relationship of GANT and GIST.
Leiomyoma and leiomyosarcoma
Well-documented true gastric leiomy-omas and leiomyosarcomas are so infre-quent that there is no significant data on
demographic, clinical or gross features.
Leiomyomas are composed of bland
spindle cells showing low or moderate
cellularity and slight if any mitotic activity.
There may be focal nuclear atypia. The
cells have eosinophilic, fibrillary, often
clumped cytoplasm. Leiomyosarcomas
are tumours that show histologically and
immunohistochemically evident smooth
muscle differentiation. They usually pres-ent in older age and are typically of high-grade malignancy. As defined here,
leiomyomas and leiomyosarcomas are
typically globally positive for desmin and
smooth muscle actin, and are negative
for CD34 and CD117 (KIT). Tumours with
mitotic counts exceeding 10 mitoses per
10 high power fields are classed as high-grade.
Glomus tumours
Lesions similar to glomus tumours of
peripheral soft tissue occur predominant-ly in the gastric antrum as small intramu-ral masses (1-4 cm in diameter, average
2 cm). They occur in older adults (mean
6th decade) with equal sex incidence
{77}. One-third manifests as ulcer,
one-third as bleeding, and one-third is
asymptomatic. The lesions are often sur-rounded by hyperplastic smooth muscle
and have sheets of rounded or epithe-lioid cells with sharp cell borders outlined
by well-defined basement membranes
demonstrable by PAS-stain or immunos-taining for basement membrane proteins
such as laminin and collagen type IV.
The tumour cells have small, uniform
nuclei and mitotic activity is virtually
absent. The tumour cells are positive for
smooth muscle actin and negative for
keratins. Multiple glomus tumours with
apparent intravascular spread have
been described {666}.
Schwannomas
These lesions are rare in the gastroin-testinal tract, but the stomach is their
most common site within the digestive
system. They are not associated with
neurofibromatosis types I or II and occur
predominantly in older adults (average
58 years in the largest series). They
grossly and clinically resemble GISTs.
Schwannomas are usually covered by
intact mucosa and principally involve the
muscularis propria. The tumours vary
from 0.5-7 cm (mean 3 cm) in diameter,
and are spherical or ovoid, occasionally
showing a plexiform multinodular pattern.
Histologically, gastrointestinal schwanno-mas usually show a spindle cell pattern
like cellular schwannoma with vague
nuclear palisading. The tumours often
have sprinkled lymphocytes and a nodu-lar lymphoid cuff {366, 1666}. The dis-tinction between schwannoma and GIST
is important because the former is
benign even when large and mitotically
active. Schwannomas are positive for
S100-protein and negative for desmin,
actin and KIT.
Lipoma
Lipomas composed of mature adipose
tissue may be observed in the stomach.
They typically protrude into the lumen.
Granular cell tumour
Lesions similar to those in peripheral soft
tissues are occasionally encountered in
the stomach, where they principally
occur as small submucous nodules and
less commonly as intramural or sub-serous masses. These lesions occur pre-dominantly in middle age, and show a
strong predilection for Blacks. Associa-ted gastric ulcer symptoms are common.
See chapter on mesenchymal tumours of
the oesophagus for pathological features
{862}.
Kaposi sarcoma
Kaposi sarcoma may occur in the stom-ach as a mucosal lesion or, less com-monly, as a mural mass, usually in HIV-positive patients.
Fig. 3.50 Gastric schwannoma including part of the
lymphoid cuff.
Fig. 3.51  Gastric lipoma.
Fig. 3.52 Kaposi sarcoma of the stomach.
Fig. 3.49  Glomus tumour. Uniform tumour cells and
dilated thin-walled blood vessels.
Definition
Tumours of the stomach that originate
from an extra-gastric neoplasm or which
are discontinuous with a primary tumour
elsewhere in the stomach.
Incidence
Metastatic disease involving the stomach
is unusual. An autopsy study from the
USA found 17 metastases to the stomach
in 1010 autopsies of cancer patients, giv-ing a frequency of 1.7% {1220}. In a large
series of autopsies from Malmö (Table
3.02), 92 gastric metastases were found
in 7165 patients (1.28%) who had cancer
at the time of death {130}.
Clinical features
Gastrointestinal symptoms may occur in
up to 50% of patients with gastric metas-tases. Bleeding and abdominal pain are
the most common clinical features, fol-lowed by vomiting and anorexia. Intesti-nal and gastric metastases were found
after a median interval of 6 years (range,
0.12-12.5 years) following the diagnosis
of primary breast cancer {1700}. Gastric
metastasis from a breast cancer has
occurred up to 30 years after diagnosis
of the primary neoplasm {1148}. Occa-sionally, metastatic breast cancer in the
stomach is detected before the primary
tumour is diagnosed.
Imaging and endoscopy
An upper gastrointestinal endoscopy
study identified 14 metastatic tumours in
the upper gastrointestinal tract, 13 of
which were in the stomach {873}. Many
metastases are described as volcano-like ulcers {618; 1108}. On endoscopy,
pigmentation may not be evident in some
melanomas {1069}. In patients with meta-static lobular breast carcinoma the endo-scopic appearance may be that of linitis
plastica. In such cases, conventional
biopsies may be too superficial to
include diagnostic tissue in the submu-cosa. Endosonography may help direct
attention to the deeper infiltrate {1097}.
Gastric melanomas often appear as
polypoid or target lesions on barium
X-ray studies {1718} and, less commonly,
as a submucosal mass {1148}.
Origin
In a large Swedish autopsy series {130} ,
most gastric metastases were from pri-mary breast cancer, followed by mela-noma and lung cancer (Table 3.02).
There were gastric metastases in 25 of
695 (3.6%) patients with breast cancer,
whereas gastric metastases were found
in 10 of 747 (1.3%) of patients with lung
cancer (see Table 4.01) {1220}. Several
studies have shown lung, breast, other
gastrointestinal carcinomas, and mela-noma to be the most frequent primary
lesions {1220, 158, 873, 618}. Less fre-quently, cancers of the ovary, testis, liver,
colon, and parotid metastasize to the
stomach {1220; 618; 1148; 1872}.
Of all the primary cancers that can lead
to gastric metastasis, breast cancer
does so most frequently. Some reports
show that between 50% and 75% of
patients with breast cancer develop gas-tric metastases {1148; 455}. However, in
a Dutch study covering a 15-year-period,
there were only 27 patients with gastric
metastases from primary breast cancer
{1872}.
There is no preferential localization of
metastases to subsites in the stomach.
Cancers at any site can produce gastric
metastases through haematogeneous
spread. Lesions  of the pancreas,  oeso-Fig. 3.54 Metastatic lobular carcinoma of the
breast. Typical single file growth pattern.
66 Tumours of the stomach
C. Niederau
L.H. SobinSecondary tumours of the stomach
Fig. 3.53 Multiple gastric metastases from rhab-domyosarcoma of the spermatic cord in a 15-year
old boy.
Site of metastasis No. of cases with metastasis % of all autopsies Most frequent primary cancer Next most frequent primary cancer
Stomach 92 0.58% Breast (25 cases) Melanoma (19)
Small intestine 125 0.78% Lung (33 cases) Melanoma (33)
Colon 62 0.39% Lung (14 cases) Breast (10)
Appendix 7 0.04% Breast (2 cases) Various
Table 3.02
Metastases to the stomach, small intestine, colon and appendix. Data are from 16,294 autopsies {130}.

CHAPTER 4
Tumours of the Small Intestine
The small intestine has a remarkably low incidence of primary
carcinomas, especially considering its size. Those that do
occur are often related to genetic syndromes, especially famil-ial adenomatous polyposis.
Lymphomas and endocrine tumours are as frequent as carci-nomas and have important associations with precursor condi-tions such as coeliac sprue, multiple endocrine neoplasia and
Von Recklinghausen Syndrome.
The small intestine is the main site for metastatic tumours in
the gastrointestinal tract.
WHO histological classification of tumours of the small intestine1
70 Tumours of the small intestine
Epithelial tumours
Adenoma 8140/02
Tubular 8211/0
Villous 8261/0
Tubulovillous 8263/0
Intraepithelial neoplasia2
(dysplasia)
associated with chronic inflammatory diseases
Low-grade glandular intraepithelial neoplasia
High-grade glandular intraepithelial neoplasia
Carcinoma
Adenocarcinoma 8140/3
Mucinous adenocarcinoma 8480/3
Signet-ring cell carcinoma 8490/3
Small cell carcinoma 8041/3
Squamous cell carcinoma 8070/3
Adenosquamous carcinoma 8560/3
Medullary carcinoma 8510/3
Undifferentiated carcinoma 8020/3
Carcinoid (well differentiated endocrine neoplasm) 8240/3
Gastrin cell tumour, functioning (gastrinoma)  8153/1
or non-functioning
Somatostatin cell tumour 8156/1
EC-cell, serotonin-producing neoplasm 8241/3
L-cell, glucagon-like peptide and PP/PYY producing tumour
Mixed carcinoid-adenocarcinoma 8244/3
Gangliocytic paraganglioma 8683/0
Others
Non-epithelial tumours
Lipoma 8850/0
Leiomyoma 8890/0
Gastrointestinal stromal tumour 8936/1
Leiomyosarcoma 8890/3
Angiosarcoma 9120/3
Kaposi sarcoma 9140/3
Others
Malignant lymphomas
Immunoproliferative small intestinal disease 9764/3
(includes α-heavy chain disease)
Western type B-cell lymphoma of MALT 9699/3
Mantle cell lymphoma  9673/3
Diffuse large B-cell lymphoma 9680/3
Burkitt lymphoma 9687/3
Burkitt-like /atypical Burkitt-lymphoma 9687/3
T-cell lymphoma 9702/3
enteropathy associated 9717/3
unspecified 9702/3
Others
Secondary tumours
Polyps
Hyperplastic (metaplastic)
Peutz-Jeghers
Juvenile
_____________
1
This classification is modified from the previous WHO histological classification of tumours {845} taking into account changes in our understanding of these lesions. In the case of
endocrine neoplasms, it is based on the recent WHO classification {1784} but has been simplified to be of more practical utility in morphological classification.
2
Morphology code of the International Classification of Diseases for Oncology (ICD-O) {542} and the Systematized Nomenclature of Medicine (http://snomed.org). Behaviour is coded
/0 for benign tumours, /3 for malignant tumours, /2 for in situ carcinomas and grade III intraepithelial neoplasia, and /1 for unspecified, borderline or uncertain behaviour. Intraepithelial
neoplasia does not have a generic code in ICD-O. ICD-O codes are available only for lesions categorized as glandular intraepithelial neoplasia grade III (8148/2), and adenocarcino-ma in situ (8140/2).
TNM classification1,  2
T – Primary Tumour
TX Primary tumour cannot be assessed
T0 No evidence of primary tumour
Tis  Carcinoma in situ
T1 Tumour invades lamina propria or submucosa
T2 Tumour invades muscularis propria
T3 Tumour invades through muscularis propria into subserosa or
into non-peritonealized perimuscular tissue (mesentery or
retroperitoneum3
) with extension 2 cm or less
T4 Tumour perforates visceral peritoneum or directly invades other
organs or structures (includes other loops of small intestine,
mesentery, or retroperitoneum more than 2 cm and abdominal
wall by way of serosa; for duodenum only, invasion of pancreas)
N – Regional Lymph Nodes
NX Regional lymph nodes cannot be assessed
N0 No regional lymph node metastasis
N1 Regional lymph node metastasis
M – Distant Metastasis
MX Distant metastasis cannot be assessed
M0 No distant metastasis
M1 Distant metastasis
Stage Grouping
Stage 0 Tis N0 M0
Stage I T1 N0 M0
T2 N0 M0
Stage II T3 N0 M0
T4 N0 M0
Stage III Any T N1 M0
Stage IV Any T Any N M1
_____________
1
{1, 66}. This classification applies only to carcinomas.
2
A help desk for specific questions about the TNM classification is available at http://tnm.uicc.org.
3
The non-peritonealized perimuscular tissue is, for jejunum and ileum, part of the mesentery and, for duodenum in areas where serosa is lacking, part of the retroperitoneum.
TNM classification of tumours of the small intestine
71Squamous cell carcinoma
Definition
A malignant epithelial tumour of the small
intestine. Neoplasms of the periam-pullary region include those of the duo-denal mucosa, ampulla of Vater, common
bile duct and pancreatic ducts.
ICD-O codes
Adenocarcinoma 8140/3
Mucinous adenocarcinoma 8480/3
Signet-ring cell carcinoma 8490/3
Epidemiology
Relative to the length and surface area of
the small intestine, adenocarcinomas of
the duodenum, jejunum and ileum are
remarkably rare. Data from the United
States SEER program {1928} for 1973 to
1987 show an age-adjusted incidence
rate for adenocarcinoma of the small
intestine of 0.4 per 100,000 per year.
Although some reports suggest an
increasing incidence of adenocarcinoma
of the small intestine {1339, 1715}, this is
not reflected in the SEER data base. The
median age at manifestation is approxi-mately 67 years for non-mucinous ade-nocarcinoma, mucinous carcinoma and
carcinoids.
Aetiology
A major factor in the development of
small bowel adenocarcinoma is chronic
inflammation. In particular, long-standing
Crohn’s disease with multiple strictures is
associated with small bowel carcinoma
{1016, 1223, 582, 1578}. One study
showed that individuals with Crohn’s dis-ease have an 86-fold increased risk of
adenocarcinoma of the small intestine
{623}. Coeliac disease is another well
recognized aetiological factor for small
bowel carcinoma {116, 1354, 2141}.
There is some epidemiological evidence
that cigarette use and alcohol consump-tion are also risk factors {1339}.
Carcinoma can develop in ileostomies in
patients with ulcerative colitis or familial
adenomatous polyposis (FAP) subse-quent to colonic metaplasia and intraepi-thelial neoplasia in the ileostomy mucosa
{1599, 558}. Carcinoma can also arise in
ileal conduits {1965} and in ileal reser-voirs, both continent abdominal (Kock)
{347} and pelvic {2013, 1730}. The
occurrence of adenocarcinomas in
Meckel’s diverticulum {985} and in small
bowel duplications {496} has been
reported.
Localization
The duodenum is the main site, contain-ing more adenocarcinomas than the
jejunum and ileum combined {1928}. In
the duodenum, carcinomas are most
common around the ampulla of Vater
{1657, 2123}, possibly due to biliary or
pancreatic effluents.
Clinical features
Symptoms and signs
The symptoms of small bowel adenocar-cinoma are related to the size and loca-tion of the tumour.
In the  jejunum and ileum, early symp-toms are often non-specific, with vague
periumbilical abdominal pain and rum-bling. Later, cramp-like pain is present in
up to 80% of cases, and this may be
accompanied by nausea, vomiting,
weight loss, asthenia, and intermittent
obstructive episodes. Massive bleeding
is rare (8%), but an important clinical
finding is chronic bleeding with second-ary iron-deficiency anaemia, which may
be found in the early stages of develop-ment of the tumour. Other clinical signs
are bloating of the loops of the bowel,
meteorism, and the presence of a palpa-ble mass {20}. Perforation is a possible
complication of small intestinal carcino-mas {681}.
Duodenal carcinomas present in a differ-ent manner, because of the larger cir-cumference of the duodenum compared
with the more distal parts of the small
intestine, and because of the relative
accessibility of the duodenum to endo-scopy {498, 1657}. Unlike jejunal and
ileal carcinomas, carcinomas of the duo-denum, especially those of the proximal
duodenum, do not present with bowel
obstruction. Biliary obstruction, frank or
occult blood loss and abdominal pain
are the commonest presentations {2123}.
Some tumours are largely asymptomatic
and may be discovered by endoscopy
{1809}.
Imaging
The radiological methods that have the
highest diagnostic accuracy are spiral
CT scan with contrast medium and ente-roclysis; the two methods can be com-plementary. With enteroclysis, a filling
defect, an irregular and circumscribed
thickening of the folds with wall rigidity,
slowed motility, eccentric passage of the
contrast medium, or a clear stenosis may
be observed {199}. Small bowel adeno-carcinoma may appear on CT scan as an
annular lesion, a discrete nodular mass,
or an ulcerative lesion. CT scan, with
global vision of the abdomen, can con-tribute to staging the tumour {1145}.
With push enteroscopy, it is possible to
visualize endoscopically the entire
jejunum. Expansion or infiltrative growth
of the tumour causes at a relatively early
phase, an alteration of the endoluminal
surface; via push enteroscopy it is thus
possible to identify small lesions and to
take biopsies. Push enteroscopy is also a
good diagnostic method to diagnose
tumours causing occult bleeding {1495,
1619}.
Exploration of the ampulla of Vater
requires a lateral viewing fibroscope,
adapted to tissue sampling and endo-scopic sphincterotomy. The terminal
ileum may be visualized through retro-grade ileoscopy during colonoscopy.
Sonde enteroscopy can identify tumours
throughout the small bowel, but it is ham-pered by the inability to take biopsies
{1064}.
Macroscopy
The macroscopic pathology of small
bowel carcinomas is determined by a
number of factors, of which stage and site
are the most significant. Many carcinomas
of the jejunum and ileum are detected at
an advanced stage {498, 189}. A further
determinant of the macroscopic features
is the presence or absence of predispos-N.H. Wright M. Pennazio
J.R. Howe L.H. Sobin
F.P. Rossini N.J. Carr
N.A. Shepherd I. Talbot
Carcinoma of the small intestine
72 Tumours of the small intestine
ing factors, namely, an associated adeno-ma, coeliac disease, Crohn’s disease,
radiotherapy, previous surgery (notably
pouch surgery and ileostomy), polyposis
syndromes, Meckel‘s diverticulum, and
intestinal duplication.
Carcinomas may be polypoid, infiltrating
or stenosing. Jejunal and ileal carcino-mas are usually relatively large, annular,
constricting tumours with circumferential
involvement of the wall of the intestine
{189}. Most have fully penetrated the
muscularis propria and there is often
involvement of the serosal surface {16}.
Adenocarcinoma of the ileum may mimic
Crohn’s disease clinically, radiologically,
endoscopically, and at macroscopic
pathological assessment {745}.
Although circumferential involvement
can occur, duodenal carcinomas are
usually more circumscribed, with a
macroscopically demonstrable adeno-matous component in 80% of cases
{966, 496}. Thus, they are often protuber-ant or polypoid, and the central carcino-matous component may show ulceration
{1267}. Carcinomas arising at the ampul-la of Vater tend to cause obstructive
jaundice before they have reached a
large size; they are usually circum-scribed nodules measuring not more
than 2-3 cm in diameter. They may be
within the wall of the duodenum or proj-ect into the lumen as a nodule.
Unusual macroscopic features, e.g., the
lack of ulceration, the predominance of
an extramural component and the pres-ence of multicentricity, should alert the
pathologist to the possibility that the
tumour is a metastasis.
Microscopy
Histologically, small bowel carcinomas
resemble their more common counter-parts in the colon, but with a higher pro-portion of poorly differentiated tumours
{496, 1006}. Some are adenosquamous
carcinomas {624, 1345, 1525}.
Carcinomas with prominent neoplastic
endocrine cells {821} and with tripartite
differentiation, i.e. with glandular, squa-mous, and neuroendocrine components
{111, 207}, have also been reported.
Small cell carcinomas (poorly differenti-ated endocrine carcinomas) are rare
{2196} (see next chapter).
In metastatic carcinoma of the small
intestine, evidence of a pre-existing
adenomatous component can be mim-icked by the ability of the intestinal
mucosa to cause differentiation of the
metastatic tumour {1732}; this phenome-non can give the erroneous impression of
a primary carcinoma of the small intes-tine.
Tumour spread and staging
Spread of small bowel carcinomas is
similar to that of the large bowel. Direct
spread may cause adherence to adja-cent structures in the peritoneal cavity,
usually a loop of small intestine, although
the stomach, colon or greater omentum
may also be involved. Lymphatic spread
to regional lymph nodes is common.
Haematogenous and transcoelomic
spread also occur. Diffuse involvement of
the ovaries, Krukenberg tumour, has
been reported {1089}. Staging of carci-nomas of the small intestine is by the
TNM classification {1, 66}. For tumours of
the ampulla of Vater, because of the
complicated anatomy at this site, a sep-arate TNM classification is used.
Alternative staging systems have been
proposed {1888}.
Grading
Grading of small intestinal carcinomas is
identical to that used in the large bowel,
namely, well, moderately and poorly dif-ferentiated, or high- and low-grade.
Precursor and associated lesions
Adenomas
There is good evidence for an adenoma-carcinoma sequence in the small intes-tine as in the colon {1506, 1709}.
Residual adenomatous tissue at the mar-gins is seen in 80% of duodenal adeno-carcinomas {966}. Perzin and Bridge
{1505} described 51 patients with adeno-mas of the small intestine – 65% had co-existing carcinoma. In patients with
familial adenomatous polyposis (FAP),
38/45 (84%) of duodenal carcinomas
harboured adenomatous tissue {1709};
whereas 30% of 185 sporadic adenomas
showed carcinoma {1706}. The age at
diagnosis of adenomas without carcino-ma is lower than for adenomas with car-cinoma or for carcinomas, and there is a
nearly identical spatial distribution of
these three types of tumour in the small
intestine {1706}.
Since the advent of endoscopic tech-niques, the earliest stages of malignant
changes can be followed in adenomas of
the duodenum and peri-ampullary region
{147}, where often the size of the lesion
may warrant extensive sampling. In a
study of post-colectomy patients with
FAP, random biopsy specimens of ileal
mucosa showed foci of abnormal, dys-plastic crypts resembling dysplastic
aberrant crypt foci of the colon in some
patients, supporting the concept that, at
least in patients with FAP, oligocryptal
adenomas are a step in the development
of epithelial neoplasms of the small intes-tine {132}.
Although adenomas can occur through-out the small intestine {399}, the com-monest site is the ampullary and peri-ampullary region {1366}. Adenomas can
be multiple, even in patients without a
history of FAP {958, 1317, 685}.
A B
Fig. 4.01  A Tubulovillous adenoma of the duodenum and the ampulla of Vater which is greatly distended.
B Villous adenoma of duodenum adjacent to normal mucosa.
Fig. 4.02 Adenocarcinoma of small intestine.
73Carcinoma
Histologically, adenomas in the small
intestine are similar to those in the colon,
but with a propensity to be more villous
or tubulovillous in architecture {2127A,
1342}. The adenomatous cells resemble
those of colonic adenomas, with varying
degrees of dysplasia, but the columnar
cells are unequivocally enterocytic in
nature; goblet cells are frequent and
some lesions have Paneth and endocrine
cells {500, 1237}.
Other associated conditions
Juvenile polyposis and Peutz-Jeghers
syndrome have a recognized association
with small intestinal carcinoma {1830,
1604, 1506}.
Genetic susceptibility
These include: familial adenomatous
polyposis (FAP), hereditary non-polypo-sis colorectal cancer (HNPCC), Crohn’s
disease, coeliac disease, ileostomies,
ileal conduits and pouches (especially
after colectomy for FAP), Peutz-Jeghers
syndrome and juvenile polyposis. The
highest risk is in FAP. Duodenal adeno-mas develop in a high proportion of FAP
patients {228}, and the relative risk of
duodenal carcinoma is over 300 times
that of the normal population {1397};
these carcinomas represent a major
cause of death in FAP patients after total
colectomy.
In FAP, carcinomas are usually associat-ed with a macroscopically definable ade-nomatous component and are usually
accompanied by many other adenomas
in the second and third parts of the duo-denum {1808, 204}. Adenomas do occur
elsewhere in the small bowel in FAP,
including the ileum and the pelvic ileal
reservoir {1376}, but carcinomas are dis-tinctly unusual.
It has been proposed that patients with
carcinoma of the small intestine have an
increased incidence of multicentric car-cinomas of the gastrointestinal tract, with
an increased incidence of gastric and
colonic carcinomas in first-degree rela-tives {1830}. Primary small bowel carci-noma can be the presenting neoplasm in
hereditary non-polyposis colorectal can-cer (HNPCC), occurring at an earlier age
than sporadic cases and carrying a bet-ter prognosis {1604, 125}.
Genetics
Patients with HNPCC and germline muta-tions of  hMSH2 or hMLH1 have an
approximately 4% lifetime risk of small
bowel cancer, which exceeds the risk of
the normal population 100 fold {2005}. In
Peutz-Jeghers syndrome, the most com-mon site of polyps is in the small intes-tine, and 2-3% of patients are at risk for
developing intestinal carcinoma {431,
721}. In juvenile polyposis, small intestin-al polyps occur with less frequency, but
duodenal carcinoma has been reported
{749}. Genes mutated in the germline of
patients with inherited syndromes that
BA
Fig. 4.03 Adenocarcinoma. A Well differentiated, invasive. B Poorly differentiated, infiltrating fat.
BA
Fig. 4.04 Mucinous adenocarcinoma of the ileum arising in a patient with Crohn’s disease. A Large mucin filled lakes. B More mucin than neoplastic epithelium.
Definition
Peutz-Jeghers syndrome (PJS) is an
inherited cancer syndrome with autoso-mal dominant trait, characterized by
mucocutaneous melanin pigmentation
and hamartomatous intestinal polyposis,
preferentially affecting the small intes-tine. Associated extra-intestinal neo-plasms are less common and include
tumours of the ovary, uterine cervix,
testis, pancreas and breast.
MIM No.  175200
Synonyms and historical annotation
The syndrome was first described by
Peutz {1512} and Jeghers {850}. Several
designations have been used synony-mously, including Peutz-Jeghers polypo-sis, periorificial lentiginosis, and polyps-and-spots syndrome.
Incidence
As the condition is rare, well documented
data on the incidence are not available.
Based on numbers of families registered
in the Finnish Polyposis Registry, the inci-dence of PJS is roughly one tenth of that
of familial adenomatous polyposis.
Diagnostic criteria
The following criteria are recommended:
(1) three or more histologically confirmed
Peutz-Jeghers polyps, or (2) any number
of Peutz-Jeghers polyps with a family his-tory of PJS, or (3) characteristic, promi-nent, mucocutaneous pigmentation with
a family history of PJS, or (4) any number
of Peutz-Jeghers polyps and character-istic, prominent, mucocutaneous pig-mentation.
Some melanin pigmentation is often
present in unaffected individuals, hence
the emphasis on the prominence of the
pigmentation.
Intestinal neoplasms
Penetrance appears to be high, and both
sexes are equally affected {691}. Polyps
are most common in the small intestine,
L.A. Aaltonen M. Billaud
H. Järvinen J.R. Jass
S.B. Gruber
Peutz-Jeghers syndrome
Fig. 4.05  Peutz-Jeghers syndrome. Pigmentation of
lips, peri-oral skin, tongue and fingers.
74 Tumours of the small intestine
predispose to small bowel neoplasia
(APC, hMSH2, hMLH1, LKB1,  and
Smad4) may therefore play a role in the
genesis of these tumours.
Studying the genetics of small bowel
adenocarcinomas has been difficult due
to the rarity of these tumours {1715}.
There is evidence supporting a multistep
pathway of carcinogenesis similar to that
described for colorectal carcinomas
{2018}. The incidence of KRAS mutation
is 14-52% {83, 2185, 14}, p53 overex-pression 40-67%, 17p loss 38-67%, and
18q loss 18-30% {14, 1562}. One report
found no 5q loss {1562} while another
found the frequency to be 60% {14}.
15-45% of small bowel tumours have
high levels of microsatellite instability
{14, 1562, 705}, and mutations in the
TGF beta-RII gene have been identified
in some of these tumours {14}.
In one study of Crohn-associated small
bowel cancers, 43% had  KRAS muta-tions, 57% had p53 overexpression, 33%
had 17p loss, 17% had 5q loss, none had
18q loss, 1 had microsatellite instability,
and none had TGF beta-RII mutations
{1562}. These findings were similar to
those seen in sporadic small bowel carci-noma, and indicate that the transforma-tion from intraepithelial neoplasia to carci-noma may occur in a similar fashion.
Prognosis and predictive factors
In SEER data, the overall 5-year survival
for adenocarcinoma of the small bowel
was 28%, and for mucinous adenocarci-noma 22% {1928}. 5-year survival for
localized adenocarcinomas (63%) was
higher than for gastric adenocarcinoma
(56%) and lower than for colon (87%)
and rectum (79%). This relation is reflect-ed in survival figures for all stages.
Another recent population-based study
from Sweden showed 5- and 10-year sur-vival rates for small intestinal adenocarci-noma of 39% and 37% for duodenal
tumours and 46-41% for jejuno-ileal
tumours {2201}. The survival of patients
undergoing curative resection is 63%
when regional lymph nodes are not
involved, and 52% when there are nodal
metastases {2011}. Long-term survival is
associated with well differentiated
tumours and local invasion only {1888,
1336}.
One study found a significant inverse
association between immunoreactivity for
c-neu and survival in duodenal adeno-carcinoma {2208}.
75Peutz-Jeghers syndrome
but may occur anywhere in the gastroin-testinal tract.
Signs and symptoms
These include abdominal pain, intestinal
bleeding, anaemia, and intussusception.
Typical age at clinical manifestation is
from two to twenty years. Characteristic
pigmentation allows diagnosis of asymp-tomatic patients in familial cases.
Imaging
The presence of polyps may be demon-strated by upper gastrointestinal and
small bowel contrast radiography, and by
air contrast barium enema. Periodic
small bowel X-ray examination at two to
five-year intervals is advisable in the fol-low-up of the affected patients.
Endoscopy is superior to radiological
imaging in that it enables polypectomy
for diagnostic and therapeutic purposes.
Upper gastrointestinal tract endoscopy
and colonoscopy every two years with
snare excision of all polyps detected is
presently recommended. Small bowel
polyps may be reached by an entero-scope but rarely for the full bowel length;
thus, imaging remains an integral com-ponent of clinical management.
Macroscopy
Peutz-Jeghers polyps occur within the
stomach, small and large intestines, and
rarely within oesophagus, nasopharynx
and urinary tract. The small intestine is
the site of predilection. The polyps are
lobulated with a darkened head and
closely resemble adenomas. The stalk is
short and broad or absent. Size is typi-cally 5 to 50 mm.
Histopathology
A typical Peutz-Jeghers polyp has a
diagnostically useful central core of
smooth muscle that shows tree-like
branching. This is covered by the
mucosa native to the region, heaped into
folds producing a villous pattern. Diag-nostic difficulty occurs when there is sec-ondary ischaemic necrosis. This compli-cation arises when a polyp has caused
intussusception, a common form of pres-entation. Some polyps may lack diagnos-tic features.
Epithelial misplacement involving all lay-ers of the bowel wall (pseudoinvasion)
has been described in up to 10% of
small intestinal Peutz-Jeghers polyps
{1728}. Mechanical forces associated
with intussusception or raised intralumi-nal pressure due to episodic intestinal
obstruction are the likely explanation for
this observation. Epithelial misplacement
may be florid and extend into the serosa,
thereby mimicking a well differentiated
adenocarcinoma. Useful diagnostic fea-tures are the lack of cytological atypia,
presence of all the normal cell types,
mucinous cysts and haemosiderin depo-sition {1728}.
Dysplasia and cancer in Peutz-Jeghers
polyps
While the Peutz-Jeghers syndrome is
associated with a 10 to 18-fold excess of
gastrointestinal and non-gastrointestinal
cancers {579, 154}, the question of
whether or not the Peutz-Jeghers polyp
is itself precancerous has proved difficult
to resolve. Epithelial misplacement has
apparently been overdiagnosed as can-cer in the past {1728}, but it is likely that
the increased risk of malignancy in the
stomach, small bowel and colon {154,
1807} is due to malignant progression
from hamartoma to adenocarcinoma.
The evidence is threefold: (1) intraepithe-lial neoplasia (dysplasia), though uncom-mon, has been described in Peutz-Jeghers polyps {1506, 2017}; (2) carci-nomas may occur in contiguity with
Peutz-Jeghers polyps {317, 1506}; (3)
the responsible gene  LKB1 (STK11) is
located on chromosome 19p, and loss of
heterozygosity at this locus has been
demonstrated in the majority of Peutz-Jeghers polyps and associated intestinal
cancers {633, 691, 2052}.
Extraintestinal manifestations
Predisposition to cancer of multiple
organ systems is an important feature of
the syndrome {579, 154}. The most well
documented extra-intestinal neoplasms
include sex cord tumours with annular
tubules (SCTAT) of the ovary {2188}, ade-noma malignum of the uterine cervix
{2188}, Sertoli cell tumours of the testis
BA
Fig. 4.07 A A lobulated pedunculated Peutz-Jeghers polyp of the small intestine.  B This small intestinal
Peutz-Jeghers polyp exhibits haemorraghic infarction due to intussusception.
BA
Fig. 4.08 Peutz-Jeghers polyps. A Small intestine. B Colon.
Fig. 4.06 Peutz-Jeghers polyp of the colon. Arbor-izing smooth muscle separating colonic glands into
lobules (Masson trichrome stain).
76 Tumours of the small intestine
{231, 2118}, carcinoma of the pancreas
{579}, and carcinoma of the breast
{1587, 1952}.
The cutaneous melanin pigmentation
occurs typically around the mouth as
freckle-like spots. Other sites commonly
affected are digits, palms and feet, buc-cal mucosa, and anal region. While dra-matic pigmentation is a helpful sign, it
may fade with time, and some affected
individuals never display pigmentation.
Genetics
Chromosomal location and mode of
inheritance
PJS is an autosomal dominant trait with
nearly complete penetrance. The PJS
gene, LKB1 (STK11), maps to 19p13.3,
and there is some evidence suggestive
of locus heterogeneity {1210}.
Gene structure
LKB1 consists of 9 coding exons. The
open reading frame consists of 1302
base pairs, corresponding to 433 amino
acids. Codons 50 to 337 encode the cat-alytic kinase domain of the gene.
Gene product
The human  LKB1 gene is ubiquitously
expressed in adults {853, 690}. It
encodes a protein of 433 amino acids
which possesses a serine/threonine
kinase domain framed by a short N-ter-minus sequence (48 residues) and a
more extended C-terminus region of 122
amino acids {853, 690}.  LKB1 shares a
significant sequence similarity with the
Saccharomyces cerevisiae SNF1 kinase
which phosphorylates transcriptional
repressor and regulates glucose-repressible genes. Homologs of  LKB1
have been identified in several species
including mouse,  Xenopus, and
Caenorhabditis elegans  {1852, 1768,
2072}. Sequence alignments revealed
that these proteins are most conserved
within the kinase domain, with 96% of
identity between human and mouse and
42% identity between human and the
nematode. Human  LKB1 contains a
nuclear localization signal (NLS) flanking
the N-terminus part of the catalytic
domain {1343, 1768} and a putative
prenylation motif within the C-terminus
{325}. The LKB1 gene product is located
both in the nucleus and in the cytoplasm
{1343}. LKB1 displays an autocatalytic
activity in vitro, and is the substrate of the
cAMP-dependent protein kinase (PKA)
{325}. Although the function of  LKB1
remains to be determined, it is worth not-ing that PAR-4, the C.elegans orthologue
of LKB1, is required for establishing
polarity during the first cell cycles of the
embryo {2072}. PAR-4 expression is also
essential for embryonic viability and for
intestinal organogenesis. Since the car-dinal clinical feature of PJS is the pres-ence of intestinal hamartomatous polyps,
it appears plausible that the function of
LKB1 has been conserved across evolu-tion as it exerts a key regulatory role dur-ing intestinal development.
Gene mutations and their relationship to
clinical manifestations
Germline mutations are usually truncat-ing, but missense type mutations have
also been described {853, 690}. Wild
type LKB1 is capable of autophosphory-lation {1210, 2176}, and the effect of mis-sense mutations occurring in the kinase
domain can be evaluated observing this
property in autophosphorylation assays.
Somatic mutations of  LKB1 in tumours
have been reported but are rare.
Prognosis
While intussusception has been a major
source of mortality in PJS kindreds
{2093} surgery constitutes an effective
treatment. Thus, prognosis of the affect-ed individuals is mainly related to the risk
of malignancy in PJS {579, 154}. Due to
the rarity of the syndrome, there is little
information on prognosis, but one report
suggests that PJS-associated cancers
are particularly aggressive {1807}.
Fig. 4.11 Structure of the  LKB1 gene. Germline
mutations in Peutz-Jeghers patients are most fre-quent in the kinase domain.
BA
Fig. 4.09 Peutz-Jeghers polyp of small intestine. Pseudoinvasion characterized by benign mucinous cysts
extending through bowel wall into mesentery. Patient was well ten years after removal.
Fig. 4.10  Peutz-Jeghers polyp of small intestine.
Pseudoinvasion. Islands of mucosa are separated
by smooth muscle.
77Endocrine tumours
Endocrine tumours of the small intestine C. Capella
E. Solcia
L.H. Sobin
R. Arnold
Definition
Endocrine tumours of the small intestine
exhibit site-related differences, depend-ing on their location in the duodenum
and proximal jejunum or in the distal
jejunum and ileum. They include  carci-noid tumours (well differentiated neo-plasms of the diffuse endocrine system),
small cell carcinomas (poorly differentiat-ed endocrine neoplasms) identical to
small cell carcinomas of the lung and
malignant large cell neuroendocrine car-cinomas. The classification used here is
adapted from the WHO histological clas-sification of endocrine tumours {1784}.
ICD-O Codes
Carcinoid 8240/3
Gastrin cell tumour 8153/1
Somatostatin cell tumour 8156/1
EC-cell, serotonin-producing
neoplasm 8241/3
L-cell, glucagon-like peptide
and PP/PYY producing tumour
Gangliocytic paraganglioma 8683/0
Small cell carcinoma 8041/3
Endocrine tumours of the duode-num and proximal jejunum
Epidemiology
Incidence and time trends
Endocrine tumours of the duodenum
were rare in some older series, accoun-ting for 1.8-2.9% of gastrointestinal
endocrine tumours {587, 2016}. However,
in recent histopathology series, duodenal
tumours amount to 22% of all gastroin-testinal endocrine neoplasms {1780}.
Jejunal tumours account for about 1%
{587, 1780} of all gut endocrine tumours.
Gastrin-cell (G-cell) tumours represent
the largest group (62%) in reported
series of endocrine tumours arising in
the upper small intestine, followed by
somatostatin-cell tumours (21%), gan-gliocytic paragangliomas (9%), unde-fined tumours (5.6%) and PP-cell
tumours (1.8%) {1780}.
An extensive review of all cases record-ed in the Zollinger-Ellison Syndrome
(ZES) registry showed 13% of patients to
have duodenal wall gastrinomas, while
the majority of patients had a pancreatic
tumour {726}. More recent studies have
shown a higher proportion of duodenal
tumours (38-50%), possibly related to
improved diagnostic tools {429, 2076}.
Age and sex distribution
In a series of 99 cases of endocrine
tumours of the duodenum, males were
more frequently affected (M/F ratio:
1.5:1), with a mean age at manifestation
of 59 years (range, 33 to 90 years) {208}.
G-cell tumours associated with overt ZES
(gastrinomas) differ from their apparently
nonfunctioning counterpart in arising ear-lier in life (mean age at diagnosis is 39
years, as opposed to 66 years) {1780}.
Somatostatin-cell tumours affect females
slightly more frequently than males
(1.2:1) and become clinically manifest at
a mean age of 45 years (range 29 to 83
years) {1780}. Gangliocytic paragan-gliomas are slightly more common in
males than in females and affect patients
ranging in age from 23 to 83 years, with
an average of 54 years {210}. The few
cases of small cell carcinoma recorded in
the literature were in males ranging in
age from 51 to 76 years.
Aetiology
Apart from genetic susceptibility (see
below), there is little knowledge about
possible aetiological factors involved in
the pathogenesis of duodenal and proxi-mal jejunal endocrine tumours. An isolat-ed report demonstrates that a sporadic
gastrin-cell tumour of the duodenum orig-inated from hyperplastic and differentiat-ed G-cells located in the mucosal crypts
{1114}. A case of a small multifocal
somatostatin-cell tumour of the proximal
duodenum has been reported in a patient
with celiac sprue, showing somatostatin-cell hyperplasia in the mucosa, suggest-ing a relationship between D-cell growth
and a long standing chronic inflammato-ry process {233}.
Localization
In a series of duodenal endocrine
tumours {208}, 43 lesions were located in
the first part, 41 in the second part, 2 in
the third part, and 2 in the fourth part.
Nonfunctioning G-cell tumours are locat-ed in the duodenal bulb, while the site of
about 1/3 gastrinomas associated with
overt ZES is in the first, second or third
part of the duodenum or in the upper
jejunum {1780}. The preferential location
of somatostatin-cell tumours, gangliocyt-ic paragangliomas and small cell carci-nomas is at, or very close to, the ampulla
of Vater {206, 210, 233, 1149, 1780,
1870, 2196}.
Clinical features
Endocrine tumours of the duodenum
produce symptoms either by virtue of
local infiltration causing obstructive jaun-dice, pancreatitis, haemorrhage, and
intestinal obstruction (nonfunctioning
tumours) or, less frequently, by secreted
peptide hormones (functioning tumours).
The prevalent position of somatostatin-cell tumours, gangliocytic paraganglio-mas, and small cell carcinomas in the
ampullary region explains their frequent
association with obstructive biliary dis-ease. About 20% of the tumours, espe-cially those located in the duodenal bulb,
are asymptomatic and often incidentally
discovered, e.g. by imaging analysis,
endoscopy or pathological examination
of gastrectomy and duodenopancreate-ctomy specimens removed for gastric
and pancreatic cancers.
Zollinger-Ellison Syndrome (ZES) with
hypergastrinaemia, gastrin hypersecre-tion, and refractory peptic ulcer disease,
is the only syndrome of endocrine hyper-function consistently observed in associ-ation with endocrine tumours of the duo-denum and upper jejunum {208, 429,
726, 1780, 2076}. The association with
ZES is found in about 15% of duodenal
gastrin-cell tumours {1780}. Tumours
associated with overt ZES differ from
their apparently nonfunctioning counter-part in arising earlier in life and having a
higher incidence of metastatic and non-bulbar cases {1780}.
Argentaffin, serotonin-producing, carci-noids are unusual in the upper small
intestine. It follows that duodenal carci-noids only exceptionally give rise to a
clinical carcinoid syndrome, associated
with liver metastases of the tumour {233,
1816}. In none of the cases of somato-statin-cell tumours, so far reported, did
the patients develop the full ‘somato-statinoma’ syndrome (diabetes mellitus,
diarrhoea, steatorrhoea, hypo- or achlor-hydria, anaemia and gallstones) that has
been described in association with some
pancreatic somatostatin-cell tumours
{1780}.
Macroscopy
Endocrine tumours of the duodenum
and upper jejunum usually form small
(< 2 cm in diameter), grey, polypoid
lesions within the submucosa with an
intact or focally ulcerated overlying
mucosa. However, some examples
appear as infiltrative intramural nodules
of rather large size (up to 5 cm in diam-eter). The tumours are multiple in about
13% of cases {208}. In a large series of
96 cases, the mean size was 1.8 cm
(range, 0.2 to 5.0 cm) {208}. The mean
size was 0.8 cm  for gastrin-cell tumours
{233}, 2.3 cm for somatostatin-cell
tumours {1816} and 1.7 cm for ganglio-cytic paragangliomas {233}. Small cell
carcinomas typically measure 2-3 cm,
and present as focally ulcerated, or pro-tuberant lesions {1870, 2196}.
Microscopy
Gastrin cell tumours.  These tumours are
formed by uniform cells with scanty cyto-plasm, arranged in broad gyriform
trabeculae and vascular pseudo-rosettes
and show predominant immunoreactivity
for gastrin. Other peptides detected in
tumour cell sub-populations are chole-cystokinin, pancreatic polypeptide (PP),
neurotensin, somatostatin, insulin, and
the α-chain of human chorionic gona-dotrophin {233}. Interestingly, somato-statin, which is known to inhibit gastrin
release from gastrinomas, is detected
more frequently in nonfunctioning G-cell
tumours than in tumours associated with
ZES {233}. Ultrastructurally, typical
G–cells with vesicular granules are found
{233}.
Somatostatin cell tumours.   These neo-plasms usually exhibit a mixed architec-tural pattern with a predominant tubulo-glandular component admixed with a
variable proportion of insular and trabec-ular areas. Concentrically laminated
psammoma bodies are detected mostly
within glandular spaces. The glandular
pattern and psammoma bodies may be
so prominent that these tumours have
been misdiagnosed as well differentiat-ed ampullary adenocarcinomas. Unlike
adenocarcinomas, however, the somato-statin cell tumours are composed of uni-form cells with rather bland nuclei and
few mitotic figures. Grimelius silver stain
and chromogranin A are not very useful
to diagnosis this tumour, because they
are negative in about 50% of cases. The
presence of somatostatin in tumour cells
can be demonstrated by immunohisto-chemistry. In addition to the somatostatin
cells, some tumours have minor popula-tions positive for calcitonin, pancreatic
polypeptide and ACTH {233, 381}. In
addition, the apical cytoplasm of
glandular structures binds WGA and
PNA lectins and expresses epithelial
membrane antigen {233, 1780}. Ultra-structural examination shows large,
moderately electron dense secretory
granules, similar to those found in nor-mal D–cells of the intestinal mucosa
{233}.
EC-cell, serotonin-producing carcinoid.
The classic argentaffin ‘midgut’ EC-cell
carcinoid, with its characteristic pattern
of solid nests of regular cells with bright-ly eosinophilic serotonin-containing gran-ules and other morphological character-istics of ileal argentaffin EC-cell carci-noid, is very rare both in the duodenum
and upper jejunum.
Gangliocytic paraganglioma  This tumour
appears as an infiltrative lesion com-posed of an admixture of three cell types:
spindle cells, epithelial cells, and gan-glion cells. The spindle cells, which usu-ally represent the major component, are
neural in nature. They form small fasci-cles or envelop nerve cells and axons
and show intense immunoreactivity for
S–100 protein. The epithelial cells are
larger cells with eosinophilic or ampho-philic cytoplasm and uniform ovoid
nuclei that are arranged in ribbons, solid
nests, or pseudo-glandular structures.
These are non-argentaffin and frequently
non-argyrophil endocrine cells, often
containing somatostatin {233, 1816}.
In addition, PP cells and rare glucagon or
insulin cells have been detected in gan-gliocytic paragangliomas, suggesting that
they may be a hamartoma of pancreatic
anlage {655, 1502}. The ganglion cells
may be scattered singly or aggregated
into clusters. The three components of the
gangliocytic paraganglioma also inter-mingle with the normal smooth muscle
and small pancreatic ducts at the ampul-la to produce a very complex lesion.
Ultrastructurally, the epithelial cells have
Tumours of the small intestine78
Fig. 4.12  Gastrin cell tumour with typical gyriform trabecular pattern.
79Endocrine tumours
abundant cytoplasm packed with dense-core secretory granules, while the gan-glion cells are larger and contain a small
number of neuroendocrine granules of
small size and more numerous second-ary lysosomes. The spindle cells are
packed with intermediate filaments and
resemble either sustentacular cells or
Schwann cells {1502}.
Genetic susceptibility
MEN-1.  This inherited tumour syndrome
is significantly associated with gastrin-cell tumours, but not with other types of
endocrine tumours of the duodenum and
upper jejunum. The prevalence of MEN-1
in all gastrin cell tumours of the duode-num-upper jejunum has been reported to
be 5.3% {1780}. Among duodenal-upper
jejunal cases with an overt ZES, the
association with MEN-1 syndrome is
found in 7 to 21% of cases {1780, 2076}.
Loss of heterozygosity (LOH) at MEN-1
gene locus has been found in 4/19 (21%)
duodenal MEN-1 gastrin cell tumours
{1105}, while a slightly higher 11q13
LOH rate for MEN-1 gastrinomas (41%;
14 of 34 tumours) was reported in an
extended study of MEN-1 and sporadic
gastrinomas {395}. A low incidence of
LOH on 11q13 in MEN-1-associated
gastrinomas suggests that these
tumours could arise due to inactivation of
the wild-type allele via point mutations or
small deletions rather than via a loss of a
large segment of chromosome 11
{1105}.
Neurofibromatosis type I.  Patients with
von Recklinghausen disease are at sig-nificant risk for development of peri-ampullary neoplasms {210, 233, 933,
1780}. The majority of these lesions are
somatostatin cell tumours, gastrointesti-nal stromal tumours or gastrointestinal
autonomic nerve tumours, but other neo-plasms of neural crest and non-neural
crest origin are known to occur. Soma-tostatin cell tumours were the most com-mon periampullary neoplasms identified
in one review {933}, whereas carcinoids
account for only 2-3% of periampullary
tumours in the general population
{1149}.
Some patients with neurofibromatosis
and ampullary somatostatin cell tumour
also have a phaeochromocytoma involv-ing one or both adrenal glands, a clinical
situation that can have considerable
implications for complicated patient
management {210}. Association of gan-gliocytic paraganglioma with neurofibro-matosis type I {906} and somatostatin-cell tumour has been reported {1832}.
Genetics
Point mutations of  KRAS at codon 12,
which are detected in small bowel adeno-carcinomas, are absent in endocrine
tumours of the small intestine, including
the duodenal ones {2185}. Incidental gas-trin cell tumours do not overexpress either
basic fibroblast growth factor (bFGF),
acidic fibroblast growth factor (aFGF),
transforming growth factor-α (TGFα), or
their respective receptors FGFR4 and
EGFR {995}. On the contrary, these
tumours overexpress the  βA-subunit of
activin, which may be involved in the reg-ulation of proliferation of tumour cells
{994}.
Prognosis and predictive factors
Aggressive endocrine tumours include
gastrin cell, somatostatin cell, and EC-cell tumours that invade beyond the sub-mucosa or show lymph node or distant
(liver) metastases. Aggressive tumours
have been reported to be 10% of all gas-trin cell duodenal-upper jejunal tumours
{233}, 58% of sporadic ZES cases {429}
and 45% of ZES-MEN-1 cases {429}. In
the case of somatostatin cell tumours,
about two-thirds were aggressive in one
study {381}.
Gastrin cell tumours associated with an
overt ZES are prognostically less
favourable than their nonfunctioning
counterparts, having a higher incidence
of metastases (3 of 14 cases as against
0 of 28), and being deeply infiltrative (7
of 14 as against 3 of 19) {1780}. These
findings suggest a different natural histo-ry of gastrin cell tumours in the two con-ditions. Nonfunctioning tumours repre-sent a generally benign condition, while
ZES tumours have a low-grade malig-nancy, especially when arising in sites
where gastrin cells are not normally
present, such as in the jejunum or pan-creas {233}. Metastases in regional
lymph nodes have been reported in 4 of
8 cases of duodenal gastrinomas with
ZES-MEN-1 syndrome {1521}, in 2 of 3
BA
Fig. 4.13 Gangliocytic paraganglioma.  A Distortion of duodenal glands by stromal infiltrate.  B Masson
trichrome stain highlights islands of epithelial cells (red). C Spindle cells and epithelial cells. D Ganglion cells
with pale nuclei and prominent nucleoli.
Fig. 4.14 Somatostatin cell tumour exhibiting char-acteristic tubuloglandular pattern and a psammo-ma body.
DC
80 Tumours of the small intestine
cases of jejunal gastrinomas {233} and
in 25% of 103 cases of duodenal
tumours with ZES, 24% of which also
had MEN-1 syndrome {724}. Local
lymph node metastases seem to have lit-tle influence on survival of patients with
ZES {398, 2076}. In a study focusing on
metastatic rate and survival in patients
with ZES, no difference was found in the
frequency of metastases to lymph nodes
{429}, when comparing primary pancre-atic (48%) and duodenal (49%) tumours.
In contrast, the same study found a sig-nificantly higher frequency of metas-tases to the liver in patients with pancre-atic gastrinomas than in patients with
duodenal gastrinomas (52% vs. 5%).
The 10-year survival rate of patients with
duodenal gastrinomas (59%) is signifi-cantly better than for patients with pan-creatic gastrinomas (9%) {2076}. The
more favourable prognosis of duodenal
tumours is mainly linked to their smaller
size and less frequent association with
liver metastases.
Somatostatin cell tumours are often
malignant, despite their rather bland his-tological appearance {1780, 210, 381}.
Malignant somatostatin cell tumours are
*2 cm in diameter {381}, invade the duo-denal muscularis propria, the sphincter
of Oddi, and/or the head of the pancreas,
and can metastasise to paraduodenal
lymph nodes and liver.
Gangliocytic paragangliomas are usually
benign, in contrast to gastrin and
somatostatin cell tumours that arise in the
same area. However, occasional  large
tumours (size > 2 cm) may spread to
local lymph nodes, mainly attributable to
the endocrine component of the lesion
{197, 783}.
Small cell carcinomas show histological
signs of high-grade malignancy (high
mitotic rate, tumour necrosis, deep mural
invasion, angioinvasion, and neuroinva-sion). Metastases are present in all cases
{2196} and patients die usually within
7-17 months of diagnosis.
Endocrine tumours of the
distal jejunum and ileum
Endocrine tumours of this segment of the
small intestine are mainly EC-cell, sero-tonin-producing carcinoids, and, less fre-quently, L-cell, glucagon-like peptide
and PP/PYY-producing tumours.
Epidemiology
Incidence and time trends
Endocrine tumours of the lower jejunum
and ileum have an incidence of 0.28-0.89
per 100,000 population per year {60,
587}. Jejuno-ileal lesions account for
23–28% of all gastrointestinal endocrine
tumours, making this site the second
most frequent location for endocrine
tumours, following the appendix {587,
2016}. A recent SEER analysis of 5468
cases found an increase in the proportion
of ileal and jejunal carcinoids and
decrease in the proportion of appen-diceal carcinoids {60}.
Age and sex distribution
Endocrine tumours of lower jejunum and
ileum are distributed more or less equal-ly between males and females. Patients
range in age from the third to the tenth
decade, with a peak in the 6th and 7th
decades {211, 587, 1253, 1780}.
Aetiology
At present, there is little knowledge about
the aetiology of jejuno-ileal EC-cell carci-noids. Although endocrine tumours of
lower jejunum and ileum are not general-ly associated with preneoplastic lesions,
there have been reports of focal micro-proliferations of EC-cells in cases of mul-tiple ileal tumours {1736} and of intraep-ithelial endocrine cell hyperplasia in the
mucosa adjacent to jejuno-ileal carci-noids {1291}.
Approximately 15% of carcinoid tumours
of the small intestine are associated with
non-carcinoid neoplasms, most frequent-ly adenocarcinomas of the gastrointesti-nal tract {1251, 1253}, supporting the
hypothesis that secretion of growth fac-tors is involved in their aetiopathogenesis
{1251}.
Localization
In the AFIP series of 167 jejuno-ileal
endocrine tumours {211}, 70% were
located in the ileum, 11% in the jejunum,
3% in Meckel diverticulum. These data
suggest that small bowel endocrine
tumours occur 6.5 times more frequently
in the ileum than in the jejunum. The
majority of the tumours are located in the
distal ileum near the ileocaecal valve.
Clinical features
Patients with jejuno-ileal endocrine
tumours present most commonly with
intermittent crampy abdominal pain, sug-gestive of intermittent intestinal obstruc-tion {1253}. Patients frequently have
vague abdominal symptoms for several
years before diagnosis, reflecting the
slow growth rate of these neoplasms
{1253}. Preoperative diagnosis is difficult
Fig. 4.15 Gangliocytic paraganglioma. A Immunoreactivity for cytokeratin (CAM 5.2) in epithelial cells. B Immunoreactivity for S100 in spindle cells.
BA
81Endocrine tumours
since standard imaging techniques rarely
identify the primary tumour. Scintigraphic
imaging with radiolabeled somatostatin
(octreotide) is widely used to localise pre-viously undetected primary or metastatic
lesions {991}.
The ‘carcinoid syndrome’ is found in
5–7% of patients with EC-cell carcinoid
tumours {587, 1253} that typically arise in
the ileum, all of which metastasise, most-ly to the liver. Symptoms include cuta-neous flushing, diarrhoea, and fibrous
thickening of the endocardium and
valves of the right heart.
Macroscopy
Jejuno-ileal endocrine tumours are multi-ple (ranging from 2 to 100 tumours) in
about 25-30% of cases {211, 1253,
1845}. The size of the tumours is < 1 cm
in 13% and *2 cm in 47% of cases {211}.
They usually appear as deep mucosal-submucosal nodules with apparently
intact or slightly eroded overlying
mucosa. Deep infiltration of the muscular
wall and peritoneum is frequent.
Extensive involvement of the mesentery
stimulates considerable fibroblastic or
desmoplastic reaction, with consequent
angulation, kinking of the bowel and
obstruction of the lumen. Infarction of the
involved loop of the small intestine may
occur as a consequence of fibrous adhe-sions, volvulus, or occlusion of the
mesenteric blood vessels.
Microscopy
EC-cell, serotonin-producing carcinoids
are formed by characteristic rounded
nests of closely packed tumour cells,
often with peripheral palisading (Type A)
{1775}. Often, within the solid nests,
rosette type, glandular-like structures are
detected. This variant of the fundamental
structure designated as mixed insular +
glandular (A + C) structure seems prog-nostically more favourable than the pure
type A structure {1780}. In areas of deep
invasion with abundant desmoplastic
reaction, the cell nests may be oriented
into cords and files. Mesenteric arteries
and veins located near the tumour, or
away from it, may be thickened and their
lumen narrowed or even occluded by a
peculiar elastic sclerosis, which may
lead to ischaemic lesions in the intestine
{72}. Most tumour cells are intensely
argyrophilic and reactive with chromo-granin A and B antibodies. In about 30%
of cases, a variable number of cells is
also reactive for prostatic acid phos-phatase {211}.
The identification of tumour cells as EC-cells can be accomplished using histo-chemical methods for serotonin, includ-ing argentaffin, diazonium, and immuno-histochemical tests. Because serotonin
occurs in some non EC-cell and related
tumours {655}, electron microscopic
examination of serotonin-immunoreactive
tumours (particularly those failing to
react with histochemical tests) can con-firm their EC-cell nature by detecting
characteristic pleomorphic, intensely
osmiophilic granules {1778}.
Substance P and other tachykinins, such
as neurokinin A, are reliable markers of a
fraction of jejuno-ileal EC-cell tumours
{144, 1173}; foregut (gastric, pancreatic
and duodenal) EC-cell tumours remain
mostly unreactive {1780}. Minor popula-tions of enkephalin, somatostatin, gastrin,
ACTH, motilin, neurotensin, glucagon/gli-centin, and PP/PYY immunoreactive cells,
unassociated with pertinent hyperfunc-tional signs, have been reported in some
ileal and jejunal tumours mostly com-posed of EC-cells {1173, 2168}.
Dopamine and norepinephrine have also
Fig. 4.16  Multiple carcinoids of the ileum with mesenteric lymph node metastases.
B CA
Fig. 4.17 EC-cell carcinoid. A Typical mixed insular-acinar structure. B Positive Grimelius silver reaction. C Immunoexpression of TGFα.
82 Tumours of the small intestine
been detected in addition to serotonin in
a type A (insular) argentaffin carcinoid of
the ileum {588}. In many cases of jejuno-ileal EC-cell tumours, however, no other
hormones apart from serotonin and sub-stance P or related tachykinins are
detected {1173}.
The main criteria for considering a
jejuno-ileal carcinoid to have an aggres-sive potential are deep invasion of the
wall (muscularis propria or beyond)
and/or presence of metastases.
According to these criteria, in the large
AFIP series {211}, 141 of 159 cases
(89%) of jejuno-ileal carcinoids were con-sidered aggressive.
Genetic susceptibility
Unlike gastric ECL-cell tumours and duo-denal gastrin cell tumours, jejuno-ileal
carcinoids are only occasionally associ-ated with MEN-1 {1444}. Rare examples
of familial occurrence of ileal EC-cell car-cinoids have been reported {1252A}.
Genetics
A recent study {829} reported frequent
(78%) LOH on chromosome 11q13 in
sporadic carcinoids of both foregut (lung
and thymic) and midgut/hindgut (intes-tinal, including EC-cell tumours, and rec-tosigmoidal) origin. Other studies, how-ever, have shown retention of heterozy-gosity on 11q13 in sporadic carcinoids of
midgut and hindgut origin {394, 1938},
suggesting that LOH of the MEN-1 gene,
unlike gastric and duodenal endocrine
tumours, is not involved in the pathogen-esis of EC-cell tumours.
Accumulation of p53 has not been
detected in EC-cell tumours examined
immunohistochemically, suggesting that
this tumour suppressor gene is not impli-cated in the pathogenesis of these
tumours {1780, 2044, 2077}.
Several growth factors and related
receptors have been localised in tumour
cells of EC-cell carcinoids, including
transforming growth factor-α (TGFα) and
epidermal growth factor (EGF)-receptor,
insulin-like growth factor-1 (IGF-1), and
IGF-1 receptors, platelet-derived growth
factor (PDGF), transforming growth fac-tor-β (TGFβ), basic fibroblast growth fac-tor (bFGF), acidic fibroblast growth factor
(aFGF), and fibroblast growth factor
receptor-4 (FGFR4) {22, 284, 993, 995,
1291}.
Some of these growth factors, such as
TGFα, exert a proliferative effect reflected
by an increased mitotic index and signifi-cantly increased DNA levels in primary
cell cultures of midgut carcinoids. These
findings suggest the involvement of an
autocrine loop {22}. A similar growth pro-moting role in midgut carcinoid tumour
cells is assigned to IGF-1 {22}. PDGF,
TGFα, bFGF, and aFGF seem to be main-ly involved in tumour stromal reaction,
including stromal desmoplasia {22, 993,
995}, by acting on receptors expressed
on fibro-blasts or stimulating the promo-tion of new vasculature and tumour pro-gression {22, 993, 995}.
Neural adhesion molecule (NCAM), a
member of the immunoglobulin super-family of cell adhesion molecules, is
highly expressed in midgut carcinoid
tumours {22}.
Because NCAM has not been shown in
normal gut endocrine cells, the novel
expression of this adhesion molecule in
carcinoids may be of importance for
growth and metastases.
Prognosis and predictive factors
A recent report revealed a 21% mortality
rate for jejuno-ileal carcinoids, compared
with 4% for duodenal, 6% for gastric, and
3% for rectal carcinoids {211}. In two stud-ies, the overall 5-year survival rate of
patients with jejuno-ileal endocrine
tumours was about 60% and the 10-year
survival rate was 43% {211, 1845}. In
patients with no liver metastases, the
5- and 10-year survival rates were 72%
and 60%, respectively, as opposed to
35% and 15% for patients with liver
metastases {1845}, demonstrating the rel-atively slow rate of growth of some EC-cell
tumours. Metastases are generally con-fined to regional lymph nodes and liver.
Extra-abdominal metastases were found
in only 0.5% of the cases reported by
Moertel et al. {1253}. In one study, univari-ate analysis showed that survival was
negatively correlated with distant metas-tases at the time of surgery, mitotic rate,
tumour multiplicity, the presence of carci-noid syndrome, depth of intestinal wall
invasion, and female gender; by multivari-ate analysis, survival was negatively asso-ciated with distant metastases, carcinoid
syndrome, and female gender {211}.
In summary, jejuno-ileal carcinoid
tumours that are clinically nonfunctioning,
1 cm or less in diameter, confined to the
mucosa/submucosa and non-angioinva-sive, are generally cured by complete
local excision. Invasion beyond submu-cosa or metastatic spread indicates that
the lesion is aggressive. If the lesion,
although confined to the mucosa/submu-cosa, shows angioinvasion, or is over
1 cm in size, it is of uncertain malignant
potential.
83B-cell lymphoma
Definition
Primary small intestinal lymphoma is
defined as an extranodal lymphoma aris-ing in the small bowel with the bulk of dis-ease localized to this site. Contiguous
lymph node involvement and distal
spread may be seen, but the primary
clinical presentation is the small intes-tine, with therapy directed to this site.
ICD-O codes
MALT lymphoma 9699/3
IPSID 9764/3
Mantle cell lymphoma 9673/3
Burkitt lymphoma 9687/3
Diffuse large B-cell lymphoma     9680/3
Epidemiology
In contrast to lymphomas involving the
stomach, primary small intestinal lym-phomas are uncommon in Western coun-tries {792}. However, since epithelial and
mesenchymal tumours are uncommon in
the small bowel, lymphomas constitute a
significant proportion (30-50%) of all
malignant tumours at this site.
Lymphomas of mucosa-associated lym-phoid tissue (MALT) type are the most
frequent lymphomas of both the small
intestine and the colorectum, although
controversy surrounds the histogenesis
of de novo diffuse large B-cell lymphoma
arising along the gastrointestinal tract.
A unique form of intestinal MALT lym-phoma occurs predominantly in the
Middle East and Mediterranean areas,
and is referred to as immunoproliferative
small intestinal disease (IPSID)  {1649}.
This entity represents part of a spectrum
of small intestinal lymphoproliferations,
including alpha heavy chain disease
(αHCD) and may represent different
manifestations or phases of the same
disease. αHCD and IPSID occur pre-dominantly in the Mediterranean area,
but may be seen outside this region.
They typically affect young adults,
whereas small intestinal lymphomas in
the Western world increase in frequency
with age with a peak incidence in the 7th
decade. Most studies have shown a
slight male predominance {424}.
Aetiology
In contrast to the well-established rela-tionship between Helicobacter pylori and
gastric MALT lymphoma, no infectious
organism has been clearly implicated in
the pathogenesis of small intestinal
MALT lymphoma. IPSID appears to be
related to bacterial infection, as antibiot-ic responsiveness is typical of the early
phases of the disease. However, no spe-cific organism has been identified.
Lymphomas involving the small intestine
or colorectum may occur in distinct clini-cal settings. Chronic inflammatory bowel
disease, including Crohn disease and
ulcerative colitis, are recognized risk fac-tors for non-Hodgkin lymphoma at this
site. Importantly, the risk is much less
than that associated with gluten-sensitive
enteropathy and primary T-cell lym-phomas of the small bowel (see T-cell
lymphoma section). Crohn disease is
more often implicated in the develop-ment of lymphoma in the small intestine,
while ulcerative colitis is associated with
lymphomas of the colorectum {1733}. An
increased incidence of lymphoma has
been associated with both acquired and
congenital immunodeficiency states,
including congenital immune deficiency,
iatrogenic immunodeficiency associated
with solid organ transplantation, and
acquired immunodeficiency syndrome
(AIDS) {357}. In general, lymphomas
associated with immunodeficiency show
a predilection for extranodal sites, partic-ularly the gastrointestinal tract, irrespec-tive of the cause of the immunodeficien-cy {1057, 787}.
Clinical features
Symptoms produced by small intestinal
lymphomas depend upon the specific
histological type. Indolent lymphomas of
B-cell lineage typically present with
abdominal pain, weight loss and bowel
obstruction {424}. Occasional cases
present with nausea and vomiting, while
rare cases are discovered incidentally.
More aggressive tumours, such as those
of T-cell lineage (described separately)
or Burkitt lymphoma, may present as a
large intra-abdominal mass or acutely
with intestinal perforation. IPSID often
manifests as abdominal pain, chronic
severe intermittent diarrhoea and weight
loss {1649}. The diarrhoea is mainly the
result of steatorrhoea, and a protein-los-ing enteropathy can be seen. Peripheral
oedema, tetany and clubbing are
observed in as many as 50% of patients.
Rectal bleeding is uncommon in small
bowel lymphoma, but a common pre-senting sign in primary colonic lym-phoma.
Burkitt lymphoma is most frequently seen
in the terminal ileum or ileocaecal region,
and may cause intussusception.
Imaging and endoscopy
Radiological studies are useful adjuncts
to the diagnosis of small intestinal lym-phomas, including barium studies and
computerized tomography scans. T-cell
lymphomas are typically localized in the
jejunum, presenting as thickened
plaques, ulcers, or strictures. Most B-cell
lymphomas manifest as exophytic or
annular tumour masses in the ileum {792}.
B-cell lymphomas of both low- and inter-mediate-grade may produce nodules or
polyps that can be seen both endoscopi-cally and by imaging. Most small intestin-al lymphomas are localized to one
anatomic site, but multifocal tumours are
detected in approximately 8% of cases.
Multiple lymphomatous polyposis  con-sists of numerous polypoid lesions
throughout the gastrointestinal tract
{791}. Most often, the jejunum and termi-nal ileum are involved, but lesions can
appear in the stomach, duodenum,
colon, and rectum. This entity produces
a characteristic radiological picture that
is virtually diagnostic. As discussed
below, the majority of such cases is
caused by mantle cell lymphoma, but
other subtypes of lymphoma may pro-duce a similar radiological pattern
{1034}.
IPSID.  The macroscopic appearance of
IPSID depends on the stage of disease.
Early on, the bowel may appear endo-scopically normal, with infiltration appar-R.D. Gascoyne
H.K. Müller-Hermelink
A. Chott
A. Wotherspoon
B-cell lymphoma of the small intestine
84 Tumours of the small intestine
ent only on intestinal biopsy. The disease
may then progress to thickening of the
upper jejunum together with enlargement
of the mesenteric lymph nodes and the
development of lymphomatous masses.
Typically, the spleen is not involved and
may even be small and fibrotic, as
described in coeliac disease. Distal
spread beyond the abdomen is uncom-mon {1649, 798}.
Histopathology
MALT lymphoma
The majority of intestinal lymphomas
involving the small bowel are B-cell lym-phomas of MALT type, including both
low-grade and aggressive types {792,
793, 796}. These so-called ‘Western’
types are distinct from IPSID and αHCD.
The histological features of Western type
small intestinal lymphoma are similar to
gastric MALT lymphoma, except that
lymphoepithelial lesions are less promi-nent {792}.
In contrast to gastric MALT lymphomas,
diffuse large B-cell lymphomas arising in
the small bowel are much commoner
than low-grade B-cell lymphomas of
MALT-type {796}. Some of these lym-phomas may have a low-grade MALT
component, providing evidence that their
histogenesis is related to the mucosal
immune system. Precise criteria for
defining a MALT lymphoma of large cell
type are lacking, as are the criteria for
distinguishing transformation within a
low-grade MALT lymphoma {383}. When
both histologies are evident, the lesion is
best described as composite. When
small foci of large transformed cells or
early sheeting-out of large cells are
detected within a background of low-grade intestinal MALT lymphoma, their
presence should be noted. Currently, the
prognostic impact of these findings and
their effect on treatment are undeter-mined. Diffuse large B-cell lymphomas
arising in the small bowel that lack a
background of low-grade MALT lym-phoma are currently best classified as
extranodal diffuse large B-cell lym-phoma, not otherwise specified {670}.
IPSID / αHCD
Immunoproliferative small intestinal dis-ease and α heavy chain disease are part
of a spectrum of lymphoproliferative dis-eases prevailing in the Middle East and
Mediterranean countries {792}. They are
subtypes of small intestinal MALT lym-phoma characterized by the synthesis of
α heavy chain. The histology is charac-teristic of MALT lymphoma with marked
plasma cell differentiation.
Three stages of IPSID are recognized. In
stage A, the lymphoplasmacytic infiltrate
is confined to the mucosa and mesen-teric lymph nodes, and cytological atyp-ia is not present. Although the infiltrate
may obliterate the villous architecture,
endoscopic examination appears nor-mal. Resection specimens reveal reac-tive lymphoid follicles, lymphoepithelial
lesions and small clusters of parafollicu-lar clear cells. This phase of the disease
is typically responsive to antibiotic thera-py. In stage B, nodular mucosal infiltrates
develop and there is extension below the
muscularis mucosae. A minimal degree
of cytological atypia is apparent. This
stage appears to represent a transitional
phase, can be seen macroscopically as
thickening of mucosal folds, and is typi-cally not reversible with antibiotics. The
characteristic features of MALT lym-phoma are now evident, and follicular
colonization may be so marked as to
mimic follicular lymphoma. Stage C is
characterized by the presence of large
masses and transformation to frank large
cell lymphoma. Numerous centroblasts
and immunoblasts are present. Plasma-cytic differentiation is still evident, but
marked cytological atypia is usually
found, including Reed-Sternberg-like
cells. Mitotic activity is increased.
Mesenteric lymph node involvement
occurs early in the course of disease,
with both plasma cell infiltration of nodal
sinuses and marginal-zone areas dis-tended by small atypical lymphoma cells
with moderate amounts of pale, clear
cytoplasm.
Immunohistochemical studies demon-strate the production of  α heavy chain
without light chain synthesis {798}. The
IgA is almost always of the IgA1 type,
with intact carboxy-terminal regions and
BA
Fig. 4.19 Malignant lymphomatous polyposis. A Typical polypoid mucosa. B Polypoid mantle cell lymphoma.
Fig. 4.18  High-grade B-cell lymphoma of the small intestine.
85B-cell lymphoma
deletion of most of the V and all of the
CH1 domains. The molecular characteri-zation of individual cases is variable. The
small lymphoma cells express CD19 and
CD20, but fail to express CD5, CD10 and
CD23.
Mantle cell lymphoma
Mantle cell lymphoma (MCL) typically
involves both spleen and intestines and
may present as an isolated mass or as
multiple polyps throughout the gastroin-testinal tract where it is referred to as
multiple lymphomatous polyposis  {424,
791, 1292}. Importantly, other histologi-cal subtypes of non-Hodgkin lymphoma
can also produce this clinico-pathologi-cal entity.
The polyps range in size from 0.5 cm to
2 cm with much larger polyps found in
the ileocaecal region. The histology of
MCL involving the small bowel is identi-cal to MCL at nodal sites {110}. The
architecture is most frequently diffuse,
but a nodular pattern and a less com-mon true mantle-zone pattern are also
observed. Reactive germinal centers
may be found and are usually com-pressed by the surrounding lymphoma
cells, thereby appearing as replacing
the normal mantle zones. Intestinal
glands may be destroyed by the lym-phoma, but typical lymphoepithelial
lesions are not seen. The low power
appearance is monotonous with frequent
epithelioid histiocytes, mitotic figures
and fine sclerosis surrounding small
blood vessels. The lymphoma cells are
small to medium sized with irregular
nuclear outlines, indistinct nucleoli and
scant amounts of cytoplasm. Large
transformed cells are typically not pres-ent. The lymphoma cells are mature
B-cells and express both CD19 and
CD20. Characteristically the cells co-express CD5 and CD43. Surface
immunoglobulin is found including both
IgM and IgD. Light chain restriction is
present in most cases, with some studies
demonstrating a predominance of lamb-da. CD10 and CD11c are virtually always
negative. Bcl-1 (cyclin D1) is found in vir-tually all cases and can be demonstrat-ed within the nuclei of the neoplastic
lymphocytes in paraffin sections.
MCL is an aggressive lymphoma, which
typically presents in advanced stage
with involvement of mesenteric lymph
nodes and spread beyond the abdomen,
including peripheral lymph nodes,
spleen, bone marrow and peripheral
blood involvement {84}.
Burkitt lymphoma
Burkitt lymphoma occurs in two major
forms, defined as endemic and spo-radic. Endemic Burkitt is found primarily
in Africa and typically presents in the jaw,
orbit or paraspinal region, and is strong-ly associated with Epstein-Barr virus
(EBV).
In other endemic regions however, it is
relatively common for Burkitt lymphoma
to present in the small intestine, usually
involving the ileum, with preferential
localization to the ileocaecal region
{792}. In parts of the Middle East, pri-mary gastrointestinal Burkitt lymphoma is
a common disease of children. Sporadic
or non-endemic Burkitt lymphoma is a
rare disease, not associated with EBV
infection, that frequently presents as pri-mary intestinal lymphoma. Burkitt lym-phoma is also seen in the setting of HIV
infection when it often involves the gas-trointestinal tract {236}.
The histology in all cases is identical and
is characterized by a diffuse infiltrate of
medium-sized cells with round to oval
nuclear outlines, 2-5 small but distinct
nucleoli and a small amount of intensely
basophilic cytoplasm. Numerous mitotic
figures and apoptotic cells are present.
The prominent starry-sky appearance is
caused by benign phagocytic histiocytes
engulfing the nuclear debris resulting
from apoptosis. Thin sections often show
an unusual finding for lymphomas,
whereby the cytoplasmic borders of indi-vidual cells ‘square-off’ against each
other.
Burkitt lymphoma may rarely demon-strate a true follicular architecture, con-sistent with the proposed germinal cen-ter histogenesis of this neoplasm. It is a
mature B-cell lymphoma and the neo-plastic cells express pan-B-cell antigens
A
Fig. 4.20 Burkitt lymphoma.  A Large ileocecal
mass. B Starry-sky effect due to phagocytic histio-cytes.
B
Fig. 4.21  Follicular lymphoma of terminal ileum.
86 Tumours of the small intestine
CD19, CD20, CD22, and CD79a. In
approximately 60-80% of cases, the neo-plastic cells co-express CD10, but fail to
express CD5 or CD23. Surface immuno-globulin expression is moderately
intense and is nearly always IgM with
either kappa or lambda light chain
restriction. The growth fraction, as
assessed by Ki-67 or the paraffin equiva-lent MIB-1, is typically in excess of 90%
of tumour cells. Burkitt lymphoma cells
uniformly fail to express bcl-2.
Burkitt-like lymphoma
This group of atypical Burkitt lymphomas
appears to represent a morphological
overlap between Burkitt lymphoma and
diffuse large B-cell lymphoma. The over-all cell size is similar to Burkitt, but with
greater pleomorphism {827}. These
cases lack the typical monomorphic
appearance of Burkitt lymphoma and
demonstrate slight variation in both cell
size and shape. The cells may have mul-tiple nucleoli as in Burkitt lymphoma or a
single distinct nucleolus. A starry-sky
pattern may be evident and the mitotic
rate is usually significantly increased.
These lymphomas have a predilection
for the gastrointestinal tract of adults,
and also occur in the setting of HIV infec-tion.
Other B-cell lymphomas
Any subtype of B-cell lymphoma can
present as a primary small intestinal lym-phoma, including those thought to arise
from peripheral lymph node equivalents.
De novo diffuse large B-cell lymphomas
are the commonest lymphomas in the
small bowel, and may develop from low-grade MALT lymphomas.
Indolent lymphomas such as small lym-phocytic lymphoma, lymphoplasmacytic
lymphoma and follicular lymphoma (cen-troblastic/centrocytic) can present as pri-mary small intestinal disease. The latter
subtype can occasionally produce the
clinico-pathological entity of multiple
lymphomatous polyposis, but can usual-ly be distinguished from MCL by immu-nophenotypic and molecular genetic
analysis {1034}.
Lymphoblastic lymphoma may underlie
small intestinal lymphoma and frequently
produces a mass in the ileocaecal
region. Characteristic nuclear features
and the expression of terminal
nucleotidyl transferase may aid in estab-lishing the diagnosis.
Genetics
MALT lymphoma
Cytogenetic and molecular features of
intestinal MALT lymphomas are incom-pletely understood; the presence of either
t(1;14)(p22;q32) or t(11;18)(q21;q21) and
the corresponding molecular abnormali-ties, rearrangement of  bcl-10 or AP12-MLT, have not been described at this site;
thus their relationship to gastric MALT
lymphomas is unclear {2116, 412}.
Trisomy 3 is common in gastric MALT
lymphomas, but the frequency of this
cytogenetic abnormality in primary intes-tinal lymphomas is unknown {413}.
IPSID
Although cytogenetic abnormalities have
been detected in IPSID, no consistent
changes have been described. Southern
blot analysis reveals clonal immunoglob-ulin heavy-chain (IgH) gene rearrange-ments, but consensus IgH polymerase
chain reaction (PCR) strategies may
yield false negative results.
Mantle cell lymphoma
MCL is cytogenetically characterized by
a t(11;14)(q13;q32) translocation which
deregulates expression of the bcl-1 onco-gene on chromosome 11. Rearrange-ment can be detected using Southern
blot analysis, PCR or fluorescent  in situ
hybridization (FISH).
Burkitt lymphoma
Burkitt lymphoma demonstrates a con-sistent cytogenetic abnormality in all
cases, with rearrangement of the  c-myc
oncogene on chromosome 8. The char-acteristic translocation, t(8;14)(q24;q32),
is seen in most cases; the remainder
shows variant translocations including
the immunoglobulin light chain loci,
t(2;8)(p12;q24) or t(8;22)(q24;q11), invol-ving kappa and lambda light chain
genes, respectively. In the classical
t(8;14), the  c-myc oncogene is translo-cated from chromosome 8 to the heavy
chain locus on chromosome 14. In the
variant translocations, a part of the light
chain constant region is translocated to
chromosome 8, distal to the c-myc gene.
Thus, in the variant translocations, c-myc
remains on chromosome 8 and is dereg-ulated by virtue of its juxtaposition to the
immunoglobulin light chain genes. The
molecular characteristics of the  c-myc
translocation also differ between endem-ic and sporadic cases. In endemic
Burkitt lymphoma, the chromosome 8
breakpoints are usually far 5’ of the
c-myc gene, while their chromosome 14
breakpoints most often occur in the loca-tion of the IgH gene joining segments.
The variable chromosome 8 breakpoints
and their location far from the c-myc cod-ing sequences make it impossible in
most cases to demonstrate  c-myc
rearrangements by Southern blot analy-sis. In contrast, sporadic cases frequent-ly have  c-myc breakpoints within non-coding introns and exons of the gene
itself, typically in the first exon or intron,
or in the 5’ flanking regions of the gene.
In most of these cases, c-myc rearrange-ments can be demonstrated using
Southern analysis {670}.
Burkitt-like lymphoma/
Atypical Burkitt lymphoma
This category is cytogenetically hetero-geneous and may contain three or more
biological groups {1387}. Importantly, the
frequency of variant c-myc translocations
precludes the accurate recognition of
cases using molecular techniques alone.
Prognostic factors
The main determinants of clinical out-come in small intestinal lymphomas are
histological grade, stage, and resectabil-ity {424}. Advanced age at diagnosis, an
acute presentation with perforation, and
the presence of multifocal tumours have
an adverse impact on survival. The
behaviour of diffuse large B-cell lym-phoma is not affected by the presence of
a low-grade MALT component {424}. The
expression of bcl-2 protein and the pres-ence of  TP53 mutations may adversely
affect outcome in this group, but a sys-tematic study of small intestinal lym-phomas is lacking {567, 770}.
MCL is an aggressive neoplasm. A blas-toid cytology, increased mitotic index
and peripheral blood involvement are
recognized as adverse factors {84}.
Mutations in the p53 gene and homozy-gous deletions of p16 have recently been
shown to be associated with poor prog-nosis {1099, 700}. Burkitt-like lymphomas
with ‘dual translocation’ of both bcl-2 and
c-myc oncogenes have a markedly
shortened overall survival {1137}.
87T-cell lymphoma
Definition
A peripheral T-cell lymphoma arising in
the intestine, usually as a complication of
coeliac disease (gluten sensitive entero-pathy), histologically characterised by
differentiation towards the intestinal
intraepithelial T-cell phenotype.
ICD-O codes
T-cell lymphoma 9702/3
Enteropathy associated 9717/3
Epidemiology and aetiology
Intestinal T-cell lymphoma (ITL) is rare,
accounting for only about 5% of all gas-trointestinal lymphomas, and is normally
associated with coeliac disease {305}.
There is marked geographic variation in
the incidence of ITL, with a high inci-dence in Northern Europe, reflecting the
notion that ITL arises against the same
genetic background as that predispos-ing to coeliac disease {753}.
There is no clear sex predominance and
in Europe, the median age at diagnosis is
around 60 years {305, 424, 374}. In con-trast, a small series of Mexican patients
had a median age of 24 years and there
was circumstantial evidence for a possi-ble aetiological role of the Epstein Barr
virus, which is absent in European cases
{1552, 795}. Congenital or acquired
immunodeficiency disorders are not
known to be associated with ITL.
Localization
The proximal jejunum is the most frequent
site of disease, although it may occur
elsewhere in the small intestine and,
rarely, in the stomach and colon {305}.
Clinical features
The most frequent symptoms are abdom-inal pain and weight loss {303}. About
40% of patients present as acute abdom-inal emergencies due to intestinal perfo-ration and/or obstruction {305, 424}.
Patients may have a short history of mal-absorption, sometimes diagnosed as
adult coeliac disease which is usually
gluten-insensitive or, less frequently, a
long history of coeliac disease lasting for
years or even decades {796}.
Signs and symptoms of the disease may
mimic inflammatory bowel disease (IBD),
particularly Crohn disease. Radiographic
studies may be helpful, but they are often
interpreted as consistent with a segmen-tal or diffuse inflammatory process.
Except for leukocytosis, laboratory data
are usually unremarkable, including nor-mal levels of lactate dehydrogenase
{303}.
Refractory coeliac disease and ulcera-tive jejunitis are two conditions that fre-quently have a history of coeliac disease
for years, become resistant to gluten-free
diet and may, but not necessarily,
progress to ITL {1385, 92}. In ulcerative
jejunitis, patients develop non-specific
inflammatory ulcers without overt histo-logical evidence of lymphoma.
Macroscopy
The affected bowel segment is often
dilated and oedematous, and usually
shows multiple circumferential ulcers,
ulcerated plaques and strictures, without
the formation of large tumour masses
{424}. The intact mucosa between the
lesions may contain thickened folds or
appear completely normal. Loops of
bowel may adhere to each other or addi-tionally to the left or right colon, causing
palpable conglomerate tumours.
Tumour spread and staging
About 70% of the patients present with
localized intestinal disease with or with-out contiguous lymph node involvement
{305}. Disseminated disease involves
liver, spleen, lung, testes, and skin, but
rarely the bone marrow {303, 794}.
Histopathology
The histological appearances of ITL are
variable both between cases and
between different tumour sites in the
same patient. The most frequently
encountered type is composed of highly
pleomorphic, medium to large cells, fol-lowed by a lymphoma type that shows a
morphology most consistent with ana-plastic large cell lymphoma. The border
between these two histologies is not
sharp and transition from one to the other
may occur, even within the same tumour
{307}.
About 20% of ITL are characterized by
the monotonous appearance of densely
packed small to medium-sized cells
almost without any recognizable stroma
components. Most of the rather
monomorphic cells contain only slightly
R.D. Gascoyne
H.K. Müller-Hermelink
A. Chott
A. Wotherspoon
Intestinal T-cell lymphoma
B C
Fig. 4.22  Intestinal T-cell lymphoma. Histological features of the most common variants.  A Pleomorphic medium and large cells.  B Anaplastic large cells.  C
Monomorphic small to medium cells.
A
88 Tumours of the small intestine
irregular nuclei with small nucleoli and
moderately wide, pale or sometimes
clear cytoplasm {307}. Rare variants of
ITL are composed predominantly of pleo-morphic small cells or immunoblasts.
Irrespective of morphology, the lym-phoma cells often invade and destroy the
overlying epithelium. Most frequently, the
enterocytes of the upper and intermedi-ate villous regions, or in cases of severe
villous atrophy, the epithelium of the
upper parts of the elongated crypts are
the preferential targets of lymphoma cell
attack. These features are best appreci-ated at the borders of ulcerated tumours.
However, they may also be present as
band-like or patchy microscopic lesions
entirely confined to the mucosa {303}.
Fibrosis and admixed inflammatory cells
are constant features of the pleomorphic
medium and large cell and the anaplas-tic large cell ITL types; in the former, an
abundance of eosinophils may mask the
neoplastic infiltrate {1731}. In contrast,
the monomorphic small to medium-sized
variant characteristically lacks fibrotic
changes and inflammatory background
{307}.
Histopathology
of the enteropathic mucosa
In the vast majority of cases, the macro-scopically normal intestinal mucosa
shows features of coeliac disease, i.e.
increase in normal appearing intraepithe-lial lymphocytes (IEL), villous atrophy, and
crypt hyperplasia {794}, which has
prompted O’Farrelly and co-workers to
coin the term ‘enteropathy associated
T-cell lymphoma’ {1383}. An increase in
normal appearing IEL (duodenum /
jejunum, * 40/100 enterocytes; ileum,
* 20/100 enterocytes) represents the sin-gle most important feature suggestive of
coeliac disease {1172}. The severity of
these enteropathic changes is highly vari-able and similar to coeliac disease; they
are most pronounced proximally and
improve distally so that the lower jejunum
and ileum may appear normal. Further-more, enteropathy may be minimal or
absent if the patient is on a gluten free
diet, or if enteropathic sites are missed
because of their patchy distribution.
Occasionally, the non-neoplastic mucosa
in ITL shows a strikingly intense or florid
intraepithelial lymphocytosis {2142}.
Immunological phenotyping
Similarities of the immunophenotypes in
normal or activated (reactive) intraep-ithelial lymphocytes (IEL) and the tumour
cells in ITL provide an important part of
evidence that ITL cells are the neoplastic
counterpart of IEL. The expression of the
HML-1 defined  αE
β7 (CD103) on non-neoplastic IEL and in > 50% of ITL, but
not in resting peripheral blood T-cells,
strongly supports this view {1802}. The
vast majority of normal IEL are resting
cytotoxic CD3+CD8+CD4-CD2+CD7+
CD5low
TIA-1+ T-cells using the  αβ T-cell
receptor, but minor subsets such as
CD4-CD8- or CD56+ are present as well
as predominantly CD4-CD8-  γδ  T-cells
{1113, 304}. In ITL, most cases are
CD3+CD4-CD8-CD7+CD5- and co-express the cytotoxic granule-associated
protein TIA-1, often together with the acti-vation-dependent cytotoxic molecule
granzyme B {305, 382}. Some correla-tions between ITL morphology and phe-notype exist; pleomorphic medium and
large cell lymphomas and lymphomas of
anaplastic large cell histology are often
CD4-CD8-, the latter express CD30+ but
are always ALK1 negative; the monomor-phic small to medium-sized variant is fre-quently associated with a CD56+CD8+
phenotype {307}.
Cytologically normal IEL abundantly
present in the intact enteropathic
mucosa in ITL, in ulcerative jejunitis, and
in refractory coeliac disease share an
identical aberrant phenotype with ITL
and are monoclonal, as demonstrated by
PCR {103}. They therefore are consid-ered a neoplastic population which, in
the absence of concurrent overt ITL, may
represent the first step in ITL lymphoma-genesis (‘intraepithelial lymphoma’) and
may have already persisted for years
{238}.
ITL diagnosis of endoscopic biopsies
Most cases of ITL are diagnosed on sur-gical resection specimens. In a minority
however, endoscopic biopsies, usually
taken from the stomach, duodenum, or
colon, are available. These patients fre-quently have a longer than 6 months his-tory of abdominal pain and weight loss.
Some of them are clinically suspected to
have inflammatory bowel disease, and
occasionally patients had already been
biopsied with the diagnosis of IBD or an
unclear inflammatory process, thus
emphasizing the challenging task of ITL
diagnosis in endoscopic biopsies. The
immunohistochemical demonstration of
an aberrant phenotype is essential in
diagnosing ITL, especially in cases
which lack overt cytological atypia
and/or invasiveness. Furthermore, the
neoplastic infiltrate may be subtle or
superficial and therefore easily over-looked in routinely stained sections.
Genetics
Very few data on chromosomal abnor-malities in ITL exist. Deletion of the Y
chromosome and chromosome 9 abnor-malities were found among a phenotypi-cally aberrant intraepithelial T-cell popu-lation {2142}; a t(4;16)(q26;p13) translo-cation was present in a mesenteric
B
C
A
Fig. 4.23  Coeliac disease. The non-neoplastic
mucosa distant from an anaplastic large cell intes-tinal T-cell lymphoma displays villous atrophy, crypt
hyperplasia (A) and an increase in cytologically
unremarkable intraepithelial lymphocytes  (B) with-out evidence of lymphoma. Both the lymphoma
(ALCL) and the intraepithelial lymphocytes (IEL)
share the same dominant T-cell clone  (C) and the
same aberrant immunological phenotype.
89T-cell lymphoma
lymph node associated with extensive
ITL {239}. In two cases of anaplastic
large cell ITL very complex abnormalities
were detected in ascitic fluid and lymph
node, respectively {1436}.
Southern blotting and PCR studies
demonstrated monoclonal rearrange-ments of the T-cell receptor (β-chain) in
ITL, consistent with the derivation from
αβ T-cells {799}. ITL using the  γδ T-cell
receptor are rare {86}, but nevertheless
seem to outnumber the few well docu-mented cases of true intestinal natural
killer (NK) cell lymphomas {1176}. The
latter finding is not surprising as NK cells
are not present among IEL.
Prognosis and predictive factors
The clinical course is very unfavorable
due to complications from peritonitis and
malnutrition and later from progressive
disease typically characterized by intes-tinal recurrences. The malabsorption due
to underlying coeliac disease is detri-mental to these patients, particularly
when recovering from surgery or receiv-ing multiagent chemotherapy {444}.
Consequently, only one half of the
patients is amenable to chemotherapy
and only a proportion of these is able to
finish the complete course. The overall
median survival in the largest published
series is only 3 months, and 5-year sur-vival in this and other series ranges from
8-25% {305, 424, 444}. The small group
of long-term survivors usually received
chemotherapy and, interestingly, none
had a previous diagnosis of coeliac dis-ease {305, 444}.
Fig. 4.24  CD3 immunoexpression in a T-cell lymphoma of the small intestine.
90 Tumours of the small intestine
Definition
A variety of benign and malignant mes-enchymal tumours can arise in the small
intestine, but the neoplasms that occur in
any appreciable numbers are gastroin-testinal stromal tumours (GISTs).
Epidemiology
Sarcomas account for approximately
14% of malignant small intestinal tumours
{1928}. Males are affected somewhat
more than females (M:F 1.2:1). The peak
incidence is in the 6th to 8th decade. Age
of onset for sarcomas was lower than for
carcinomas, with black females showing
the lowest median age, 50 years. In the
U.S. SEER database, the incidence rate
for sarcoma was 0.2 per 100,000 per year
compared to 0.3 for lymphomas, 0.4 for
adenocarcinomas and 0.4 for carcinoids,
and appears to be stable.
Localization
Sarcomas show a much more even dis-tribution throughout the small bowel
compared to adenocarcinomas and car-cinoids {1928}. GISTs have been specifi-cally identified in duodenum, jejunum,
and ileum {183, 594, 1980}.
Clinical features
Vague abdominal discomfort is the usual
complaint. Mesenchymal neoplasms of
small bowel are more difficult to diag-nose by endoscopy or imaging studies
than those in the stomach.
Macroscopy
Small bowel sarcomas generally appear
macroscopically as those in the stom-ach. Some small intestinal tumours may
cause aneurysmal bowel dilatation, while
others have a diverticulum-like appear-ance.
Histopathology
Gastrointestinal stromal tumours
Small bowel GISTs resemble those of the
stomach histologically, although epithe-lioid lesions are uncommon. Globoid
extracellular collagen accumulations (so-called skeinoid fibers) are frequently
observed, especially in benign small
intestinal GISTs {1235}. Factors that cor-relate with malignancy are tumour size
> 5 cm, mitotic count > 5 per 50 HPF,
dense cellularity, and mucosal invasion
(rarely observed). Even with low or
absent mitotic activity, tumours larger
than 5 cm are considered to have malig-nant potential. Small intestinal GISTs are
positive for KIT (CD117) and usually for
CD34, and a subset (30-50%) are posi-tive for  α–smooth muscle actin; most
tumours are negative for desmin and
almost all are negative for S100-protein.
Leiomyomas and leiomyosarcomas are
rare in the small intestine, and can be
identified immunohistochemically by
their smooth muscle actin and desmin
expression and lack of KIT.
Angiosarcomas are recognized by an
anastomosing proliferation of atypical
endothelial cells. Immunohistochemical
demonstration of CD31, less consistently
von Willebrand factor, is diagnostically
useful {1904}.
Kaposi sarcomas may involve small
intestine, either the mucosa alone or
more extensively. Histologically typical
are elongated spindle cells with vascular
slits. Cytoplasmic PAS-positive hyaline
globules are present in some tumour
cells. Immunohistochemically, the lesion-al cells are positive for CD31 and CD34.
Human herpesvirus 8 can be demon-strated by PCR.
Lipomas exhibit the same morphological
features as their colonic counterparts.
Genetics
Small intestinal GISTs show similar  c-kit
mutations in exon 11 as observed in gas-tric GISTs, and most mutations occur in
the malignant cases. Comparative
genomic hybridization shows common
losses in chromosomes 14 and 22 similar
to those seen in gastric GISTs.
Prognosis
The prognosis of small bowel sarcomas
is largely dependent on the mitotic count,
size, depth of invasion, and presence or
absence of metastasis. In the SEER data-base, 5-year survival for localized
tumours was 45% for sarcomas, com-pared to 92% for carcinoids and 63% for
carcinomas {1928}. In a study of over
one thousand stromal/smooth muscle
sarcomas, the 5-year survival rate was
55% for sarcomas of small bowel, 60%
for colorectum, 70% for stomach and
75% for oesophagus {462}.
M. Miettinen
J.Y. Blay
L.H. Sobin
Mesenchymal tumours
of the small intestine
Fig. 4.25 A Stromal tumour of small intestine. B Cut
surface of lesion illustrated in A.
B
A
Fig. 4.26 Small intestinal stromal tumour. Extra-cellular accumulation of skeinoid fibres produces
eosinophilic globules.
91Secondary tumours
Definition
Tumours of the intestines that originate
from an extra-intestinal neoplasm or which
are discontinuous with a primary tumour
elsewhere in the gastrointestinal tract.
Epidemiology
Metastatic spread to the small intestine is
more frequent than to any other site in the
gastrointestinal tract (see Table 3.02).
Secondary carcinomas of the small
bowel are as common as primary carci-nomas at this site {1234}.
Origin
For small intestine, melanoma, lung,
breast, colon and kidney are the most
frequent primary sites (see Table 3.02)
{130, 1022, 1378, 1209, 1457, 458}.
Metastatic spread from primary lung
cancer to the small intestine is more fre-quent than to stomach and colon (Table
4.01). Virtually all primary cancers can
occasionally lead to metastases in the
small intestine and, because of the low
frequency of primary small bowel cancer,
a high proportion of small intestinal
malignancies are metastatic.
The pathogenesis of intestinal metastasis
usually involves haematogenous spread
of tumour cells. Invasion from neighbour-ing primary tumours also occurs, e.g.
pancreatic carcinoma to duodenum and
prostate carcinoma to rectum.
Primary melanomas of the intestine are
very rare. Although most melanomas
found in the small bowel have no history
C. Niederau
L.H. SobinSecondary tumours of the
small and large intestines
Table 4.01
Frequency of metastasis from breast (695 cases)
and lung (747 cases) to gastrointestinal tract {130}.
Fig. 4.27 Metastatic adenocarcinoma, small intestine. A Tumour is beneath swollen mucosa. B Tumour in muscularis propria. Submucosa is oedematous.
BA
Metastasis
Fig. 4.28  A, B Metastatic malignant melanoma, small intestine.
BA
Primary Stomach Small Colon
site intestine
Breast 3.6% 1.7% 1.4%
Lung 1.3% 4.4% 1.9%
92 Tumours of the small intestine
of a primary tumour, the general consen-sus is that they are virtually all secondary,
usually from misdiagnosed or regressed
primary melanomas {458}.
Clinical features
Small intestinal metastases can cause
bleeding and obstruction as well as non-specific symptoms such as abdominal
discomfort, gas distension, and diar-rhoea {1378, 580}.
Imaging
The identification of a small bowel tumour
always raises the question of whether the
tumour is primary or secondary. Contrast
radiography shows narrowing and
abnormalities of the small intestinal wall.
Advanced cases result in stenosis with
distension due to obstruction.
Macroscopy
Typical features of intestinal metastases
include intestinal wall thickening, submu-cosal spread, and ulcers. Melanomas
may not be pigmented and may appear
as nodules or polyps.
Histopathology
Metastases are typically submucosal or
subserosal making the distinction
between primary and secondary tumours
relatively easy. Cytokeratin immunohisto-chemistry may help to differentiate
between primary colon cancer (positive
for cytokeratin 20), metastases from
ovary and breast (usually  positive for
cytokeratin 7) and those from liver, kidney
and prostate (usually negative for both
cytokeratins 7 and 20) {2047, 129}. On
the other hand, the distinction between
multiple primary small bowel carcinoids
and their metastases may not be possi-ble. This also applies to leiomyosarco-mas/stromal tumours of the small intes-tine.
Prognosis
Intestinal metastases usually represent a
late stage of disease in which other
haematogenous metastases are also fre-quently found. Therefore, the prognosis
is poor. Exceptions are melanoma and
renal cancer in which metastases con-fined to the bowel may be associated
with prolonged survival after resection.
Fig. 4.30  Metastatic breast carcinoma, colon.
Tumour cells expand submucosa.
Fig. 4.31 Metastatic breast carcinoma, caecum,
diastase-PAS stain. Many tumour cells are mucin
positive.
Fig. 4.29 Metastatic adenocarcinoma, small intes-tine. Muscularis propria contains tumour. Mucosa
is free of neoplasia.
CHAPTER 5
Tumours of the Appendix
The appendix is the most frequent site of carcinoids,
i.e. tumours with endocrine differentiation, that span a wide
range of morphological variety.
Adenocarcinomas of the appendix also show interesting mor-phological variations, from those that resemble the usual
colorectal carcinoma to those that arise from a carcinoid and
to mucinous tumours that may appear well differentiated and
indistinguishable from adenoma and yet spread widely
through the peritoneal cavity.
Epithelial tumours
Adenoma 8140/02
Tubular 8211/0
Villous 8261/0
Tubulovillous 8263/0
Serrated 8213/0
Carcinoma
Adenocarcinoma 8140/3
Mucinous adenocarcinoma 8480/3
Signet-ring cell carcinoma 8490/3
Small cell carcinoma 8041/3
Undifferentiated carcinoma 8020/3
Carcinoid (well differentiated endocrine neoplasm) 8240/3
EC-cell, serotonin-producing neoplasm 8241/3
L-cell, glucagon-like peptide
and PP/PYY producing tumour
Others
Tubular carcinoid 8245/1
Goblet cell carcinoid (mucinous carcinoid) 8243/3
Mixed carcinoid-adenocarcinoma 8244/3
Others
Non-epithelial tumours
Neuroma 9570/0
Lipoma 8850/0
Leiomyoma 8890/0
Gastrointestinal stromal tumour 8936/1
Leiomyosarcoma 8890/3
Kaposi sarcoma 9140/3
Others
Malignant lymphoma
Secondary tumours
Hyperplastic (metaplastic) polyp
WHO histological classification of tumours of the appendix1
TNM classification1,  2
T – Primary Tumour
TX Primary tumour cannot be assessed
T0 No evidence of primary tumour
Tis  Carcinoma in situ: intraepithelial or invasion of lamina propria3
T1 Tumour invades submucosa
T2 Tumour invades muscularis propria
T3 Tumour invades through muscularis propria into subserosa
or into non-peritonealized periappendiceal  tissue
T4 Tumour directly invades other organs or structures
and/or perforates visceral peritoneum
N – Regional Lymph Nodes
NX Regional lymph nodes cannot be assessed
N0 No regional lymph node metastasis
N1 Metastasis in 1 to 3 regional lymph nodes
N2 Metastasis in 4 or more regional lymph nodes
M – Distant Metastasis
MX Distant metastasis cannot be assessed
M0 No distant metastasis
M1 Distant metastasis
Stage Grouping
Stage 0 Tis N0 M0
Stage I T1 N0 M0
T2 N0 M0
Stage II T3 N0 M0
T4 N0 M0
Stage III Any T N1 M0
Any T N2 M0
Stage IV Any T Any N M1
______________
1
This classification is modified from the previous WHO histological classification of tumours {845} taking into account changes  in our understanding of these lesions. In the case of
endocrine neoplasms, it is based on the recent WHO classification {1784} but has been simplified to be of more practical utility in morphological classification.
2
Morphology code of the International Classification of Diseases for Oncology (ICD-O) {542} and the Systematized Nomenclature of Medicine (http://snomed.org). Behaviour is coded
/0 for benign tumours, /3 for malignant tumours, and /1 for unspecified, borderline or uncertain behaviour.
TNM classification of tumours of the appendix
94 Tumours of the appendix
______________
1
{1, 66}. The classification applies only to carcinomas.
2
A help desk for specific questions about the TNM classification is available at http://tnm.uicc.org.
3
This includes cancer cells confined within the glandular basement membrane (intraepithelial) or lamina propria (intramucosal) with no extension through muscularis mucosae into
submucosa.
95
Definition
A malignant epithelial neoplasm of the
appendix with invasion beyond the mus-cularis mucosae.
ICD-O codes
Adenocarcinoma 8140/3
Mucinous adenocarcinoma 8480/3
Signet-ring cell carcinoma 8490/3
Epidemiology
Adenocarcinoma of the appendix occurs
in 0.1% of appendicectomies, corre-sponding to an estimated incidence of
0.2/100,000 per annum {393, 1928}.
Adenocarcinomas accounted for 58% of
malignant appendiceal tumours in the
SEER database, the remainder being
mostly carcinoids. The rates for the car-cinomas stayed constant during the peri-od 1973-1987 {1928}. The median age of
patients with mucinous and non-muci-nous adenocarcinoma was about 65
years in SEER data; other studies sug-gest a peak age at manifestation in the
sixth decade {250, 393}. Males appear to
be more commonly affected than
females {393}.
Aetiology
Patients with chronic ulcerative colitis
(UC) have an increased susceptibility to
formation of epithelial dysplasia and
malignancy in affected segments of
bowel; inflammatory involvement of the
appendix is seen in approximately half of
UC cases with pancolitis.
Both adenoma and adenocarcinoma of
the appendix have been described in
patients affected by long-standing ulcer-ative colitis {1394}.
Clinical features
Signs and symptoms
Many patients with appendiceal adeno-carcinoma have clinical features indistin-guishable from acute appendicitis. Most
of the remaining cases present as an
abdominal mass {250, 393}. Spread to
the peritoneal cavity may produce large
volumes of mucus, causing pseudomyx-oma peritonei. Such cases may present
with abdominal distension. Rarely, exter-nal fistulation occurs {251, 393, 707}.
Imaging
Ultrasound, computerised tomography
(CT) scan or barium enema are of limited
benefit in the pre-operative diagnosis of
cases presenting as acute appendicitis.
Ultrasound and CT scan are the pre-ferred imaging procedures in cases pre-senting with abdominal mass or
pseudomyxoma peritonei {393, 707}.
Serial CT scanning and CEA measure-ments can assess the extent of peri-toneal involvement and the subsequent
course of the disease. Intraepithelial neo-plasia of the appendix may occur con-currently with a carcinoma elsewhere in
the large intestine {393}.
Macroscopy
In cases of primary adenocarcinoma, the
appendix may be enlarged, deformed or
completely destroyed {250, 251, 1612}.
Well differentiated lesions are often cys-tic and may be called cystadenocarcino-mas. A grossly appreciated swelling of
the appendix due to the accumulation of
mucus within the lumen can be termed
mucocoele, but this is descriptive not a
pathological diagnosis {250, 251}.
Tumour spread and staging
Although the TNM classification currently
uses the same criteria as for colorectal
tumours, appendiceal cases should be
separately classified. This is particularly
important because of the special nature
of pseudomyxoma peritonei, where
malignant cells may be scarce and acel-lular mucin may seem to have spread fur-ther than the malignant cells {250}.
Well differentiated mucinous appen-diceal adenocarcinomas generally grow
slowly, and typically produce the clinical
picture of pseudomyxoma peritonei.
Lymph node metastases tend to occur
late. Rarely, tumour growth in the
retroperitoneum may produce ‘pseudo-myxoma retroperitonei’ {1194}. The
behaviour of non-mucinous carcinomas
resembles that of their colonic counter-parts.
Pseudomyxoma peritonei
Pseudomyxoma peritonei is the pres-ence of mucinous material on peritoneal
surfaces. It is not a complete histological
N.J. Carr
M.J. Arends
G.T. Deans
L.H. Sobin
Adenocarcinoma of the appendix
Fig. 5.01 Mucinous adenocarcinoma arising in a villous adenoma. The lumen is lined by a villous adenoma.
Adenocarcinoma
96 Tumours of the appendix
diagnosis in itself; the prognosis will
depend on the nature of the causative
lesion. Nevertheless, pseudomyxoma
peritonei is often applied to a distinctive
clinical picture produced by well differ-entiated mucinous adenocarcinomas in
which the growth of malignant cells with-in the peritoneal cavity causes a slow but
relentless accumulation of mucin. Cells
may be very scanty within this mucinous
material.
A distinctive feature of well differentiated
mucinous carcinomatosis is its distribu-tion in the abdomen. There is a tendency
to spare the peritoneal surfaces of the
bowel, whereas large-volume disease is
found in the greater omentum, beneath
the right hemidiaphragm, in the right
retrohepatic space, at the ligament of
Treitz, in the left abdominal gutter and in
the pelvis {1854}. In these cases, tumour
growth tends to remain confined to the
abdomen for many years. Mucinous
cysts within the spleen occur occasional-ly {433}.
It has been suggested that appendiceal
adenomas can cause widespread pseu-domyxoma peritonei with an ultimately
fatal outcome, and some authors use the
term ‘adenomucinosis’ for the spread of
such lesions through the abdomen {1611,
1612}. It is considered more likely that
such cases are examples of well differen-tiated adenocarcinoma.
Although most cases of pseudomyxoma
peritonei are due to spread from a pri-mary carcinoma of the appendix, cases
have been reported in association with
mucinous carcinomas of other sites,
including gallbladder, stomach, colorec-tum, pancreas, fallopian tube, urachus,
lung, and breast {346, 612, 707, 981,
1199, 2199}.
Although the ovary has been thought of
as a common primary site {104, 1705},
there is an accumulating body of evi-dence based on immunohistochemistry
and molecular genetics suggesting that
this is not the case, and that in most
patients with low-grade mucinous tu-mours of the ovary and appendix with
pseudomyxoma peritonei the lesions are
probably metastatic from an appendiceal
primary {1536, 1611, 1612, 1871, 2187}.
Histopathology
The majority of appendiceal adenocarci-nomas are well differentiated and muci-nous {250, 706}. If signet-ring cells
account for more than 50% of the neo-plasm, the term signet-ring cell carcino-ma is appropriate.
The term mucinous cystadenocarcinoma
may be used for well differentiated muci-nous tumours with cystic structures. How-ever, this designation is descriptive and
does not constitute a separate disease
entity {251, 2115}.
Diagnostic criteria
The fundamental criterion for making the
diagnosis of adenocarcinoma is the
presence of invasive neoplasm beyond
the muscularis mucosae; this is the same
criterion that is applied throughout the
large intestine (see Table 5.01). However,
in practice it is not always easy to deter-mine the extent of invasion, because well
differentiated carcinomas of the appen-dix can mimic adenomas by invading on
a broad front rather than showing infiltra-tive or single-cell invasion. Conversely, in
some adenomas, acellular mucin dis-sects through the wall, mimicking inva-sion; this feature may be especially
prominent if there is inflammation. If there
is acellular mucin in the appendiceal
wall, the diagnosis of adenoma should
only be made if the muscularis mucosae
is intact since this term implies that the
lesion is curable by complete excision.
It is appropriate to use the term  muci-nous tumour of uncertain malignant
potential for neoplasms in which the his-tological features do not allow distinction
between a lesion that is benign (an ade-noma) from one that has the potential to
cause metastases (an adenocarcinoma).
The term  low-grade mucinous cystic
tumour has also been used for lesions
that are histologically not frankly malig-nant {2187A}.
Grading
Grading is the same as in the large intes-tine. Some adenocarcinomas of the
appendix are so well differentiated that
their neoplastic features may be very
subtle {250}.
Fig. 5.02 Appendiceal mucinous adenocarcinoma.
A B
Fig. 5.03  Pseudomyxoma peritonei. A Several loops of bowel are encased in a multilocular mucinous mass.
B Well differentiated mucus producing epithelium embedded in a fibrous matrix; mucus is present within the
lumen and is extravasated into the stroma.
Fig. 5.04  Pseudomyxoma peritonei. Fig. 5.05 Mucocoele of appendix.
97Adenocarcinoma
Precursor lesions and benign tumours
By analogy with the rest of the large intes-tine, an adenoma-carcinoma sequence is
assumed to occur in the appendix; the
finding of a residual adenoma in some
cases of adenocarcinoma supports this
contention {1548}. However, some ade-nocarcinomas appear to arise from gob-let cell carcinoid tumours {209, 250}.
Compared to adenomas of the colon,
adenomas of the appendix are more like-ly to be villous or serrated {250, 706,
1548, 2115, 2110}.
Many appendiceal serrated and villous
adenomas display minimal cytological
abnormalities; such lesions need to be
distinguished from hyperplastic polyps or
mucosal hyperplasia. Pedunculated
hyperplastic polyps of the type seen in
the colon are unusual in the appendix,
but diffuse hyperplasia is relatively com-mon {2184}. The diagnosis of hyperplas-tic polyp/diffuse hyperplasia should not
be made if there are cytological abnor-malities in the epithelial cells; if any are
present, then the diagnosis of adenoma
should be considered. The presence of
villous structures is also a pointer towards
adenoma.
As they grow, adenomas of the appendix
typically become cystic, and the lining
epithelium becomes undulating rather
than villous. Such lesions may produce a
mucocoele and be given the descriptive
appellation of cystadenoma.
Genetic susceptibility
Familial adenomatous polyposis coli
(FAP)
A review of 71 000 appendix specimens
revealed 33 benign and 6 malignant
appendiceal tumours in patients with
familial polyposis coli {324}. Several
cases of adenocarcinoma of the appen-dix have been reported in FAP patients,
including a patient with appendiceal
adenocarcinoma as the presenting fea-ture {1464}.
Hereditary non-polyposis colorectal can-cer (HNPCC)
This familial cancer syndrome confers
increased susceptibility to proximal
colon cancer {1936}, but it is not yet clear
whether there is also an increased risk of
appendiceal neoplasms.
Other polyposis syndromes
It is difficult to establish accurately the
risk of genetic susceptibility to tumours of
the appendix in Peutz-Jeghers and juve-nile polyposis syndrome on account of
the rarity of these conditions. Intussus-ception with an ‘inside-out’ appendix in
Peutz-Jeghers syndrome has been
reported, caused by a hamartomatous
polyp of the appendix or an appendiceal
polyp with villous adenomatous changes
and focal carcinoma in situ {1243}.
Genetics
Limited data are available on molecular
genetic alterations in appendiceal
tumours, and these data indicate similar-ities to those in colorectal tumours. KRAS
mutations have been identified in
approximately 70% of appendiceal muci-nous adenomas, mostly in codon 12 and
a few in codon 13 {1871}. In addition,
KRAS mutation has been identified in an
appendix cystadenoma associated with
a long history of ulcerative colitis {1123}.
Tumour suppressor gene allelic imbal-ances have been found in about half of
appendiceal mucinous adenomas with
loss of heterozygosity (LOH) at several
chromosomal loci, including 5q22, 6q,
17p13, and 18q21. LOH was most fre-Fig. 5.06  Serrated adenoma of appendix. Fig. 5.07  Serrated adenoma (left) and tubulovillous
adenoma (right).
Fig. 5.09  Hyperplastic polyp of appendix. Cytological abnormalities of intraepithelial neoplasia are absent.
Fig. 5.08  Adenoma with undulating morphology.
98 Tumours of the appendix
quent at the 5q locus linked to the APC
tumour suppressor gene which in the
colorectum is strongly associated with
transition to adenoma {1871}. In cases of
pseudomyxoma peritonei (well differenti-ated mucinous adenocarcinoma), LOH
at one or two polymorphic microsatellite
loci was seen in approximately half of the
cases and was considered an indication
of monoclonality.
Prognosis and predictive factors
SEER data showed the 5-year survival
rates for localized adenocarcinoma to be
95%, compared with a 5-year survival of
80% for mucinous or cystadenocarcino-ma. When distant metastases were pres-ent, the 5-year survival rates were 0%
and 51% respectively {1928}. This
reflects the low aggressive potential of
mucinous tumours that spread to the
peritoneum {1769}.
Features that have been associated with
a poor prognosis in appendiceal adeno-carcinoma include advanced stage,
high-grade, and nonmucinous histology
{345, 1365, 1769}. The spread of mucus
beyond the right lower quadrant of the
abdomen (whether or not cells are iden-tified within it) is an independent prog-nostic variable, as is the presence of
neoplastic cells outside the visceral peri-toneum of the appendix {250}. When
pseudomyxoma peritonei is present,
abdominal distension, weight loss, high
histological grade, and morphological
evidence of invasion of underlying struc-tures have been found to be poor prog-nostic factors, whereas complete exci-sion of tumour is associated with pro-longed disease-free survival {346, 1612,
612}.
Cytological examination of aspirated
mucus and DNA flow cytometry are
unhelpful in predicting prognosis {612,
707}.
Diagnosis Criteria Significance
Adenoma Tumour confined to appendiceal mucosa
(Cystadenoma) and
No histological evidence of invasion
Adenocarcinoma Histological evidence of mural invasion
(Cystadenocarcinoma) or
Presence of metastases,
including spread to peritoneal cavity
Table 5.01
Terminology of epithelial neoplasms of the appendix.
Does not have the capacitiy to
metastasize and can be cured by
complete local excision.
Can spread beyond the appendix
with peritoneal, lymph node or dis-tant metastases.
99Endocrine tumours
Definition
Tumours with endocrine differentiation
arising in the appendix.
Epidemiology
Incidence and time trends
Carcinoids account for 50-77% of all
appendiceal neoplasms {1252, 1131}.
Their incidence rate is 0.075 new cases
per 100,000 population per year and
appears to have been decreasing in the
time period 1950-1991 {1251}. Approx-imately 19% of all carcinoids are located
in the appendix.
Age and sex distribution
The mean age at presentation is 32-43
years (range, 6 to 80 years) {1251, 1252,
1607}. Tubular carcinoids occur at a sig-nificantly younger age than goblet cell
carcinoids (average, 29 versus 53 years)
{209}.
Appendiceal carcinoids occur more fre-quently in females than in males {1251}.
This could reflect the greater number of
incidental appendicectomies performed
in women {1252} but in the SEER data-base, the frequency of non-carcinoid
appendiceal tumours is similar among
males and females, suggesting that the
higher rate of appendiceal carcinoids in
women may not be due solely to higher
rates of appendicectomy {1251}.
Furthermore, the prevalence of girls
among children with appendiceal carci-noids can not be explained by differ-ences in appendicectomy rates {866A,
1255}.
Clinical features
The majority of appendiceal endocrine
tumours are found incidentally in appen-dicectomy specimens; the majority of
these are asymptomatic and located in
the distal end of the appendix. In a small
number of cases, carcinoids involving
the remaining portions of the appendix
may obstruct the lumen and produce
appendicitis {2059, 209}.
Carcinoid syndrome caused by an
appendiceal carcinoid is extremely rare
and almost always related to widespread
metastases, usually to the liver and
retroperitoneum {1252, 1927}.
Macroscopy
Appendiceal EC-cell carcinoids are firm,
greyish-white (yellow after fixation), and
fairly well circumscribed, but not encap-sulated, and measure usually less than
1 cm in diameter {1252}. Tumours > 2 cm
are rare; most are located at the tip of the
appendix {1254}. Goblet-cell carcinoids
and mixed endocrine-exocrine carcino-mas of the appendix may be found in any
portion of the appendix and appear as
an area of whitish, sometimes mucoid
induration without dilatation of the lumen.
They range in size from 0.5 to 2.5 cm
{442}.
Because of their diffusely infiltrative
nature, goblet cell carcinoids tend not to
form distinct tumours and their size gen-erally cannot be assessed accurately. In
a series of 33 cases {209} only two were
suspected grossly; 11 involved the tip
and 22 were circumferential.
Histopathology
Carcinoid (well differentiated endocrine
neoplasm)
Most endocrine tumours of the appendix
are serotonin-producing enterochromaf-fin (EC)-cell carcinoids, while only a
minority are glucagon-like peptide and
PP/PYY-producing L-cell carcinoids and
mixed endocrine-exocrine carcinomas.
They are classifiied according to the
WHO histological classification of
endocrine tumours {1784}.
C. Capella
E. Solcia
L.H. Sobin
R. Arnold
Endocrine tumours of the appendix
Fig. 5.11 Carcinoid tumour of appendix with typical
yellow colouration.
Fig. 5.10  A, B EC-cell carcinoid tumour.
BA
100 Tumours of the appendix
EC-cell, serotonin-producing carcinoid
Argentaffin EC-cells, producing both
serotonin and substance P, are arranged
in rounded solid nests with some periph-eral palisading (type A structure accord-ing to Soga and Tazawa {1775}). Occa-sionally, there may also be glandular for-mations (type C structures), forming a
mixed (A+C) pattern. Most tumours dis-play muscular and lymphatic invasion or
perineural involvement; two thirds of the
cases  invade the peritoneum, possibly
through endolymphatic spread {1252}.
Despite these signs of apparent aggres-siveness appendiceal carcinoids infre-quently produce lymph node or distant
metastases, in contrast to ileal carci-noids.
No relevant histologic, cytological, or
cytochemical differences have been
detected between ileal and appendiceal
carcinoids, despite their very different
clinical behaviour, with the exception of
the presence of S100-positive sustentac-ular cells surrounding tumour nests in
appendiceal lesions. In this respect, EC-cell appendiceal carcinoids resemble
subepithelial neuroendocrine complexes
rather than intraepithelial endocrine cells
{1115, 586, 1182}. In contrast, sustentac-ular cells are lacking in ileal and colonic
EC-cell tumours, which develop from EC-cells of the mucosal crypts {1115, 1291}.
L-cell, glucagon-like peptide
and PP/PYY-producing carcinoid
These are much less common. L-cell
tumours are non-argentaffin, producing
glucagon-like peptides (GLP-1, GLP-2,
and the enteroglucagons glicentin and
oxyntomodulin) and PP/PYY. They feature
a characteristic tubular or trabecular pat-tern (type B pattern according to Soga
and Tazawa {1775, 820, 1724, 1783}).
These tumours generally measure only 2
to 3 mm and are the appendiceal coun-terpart of L-cell tumours that are most fre-quent in the rectum.
Mixed endocrine-exocrine neoplasms
This term is used for certain tumours of
the appendix that show features of both
glandular and endocrine differentiation,
i.e. goblet cell carcinoid, tubular carci-noid and mixed carcinoid-adenocarcino-mas {2059, 1254}.
Goblet-cell carcinoid.   This tumour is
characterized by a predominant submu-cosal growth. It typically invades through
the appendiceal wall in a concentric
manner that does not produce a well-defined tumour {209}. The mucosa is
characteristically spared, with the excep-tion of areas of connection of tumour
nests with the base of the crypts. The
tumour is composed of small, rounded
nests of signet-ring-like cells resembling
normal intestinal goblet cells, except for
nuclear compression. Lumens are infre-quently observed. Lysozyme-positive
Paneth cells as well as foci resembling
Brunner glands may be present {2059,
790}. Mucin stains are intensely positive
within goblet cells and extracellular
mucin pools {790}. Argentaffin and argy-rophil cells, sparse or forming small
nests, are identified in 50% and 88% of
cases, respectively {2059}.
Immunohistochemically, the endocrine
cell component is positive for chromo-granin A, serotonin, enteroglucagon,
somatostatin, and/or PP {790, 725}. The
goblet cells express CEA. On ultrastruc-tural examination, both dense core
endocrine granules and mucin droplets
are found {442, 725}. Both elements are
occasionally present within the cyto-plasm of the same cell {442, 790}.
Tubular carcinoid.   This tumour is often
misinterpreted as a metastatic adenocar-cinoma, because it does not resemble
the typical carcinoid and shows little con-tact with the mucosa. It is composed of
small, discrete tubules, some with inspis-sated mucin in their lumen. Short trabec-ular structures are frequent, but solid
nests are generally absent. In sparse
cells or in small groups of tumour cells,
the argentaffin reaction is positive in 75%
Fig. 5.12 Carcinoid tumour infiltrating mesoappendix.
Fig. 5.14 EC-cell carcinoid tumour. A Chromogranin B. B S-100 immunohistochemistry demonstrating sustentacular cells.
BA
Fig. 5.13  Small cell carcinoma arising in an appen-diceal tubulovillous adenoma.
101Endocrine tumours
and the argyrophil reaction in 89% of
cases {2059}. Useful criteria for diagnos-ing this tumour are origin from the base
of the crypts, integrity of the luminal
mucosa, orderly arrangements, and
absence of cytological abnormalities and
mitoses. Immunohistochemically, tumour
cells are often positive for chromogranin
A, glucagon, serotonin, and IgA, while
they are unreactive for S100 protein {586,
209}.
Mixed carcinoid-adenocarcinoma.   This
term has been proposed to designate
carcinomas of the appendix that arise by
progression from a pre-existing goblet-cell carcinoid. These carcinomas occur
in the apparent absence of neoplastic
change in the mucosal epithelium {209}.
Genetics
Loss of heterozygosity at  MEN-1 gene
locus in sporadic appendiceal carci-noids was reported {829}, but has not
been confirmed in more recent studies
{394, 1938}.
Unlike colonic adenocarcinomas, KRAS
mutations have not been detected either
in typical or in goblet-cell carcinoid of the
appendix {1556}, while in the same
study, TP53 mutations (mainly G:C to A:T
transitions) were detected in 25% of gob-let-cell carcinoids.
Prognosis and predictive factors
The majority of patients with endocrine
tumours of the appendix have a
favourable prognosis. Clinically non-functioning, non-angioinvasive lesions
confined to the appendiceal wall, and
< 2 cm in diameter are generally cured
by complete local excision, whereas
invasion of the mesoappendix or beyond
or metastatic spread indicates that the
lesion is aggressive. The most important
risk factors appear to be tumour size
> 2 cm and invasion of the mesoappen-dix {1134}. Lesions confined to the
appendiceal wall that show angioinva-sion or are > 2 cm in size, carry an uncer-tain malignant potential.
Location of tumours at the base of the
appendix with involvement of the surgi-cal margin or of the caecum is prognos-tically unfavourable, requiring at least a
partial caecectomy to avoid residual
tumour or subsequent recurrence {1931}.
The reported frequency of metastases
from appendiceal carcinoids ranged
from 1.4% and 8.8% in older series
{1252, 1927, 1254, 1780}, while in a more
recent study the frequency of regional
metastases was 27%, and that of distant
metastases 8.5% {1251}.
The 5-year survival of patients with
appendiceal carcinoid is 94% for local-ized disease, 85% for regional disease,
and 34% for distant metastases {1251}.
Goblet-cell carcinoids are more aggres-sive than conventional carcinoids, but not
as malignant as adenocarcinomas of the
appendix. In one study the percentage of
patients dead of goblet cell carcinoids
was 12.5% {442}. Tubular carcinoids, in
contrast, are clinically benign {209}.
Fig. 5.17  Tubular carcinoid.Fig. 5.16  Clear cell carcinoid.Fig. 5.15  L-cell tumour showing trabecular pattern
and glicentin immunoexpression.
A C
Fig. 5.18  Goblet cell carcinoid tumour. A Typical concentric mural distribution of tumour with preservation of the appendiceal lumen. Mucin positive tumour nests
(green) are seen in this Movat stain. Lumen is compressed, but intact. B Typical clusters of goblet cells. C Chromogranin A positive cells.
B
102 Tumours of the appendix
Neuromas are common in the appendix.
The most frequent manifestation is the
axial neuroma, which causes fibrous
obliteration of the appendiceal lumen.
Occasionally, neuromas may be found in
the mucosa or submucosa without lumi-nal obliteration {1423, 251, 1818}.
Appendiceal neuromas may be reactive
lesions. Histologically, they consist of a
myxoid and collagenous background
within which a variety of cells is present,
including nerve fibres, spindle cells that
immunoexpress S-100 protein, endo-crine cells, mast cells and eosinophils. In
this context, the presence of endocrine
cells should not be mistaken for carci-noid tumour. However, it has been sug-gested that some carcinoids of the
appendix might develop in the same set-ting as appendiceal neuroma. {251}.
Stromal tumours may affect the appendix
on rare occasions; they have generally
been described in the literature as being
of smooth muscle type {324, 865}.
Kaposi sarcoma may be found in the
appendix as part of the acquired immuno-deficiency syndrome {406}. Rarely, it
occurs in individuals without evidence of
HIV infection {295}.
Malignant lymphomas involve the appen-dix usually as part of more general intes-tinal spread. Lymphomas presenting as
primary disease of the appendix are rare;
some are of Burkitt type {1295, 1761}.
Secondary tumours are unusual in the
appendix. Primary sites include carcino-mas of the gastrointestinal and urogenital
tract, breast, lung, and gallbladder.
Metastatic thymoma and melanoma have
also been reported {130, 98, 570, 607,
1051, 1407, 1615, 1822, 2129}. A com-mon pattern is serosal involvement, pre-sumably due to transcoelomic spread.
N.J. Carr
L.H. Sobin
C. Niederau
Miscellaneous tumours of the appendix
Fig. 5.19  Burkitt lymphoma of appendix.
CHAPTER 6
Tumours of the Colon and Rectum
Colorectal carcinomas vary considerably throughout the
world, being one of the leading cancer sites in the developed
countries. Both environmental (diet) and genetic factors play
key roles in its aetiology. Genetic susceptibility ranges from
well-defined inherited syndromes, e.g. familial adenomatous
polyposis, to ill-defined familial aggregations. Molecular
genetic mechanisms are diverse, and recent data suggest two
main pathways: a mutational pathway, which involves inacti-vation of tumour suppressor genes such as APC; and
microsatellite instability which occurs in hereditary nonpolypo-sis colon cancer (HNPCC) and a proportion of sporadic carci-nomas.
The main precursor lesion is the adenoma, which is readily
detected and treated by endoscopic techniques. Non-neo-plastic polyps are not considered precancerous unless they
occur in polyposis syndromes. Inflammatory bowel diseases,
such as chronic ulcerative colitis, bear resemblance to Barrett
oesophagus as a precursor lesion with a potential for control
by endoscopic surveillance. Cure is strongly related to
anatomic extent, which makes accurate staging very impor-tant.
Lymphomas, endocrine tumours, and mesenchymal tumours
are quite uncommon at this site.
Epithelial tumours
Adenoma 8140/0
Tubular 8211/0
Villous 8261/0
Tubulovillous 8263/0
Serrated 8213/0
Intraepithelial neoplasia2
(dysplasia)
associated with chronic inflammatory diseases
Low-grade glandular intraepithelial neoplasia
High-grade glandular intraepithelial neoplasia
Carcinoma
Adenocarcinoma 8140/3
Mucinous adenocarcinoma 8480/3
Signet-ring cell carcinoma 8490/3
Small cell carcinoma 8041/3
Squamous cell carcinoma 8070/3
Adenosquamous carcinoma 8560/3
Medullary carcinoma 8510/3
Undifferentiated carcinoma 8020/3
Carcinoid (well differentiated endocrine neoplasm) 8240/3
EC-cell, serotonin-producing neoplasm 8241/3
L-cell, glucagon-like peptide and PP/PYY producing tumour
Others
Mixed carcinoid-adenocarcinoma 8244/3
Others
Non-epithelial tumours
Lipoma 8850/0
Leiomyoma 8890/0
Gastrointestinal stromal tumour 8936/1
Leiomyosarcoma 8890/3
Angiosarcoma 9120/3
Kaposi sarcoma 9140/3
Malignant melanoma  8720/3
Others
Malignant lymphomas
Marginal zone B-cell lymphoma of MALT Type 9699/3
Mantle cell lymphoma  9673/3
Diffuse large B-cell lymphoma 9680/3
Burkitt lymphoma 9687/3
Burkitt-like /atypical Burkitt-lymphoma 9687/3
Others
Secondary tumours
Polyps
Hyperplastic (metaplastic)
Peutz-Jeghers
Juvenile
WHO histological classification of tumours of the colon and rectum1
104 Tumours of the colon and rectum
_________
1
This classification is modified from the previous WHO histological classification of tumours {845} taking into account changes in our understanding of these lesions. In the case of
endocrine neoplasms, it is based on the recent WHO classification {1784} but has been simplified to be of more practical utility in morphological classification.
2
Morphology code of the International Classification of Diseases for Oncology (ICD-O) {542} and the Systematized Nomenclature of Medicine (http://snomed.org). Behaviour is coded
/0 for benign tumours, /3 for malignant tumours, /2 for in situ carcinomas and grade III intraepithelial neoplasia, and /1 for unspecified, borderline or uncertain behaviour. Intraepithelial
neoplasia does not have a generic code in ICD-O. ICD-O codes are available only for lesions categorized as glandular intraepithelial neoplasia grade III (8148/2), and adenocarcino-ma in situ (8140/2).
TNM classification1, 2
T – Primary Tumour
TX Primary tumour cannot be assessed
T0 No evidence of primary tumour
Tis Carcinoma in situ: intraepithelial or invasion of lamina propria3
T1 Tumour invades submucosa
T2 Tumour invades muscularis propria
T3 Tumour invades through muscularis propria into subserosa
or into non-peritonealized pericolic or perirectal tissues
T4 Tumour directly invades other organs or structures4
and/or perforates visceral peritoneum
N – Regional Lymph Nodes
NX Regional lymph nodes cannot be assessed
N0 No regional lymph node metastasis
N1 Metastasis in 1 to 3 regional lymph nodes
N2 Metastasis in 4 or more regional lymph nodes
M – Distant Metastasis
MX Distant metastasis cannot be assessed
M0 No distant metastasis
M1 Distant metastasis
Stage Grouping
Stage 0 Tis N0 M0
Stage I T1 N0 M0
T2 N0 M0
Stage II T3 N0 M0
T4 N0 M0
Stage III Any T N1 M0
Any T N2 M0
Stage IV Any T Any N M1
TNM classification of tumours of the colon and rectum
_________
1
{1, 66}. This classification applies only to carcinomas.
2
A help desk for specific questions about the TNM classification is available at http://tnm.uicc.org.
3
This includes cancer cells confined within the glandular basement membrane (intraepithelial) or lamina propria (intramucosal) with no extension through muscularis mucosae into
submucosa.
4
Direct invasion in T4 includes invasion of other segments of the colorectum by way of the serosa, e.g. invasion of sigmoid colon by a carcinoma of the cecum.
105
Definition
A malignant epithelial tumour of the colon
or rectum. Only tumours that have pene-trated through muscularis mucosae into
submucosa are considered malignant at
this site. The presence of scattered
Paneth cells, neuroendocrine cells or
small foci of squamous cell differentiation
is compatible with the diagnosis of adeno-carcinoma.
ICD-O codes
Adenocarcinoma 8140/3
Mucinous adenocarcinoma 8480/3
Signet-ring cell carcinoma 8490/3
Small cell carcinoma 8041/3
Squamous cell carcinoma 8070/3
Adenosquamous carcinoma 8560/3
Medullary carcinoma 8510/3
Undifferentiated carcinoma 8020/3
Epidemiology
An estimated 875,000 cases of colorec-tal cancer occurred worldwide in 1996,
representing about 8.5% of all new can-cers {1531}. The age-standardized inci-dence (cases/100,000 population) varies
greatly around the world, with up to 20-fold differences between the high rates in
developed countries of Europe, North
and South America, Australia/New
Zealand, and Asia  and the still lower
rates in some recently developed coun-tries (Malaysia, Korea) and in developing
countries of Africa, Asia and Polynesia.
Significant differences also exist within
continents, e.g. with higher incidences in
western and northern Europe than in
central and southern Europe {336}.
Among immigrants and their descen-dants, incidence rates rapidly reach
those of the adopted country, indicating
that environmental factors are important.
According to the U.S. SEER database,
the incidence rate for adenocarcinoma of
the colon is 33.7/100,000 and increased
by 18% during the period from 1973
through 1987 while the incidence of rec-tal adenocarcinoma (12.8/100,000) and
mucinous adenocarcinoma in the colon
and rectum (0.3 and 0.8, respectively)
remained relatively constant {1928}.
During the last decade of the 20th centu-ry, incidence and mortality have
decreased {566}. By contrast, the inci-dence in Japan, Korea and Singapore is
rising rapidly {737}, probably due to the
acquisition of a Western lifestyle.
Incidence increases with age {2121}:
carcinomas are rare before the age of 40
years except in individuals with genetic
predisposition or predisposing condi-tions such as chronic inflammatory bowel
disease.
Incidence rates in the 1973-87 SEER
data for colonic and rectal adenocarci-noma for males were higher than those
for females; whites had higher rates than
blacks for rectal adenocarcinoma, but
blacks had higher rates for colonic ade-nocarcinoma {1928}. During 1975-94, a
decrease in incidence in whites was evi-dent, while the incidence of proximal
colon cancers in blacks still increased
{1958}.
Aetiology
Diet and lifestyle
A high incidence of colorectal carcino-mas is consistently observed in popula-tions with a Western type diet, i.e. highly
caloric food rich in animal fat combined
S.R. Hamilton C.A. Rubio
B. Vogelstein L.H. Sobin
S. Kudo F. Fogt
E. Riboli S.J. Winawer
S. Nakamura D.E. Goldgar
P. Hainaut J.R. Jass
Carcinoma of the colon and rectum
Adenocarcinoma
Fig. 6.01 Worldwide annual incidence (per 100,000) of colon and rectum cancer
in males. Numbers on the map indicate regional average values.
From: Globocan, IARC Press, Lyon.
Fig. 6.03 Double contrast barium enema showing
adenocarcinoma of colon. Between the proximal
(top) and distal (bottom) segment of the colon the
lumen is narrowed with an irregular surface, due to
tumour infiltration.
Fig. 6.02 Male incidence (blue) and mortality (orange) of colorectal cancer in
some selected countries.
From: Globocan, IARC Press, Lyon.
Hungary
Australia
Japan
France
United States
Spain
Finland
Brazil
South America
0102030405060
Incidence
Mortality
106 Tumours of the colon and rectum
with a sedentary lifestyle. Epidemiologi-cal studies have indicate that meat con-sumption, smoking and alcohol con-sumption are risk factors. Inverse associ-ations include vegetable consumption,
prolonged use of non-steroidal anti-inflammatory drugs, oestrogen replace-ment therapy, and physical activity {1531,
2121}. Fibre may have a protective role,
but this has been questioned recently.
The molecular pathways underlying
these epidemiological associations are
poorly understood, but production of het-erocyclic amines during cooking of meat,
stimulation of higher levels of fecal bile
acids and production of reactive oxygen
species have been implicated as possi-ble mechanisms {416, 1439}.
Vegetable anticarcinogens such as
folate, antioxidants and inducers of
detoxifying enzymes, binding of luminal
carcinogens, fibre fermentation to pro-duce protective volatile fatty acids, and
reduced contact time with colorectal
epithelium due to faster transit may
explain some of the inverse associations.
Chronic inflammation
Chronic inflammatory bowel diseases are
significant aetiological factors in the
development of colorectal adenocarcino-mas {1582}. The risk increases after 8-10
years and is highest in patients with
early-onset and widespread manifesta-tion (pancolitis).
Ulcerative colitis.   This chronic disorder
of unknown aetiology affects children
and adults, with a peak incidence in the
early third decade. It is considered a pre-malignant disorder, with duration and
extent of disease being the major risk
factors. Population-based studies show
a 4.4-fold increase in mortality from col-orectal carcinoma {1504, 448, 1835,
1214}. In clinical studies, the increase in
incidence is usually higher, up to 20-fold
{647, 990}. Involvement of greater than
one half of the colon is associated with a
risk to develop carcinoma of approxi-mately 15%, whereas left sided disease
may bear a malignancy risk of 5% {1727,
1045}. Ulcerative proctitis is not associat-ed with an increased carcinoma risk.
Crohn disease.  Development of carcino-ma is seen both in the small intestine and
the large intestine. The risk of colorectal
malignancy appears to be 3 fold above
normal {581}. Long duration and early
onset of disease are risk factors for car-cinoma.
Modifying factors. Non-steroidal anti-inflammatory drugs and some naturally
occurring compounds block the bio-chemical abnormalities in prostaglandin
homeostasis in colorectal neoplasms.
Some of these agents cause a dramatic
involution of adenomas but their role in
the chemoprevention of adenocarcinoma
is less clear. Polymorphisms in key
enzymes can alter other metabolic path-ways that modify protective or injurious
compounds, e.g. methylenetetrahydrofo-late reductase, N-acetyltransferases, glu-tathione-S-transferases, aldehyde dehy-drogenase and cytochrome P-450 {1766,
686, 1300}. These polymorphisms may
explain individual susceptibility or predis-position among populations with similar
exposures {1555}.
Irradiation.
A rare but well recognized aetiological
factor in colorectal neoplasia is thera-peutic pelvic irradiation {1974}.
Localization
Most colorectal carcinomas are located
in the sigmoid colon and rectum, but
there is evidence of changing distribu-tion in recent years, with an increasing
proportion of more proximal carcinomas
BA
A B
Fig. 6.04 A Depressed lesion highlighted with indigo-carmine dye spray corresponding to high-grade
intraepithelial neoplasia. B Flat, elevated adenoma with high-grade intraepithelial neoplasia after indigo-carmine dye spray.
Fig. 6.05 Endoscopic features of (A) polypoid, (B) flat, slightly elevated and (C) flat adenoma.
C
107Adenocarcinoma
{1928}. Molecular pathology has also
shown site differences: tumours with high
levels of microsatellite instability (MSI-H)
or ras proto-oncogene mutations are
more frequently located in the caecum,
ascending colon and transverse colon.
{842, 1563, 1897}.
Clinical features
Signs and symptoms
Some patients are asymptomatic, espe-cially when their neoplasm is identified
by screening or surveillance. Haemato-chezia and anaemia are common pre-senting features due to bleeding from
the tumour. Many patients experience
change in bowel habit; in the right colon,
the fluid faeces can pass exophytic
masses, whereas in the left colon the
solid faeces are more often halted by
annular tumours so that constipation is
more common. There may be associated
abdominal distension. Rectosigmoid
lesions can produce tenesmus. Other
symptoms include fever, malaise, weight
loss, and abdominal pain. Some patients
present with the complications of
obstruction or perforation.
Imaging
Modern imaging techniques permit non-invasive detection and clinical staging.
Conventional barium enema detects large
tumours, while air-contrast radiography
improves the visualization of less ad-vanced lesions. Cross-sectional imaging
by CT, MRI imaging and transrectal ultra-sonography permit some assessment of
the depth of local tumour invasion and the
presence of regional and distant metas-tases {2202}. Scintigraphy and positron
emission tomography are also used.
Endoscopy
The development of endoscopy has had
a major impact on diagnosis and treat-ment. Colonoscopy allows observation of
the mucosal surface of the entire large
bowel with biopsy of identified lesions.
Chromoendoscopy employing dyes to
improve visualization of non-protruding
lesions and magnification, have been
developed. The flat neoplastic lesions
BA
DC
Fig. 6.06 A Endoscopic view of two small flat adenomas highlighted with indigo-carmine to show the abnor-mal tubular pit pattern. B Magnifying video endoscopy of a tubulovillous adenoma highlighted with indigo-carmine to show cribriform pattern. C Histological section of a flat elevated tubular adenoma showing low-grade intraepithelial neoplasia.  D Stereomicroscopic view with indigo-carmine dye spray of a depressed
adenoma with high-grade intraepithelial neoplasia containing very small round pits.
BA
Fig. 6.07  A Small adenocarcinoma invading muscularis propria, arising in a depressed adenoma. B Early adenocarcinoma invading submucosa, arising in a flat ade-noma.
108 Tumours of the colon and rectum
have been designated by Japanese gas-troenterologists as ‘type II’, with three
subtypes: IIa, ‘en plateau’ elevated; IIb,
completely flat; and IIc, ‘en plateau’
depressed. The depressed lesions have,
despite a smaller diameter, a poor prog-nosis with prompt penetration in the sub-mucosa. The pit pattern of the surface at
magnification 100 allows a reliable pre-diction of histology. Therapeutic endo-scopy, including snare polypectomy and
endoscopic mucosectomy, can be used
to remove colorectal neoplasms, espe-cially adenomas, and carcinomas with
minimal submucosal invasion. Protruded
neoplasms can usually be resected by
snare polypectomy. Superficial lesions
(flat and depressed) and some protruded
lesions may be removed by endoscopic
mucosal resection {2121, 2122, 1164}.
Macroscopy
The macroscopic features are influenced
by the phase in the natural history of
tumours at the time of discovery.
Carcinomas may be exophytic/fungating
with predominantly intraluminal growth,
endophytic/ulcerative with predominantly
intramural growth, diffusely infiltrative/lini-tis plastica with subtle endophytic
growth, and annular with circumferential
involvement of the colorectal wall and
constriction of the lumen. Overlap among
these types is common. Pedunculated
exophytic lesions have a mural attach-ment narrower than the head of the
tumour, with the stalk consisting of unin-volved mucosa and submucosa, while
sessile exophytic tumours have broad
attachment to the wall.
Carcinomas of the proximal colon tend to
grow as exophytic masses while those in
the transverse and descending colon are
more often endophytic and annular. On
cut section, most colorectal carcinomas
have a relatively homogeneous appear-ance although areas of necrosis can be
seen. Adenocarcinomas of the mucinous
(colloid) type often have areas with
grossly visible mucus. Carcinomas with
high levels of microsatellite instability
(MSI-H) are usually circumscribed and
about 20% are mucinous {842}.
Tumour spread and staging
Following transmural extension through
the muscularis propria into pericolic or
perirectal soft tissue, the tumour may
involve contiguous structures. The con-sequences of direct extension depend
on the anatomic site. An advanced rectal
carcinoma may extend into pelvic struc-tures such as the vagina and urinary
bladder, but cannot gain direct access to
the peritoneal cavity when it is located
distal to the peritoneal reflection.
By contrast, colonic tumours can extend
directly to the serosal surface. Perforation
can be associated with transcoelomic
spread to the peritoneal cavity (peritoneal
carcinomatosis). Involvement of the peri-toneal surface should only be diagnosed
if the peritoneum is ulcerated or if tumour
cells have clearly penetrated the
mesothelium. Since the peritoneal sur-face infiltrated by tumour cells may
become adherent to adjacent structures,
direct extension into adjoining organs
can also occur in colonic carcinomas that
have invaded the peritoneal portion of the
wall {62}. Implantation due to surgical
manipulation occurs only occasionally,
but has been reported after laparoscop-ic colectomy for cancer {1106}.
Spread via lymphatic or blood vessels
can occur early in the natural history and
lead to systemic disease. Despite the
presence of lymphatics in the colorectal
mucosa, lymphogenic spread does not
occur unless the muscularis mucosae is
breached and the submucosa is invad-ed, This biological behaviour stands in
sharp contrast to carcinomas of the
stomach where metastasis occurs occa-Fig. 6.11 Crohn-like lymphoid reaction associated
with a colonic adenocarcinoma.
Fig. 6.10  Well differentiated adenocarcinoma aris-ing in Crohn disease, invading wall beneath intra-epithelial neoplasia.
B C
Fig. 6.08 Advanced colorectal carcinomas. A Small depressed invasive carcinoma (arrow) with a nearby protruding adenoma, B Advanced colorectal carcinoma,
depressed type. C Cross section of adenocarcinoma with extension into the submucosa (pT1).
A
Fig. 6.09 Small ulcerating adenocarcinoma of colon
producing a depressed lesion.
109Adenocarcinoma
sionally from purely intramucosal carci-nomas. Invasion of portal vein tributaries
in the colon and vena cava tributaries in
the rectum can lead to haematogenous
dissemination.
Staging
The classification proposed by C. Dukes
in 1929-35 for rectal cancer serves as
the template for many staging systems
currently in use. This family of classifica-tions takes into account two histopatho-logical features: depth of penetration
into the wall and the presence or
absence of metastasis in regional lymph
nodes. The TNM classification {66} is
replacing the Dukes classification.
Histopathology
The defining feature of colorectal adeno-carcinoma is invasion through the muscu-laris mucosae into the submucosa.
Lesions with the morphological charac-teristics of adenocarcinoma that are con-fined to the epithelium or invade the lam-ina propria alone and lack invasion
through the muscularis mucosae into the
submucosa have virtually no risk of
metastasis. Therefore,  ‘high-grade intra-epithelial neoplasia’ is a more appropriate
term than  ‘adenocarcinoma in-situ’, and
‘intramucosal neoplasia’ is more appro-priate than  ‘intramucosal adenocarcino-ma’. Use of these proposed terms helps
to avoid overtreatment.
Most colorectal adenocarcinomas are
gland-forming, with variability in the size
and configuration of the glandular struc-tures. In well and moderately differentiat-ed adenocarcinomas, the epithelial cells
are usually large and tall, and the gland
lumina often contain cellular debris.
Mucinous adenocarcinoma
This designation is used if > 50% of the
lesion is composed of mucin. This vari-ant is characterized by pools of extracel-lular mucin that contain malignant
epithelium as acinar structures, strips of
cells or single cells. Many high-frequen-cy micro-satellite instability (MSI-H) car-cinomas are of this histopathological
type.
Signet-ring cell carcinoma
This variant of adenocarcinoma is
defined by the presence of > 50% of
tumour cells with prominent intracytoplas-mic mucin {1672}.
The typical signet-ring cell has a large
mucin vacuole that fills the cytoplasm
and displaces the nucleus. Signet-ring
cells can occur in the mucin pools of
mucinous adenocarcinoma or in a dif-fusely infiltrative process with minimal
extracellular mucin. Some MSI-H carcino-mas are of this type.
Adenosquamous carcinoma
These unusual tumours show features of
both squamous carcinoma and adeno-carcinoma, either as separate areas with-in the tumour or admixed. For a lesion to
be classified as adenosquamous, there
should be more than just occasional
small foci of squamous differentiation.
Pure  squamous cell carcinoma is very
rare in the large bowel.
Fig. 6.14 Villous adenoma of rectum and invasive
adenocarcinoma. Two of four lymph nodes in
perirectal tissue have metastasis.
Fig. 6.13  A Tubulovillous adenoma showing invasive adenocarcinoma within the core of the polyp.
B Adenocarcinoma arising in a villous adenoma.
BA
D
A
Fig. 6.12  A Well differentiated adenocarcinoma. B Moderately diffferentiated adenocarcinoma. C Poorly dif-ferentiated adenocarcinoma; this lesion was MSI-H and shows numerous intraepithelial lymphocytes.
D Undifferentiated carcinoma.
C
B
110 Tumours of the colon and rectum
Medullary carcinoma
This rare variant is characterized by
sheets of malignant cells with vesicular
nuclei, prominent nucleoli and abundant
pink cytoplasm exhibiting prominent infil-tration by intraepithelial lymphocytes
{856}. It is invariably associated with
MSI-H and has a favourable prognosis
when compared to other poorly differen-tiated and undifferentiated colorectal
carcinomas.
Undifferentiated carcinoma
These rare tumours lack morphological
evidence of differentiation beyond that of
an epithelial tumour and have variable
histological features {1946}. Despite their
undifferentiated appearances, these
tumours are genetically distinct and typi-cally associated with MSI-H.
Other variants
Carcinomas that include a spindle cell
component are best termed spindle cell
carcinoma or sarcomatoid carcinoma.
The spindle cells are, at least focally,
immunoreactive for cytokeratin. The term
carcinosarcoma applies to malignant
tumours containing both carcinomatous
and heterologous mesenchymal ele-ments. Other rare histopathological vari-ants of colorectal carcinoma include
pleomorphic (giant cell), choriocarcino-ma, pigmented, clear cell, stem cell, and
Paneth cell-rich (crypt cell carcinoma).
Mixtures of histopathological types can
be seen.
Carcinosarcoma
Carcinomas that include a spindle cell
component are best termed sarcomatoid
carcinoma or spindle cell carcinoma. The
spindle cells are, at least focally, immuno-reactive for cytokeratin. The term carci-nosarcoma applies to malignant tumours
containing both carcinomatous and het-erologous mesenchymal elements.
Grading
Adenocarcinomas are graded predomi-nantly on the basis of the extent of glan-dular appearances, and should be divid-ed into well, moderately and poorly dif-ferentiated, or into low-grade (encom-passing well and moderately differentiat-ed adenocarcinomas) and high-grade
(including poorly differentiated adeno-carcinomas and undifferentiated carcino-mas). Poorly differentiated adenocarci-nomas should show at least some gland
formation or mucus production; tubules
are typically irregularly folded and dis-torted.
When a carcinoma has heterogeneity in
differentiation, grading should be based
on the least differentiated component,
not including the leading front of inva-sion. Small foci of apparent poor differ-entiation are common at the advancing
edge of tumours, but this feature is insuf-ficient to classify the tumour as poorly dif-ferentiated {1543}.
The percentage of the tumour showing
formation of gland-like structures can be
used to define the grade. Well differentiat-ed (grade 1) lesions exhibit glandular
structures in > 95% of the tumour; moder-ately differentiated (grade 2) adenocarci-Fig. 6.16 Metastatic adenocarcinoma in regional
lymph node. Fig. 6.19 Adenocarcinoma with venous invasion.
BA
DC
Fig. 6.17  Mucinous adenocarcinoma. A Cut surface with glassy appearance. B Mucinous adenocarcinoma
beneath high-grade intraepithelial neoplasia in ulcerative colitis.  C Well-differentiated tumour with large
mucin lakes. D Multilocular mucin deposits with well-differentiated adenocarcinoma.
Fig 6.18  Signet-ring cell carcinoma invading a
nerve.
Fig. 6.15 Adenocarcinoma within lymphatic vessel.
111Adenocarcinoma
noma has 50-95% glands; poorly differen-tiated (grade 3) adenocarcinoma has
5-50%; and undifferentiated (grade 4)
carcinoma has < 5%. Mucinous adeno-carcinoma and signet-ring cell carcinoma
by convention are considered poorly dif-ferentiated (grade 3). Medullary carcino-ma with MSI-H appears undifferentiated.
Additional studies of the biological behav-iour of MSI-H cancers are needed to
relate the morphological grade and
molecular subtypes of mucinous, signet-ring cell and medullary carcinoma to out-come since MSI-H carcinomas have an
improved stage-specific survival {788,
924, 1098}.
Precursor lesions
During the past decade the natural histo-ry of colorectal carcinomas has been
extensively studied in correlation with the
underlying accumulation of genetic alter-ations.
Aberrant crypt foci (ACF)
The earliest morphological precursor of
epithelial neoplasia is the aberrant crypt
focus (ACF). Microscopic examination of
mucosal sheets dissected from the
bowel wall and stained with methylene
blue, or mucosal examination with a
magnifying endoscope, reveal ACFs to
have crypts of enlarged calibre and
thickened epithelium with reduced mucin
content. Microscopy shows two main
types: ACFs with features of hyperplastic
polyps and a high frequency of ras proto-oncogene mutations, and  dysplastic
ACFs (micro-adenomas) associated with
a mutation of the  APC gene {1375}.
Progression from ACF through adenoma
to carcinoma characterizes carcinogene-sis in the large intestine {1326}.
Adenomas
These precursor lesions are defined by
the presence of intraepithelial neoplasia,
histologically characterized by hypercel-lularity with enlarged, hyperchromatic
nuclei, varying degrees of nuclear strati-fication, and loss of polarity. Nuclei may
be spindle-shaped, or enlarged and
ovoid. Inactivation of the APC/beta-catenin pathway commonly initiates the
process and results in extension of
epithelial proliferation in dysplastic
epithelium from the base of the crypts,
where it normally occurs, toward or onto
the luminal surface {851, 1528}. Polyps
appear to grow as a consequence of
accelerated crypt fission resulting from
APC gene mutation {564}. Intraepithelial
neoplasia can be low-grade or high-grade, depending on the degree of glan-dular or villous complexity, extent of
nuclear stratification, and severity of
abnormal nuclear morphology. Paneth
cells, neuroendocrine cells and squa-mous cell aggregates may be seen in
adenomas and may become a dominant
constituent of the epithelium.
Macroscopy.  Colorectal adenomas can
be classified into three groups: elevated,
flat, and depressed {973}. Elevated ade-nomas range from pedunculated polyps
with a long stalk of non-neoplastic
mucosa to those that are sessile. Flat or
non-protruding adenomas and de-pressed adenomas are recognized
macroscopically by mucosal reddening,
subtle changes in texture, or highlighting
by dye techniques. The term adenoma is
applied even though the lesions are not
polypoid because intraepithelial neopla-B CA
Fig. 6.20  A Signet-ring cell carcinoma arising in an adenoma; intramucosal signet-ring cells adjacent to adenomatous glands. B Signet-ring cells infiltrating mus-cularis propria. C Lymph node metastasis of a signet-ring cell carcinoma.
Fig. 6.21 Sporadic proximal colonic carcinomas. Comparison of pathology of MSI-H
(red) and microsatellite stable MSS (blue) carcinomas.
Fig. 6.22 Frequency of adenocarcinoma in adenomas relative to size and archi-tecture.
MSI-H
MSS* p<0.05;  ** p<0.01
112 Tumours of the colon and rectum
sia (dysplasia) is the hallmark of these
lesions. Depressed adenomas are usual-ly smaller than flat or protruding ones
and tend to give rise to adenocarcinoma
while still relatively small (mean diameter,
11 mm) due to a greater tendency to
progress {1628}. These adenomas have
a lower frequency of  ras mutation than
polypoid adenomas {974}.
Histopathology.  Tubular adenomas are
usually protruding, spherical and pedun-culated, or non-protruding (flat). Micro-scopically, dysplastic glandular struc-tures occupy at least 80% of the luminal
surface.  Villous adenomas are typically
sessile with a hairy-appearing surface.
Microscopically, leaf-like projections lined
by dysplastic glandular epithelium com-prise more than 80% of the luminal sur-face. Distinction of villous structures from
elongated separated tubules is some-times problematical. Villous architecture
is defined arbitrarily by the length of the
glands exceeding twice the thickness of
normal colorectal mucosa.  Tubulovillous
adenomas have a mixture of tubular and
villous structures with a ratio between
80%/20% and 20%/80%. Serrated adeno-mas are characterized by the saw-tooth
configuration of a hyperplastic (metaplas-tic) polyp on low power microscopy, but
the epithelium lining the upper portion of
the crypts and luminal surface is dysplas-tic. Serrated adenomas can also have a
tubular or villous component, but low-lev-els of microsatellite instability (MSI-L) and
altered mucin are characteristic of these
serrated lesions {840}. By contrast, mixed
hyperplastic polyp/adenoma  contains
separate identifiable areas of each histo-pathological type {1092}. Occasionally,
some villous adenomas show in the
slopes of the villi closely packed small
glands; those adenomas have been
referred to as villo-microglandular adeno-mas {972}.
Although tiny flat or depressed adeno-carcinomas are well-described, it is diffi-cult to determine if de novo adenocarci-nomas without a benign histopathologi-cal precursor lesion ever occur in the
large bowel, because adenocarcinoma
can overgrow the precursor lesion. The
prolonged time interval usually required
for progression of intraepithelial to inva-sive neoplasia offers opportunities for
prevention or interruption of the process
to reduce mortality due to colorectal car-cinoma.
Intraepithelial neoplasia can also occur
in the absence of an adenoma, in a pre-existing lesion of another type (such as a
hamartomatous polyp in juvenile polypo-sis syndrome and Peutz-Jeghers syn-drome), and in chronic inflammatory dis-eases.
Hyperplastic (metaplastic) polyps
The definition is a mucosal excrescence
characterized by elongated, serrated
crypts lined by proliferative epithelium in
the bases with infolded epithelial tufts
and enlarged goblet cells in the upper
crypts and on the luminal surface,
imparting a saw-tooth outline. In the
appendix, diffuse hyperplasia may occur
as a sessile mucosal proliferation.
The epithelial nuclei in the serrated region
are small, regular, round and located at
Fig. 6.23 Clear cell carcinoma of colon.
BA
Fig. 6.26  A, B Crypt adenoma in a patient with FAP.
B
A
Fig. 6.25  A Sessile villous adenoma.  B Section
through a villous adenoma.
Fig. 6.24 Tubulovillous adenoma. Pedunculated
with long stalk of non-neoplastic mucosa.
Fig. 6.27 Tubular adenoma of colon.
113Adenocarcinoma
the base of the cells adjoining the base-ment membrane, which is often thick-ened beneath the surface epithelial cells.
The cytoplasm contains prominent mucin
vacuoles, which are usually larger than
normal goblet cells. The proliferative zone
often shows increased cellularity and
mitotic activity, which can be mistaken for
adenoma. Hyperplastic polyps are tradi-tionally considered non-neoplastic, but
ras mutation is common, clonality has
been demonstrated, and biochemical
abnormalities and epidemiological asso-ciations that occur in colorectal adeno-mas and carcinomas have been found
{851, 663, 1178}. These lines of evidence
suggest that hyperplastic polyps may be
neoplastic but have a molecular patho-genesis that differs from the adenoma-adenocarcinoma sequence due to
absence of inactivation of the APC/beta-catenin pathway.
Juvenile polyps
Sporadic juvenile polyps are typically
spherical, lobulated and pedunculated
and considered hamartomatous. They
most commonly occur in children. The
surface is often eroded and friable, and
the cut surface typically shows mucin-containing cysts. On histology, the abun-dant stroma is composed of inflamed,
often oedematous granulation tissue that
surrounds cystically dilated glands con-taining mucin. The glands are lined by
cuboidal to columnar epithelial cells with
reactive changes. The juvenile polyps in
patients with juvenile polyposis syn-drome may have the macroscopic and
microscopic appearances of sporadic
juvenile polyps, but they often have a
frond-like growth pattern with less stro-ma, fewer dilated glands and more prolif-erated small glands (microtubular pat-tern) than their sporadic counterparts.
Intraepithelial neoplasia (dysplasia) is
rare in sporadic juvenile polyps. Intra-epithelial neoplasia in this setting results
from inactivation of the APC/beta-catenin
pathway analogous to the genetic basis
of adenoma formation {2145}.
Peutz-Jeghers polyps
These are discussed in the small intes-tine section.
Reactive lesions
Inflammatory polyps. These non-neoplas-tic polyps are composed of varying pro-portions of reactive epithelium, inflamed
granulation tissue and fibrous tissue,
often with morphological similarity to
juvenile polyps; inflammatory polyps are
seen in a variety of chronic inflammatory
diseases including chronic inflammatory
bowel disease and diverticulitis.
Lymphoid polyps.  These result from
aggregates of reactive mucosa-associat-ed lymphoid tissue with conspicuous
germinal centres located in the mucosa
and/or submucosa.
Mucosal prolapse.  On occasion, mucos-al prolapse can produce morphological
features that mimic neoplasia, including
polyps, masses and ulcers character-ized histologically by elongated, distort-ed, regenerative glands surrounded by a
proliferation of smooth muscle fibres from
the muscularis mucosae, together with
superficial erosions, inflamed granulation
tissue and fibrosis {159}. Widening of
gland lumina at the surface is common.
Examples of this phenomenon include
inflammatory cloacogenic polyp {1083},
solitary rectal ulcer and cap polyp. The
process can extend into the bowel wall,
producing colitis cystica profunda.
Neoplasia in chronic inflammatory
bowel disease
There is evidence that the natural history
of colorectal carcinomas associated with
chronic colitis differs from that of ordinary
adenomas both morphologically and
with respect to the type and sequence of
genetic alterations.
BA
Fig. 6.29  A Adenoma with low-grade dysplasia and well-maintained glandular architecture.  B Low-grade
dysplasia with regular but slightly elongated, hyperchromatic nuclei. Cytoplasmic mucin is retained.
BA
Fig. 6.30 Adenomas with high-grade dysplasia. A Loss of normal glandular architecture, hyperchromatic cells with multi-layered irregular nuclei and loss of mucin,
high nuclear/cytoplasmic ratio. B Marked nuclear atypia with prominent nucleoli. C Adenoma with focal cribriform pattern .
Fig. 6.28  Tubulovillous adenoma, partly sessile,
partly pedunculated.
C
114 Tumours of the colon and rectum
Ulcerative colitis (UC)
Development of carcinoma is apparently
metachronous to the development of
intraepithelial neoplasia (classified as
low-grade and high-grade) complicating
chronic colitis. Because invasion can be
associated with intraepithelial neoplasia
exhibiting relatively mild morphological
changes, high-grade intraepithelial neo-plasia is diagnosed in colitis on the basis
of abnormalities that are less severe than
the criteria for high-grade intraepithelial
neoplasia in adenomas. It may be flat or
present as a ‘dysplasia associated lesion
or mass’ (DALM); the latter is often asso-ciated with a synchronous carcinoma
arising beneath the dysplastic surface.
DALMs are considered high-grade
lesions through their architecture alone,
and both DALM of any grade of dyspla-sia and high-grade flat dysplasia are
associated with invasive carcinoma in
about 40% of cases. The diagnosis of
DALM and high-grade flat dysplasia usu-ally leads to total colectomy {1687}. It
may be difficult to distinguish a DALM
from an incidental adenoma in a patient
with UC.
Attempts have been made to identify
early dysplastic lesions in UC with cell
cycle proliferation markers. Topoiso-merase II alpha and Ki-67 have been
shown to increase significantly over
baseline expression in UC related dys-plasias. Ki-67 positive cells are found
both at the surface and the base of the
crypts, indicating a fundamental deregu-lation of the proliferative cell pool {1368}.
Mutations of TP53 appear to be an early
event and are already present in intraep-ithelial neoplasia associated with UC, in
contrast to the adenoma-carcinoma
sequence in sporadic colorectal carcino-mas. Some  TP53 mutations have even
been observed in non-dysplastic muco-sa of chronic inflammation {516, 1463,
2175}.
Alterations of p16 have also been identi-fied in early UC but only very infrequent-ly in adenomas. Both tumour tissue and
multiple colorectal cancer cell lines stud-ied showed absence of LOH in 9p 1
{2019, 878}.
Microsatellite instability and gene alter-ations in p16 and p53 may represent
early events during the development of
dysplasia and carcinoma, and these
changes may lead to susceptibility for
allelic loss of other genes such as  APC
and DCC. It has been shown that LOH of
genetic areas close to the VHL locus on
3p is frequently present in DALM lesions
and, less frequently, in flat dysplastic
lesions. These changes are not usually
seen in sporadic adenomas {515}. This
may indicate that dysplasia in UC and
sporadic adenomas may follow different
genetic pathways.
Crohn disease
Intraepithelial neoplasia, classified as
low-grade or high-grade, is associated
with a high proportion of Crohn carcino-mas, either adjacent to the invasive
lesion or at a distance from it {1757}.
Similar to UC, polypoid dysplastic
lesions are diagnosed as DALM in
Crohn’s disease.
Mucinous adenocarcinomas are seen in
Crohn disease more frequently than in
sporadic colorectal carcinomas {656}.
There is an increased frequency of ade-nocarcinomas within perianal fistulas,
and of squamous cell carcinomas of the
anal mucosa {992}.
Similar to UC,  TP53 and c-KRAS muta-tions are observed earlier in Crohn-asso-ciated intraepithelial neoplasia than in
the adenoma-carcinoma sequence of
sporadic colorectal cancer {1562}.
Genetic susceptibility
The spectrum of genetic susceptibility is
broad, ranging from well-defined autoso-mal dominantly inherited syndromes with
known germline genetic mutations to ill-defined familial aggregation {1531, 1928,
642}. The diseases are traditionally divid-ed into polyposis syndromes character-ized by large numbers of polyps, e.g.
familial adenomatosis coli (FAP), and
non-polyposis syndromes with a small
number of or absence of polyps, e.g.
hereditary nonpolyposis colorectal can-cer (HNPCC). They are described in the
following chapters.
A non-truncating polymorphism of the
APC gene that induces an unstable
polyadenin repeat sequence, occurs in
approximately 5% of Ashkenazi Jews
Fig. 6.31 Serrated adenoma with irregular indenta-tion of the neoplastic epithelium.
Fig. 6.32 Microtubular adenoma.
Fig. 6.34 Tubulovillous adenoma with pseudoinva-sion. Small clusters of adenomatous cells produce
multilocular, large mucin deposits that expand the
adenoma’s stalk. This growth pattern resembles
mucinous carcinoma but is not malignant.
Fig. 6.33  Apoptotic cells in an adenoma demon-strated by M30 immunohistochemistry.
115Adenocarcinoma
and carries a modestly elevated risk of
colorectal cancer. Only small numbers of
adenomas occur in patients with this
form of germline APC alteration {1004}.
Li-Fraumeni syndrome
MIM No: Li-Fraumeni syndrome 151623;
TP53 mutations 191170
Li-Fraumeni syndrome is an autosomal
dominant disorder characterized by mul-tiple primary neoplasms in children and
young adults, with a predominance of
soft tissue sarcomas, osteosarcomas
and breast cancer, and an increased
incidence of brain tumours, leukaemia
and adrenocortical carcinomas {1403}.
Criteria for proband identification are: (1)
occurrence of sarcoma before age 45,
(2) at least one first-degree relative with
any tumour before age 45, and (3) at
least one first- or second-degree relative
with cancer before age 45 or with sarco-ma at any age {717, 141, 1066}.
In about 70% of Li-Fraumeni kindreds,
affected family members carry a germline
mutation in  TP53 {1151}. From 1990 to
1999, a total of 144 families with a  TP53
germline mutation were identified. A data-base of these mutations is available at
http://www.iarc.fr/p53/Germ. htm {699}.
As with somatic mutations, germline
mutations cluster in conserved regions of
exons 4 to 9, with major hotspots at
codons 175, 248 and 273. It has been
suggested that cancer phenotype corre-lates with the position of the mutation
within the coding sequence, with lower
age of clinical manifestation in probands
with mutations falling in the DNA-binding
domain of the p53 protein {142}. The
most frequent type of germline mutation
is transition (GC to AT) at CpG dinu-cleotides 556. The molecular basis of
tumour predispositions in families within
TP53 germline mutations is not known.
Recent studies have excluded tumour
suppressor genes such as  PTEN and
CDKN2 {214}.
Gastrointestinal manifestations
Neoplasms of the digestive tract repre-sent 7% of the tumours observed in Li-Fraumeni families. Most of these tumours
are colorectal carcinoma, with a minority
of stomach carcinomas. The male:female
ratio is 1.5 and the mean age at clinical
manifestation is 45, which correspond to
a relatively long latency period as com-pared to other types of cancers occurring
in Li-Fraumeni families {1403}. Preferen-tial familial occurrence of stomach cancer
Fig. 6.35  Proliferating cells demonstrated by immunohistochemistry for MIB1. A Hyperplastic polyp with pro-liferative cells restricted to the basal parts of the crypts. B Tubular adenoma with proliferating adenomatous
epithelium also at the luminal surface.
Fig. 6.38 Hyperplastic polyp.  A Pedunculated. B Short deep proliferative zone and superficial serrated
mature zone.
Fig. 6.36 Hyperplastic polyps. Typical sessile
appearance.
Fig. 6.37  Hyperplastic polyp with deep proliferative,
non-serrated zone protruding into submucosa.
BA
BA
116 Tumours of the colon and rectum
(familial clustering) has been observed
only in Japan, a country at high incidence
for that type of tumour. Cancers of the
liver and of the upper gastrointestinal
tract are exceedingly rare (less than 0.5%
of all Li-Fraumeni neoplasms). In these
neoplasms, sporadic cases often carry
somatic TP53 mutations. The low fre-quency of these tumours in families with
germline  TP53 mutations suggests that
the pre-existence of a  TP53 mutation is
not sufficient to increase the likelihood of
cancer development.
BRCA 1 and BRCA 2
In a retrospective analysis of 33 large,
high-risk breast and breast/ovarian can-cer families linked to the BRCA1 locus, a
significantly elevated risk of colon cancer
was found, with an estimated relative risk
of 4.11 (95% CI 2.36 – 7.15) {518}. This
corresponds to a risk of colon cancer by
age 70 of about 6%. In this study, there
did not seem to be any increased relative
risk at younger ages, although power to
detect either sex or age effects was
somewhat low in this set of data. In a sim-ilar study of  BRCA2 carriers {69}, no
increased risk of colorectal cancer was
observed. However, there was a signifi-cantly elevated risk for both stomach and
gallbladder tumours among known or
likely mutation carriers with estimated rel-ative risks associated with BRCA2 of 2.6
(95% CI 1.46 – 4.61) and 5.0 (1.50 -16.5), respectively.
Molecular genetics
The development of most colorectal car-cinomas is believed to begin in a col-orectal epithelial cell with a mutational
inactivation of the  APC (adenomatous
polyposis coli) suppressor gene {922,
636, 186}. This inactivation has multiple
consequences, including interference
with E-cadherin homeostasis and dys-regulation of transcription of genes.
Clonal accumulation of additional genet-ic alterations then occurs, including acti-vation of proto-oncogenes such as
c-myc {680} and ras, and inactivation of
additional suppressor genes. The genes
commonly inactivated during progres-sion include genes on chromosome 18
{1583, 614} and the  TP53 gene on the
short arm of chromosome 17 {1056,
415}. The mutated TP53 gene product, in
turn, fails to regulate normally a variety of
genes regulated by wild-type p53,
including p21WAF1/CIP1 cyclin-depend-ent kinase inhibitor which complexes
with proliferating cell nuclear antigen
{349}, and genes leading to apoptosis,
including BAX {278}. For many suppres-sor genes, inactivation of one allele is
often caused by loss of all or part of the
chromosome where the gene resides.
Various other chromosomal loci have
high frequencies of loss in colorectal
cancer due to chromosomal instability
{1044}, but the target genes are not yet
known.
Microsatellite instability (MSI)
Some colorectal cancers are distin-guished by extensive nucleotide inser-tions or deletions in numerous, intrinsical-ly unstable repeated sequences in
tumour DNA, termed microsatellite insta-bility (MSI), also termed ubiquitous
somatic mutations, DNA replication errors
(RER), or nucleotide instability {1540,
860}.
MSI is defined as a change of any length
due to either insertion or deletion of
repeating units, in a microsatellite within a
Fig. 6.41 Reactive epithelial changes in ulcerative
colitis.
A
B
Fig. 6.40 Juvenile polyp. A Smooth eroded surface
with numerous mucous retention cysts, typical of
sporadic juvenile polyps. B Expanded inflamed stro-ma with distorted glands showing reactive atypia.
Fig. 6.42 Low-grade intraepithelial neoplasia in ulcerative colitis. A Patchy hyperbasophilic regular glands,
with dysplasia extending to the luminal surface. B Haphazardly arranged dysplastic glands.
B
Fig. 6.39 Inverted hyperplastic polyp. Endophytic
growth of hyperplastic glands projects into submu-cosa. Proliferative zone at the periphery, maturation
at the center.
A
117Adenocarcinoma
tumour when compared to normal tissue.
It has been recommended that a panel of
five microsatellites should be used as a
reference standard (BAT25, BAT26,
D5S346, D2S123, D17S250) for carcino-mas of the large intestine {164}. If two or
more of these markers show MSI, the
lesion is classified as high-frequency
microsatellite instability (MSI-H); if only
one marker shows MSI, it is classified as
low-frequency microsatellite instability
(MSI-L); if no markers show MSI it is clas-sified as microsatellite stable (MSS). If
more than five markers are used, the cri-teria should be modified to reflect the per-centage of markers demonstrating MSI.
Thus, MSI-H lesions would exhibit MSI in
more than 30-40% of markers tested.
MSI-H carcinomas are characteristic of
hereditary nonpolyposis colorectal can-cer syndrome (HNPCC) due to germline
mutation of one of a group of DNA mis-match repair genes followed by somatic
inactivation of the other allele. Sporadic
MSI-H tumours comprise about 15% of
colorectal carcinomas. They usually fol-low transcriptional silencing of both alle-les of the  hMLH1 mismatch repair gene
due to aberrant methylation of cytosine
residues in the cytosine and guanine-rich
promoter region {886, 696}. The alter-ations that accumulate during progres-sion of both hereditary and sporadic neo-plasms characterized by MSI-H include
mutations in microsatellites within the
coding region of some genes, such as
the type II receptor for TGF-beta1 and
BAX {548}. In contrast to microsatellite-stable cancers, MSI-H cancers display
nucleotide rather than chromosomal
instability; allelic deletions are rare
{1044}.
Recent studies indicate a functional link
between defective DNA mismatch repair
and the Wnt-signalling pathway. Approxi-mately 25% of sporadic colorectal carci-nomas with defective mismatch repair
(MSI-H) were shown to contain frameshift
mutations in the AXIN2 gene, which
leads to a stabilization of  β-catenin and
activation of β-catenin/T-cell factor (TCF).
This was associated with an accumula-tion in tumour cell nuclei which was
absent in colorectal cancer without mis-match repair deficiency and in the
absence of APC mutations. AXIN2
mutant protein appears to be more sta-ble than the wild-type gene product, sug-gesting a dominant-negative effect
{1079A}.
Prognosis and predictive factors
Morphology.  Macroscopic and micro-scopic features reportedly related to
prognosis are summarized in Table 6.01
{2348}.
Poor prognosis has been associated with
both large and small tumour size, with
sessile and ulcerated configuration as
contrasted with polypoid cancer, with
extensive involvement of the bowel cir-cumference, with the presence of com-plete bowel obstruction, with perforation,
and with serosal deposits.
Fig. 6.43  A – C High-grade intraepithelial neoplasia in ulcerative collitis with multilayered hyperchromatic elongated nuclei extending to the luminal surface.
B CA
BA
Fig. 6.44 Dysplasia associated lesion or mass (DALM). A Polypoid lesion. B Raised lesion simulating an ade-noma.
118 Tumours of the colon and rectum
Histopathological features related to
poor prognosis include deep infiltration
of the layers of the wall, extensive
involvement of a particular layer, an infil-trative pattern of the invasive edge of the
tumour as contrasted to an expansile
pattern, and poor differentiation, includ-ing signet-ring cell and mucinous adeno-carcinoma, adenosquamous carcinoma,
small cell carcinoma and anaplastic car-cinoma {1672, 1946, 220, 916, 266}.
Mucinous adenocarcinomas of the rec-tum often present at a later stage and
have the poorest overall prognosis
{1928}, but the MSI status influences the
aggressiveness of this histopathological
subtype {1221}. Other studies have
shown no significant difference in prog-nosis between mucinous and non-muci-nous varieties of adenocarcinoma
{1543}.
Lymph node metastasis.  Metastasis to
numerous nodes, those close to the
mesenteric margin, at great distance
from the primary tumour, or in retrograde
lymph nodes, have been associated with
poor prognosis while the prognostic
value of identification of micrometastasis
in lymph nodes by immunohistochemical
or molecular techniques is still controver-sial {1564, 1387, 221}.
Angiogenesis. Neovascularization of
tumour stroma is crucial in supporting
tumour growth, and high levels of
microvessel density have been interpret-ed as an adverse prognostic feature
{2010}.
Inflammatory response. The presence of
an intense inflammatory infiltrate with
polymorphonuclear leukocytes (particu-larly eosinophils), lymphocytes, plasma
cells, mast cells and histiocytes, as well
as prominent desmoplasia have been
associated with improved prognosis
{1352}. In the regional lymph nodes,
hyperplasia of the paracortical T-lym-phocyte areas and the B-cell germinal
centers have also been reported as
favourable, as has sinus histiocytosis.
Other features of colorectal carcinomas
that have been shown to be of prognostic
value in some studies include  angiolym-phatic invasion, perineural space involve-ment, extramural venous involvement,
peritumoural lymphocytic response, and
tumour-infiltrating lymphocytes. Some of
these features are evaluated in a classifi-cation proposed by Jass {389}. A micro-acinar pattern of growth, defined as dis-crete, small, relatively regular tubules, is
associated with reduced survival {559,
2100}.
Extent of resection. A short longitudinal
surgical resection margin (2-5 cm),
reflecting the surgical technique
employed, has been associated with
poor outcome. In rectal cancer, clear-ance from the circumferential margin is
important. The circumferential margin
represents the adventitial soft tissue mar-gin closest to the deepest penetration of
the tumour. For all segments of the large
intestine that are incompletely enveloped
by peritoneum or not enveloped, the cir-cumferential margin is created by blunt
or sharp dissection at operation. The
mesocolic margin in resection speci-mens of colon cancer is usually well dis-tant from the primary tumour, but the sta-tus of the circumferential margin is par-ticularly important in rectal carcinoma
due to the anatomic proximity of pelvic
structures {15}.
Genetic predictive markers.  Some of the
genetic alterations identified in colorectal
cancers are markers for prognosis {313,
1206}. Allelic loss of chromosome 18q
was found to be an adverse prognostic
indicator. Other studies reported that loss
of chromosomes 17p, 1p, 5q, 8p or 18q,
decreased DCC gene expression, p53
Fig. 6.47 Solitary rectal ulcer. A, B Two deep ulcers
macroscopically simulating carcinoma.
Fig. 6.48  Solitary rectal ulcer with reactive hyper-plastic polyp due to prolapse. This lesion should not
be confused with a neoplasm.
Fig. 6.49 Inflammatory cap polyp in a patient with
ulcerative collitis.
A
B
Fig. 6.46 Immunoexpression of p53 in intraepithelial
neoplasia in ulcerative collitis.
Fig. 6.45  Rectal carcinoma arising in ulcerative
colitis. Surface dysplasia overlies invasive carcino-ma in this DALM.
119Adenocarcinoma
overexpression, reduced p27KipI
expres-sion, high expression of cyclin A, ras
gene mutation, expression of enzymes
involved in matrix degradation and their
inhibitors (cathepsin-L, urokinase, tissue-type plasminogen activator, tissue inhibi-tors of metalloproteinases), expression of
genes involved in apoptosis (bcl2, bax,
survivin), expression of cell surface mole-cules (CD44 and its variants, ICAM1,
galectin 3) and metabolic enzymes
(GLUT1 glucose transporter, manganese-superoxide dismutase, thymidylate syn-thetase, ornithine decarboxylase, cyclo-oxygenase 2) have prognostic value.
In addition, colorectal cancers manifest-ing MSI-H have been reported to have a
lower frequency of metastasis and
improved prognosis when compared to
microsatellite-stable tumours.
Response to therapy. No pathological
features have been reported as predic-tive of therapeutic response, but some
molecular alterations have potential as
predictive markers. Studies in cell lines
of colonic and other carcinomas have
shown that in vitro, the status of TP53 is
crucial {1382}. The TP53 pathway is
closely linked to regulation of the cell
cycle and of apoptosis. The presence of
wild-type p53 in cell lines is associated
with in vitro growth inhibition in response
to many chemotherapeutic agents, and
with radiation-induced upregulation of
p21WAF1/CIP1
and cell cycle arrest. Tumours
manifesting MSI-H may respond to 5-FU-based chemotherapy {1109}, while p53
protein accumulation was associated
with lack of response to postoperative
adjuvant chemotherapy with 5-FU and
levamisole {24}. Chromosome 18q loss
was associated with an unfavourable
survival rate in this setting.
Major problems exist in the interpretation
of various pathological features as pro-gnostic and predictive markers. Many of
these features are interrelated but have
been treated for statistical purposes as
independent variables in studies. At
present, anatomic staging is the main-stay of clinical decision-making.
Fig. 6.51 Inflammatory cloacogenic polyp with
mucous extravasation.
Fig. 6.50 Solitary rectal ulcer. Smooth muscle
increased between glands, distorting and displac-ing them.
Anatomic extent of disease (TNM) Extramural venous involvement Angiogenesis Distance between resection margin
Extent of circumferential involvement Lymphatic vessel or Local inflammatory and desmo- and tumour
Bowel obstruction perineural space involvement plastic response to infiltrating Presence of residual tumour
Perforation tumour
Pattern of invasion Reactive changes in regional
Grade of differentiation lymph nodes
Table 6.01
Prognostic factors in colorectal carcinoma.
Features of the primary tumour Evidence of vessel invasion Evidence of host response Consequences of surgical technique
120 Tumours of the colon and rectum
Familial adenomatous polyposis I.C. Talbot
R. Burt
H. Järvinen
G. Thomas
Definition
Familial adenomatous polyposis (FAP) is
an autosomal dominant disorder charac-terized by numerous adenomatous col-orectal polyps that have an intrinsic ten-dency to progress to adenocarcinoma. It
is caused by a germline mutation in the
Adenomatous Polyposis Coli  (APC)
gene which is located on the long arm of
chromosome 5 (5q21-22). Gardner syn-drome is a variant of FAP that includes
epidermoid cysts, osteomas, dental
anomalies and desmoid tumours, in
addition to colorectal adenomas. Turcot
syndrome is a variant that is associated
with a brain tumour (medulloblastoma).
An attenuated FAP form has been distin-guished from classic FAP, where the
number of adenomas is less than 100 in
the colon.
MIM No.: FAP, including Gardner syn-drome, 175100; Turcot syndrome, 276300
Synonyms
Adenomatous polyposis coli, familial
polyposis coli, Bussey-Gardner polypo-sis, Gardner syndrome, familial multiple
polyposis, multiple adenomatosis, famil-ial polyposis of the colon and rectum,
familial polyposis of the gastrointestinal
tract, familial adenomatous polyposis
coli, etc.
Incidence
Estimates of the incidence of FAP vary
between 1 per 7000 and 1 per 30,000
newborns. The mean annual incidence
rate has been constantly from 1 to 2 per
1,000,000 in Denmark and Finland while
the prevalence has increased to more
than 25 per 1,000,000 since the creation
of preventive polyposis registries {205;
836}. In general, FAP underlies less than
1% of all new colorectal cancer cases.
Between 30 and 50% of new FAP
patients are solitary cases, probably rep-resenting new mutations of the  APC
gene.
Diagnostic criteria
Classical FAP is defined clinically by the
finding of at least 100 colorectal adeno-matous polyps {216}. Endoscopic visual-ization of diminutive polyps may require
dye spray assisted endoscopy. Histo-logical confirmation requires examination
of several polyps. In the context of endo-scopic screening on the basis of definite
family history the detection of fewer ade-nomas is sufficient at an early age. The
same applies on the attenuated disease
form (AAPC). Final diagnosis may be
achieved by demonstration of a mutated
APC, but the detection rate of mutations
has only been between 60 and 80% of all
FAP families. In patients where the clini-cal criteria remain doubtful and genetic
diagnosis is not achieved the finding of
extracolonic features of FAP (epidermoid
cysts, osteomas, desmoid tumour, gas-tric fundic gland polyps, etc.) may give
additional diagnostic support.
The following diagnostic criteria have
been established: (1) 100 or more
colorectal adenomas or (2) germline
mutation of the APC gene or (3) family
history of FAP and at least one of the fol-lowing: epidermoid cysts; osteomas;
desmoid tumour.
Colorectal polyps
The colorectal polyps are adenomas,
most often tubular, and resemble their
sporadic counterparts.
Localization
Colorectal adenomas in FAP occur
throughout the colon but follow the gen-eral distribution of sporadic adenomas,
with greatest density in the rectum and
sigmoid colon. The distribution of can-cers follows that of the adenomas.
Clinical features
Age at clinical manifestation
Colorectal adenomas become detec-table at endoscopic examination (sigmoi-doscopy) between the age of 10 and 20
years, increasing in number and size with
age. The most important clinical feature
of FAP is the almost invariable progres-sion of one or more colorectal adenomas
to cancer. The mean age of development
of colorectal cancer is about 40 years,
but the cancer risk is 1 to 6% already at
Fig. 6.52 Colectomy specimens from patients with familial adenomatous polyposis. A Hundreds of polyps of
different size cover the entire mucosal surface.  B Multiple adenomas in different stages of development.
C Lateral view of polyps. D Numerous small early (sessile) adenomas.
A B
CD
121Familial adenomatous polyposis
the age of 20 to 25 years {835}, and col-orectal cancer has been reported even in
children with FAP. Extracolonic manifesta-tions such as epidermoid cysts, mandi-bular osteomas, desmoid tumours or
congenital hypertrophy of the retinal pig-ment epithelium (CHRPE) may present in
children and can serve as markers of
FAP.
Symptoms and signs
In the early phase of FAP adenomas do
not cause any symptoms. Specific symp-toms due to colorectal adenomas are rec-tal bleeding and diarrhoea often accom-panied by mucous discharge and
abdominal pain. Symptoms appear grad-ually and may be easily overlooked; the
mean age of appearance of symptoms
was 33 years and the mean age of diag-nosis 36 years in about 200 FAP patients
who had no prophylactic screening
arranged {216}.
Two thirds of patients diagnosed to have
FAP on the basis of symptoms (propositi)
already have colorectal cancer whereas
in asymptomatic members of known FAP
families cancer is very rare at the time of
the detection of FAP provided that pro-phylactic endoscopic screening was
arranged in good time, i.e. before the
age of 20 years {836}.
Imaging and FAP screening
The appropriate screening method for
diagnosing FAP is flexible sigmoi-doscopy, which should be arranged for
all children of an affected FAP parent
from the age of 10 to 15 years and con-tinued at 1 to 2 year intervals up to the
age of 40 years if adenomas are not
detected. Endoscopies can be replaced
by genetic testing for the specific APC
mutation in those families where the
mutation has been identified. A positive
test is diagnostic for FAP and signifies
the need for prophylactic colectomy or
proctocolectomy when the colorectal
adenomas become detectable, at the
age of 20 to 25 years at the latest.
If the operation is not performed immedi-ately after the diagnosis of FAP, colono-scopy should be undertaken to evaluate
the entire colon because large adeno-mas or cancer may reside beyond the
reach of the flexible sigmoidoscope.
Endoscopic evaluation of the upper gas-trointestinal tract is recommended at the
time of prophylactic colectomy or procto-colectomy, and should be repeated at
2 to 5 year intervals depending on the
finding of adenomas in duodenal and
gastric biopsies {688}. Double contrast
barium enema and barium meal may be
used to demonstrate polyps but are infe-rior to endoscopy because biopsies are
required to provide histological evidence
for a definite diagnosis of FAP.
Macroscopy
Most polyps in FAP are sessile and spher-ical or lobulated. Scattered larger pedun-culated polyps are much less numerous
{205; 835; 836; 688}. The colorectal
polyps appear first in adolescence and,
by the late teens, usually number thou-sands, typically carpeting the lining of the
whole large bowel. Their number varies
between families, in some being little
more than 100, even in adults {1988},
whereas, in the majority of families, there
are profuse polyps, numbering thou-sands. Typically, the polyps are scattered
evenly along the whole large bowel but, in
over one third of cases, their density is
greatest in the proximal colon. Adult
patients with rectal sparing have been
described, even when adenocarcinoma
was present in the right colon {1503}.
In any one patient the polyps range from
barely visible mucosal nodules to pedun-culated polyps of up to 1 cm or more. In
some patients and families the adeno-mas mostly measure only a few millime-tres while in others they are larger, with
polyps up to several centimetres. In con-trast, in attenuated FAP, the polyps are so
few that they may not be noticed at rigid
sigmoidoscopy. Polyps rarely appear
until late childhood {216} and are rarely
larger than 1 cm until adulthood.
Adenocarcinomas arise in only a small
percentage of the adenomas.
Histopathology
Adenomas in FAP begin as single dys-plastic crypts (‘unicryptal’ adenomas). In
practice, to find more than one of these in
a colon is unique to FAP. By excessive
and asymmetrical crypt fission {1086;
433; 2062}, probably due to loss of
APC-controlled growth and tissue organ-ization, they develop into oligocryptal
adenomas, which may not be visible as
polyps before further growth into grossly
visible adenomatous polyps. Most
adenomas in FAP display a tubular archi-tecture; infrequently they are tubulovil-lous or villous. Non-polypoid, flat adeno-mas account for approximately 5% of
adenomas in the colon of affected family
members {1181}. AF denomas and carci-nomas in FAP are histologically identical
to sporadic lesions.
Fig. 6.54 Small ulcerated adenocarcinoma with
rolled edges (arrowhead), accompanied by numer-ous adenomas in a patient with FAP. Polypectomy
scars are present.
Fig. 6.55 Adenocarcinoma and innumerable adeno-mas in a case of FAP.
Fig. 6.53 Tubulovillous adenoma in familial adeno-matous polyposis.
Proliferation
The histologically normal intestinal
mucosa in FAP shows no increase in the
rate of epithelial cell proliferation {2062}.
Mitotic activity is not increased {1315}
except in the adenomatous epithelium, in
which cell proliferation is identical with
that in sporadic adenomas.
Small intestinal polyps
Small bowel polyps, particularly duode-nal polyps, are also adenomas. They
develop preferentially in the peri-ampullary region of the duodenum, prob-ably due to a co-carcinogenic effect of
bile {1679; 1805}. They become evident
ten years later than the colorectal polyps.
Using side-viewing endoscopy, adeno-mas have been found in 92% of patients
with FAP at routine screening {1809}.
They increase in size and number with
time and carry a lifetime risk of duodenal
or periampullary cancer of about 4%
{688}. Ampullary and periampullary ade-nocarcinoma is one of the principal caus-es of death in patients who have under-gone prophylactic proctocolectomy
{1809}.
Extra-intestinal manifestations
Several other organs are involved in FAP
but extra-intestinal manifestations rarely
determine the clinical course of the dis-ease.
Stomach
Gastric adenomas do occur with
increased frequency {425} but the most
common abnormality is the fundic gland
polyp. This is a non-neoplastic mucus
retention type of polyp, grossly visible as
a smooth dome-shaped nodule in the
gastric body and fundus, usually multiple.
Histologically, the lesion is characteristi-cally undramatic, consisting of gastric
body mucosa that is often normal apart
from cystic dilatation of glands There is
evidence of increased cell proliferation
and dysplasia developing in these polyps
{2144} but progression to adenocarcino-ma is only a rare occurrence {2214}.
Liver and biliary tract
There is an increased incidence of hepa-toblastoma in the male infants of families
with FAP {563; 578}. Dysplasia has been
demonstrated in the bile duct and gall-bladder epithelium in patients with FAP
{1377} and these patients are at risk of
developing adenocarcinoma of the biliary
tree {1806}.
Extra-gastrointestinal manifestations
Soft tissues
Tissues derived from all three germ lay-ers are affected in FAP. As well as the
endodermal lesions so far described,
mesodermal lesions in the form of a fibro-matosis unique to FAP, usually referred to
as desmoid tumour, develop in a sub-stantial minority of patients {315}.
Desmoid tumours arise in either the
retroperitoneal tissues or in the abdomi-nal wall, often after trauma or previous
surgery involving that site.
A desmoid is a mass of firm pale tissue,
characteristically growing by expansion,
usually rounded in shape. Desmoids
begin as small scar-like foci of fibrosis in
the retroperitoneal fat and, when large,
typically extend around and between
other structures such as the small or large
bowel, ureters and major blood vessels.
Histologically, these lesions are com-posed of sheets of elongated myofibrob-lasts, arranged in fascicles and whorls.
The lesions have a dense, tough consis-tency and there is a variable amount of
collagen. They are well vascularized and
contain numerous small blood vessels
that bleed profusely when incised.
Bones
Bone lesions include exostoses and
endostoses. Endostoses of the mandible
are found in the majority of patients
{203}. They are almost always small and
symptomless. Exostoses may be solitary
or multiple and tend to arise in the long
bones.
Teeth
Dental abnormalities have been
described in 11 to 80% of individuals
with FAP {241}. The abnormalities may
be impaction, supernumerary or absent
teeth, fused roots of first and second
molars or unusually long and tapered
roots of posterior teeth.
Eye
In 75-80% of patients, ophthalmoscopy
reveals multiple patches of congenital
122 Tumours of the colon and rectum
Fig. 6.56 Diagram of stomach and duodenum show-ing the distribution of fundic gland polyps (open cir-cles) and adenomas (solid circles) in FAP {425}.
Adenomas are concentrated in the second part of
the duodenum.
Fig. 6.57  Intraepithelial neoplasia (dysplasia) of the common bile duct from a patient with FAP.
123Familial adenomatous polyposis
hypertrophy of retinal pigment epithelium
(CHRPE) {280}. Ultrastructurally, they are
freckle-like plaques of enlarged melanin-containing retinal epithelial cells {1466}.
Their value for diagnosis is limited by
inconsistency and variation between
families.
Skin
Epidermal cysts, usually of the face and
often multiple, were first described in
FAP by Gardner {565}.
Endocrine system
There is a definite but relatively slight
increase in the incidence of endocrine
tumours in FAP, including neoplasia of
pituitary, pancreatic islets and adrenal
cortex {1160}, as well as multiple endo-crine neoplasia syndrome, type 2b
{1500} but these are of insufficient fre-quency or gravity to form part of a routine
screening protocol. The best document-ed endocrine association is papillary car-cinoma of thyroid {268}, largely restricted
to women {202}.
Nervous system
The concurrent presence of a brain
tumour and multiple colorectal polyps
constitutes Turcot syndrome. Some indi-viduals affected in this way are victims of
FAP, with a germline defect of  APC.
These are infants or young children who
present with medulloblastoma and col-orectal polyps {658}.
Other individuals present later in life with
a glioma, usually an astrocytoma or
glioblastoma multiforme and are usually
associated with hereditary non-polyposis
colon cancer (HNPCC) rather than FAP
{262}.
Genetics
FAP is an autosomal dominant disease
with almost complete penetrance by 40
years of age.  APC germline mutations
are the only known cause of FAP.
Gene structure and expression
The APC gene was localized to chro-mosome 5q21-22 by Bodmer et al.
{156} and Leppert et al. {1047}. It was
isolated by the group of White {868;
629} and by the laboratories of Naka-mura and Vogelstein {920; 1364}. It
spans over a region of 120 Kb and is
composed of at least 21 exons, 7 of
which are alternatively expressed
{1658}. 16 APC transcripts that differ in
their 5’-most regions and arise by the
alternative inclusion of 6 of these exons
have been identified.
The APC gene is ubiquitously expressed
in normal tissues, with highest levels in
the central nervous system. Tissue-spe-cific differences were observed in the
expression of  APC transcripts without
exon 1, a coding region for a heptad
repeat that supports homodimerization
of the APC protein.
Gene product and function
The APC protein is a 2,843-amino acid
polypeptide that is a negative regulator in
the Wnt signaling pathway. The protein
contains several functional domains that
act as binding and degradation sites for
β-catenin and control the  β-catenin intra-cellular concentration. A protein-binding
domain near the carboxy-terminal of APC
mediates phosphorylation by glycogen
synthase kinase 3  β (GSK3b) and stabi-lizes the formation of a complex between
the two proteins {1627}. In an unstimulat-ed cell, GSK3b promotes phosphorylation
of the protein conductin/axin which is
added to the APC GSK3b complex {2107;
124}. Phosphorylated axin recruits
β-catenin, which is in turn phosphorylated
and targeted for degradation through an
APC-dependent ubiquitin-proteasome
pathway {11}. Normal Wnt signalling
inhibits GSK3b activity and dephosphory-lates axin. As a result,  β-catenin is
released from the complex {2107}.
In the cytoplasm, β-catenin is involved in
cytoskeletal organization with binding to
microtubules. It also interacts with E-cad-herin, a membrane protein involved in cell
adhesion. Free  β-catenin shuttles to the
nucleus where it binds to the transcription
factors of the TCF/LEF family. The result-ing complexes activate c-MYC {680} and
cyclin D1 transcription {1753; 1922}. Lack
of functional APC causes unregulated
intracellular accumulation of  β-catenin
and thereby constitutive expression of
c-MYC and of the cyclin D1 gene (CDD1).
Fig. 6.58 Precursor lesion of mesenteric fibromatosis (desmoid tumour) in a patient with FAP.  A The white band in the mesentery resembles a fibrous adhesion.
B Histology shows a band of fibromatosis in the  mesenteric fat.
AB
Fig. 6.59 Epidermoid cyst on the dorsal surface of
the hand of an FAP patient.
Gene mutations
The germline mutation rate leading to a
new deleterious  APC allele is estimated
to be 5 to 9 per million gametes. As a
result, most families exhibit unique muta-tions, and individuals with no previous
family history of FAP are not uncommon.
They may represent up to one fourth of
propositi {143}.
A deleterious  APC mutation may be
found in about 95% of FAP patients. The
vast majority of the mutant alleles lead to
the synthesis of a truncated protein.
About 10% of the mutations are large
interstitial deletions that may involve the
entire gene. Rare missense mutations,
most with uncertain functional conse-quences, have been described. Muta-tions at codons 1061 and 1309 account
for 20% of all identified germline muta-tions in the APC gene. In up to 5% of fam-ilies, the genetic defect causing FAP is
not yet known {1003}.
Genetics of FAP associated tumours
Consistent with the 2-hit model of car-cinogenesis by tumour suppressor
genes, the wild type APC allele is lost or
mutated in the vast majority of FAP asso-ciated tumours, including colorectal ade-nomatous polyps and carcinoma,
desmoid tumours {1245}, medulloblas-toma {202}, gastroduodenal tumours
{1949}, thyroid carcinoma {822} and
hepatoblastoma {980}. Each colorectal
adenomatous polyp is a premalignant
lesion that may progress to carcinoma in
an unpredictable fashion. In addition to
APC mutations, colon carcinomas in FAP
patients contain somatic mutations that
are similar to those found in the most fre-quent type of sporadic colon cancers not
associated with replication errors.  TP53
mutation and 17p allele loss have been
observed in 40% of invasive carcinomas
{910}. However, in some families  TP53
may not be involved {30}. Loss of alleles
on chromosome 18 and 22 were
observed in 46% and 33% respectively.
The KRAS mutation frequency increases
from 11% inmoderately to 36% in severe-ly dysplastic adenomas {30}.  KRAS
mutations may potentiate cyclin D1 tran-scription {680}. Interestingly, the type of
APC germline mutation may influence
the mode of inactivation of the second
APC allele {30}.
Animal model
Heterozygous mutant mice for a defec-tive Apc allele develop multiple intestinal
neoplasia {1245}. The homozygous
mutant embryos die prior to gastrulation
{1811}. Expression of the secretory phos-pholipase Pla2g2a is associated with a
decreased number and size of adenoma
in heterozygous mutant Apc mice {1283}.
Implication of PLA2G2A polymorphism in
FAP expressivity has not been demon-strated in humans.
Genotype / phenotype relationships
There are well documented relationships
between the location of the mutation on
the APC gene and the FAP phenotype.
APC mutations in the first or last third of
the gene are associated with attenuated
colorectal polyposis (AAPC) character-ized by the occurrence of less than 100
polyps and a late onset {1284}. Fundic
gland polyposis is prevalent in the atten-uated form of FAP but desmoids may be
present only if the AAPC causing muta-tion lies in the 3’ end of the  APC gene.
Indeed, mutations after codon 1444 are
associated with an increased suscepti-bility to desmoid tumours {340}. CHRPE
124 Tumours of the colon and rectum
Fig. 6.60 Mesenteric fibromatosis (desmoid tumour) in a patient with FAP. A The lesion entraps loops of small intestine. B Collagen bands and small vessels.
Fig. 6.61 Structure of the APC gene and location of somatic and germline mutations.
From: P. Polakis, Biochim Biophys Acta 1332: F127-F147 (1997)
AB
125Familial adenomatous polyposis
lesions are a consistent feature, except if
the APC mutation is located before exon
9 and after codon 1387 {1810; 340}.
Mutations in the central region of the
gene, including the mutational hotspot at
codon 1309, correlate with a severe phe-notype characterized by development of
thousands of polyps at a young age
{258}. In contrast to mutant APC proteins
truncated at codon 386 or 1465, which
interfered only weakly with wild-type APC
activity in an in vitro system, a mutant
APC protein truncated at codon 1309
was shown to be a strong inhibitor and
may thus have dominant negative prop-erties {1422}. These observations point
to a possible mechanism that could con-tribute to the genotype/phenotype rela-tionships observed in FAP. There may
also be a correlation between slow
acetylation genotypes and extracolonic
manifestations of the disease {1308}.
Application of genetic testing
in the clinical setting
In the absence of systematic, family
based screening programs, the present-ing features are usually those of malig-nancy, such as weight loss and inanition,
bowel obstruction, or bloody diarrhoea.
In such cases, patient evaluation will fre-quently find a colorectal carcinoma.
Occasionally, the extracolonic features of
the condition may lead to presentation
and diagnosis. Cases of new mutation
still present in these ways, but in areas
with well organized registers, gene carri-ers among relatives of affected patients
are identified prior to symptoms either by
DNA-based genetic tests or by bowel
examination.
The most commonly used commercially
available genetic testing for FAP involves
identification of the mutant APC allele by
in vitro detection of truncated APC pro-tein {414}. This approach is referred to as
in vitro protein synthesis (IVPS) testing.
IVPS testing is able to detect mutation
carriers in about 80% of families. Once
evidence of a disease-causing mutation
is found in an index case by this method,
testing is near 100% predictive in other
family members. It is imperative that
genetic counselling be undertaken
throughout the process of genetic test-ing. Without this, genetic testing and the
use of the results are poorly applied in
the clinical setting {1703}.
Screening in gene carriers is similar to
that in families where genetic testing is
not applied or does not work and usually
involves sigmoidoscopy every 1 to 2
years, beginning between age 10 and 12
years. If a genetic diagnosis is made
after that age, full colonoscopy should
probably be done in view of the risk of
lesions higher in the colon. Preventive
total colectomy is proposed to gene car-riers when polyposis becomes conspicu-ous. Genotype/phenotype correlations
may be used to adapt clinical manage-ment to individual FAP patients.
A family member who has a negative
DNA based genetic test can forgo
screening if (1) the mutation found in
other affected family members is obvi-ously deleterious and (2) if the individual
with a negative test has been unambigu-ously shown to be a non-gene carrier by
DNA testing. Such individuals need no
further screening as their risk to develop
colon cancer is similar to that of the gen-eral population.
Definition
Hereditary nonpolyposis colorectal can-cer (HNPCC, Lynch syndrome) is an
autosomal dominant disorder, character-ized by the development of colorectal
carcinoma, endometrial carcinoma,and
cancer of the small intestine, ureter, or
renal pelvis.
MIM No. 120435-6
Diagnostic criteria
In 1990, the International Collaborative
Group on HNPCC (ICG-HNPCC) pro-posed a set of selection criteria to pro-vide a basis for uniformity in collabora-tive studies {2003}. These criteria,
referred to as Amsterdam Criteria I (ACI),
have been widely used since then.
Recently, the criteria have been revised
to include the extracolonic cancers that
are part of the syndrome. The new set of
diagnostic criteria (ACII), is shown in
Table 6.02 {2004}. They identify families
that are very likely to represent HNPCC.
On the other hand, they are not intended
to serve as a guide to exclude suspect-ed families from genetic counselling and
mutation analysis.
Clinical features
Predisposed individuals from HNPCC
families have a high lifetime risk of devel-oping colorectal carcinoma (70-85%),
endometrial carcinoma (50%), as well as
certain other cancers (below 15%) {5,
2071, 2005}. Colorectal lesions are often
diagnosed at an early age (mean, 45
years), and are located in the proximal
part of the colon in about two-thirds of
the patients. Synchronous or metachro-nous colorectal carcinoma is present in
35% of patients. In over 90% of the
cases, it shows microsatellite instability
(MSI) (Table 6.04) {839, 1166, 1129}. The
adenomas that occur in HNPCC tend to
develop at an early age, to have villous
components and to be more dysplastic
than adenomas detected in the general
population. Although multiple adenomas
may be observed in HNPCC, florid poly-posis is not a feature.
Extracolonic lesions include cancer of
the endometrium, renal pelvis/ureter,
stomach, small bowel, ovary, brain,
hepatobiliary tract, and also sebaceous
tumours. Among these tumours, carcino-ma of the endometrium, ureter, renal
pelvis, and small bowel have the highest
relative risk, and are therefore the most
specific for HNPCC (Table 6.03).
The occurrence of sebaceous gland
tumours together with HNPCC type inter-nal malignancy is referred to as the Muir-Torre syndrome {322}. The association of
primary brain tumours (usually glioblas-tomas) with multiple colorectal adeno-mas is referred to as the Turcot syndrome
{1979}. The latter has a shared genetic
basis with HNPCC on the one hand and
FAP on the other hand {658}.
Pathology
The pathology of HNPCC tumours is sim-ilar to that of sporadic colorectal carcino-ma showing high levels of instability at
short tandem repeat sequences,
microsatellites (MSI-H). Many studies
make no distinction between familial and
non-familial MSI-H carcinomas. The fol-lowing descriptions apply to all MSI-H
carcinomas, but highlight subtle differ-ences between HNPCC cancers and
their sporadic counterparts where these
are known.
P. Peltomäki
H. Vasen
J.R. Jass
Hereditary nonpolyposis colorectal
cancer
Fig. 6.62  Mucinous adenocarcinoma from a patient
with HNPCC.
126 Tumours of the colon and rectum
Fig. 6.63 Abundant lymphocytes infiltrate the neoplastic epithelium in these poorly differentiated (A) and moderately differentiated  (B) adenocarcinomas from
patients with HNPCC.
AB
127Hereditary nonpolyposis colorectal cancer
Macroscopy
HNPCC cancers show a predilection for
the proximal colon including caecum,
ascending colon, hepatic flexure and
transverse colon {1130}. At least 60%
occur in the proximal colon. The gross
appearances have not been studied in
detail. However, since HNPCC and
MSI-H colorectal carcinomas show a
consistent trend towards good circum-scription {842, 1723}, they are more like-ly to present as polypoid growths,
plaques, ulcers or bulky masses and less
likely to present as diffuse growths or
tight strictures.
Adenomas are not numerous but are like-ly to be more frequent in HNPCC sub-jects than age-matched controls {846}.
Colonoscopic studies indicate that the
distribution of adenomas in HNPCC may
not mirror the proximal colonic predilec-tion of carcinoma {846}. This could be
due to the occurrence of sporadic distal
adenomas in older HNPCC subjects or
because proximal adenomas are more
likely to progress to cancer.
Histopathology
No individual microscopic feature is spe-cific to HNPCC, but particular groups of
features are diagnostically useful {1723}.
Identical features are found in the 10 to
15% of sporadic colorectal cancers that
show high levels of DNA microsatellite
instability (MSI-H) {842}. However, spo-radic MSI-H cancers present in older
subjects lacking a family history of bowel
cancer. HNPCC and sporadic MSI-H col-orectal cancers fall into three groups
based on site and microscopic criteria:
Proximally located mucinous adenocarci-nomas. These are usually well circum-scribed and well or moderately differenti-ated. Lymphocytic infiltration is not
prominent but tumour infiltrating (intra-epithelial) lymphocytes (TIL) may be evi-dent in non-mucinous areas. Tubulo-vil-lous or villous adenomatous remnants
adjacent to the cancer may be present.
Mucin production may be more common
in subjects with an MSH2 germline muta-tion {1723}.
Proximally located, poorly differentiated
adenocarcinomas. Poor differentation
indicates a failure of gland formation, the
malignant epithelium being arranged in
small clusters, irregular trabeculae or
large aggregates. Tumours are well cir-cumscribed and lack an abundant
desmoplastic stroma. Some are pep-pered with TIL. A Crohn-like lymphocytic
reaction may be present. This subtype
has been described as medullary or
‘undifferentiated’, though the majority
contains subclones in which glandular
differentiation is evident. This subtype
may be more common in subjects with
an MSH2 mutation {1723}. In general,
colorectal cancers showing TIL and/or a
Crohn-like lymphocytic reaction appear
to be more common in subjects with an
MLH1 germline mutation {1723}.
Adenomas in HNPCC. These are more
likely to show features indicative of
increased cancer risk including villosity
and high-grade intraepithelial neoplasia
{846}. Immunohistochemical staining to
demonstrate loss of expression of MLH1
or MSH2 may assist in pinpointing the
underlying germline mutation. However,
antigenicity may be retained in the case
of MLH1, even if genetic changes have
resulted in a non-functioning protein
{1924A: 1924B}. Virtually all sporadic
MSI-H carcinomas lose MLH1 through
methylation.
Immunohistochemical staining of MSI-H
colorectal cancers confirms that the
majority of TIL are CD3 positive T-cells
and most, in turn, are cytotoxic (CD8
positive) {423}. In H&E sections, lympho-cytes are difficult to discern when the
percentage of CD3 positive lymphocytes
(out of all epithelial nuclei) is less than
about 5%. CD3 counts in excess of 5%
occur in around 70% of MSI-H cancers.
CD3 counts in excess of 10% are highly
specific for MSI-H cancers. The nodular
arrangements of lymphocytes occurring
peri-tumourally or within the serosa
(Crohn-like reaction) are B-lymphocytes
surrounded by T-lymphocytes.
Genetics
Acquired genetic changes
in HNPCC cancers
The demonstration of DNA microsatellite
instability serves as an important bio-marker for HNPCC cancers. Bandshifts in
BAT26 are highly sensitive for both famil-ial and sporadic MSI-H cancers {3},
though some cases may be missed {548}.
Fig. 6.64  Immunohistochemistry for the MLH1 gene
product in a patient with HNPCC. Normal expres-sion is seen in the non-neoplastic epithelium (left).
Expression is lost in the adenocarcinoma (right).
There should be at least three relatives with an
HNPCC-associated cancer: colorectal cancer
(CRC), or cancer of the endometrium, small
bowel, ureter or renal pelvis.
– One patient should be a first degree relative
of the other two
– At least two successive generations should
be affected.
– At least one tumour should be diagnosed
before age 50.
– Familial adenomatous polyposis should be
excluded in the CRC case(s) if any.
– Tumours should be verified by histopatho-logical examination.
Table 6.02
Revised diagnostic criteria for HNPCC
(Amsterdam criteria II)
– Familial clustering of colorectal and/or
endometrial cancer
– Excess risk of cancer of the ovary,
ureter/renal pelvis, small bowel, stomach,
brain, hepatobiliary tract, and skin (seba-ceous tumours)
– Development of multiple cancers at an early
age
– Features of colorectal adenoma include:
(1) variable numbers from one to a few; (2)
increased proportion of adenomas with a vil-lous growth pattern (3) a high degree of dys-plasia; (4) rapid progression from adenoma
to carcinoma and (5) high frequency of
microsatellite instability (MSI-H)
– Features of colorectal cancer include:
(1) predilection for proximal colon; (2)
improved survival; (3) multiple colorectal
cancers (4) increased proportion of muci-nous tumours, poorly differentiated tumours,
and tumours with marked host-lymphocytic
infiltration and lymphoid aggregation at the
tumour margin.
Table 6.03
Summary of clinical, pathological and genetic fea-tures of HNPCC (Lynch syndrome)
A panel of five markers (BAT25, BAT26,
D2S123, D5S346 and D17S250) has
been recommended for screening pur-poses {164}. Bandshifts at two or more
microsatellite loci are indicative of MSI-H.
Around 60% of HNPCC adenomas are
MSI-H {2}.
Most MSI-H cancers are diploid or near
diploid and the frequency of loss of het-erozygosity (LOH) is low for the tradition-al loci 5q, 17p and 18q {962, 841}. The
frequency of APC, KRAS and TP53 muta-tion is reduced {962, 841}. Conversely,
mutations are encountered in  TGFRII,
IGF2R, BAX, E2F-4, MSH3, MSH6 and
caspase 5 {548, 1165, 1699, 1793, 2156,
1558}. In general, the driving force for
colorectal cancer development and pro-gression may be DNA instability (mutator
pathway) or chromosomal instability
(suppressor pathway). HNPCC cancers
and sporadic MSI-H cancers share the
mutator pathway.
Mode of inheritance,
chromosomal location, and structure
HNPCC is transmitted as an autosomal
dominant trait. It is associated with
germline mutations in five genes with
verified or putative DNA mismatch repair
function, namely  MSH2 (MutS homo-logue 2),  MLH1 (MutL homologue 1),
PMS1 (Postmeiotic segregation 1), PMS2
(Postmeiotic segregation 2), and  MSH6
(MutS homologue 6). Structural charac-teristics of these genes are given in Table
6.04. Homozygous MLH1 mutations con-fer to a neurofibromatosis 1 like pheno-type {2048, 1580}.
Gene product
HNPCC genes are ubiquitously
expressed in adult human tissues, and
therefore, the expression pattern does
not seem to explain the selective organ
involvement in this syndrome. Expression
is particularly prominent in the epithelium
of the digestive tract as well as in testis
and ovary {505, 1030, 2120}. In the intes-tine, expression is confined to the repli-cating compartment, i.e. the bottom half
of the crypts. Immunohistochemical
staining against these proteins is nuclear.
Function
The protein products of HNPCC genes
are key players in the correction of mis-matches that arise during DNA replica-tion {957}. Two different MutS-related het-erodimeric complexes are responsible
for mismatch recognition: MSH2-MSH3
and MSH2-MSH6. While the presence of
MSH2 in the complex is mandatory,
MSH3 can replace MSH6 in the correc-tion of insertion-deletion mismatches, but
not single-base mispairs. Following mis-match binding, a heterodimeric complex
of MutL-related proteins, MLH1-PMS2
(and possibly another alternative com-plex formed by MLH1-MLH3) is recruit-ed, and this larger complex, together
with numerous other proteins, accom-plishes mismatch repair. The observed
functional redundancy in the DNA mis-match repair protein family may help
explain why mutations in  MSH2 and
MLH1 are prevalent in HNPCC families,
while mutations in  PMS1, PMS2, and
MSH6 are much less frequent, and no
germline mutations in  MSH3 or MLH3
have been reported, so far (see below).
Mismatch repair deficiency gives rise to
microsatellite instability, and as such may
aid in the diagnosis of this syndrome {3}.
Fig. 6.66 Microsatellite instability in HNPCC. Shifts
of allele size are evident in dinucleotide and
mononucleotide markers. N = normal tissue,
T = tumour.
128 Tumours of the colon and rectum
Fig. 6.65 Tubular adenoma from a patient with HNPCC immunostained for (A) MLH and (B) MSH2 . The neo-plastic epithelium shows loss of MSH2 expression (upper portion of B)
AB
129Hereditary nonpolyposis colorectal cancer
However, microsatellite instability is not
specific to HNPCC, occurring in 10 to
15% of apparently sporadic colorectal
and other tumours as well {164}.
Correction of biosynthetic errors in the
newly synthesized DNA is not the only
function of the DNA mismatch repair sys-tem. In particular, it is also able to recog-nize lesions caused by exogenous muta-gens, and has been shown to participate
in transcription-coupled repair {134,
1215}.
Gene mutations
The International Collaborative Group on
HNPCC maintains a database for
HNPCC-associated mutations and poly-morphisms (http://www.nfdht.nl). The
great majority is found in  MLH1 and
MSH2, with a few mutations in  MSH6,
PMS1 and PMS2. These mutations occur
in over 400 HNPCC families from differ-ent parts of the world {485}.
Most MSH2 and MLH1 mutations are
truncating {1488}. However, one-third of
MLH1 mutations is of missense type,
which constitutes a diagnostic problem
concerning their pathogenicity. Common-ly used theoretical criteria in support of
pathogenicity include the following: the
mutation leads to a nonconservative
amino acid change, the involved codon is
evolutionarily conserved, the change is
absent in the normal population, and it
segregates with the disease phenotype.
A subset of such mutations was directly
assessed for pathogenicity using a yeast-based functional assay, and there was a
good correlation {1745}. As a rule, the
mutations are scattered throughout the
genes, but exon 12 in MSH2 and exon 16
in MLH1 constitute particular hot spots
{1488}.
Mutations in the five DNA mismatch
repair genes account for two-thirds of all
classical HNPCC families meeting the
Amsterdam criteria and showing MSI in
tumours {1078}. Occurrence of these
mutations is clearly lower (< 30%) in
HNPCC kindreds not meeting the
Amsterdam criteria {1379, 2103}.
Moreover, clinically indistinguishable
phenotype (non-polypotic colon cancer
plus variable extracolonic cancers) may
be associated with germline mutations in
genes that are not involved in DNA mis-match repair, such as TGFβ-RII {1103}
and E-Cadherin {1581}. As expected,
tumours from such families do not char-acteristically show MSI.
Prognosis and predictive factors
HNPCC mutations generally have a high
penetrance. There is no clear-cut corre-lation between the involved gene, muta-tion site within the gene, or mutation type
vs. clinical features.  MSH2 mutations
may confer higher risk for extracolonic
cancer as compared to MLH1 mutations
{2005}. MSH6 mutations may be associ-ated with atypical clinical features,
including common occurence of
endometrial cancer {2102} and late age
of onset {29}. Finally, capability of the
mutant protein to block the normal homo-logue by a dominant negative fashion
may lead to a severe phenotype, in
which even normal cells may manifest
mismatch repair deficiency {1475, 1348}.
Conversely, inability to do so may be
associated with a milder phenotype and
lack of extracolonic cancers {828}.
Kindreds with the Muir-Torre phenotype
{971} as well as a subset of those with
Turcot syndrome {658} show mutations
similar to those observed in classical
HNPCC.
MSH2 2p21 2.8 16 73 {509, 956, 1029, 1079, 1686, 1486}
MLH1 3p31-p23 2.3 19 58-100 {193, 660, 955, 1077, 1075, 1453}
PMS1 2q31-q33 2.8 not known not known {1350}
PMS2 7p22 2.6 15 16 {1347, 1350}
MSH6 2p21 4.2 10 20 {13, 1686, 1451, 1349}
Gene Chromosomal  Length of cDNA (kb) Number of exons Genomic size (kb) References
location
Table 6.04
Characteristics of HNPCC-associated human DNA mismatch repair genes.
Definition
Juvenile polyposis (JP) is a familial cancer
syndrome with autosomal dominant trait,
characterized by multiple juvenile polyps
of the gastrointestinal tract, involving pre-dominantly the colorectum, but also the
stomach and the small intestine. In addi-tion to colorectal cancer, JP patients carry
an increased risk for the development of
tumours in the stomach, duodenum, bil-iary tree and pancreas.
MIM No. 174900, 175050
Synonyms
Generalized juvenile polyposis; juvenile
polyposis coli; juvenile polyposis of infan-cy; juvenile polyposis of the stomach;
familial juvenile polyposis; hamartoma-tous gastrointestinal polyposis.
Diagnostic criteria
Following the initial report by Stemper in
1975 {1831}, the following diagnostic cri-teria have been established: (1) more
than 5 juvenile polyps of the colorectum,
or (2) juvenile polyps throughout the gas-trointestinal tract, or (3) any number of
juvenile polyps with a family history of JP
{847}. Other syndromes that display
hamartomatous gastrointestinal polyps
should be ruled out clinically or by patho-logical examination.
Epidemiology
Incidence
JP is ten-fold less common than familial
adenomatous polyposis {838}, with an
incidence of from 0.6 to 1 case per
100,000 in Western nations {297, 215}.
JP may be the most common gastroin-testinal polyposis syndrome in develop-ing counties {1576, 2109}, and approxi-mately half of cases arise in patients with
no family history {316}.
Age and sex distribution
Two-thirds of patients with juvenile poly-posis present within the first 2 decades of
life, with a mean age at diagnosis of 18.5
years {316}. Some present in infancy, and
others not until their seventh decade
{749}. Though extensive epidemiological
data do not exist, incomplete penetrance
and approximately equal distribution
between the sexes can be presumed.
Localization
Polyps occur with equal frequency
throughout the colon and may range in
number from one to more than a hun-dred. Some patients develop upper gas-trointestinal tract polyps, most often in
the stomach, but also in the small intes-tine. Generalized juvenile gastrointestinal
polyposis is defined by the presence of
polyps in the stomach, small intestine
and colon {1643}.
Clinical features
Signs and symptoms. Patients with juve-nile polyposis usually present with gas-trointestinal bleeding, manifesting as
haematochezia. Melaena, prolapsed rec-tal polyps, passage of tissue per rectum,
intussusception, abdominal pain, and
anaemia are also common.
Imaging.  Air contrast barium enema and
upper gastrointestinal series may demon-strate filling defects, but are non-diag-nostic for juvenile polyps.
Endoscopy. Biopsy or excision of polyps
by colonoscopy can be both diagnostic
and therapeutic. Small juvenile polyps
may resemble hyperplastic polyps, while
larger polyps generally have a well-defined stalk with a bright red, rounded
head, which may be eroded. In the stom-ach, polyps are less often pedunculated
and are more commonly diffuse.
Macroscopy
Most subjects with juvenile polyposis
have between 50-200 polyps throughout
the colorectum. The rare and often lethal
form occurring in infancy may be associ-ated with a diffuse gastrointestinal poly-posis {1643}. In cases presenting in later
childhood to adulthood, completely unaf-fected mucosa separates the lesions.
This is unlike the dense mucosal carpet-ing that is characteristic of familial adeno-matous polyposis. The polyps are usually
pedunculated, but can be sessile in the
stomach. Smaller examples have the
spherical head of a typical solitary juve-nile polyp. They may grow up to 5 cm in
diameter, with a multilobated head. The
individual lobes are relatively smooth and
separated by deep, well-defined clefts.
The multilobated polyp therefore appears
like a cluster of smaller juvenile polyps
attached to a common stalk. Such multi-lobated or atypical juvenile polyps
account for about 20% of the total num-ber of polyps {847}.
L.A. Aaltonen
J.R. Jass
J.R. Howe
Juvenile polyposis
130 Tumours of the colon and rectum
Fig. 6.67  A – C Multiple polyps in juvenile polyposis.
The contour of polyps is highly irregular, fronded, in
contrast to solitary sporadic juvenile polyps.
A
B
C
131Juvenile polyposis
Histopathology
Smaller polyps are indistinguishable from
their sporadic counterparts. In the multi-lobated or atypical variety the lobes may
be either rounded or finger-like. There is
a relative increase in the amount of
epithelium versus stroma. Glands show
more budding and branching but less
cystic change than the classical solitary
polyp {847}.
Cancer in juvenile polyposis
There are two histogenetic explanations
for the well documented association
between colorectal cancer and juvenile
polyposis. Cancers could arise in co-existing adenomas. Alternatively, they
may develop through dysplastic change
within a juvenile polyp. While both mech-anisms may apply, pure adenomas are
uncommon in juvenile polyposis. By con-trast, foci of low-grade dysplasia may be
demonstrated in 50% of atypical or multi-lobated juvenile polyps. The dysplastic
areas may increase in size, generating a
mixed juvenile polyp/adenoma. The ade-nomatous component may be tubular,
tubulovillous or villous. Carcinomas are
more likely to be poorly differentiated
and/or mucinous {847}.
Extraintestinal manifestations
Congenital anomalies have been report-ed in 11 to 15% of JP patients {316, 727},
with the majority occurring in sporadic
cases {217}. These anomalies most
commonly involve the heart, central
nervous system, soft tissues, gastroin-testinal tract and genitourinary system
{316, 1202}. Several patients have been
reported with ganglioneuromatous prolif-eration within juvenile polyps {428, 1218,
1513, 2081}, and others with pulmonary
arteriovenous malformations and hyper-trophic osteoarthropathy {348, 1760,
101, 333}.
Fig. 6.69 Juvenile polyp with intraepithelial neopla-sia and early adenocarcinoma.
Fig. 6.68  A, B Juvenile polyposis. The bizarre architecture differs from the round, uniform structure of spo-radic juvenile polyps.
Fig. 6.70  A, B Intraepithelial neoplasia in a juvenile polyp.
Fig. 6.71  TGF-β superfamily signaling through signal-transducing SMAD (1,2,3,4,5 and 8) and inhibitory
SMAD (6 and 7) proteins. SMAD4, the protein defective in juvenile polyposis, plays a key role in the network.
After type I receptor activation, SMADs 1,2,3,5 and 8 become phosphorylated, form homomeric complexes
with each other, and assemble into heteromeric complexes with SMAD4. The complexes translocate into
the nucleus, where they regulate transcription of target genes. Inhibitory Smads act opposite from R-Smads
by competing with them for interaction with activated type I receptors or by directly competing with SMADs
1,2,3,5 and 8 for heteromeric complex formation with SMAD4. From: E. Piek et al. FASEB J 13: 2105 (1999).
AB
A B
Definition
Cowden syndrome (CS) is an autosomal
dominant disorder characterized by mul-tiple hamartomas involving organs
derived from all three germ cell layers.
The classical hamartoma associated with
CS is the trichilemmoma. Affected family
members have a high risk of developing
breast and non-medullary thyroid carci-nomas. Clinical manifestaions further
include mucocutaneous lesions, thyroid
abnormalities, fibrocystic disease of the
breast, gastrointestinal hamartomas,
early-onset uterine leiomyomas, macro-cephaly, mental retardation and dysplas-tic gangliocytoma of the cerebellum
(Lhermitte-Duclos). The syndrome is
caused by germline mutations of the
PTEN / MMAC1 gene.
MIM No. 158350
Synonyms
Cowden disease; multiple hamartoma
syndrome.
Diagnostic criteria
Because of the variable and broad
expression of CS and the lack of uniform
diagnostic criteria prior to 1996, the
International Cowden Consortium {1334}
compiled operational diagnostic criteria
for CS (Table 6.05), based on the pub-lished literature and their own clinical
experience {467}. Trichilemmomas and
papillomatous papules are particularly
important to recognize. CS usually pres-ents by the late 20s. It has variable
expression and an age-related pene-trance although the exact penetrance is
unknown. By the third decade, 99% of
affected individuals have developed the
mucocutaneous stigmata although any of
the other features could be present
already (see Table 6.05). Because the
clinical literature on CS consists mostly of
reports of the most florid and unusual
families or case reports by subspecialists
interested in their respective organ sys-tems, the spectrum of component signs
is unknown. Despite this, the most com-monly reported manifestations are muco-cutaneous lesions, thyroid abnormalities,
fibrocystic disease and carcinoma of the
breast, gastrointestinal hamartomas,
multiple, early-onset uterine leiomyoma,
macrocephaly (specifically, megen-cephaly) and mental retardation {1819,
665, 1152, 1096}.
Epidemiology
The single most comprehensive clinical
epidemiological study estimated the
prevalence to be 1 per million population
{1819, 1334}. Once the gene was identi-fied {1071}, a molecular-based estimate
of prevalence in the same population
was 1:200 000 {1333}. Because of the
difficulty in recognizing this syndrome,
prevalence figures are likely underesti-mates.
Intestinal neoplasms
Hamartomatous polyps. In a small but
systematic study comprising 9 well docu-mented CS individuals, 7 of whom had a
C. Eng
I.C. Talbot
R. Burt
Cowden syndrome
132 Tumours of the colon and rectum
Genetics
JP is autosomal dominant. Germline
mutations in  SMAD4/DPC4 tumour sup-pressor gene account for some of the
cases {748, 751}. SMAD4 maps to chro-mosome 18q21.1 {651}, i.e. a region that
is often deleted in colorectal carcinomas.
Gene structure and product
SMAD4 has 11 exons, encoding 552
amino acids. It is expressed ubiquitously
in different human organ systems, as well
as during murine embryogenesis. The
gene product is an important cellular
mediator of TGF-β signals relevant for
development and control of cell growth
and an obligate partner for SMAD2 and
SMAD3 proteins in the signalling path-way from the TGF-β receptor complex to
the nucleus {2099}.
Gene mutations
While relatively few germline mutations
have been described thus far, three stud-ies have confirmed, in different white pop-ulations, the frequent occurrence of a four
base pair deletion in SMAD4 exon 9 {531,
751, 1622}. Haplotype analyses indicate
that this is due to a mutation hotspot,
rather than an ancient founder mutation
{531, 751}. The families segregating this
particular mutation tend to be large, per-haps indicating high penetrance.
It seems likely that SMAD4 is not the only
gene underlying JP since only a subset
of the families have  SMAD4 germline
mutations {531, 748, 751, 1622}, and
many families are not compatible with
18q linkage {748, 751, 1622}. The PTEN
gene has also been proposed as under-lying JP {1421}, but this report has not
been confirmed by other studies and the
present notion is that individuals with
PTEN mutations should be considered
having Cowden syndrome, with a risk of
breast and thyroid cancer {469}.
Prognostic factors
The most severe form of juvenile polypo-sis presents in infancy, with diarrhoea,
anemia, and hypoalbuminemia; these
patients rarely survive past 2 years of age.
Although polyps in juvenile polyposis
patients have classically been described
as hamartomas, they do have malignant
potential. The risk of colorectal carcinoma
is approximately 30-40% and that of
upper gastrointestinal carcinoma is
10-15% {749}. Typical age of colon carci-noma diagnosis is between 34 and 43
years (range 15-68 years), and upper
gastrointestinal carcinoma 58 years
(range 21-73 years) {749, 847, 834}. Most
cases occur in patients who have not
been screened radiologically or endo-scopically, suggesting that cancers may
be preventable through close surveil-lance.
133Cowden syndrome
germline PTEN mutation, all 9 had hamar-tomatous polyps {2075}. Several varieties
of hamartomatous polyps are seen in this
syndrome, including lipomatous and gan-glioneuromatous lesions {2075}. Presu-mably, these polyps can occur anywhere
in the gastrointestinal tract. Those in the
colon and rectum usually measure from 3
to 10 millimetres but can reach 2 cen-timetres in diameter. Some of the polyps
are no more than tags of mucosa but oth-ers have a more definite structure. Most
are composed of a mixture of connective
tissues normally present in the mucosa,
principally smooth muscle in continuity
with the muscularis mucosae {242}.
Examples containing adipose tissue have
been described. The mucosal glands
within the lesion are normal or elongated
and irregularly formed but the epithelium
is normal and includes goblet cells and
columnar cells {242}. Lesions in which
autonomic nerves are predominant, giv-ing a ganglioneuroma-like appearance,
have been described but seem to be
exceptional {1017}. The vast majority of
CS hamartomatous polyps are asympto-matic. In a study of 9 CS individuals,
glycogenic acanthosis of the oesopha-gus was found in 6 of the 7 with  PTEN
mutation {2075}.
Gastrointestinal malignancies are gener-ally not increased in CS {1819, 468}
although rare individual CS families
appear to have an increased prevalence
of colon cancer (Eng, unpublished
observations).
Extraintestinal manifestations
Breast cancer. The two most commonly
recognized cancers in CS are carcinoma
of the breast and thyroid {1819}. In the
general population, lifetime risks for
breast and thyroid cancers are approxi-mately 11% (in women), and 1%, respec-tively. Breast cancer has been rarely
observed in men with CS {1167}. In
women with CS, lifetime risk estimates for
the development of breast cancer range
from 25 to 50% {1819, 665, 1096, 467}.
The mean age at diagnosis is likely 10
years earlier than breast cancer occur-ring in the general population {1819,
1096}. Although Rachel Cowden died of
breast cancer at the age of 31 {196,
1081} and the earliest recorded age at
diagnosis of breast cancer is 14 {1819},
the great majority of breast cancers are
diagnosed after the age of 30-35 (range
14 – 65) {1096}. The predominant histol-ogy is ductal adenocarcinoma. Most CS
breast carcinomas occur in the context
of DCIS, atypical ductal hyperplasia,
adenosis and sclerosis {1691}.
Thyroid cancer. The lifetime risk for thy-roid cancer can be as high as 10% in
males and females with CS. Because of
small numbers, it is unclear if the age of
onset is truly earlier than that of the gen-eral population. Histologically, the thyroid
cancer is predominantly follicular carci-noma although papillary histology has
also been rarely observed {1819, 665,
1152} (Eng, unpublished observations).
Medullary thyroid carcinoma has not
been observed in patients with CS.
Benign tumours. The most important
benign tumours are trichilemmomas and
papillomatous papules of the skin. Apart
from those of the skin, benign tumours or
disorders of breast and thyroid are the
most frequently noted and probably rep-resent true component features of this
syndrome (Table 6.05). Fibroadenomas
and fibrocystic disease of the breast are
common signs in CS, as are follicular
adenomas and multinodular goitre of the
thyroid. An unusual central nervous sys-tem tumour, cerebellar dysplastic gan-gliocytoma or Lhermitte-Duclos disease,
has recently been associated with CS
{1445, 468, 932}.
Other malignancies and benign tumours
have been reported in patients or fami-lies with CS. Some authors believe that
endometrial carcinoma could be a com-ponent tumour of CS as well. It remains to
be shown whether other tumours (sarco-mas, lymphomas, leukaemia, menin-giomas) are true components of CS.
Genetics
Chromosomal location and mode of
transmission
CS is an autosomal dominant disorder,
with age related penetrance and variable
expression {468}. The CS susceptibility
gene, PTEN, resides on 10q23.3 {1071,
1334, 1068}.
Gene structure
PTEN/MMAC1/TEP1 consists of 9 exons
spanning 120-150 kb of genomic dis-tance {1167, 1820, 1068}. It is believed
that intron 1 occupies much of this
(approximately 100 kb). PTEN is predict-ed to encode a 403-amino acid phos-phatase. Similar to other phosphatase
genes, PTEN exon 5 specifically
encodes a phosphatase core motif.
Exons 1 through 6 encode amino acid
sequence that is homologous to tensin
and auxilin {1065, 1820, 1068}.
Gene product
PTEN is virtually ubiquitously expressed
{1820}. Detailed expression studies in
Fig. 6.72 A, B Colonic polyps in Cowden syndrome. Distorted glands and fibrous proliferation in lamina propria.
A B
development have not been performed.
However, early embryonic death in
pten -/- mice would imply a crucial role
for PTEN in early development {1526,
1868, 407}.
PTEN is a tumour suppressor and is a
dual specificity phosphatase {1304}. It is
a lipid phosphatase whose major sub-strate is phosphtidylinositol-3,4,5-triphosphate (PIP3) which lies in the PI3
kinase pathway {553, 1814, 1142, 364,
1067}. When PTEN is ample, PIP3 is con-verted to 4,5-PIP2, which results in
hypophosphorylated Akt/PKB, a known
cell survival factor. Hypophosphorylated
Akt is apoptotic. Transient transfection
studies have shown that ectopic expres-sion of PTEN results in apoptosis in
breast cancer lines mediated by Akt
{1067} and G1 arrest in glioma lines {553,
554}. The G1 arrest is not fully explained
by the PTEN-PI3K-Akt pathway. It is also
believed that PTEN can dephosphorylate
FAK and inhibit integrin and MAP kinase
signalling {637, 1892}.
Gene mutations
Approximately 70-80% of CS cases, as
strictly defined by the Consortium crite-ria, have a germline PTEN mutation
{1167, 1071}. If the diagnostic criteria are
relaxed, then mutation frequencies drop
to 10-50% {1335, 1964, 1124}. A formal
study which ascertained 64 unrelated
CS-like cases revealed a mutation fre-quency of 2% if the criteria are not met,
even if the diagnosis is made short of
one criterion {1168}.
A single research centre study involving
37 unrelated CS families, ascertained
according to the strict diagnostic criteria
of the Consortium, revealed a mutation
frequency of 80% {1167}. Exploratory
genotype-phenotype analyses revealed
that the presence of a germline mutation
was associated with a familial risk of
developing malignant breast disease
{1167}. Further, missense mutations
and/or mutations 5’ of the phosphatase
core motif seem to be associated with a
surrogate for disease severity (multi-organ involvement). A small study com-prising 13 families with 8 PTEN mutation-positive members could not find any
genotype-phenotype associations {1333}
but this may be due to the small sample
size.
Bannayan-Riley-Ruvalcaba syndrome
(BRR). Previously thought to be clinical-ly distinct, BRR (MIM 153480), character-ized by macrocephaly, lipomatosis, hae-mangiomatosis and speckled penis, is
likely allelic to CS {1169}. Approximately
60% of BRR families and isolated cases
combined carry a germline PTEN muta-tion {1170}. There were 11 cases classi-fied as true CS-BRR overlap families in
this cohort, and 10 of these had a PTEN
mutation. The overlapping mutation
spectrum, the existence of true overlap
families and the genotype-phenotype
associations which suggest that the
presence of germline PTEN mutation is
associated with cancer strongly suggest
that CS and BRR are allelic and part of a
single spectrum at the molecular level.
The aggregate term of PTEN hamartoma
tumour syndrome (PHTS) has been sug-gested {1170}.
The identification of a germline PTEN
mutation in a patient previously thought
to have juvenile polyposis {1421}
excludes that diagnosis, and points to
the correct designation as CS or BRR
{469, 751, 983, 750, 1171}.
Prognosis
There have been no systematic studies
to indicate if CS patients who have can-cer have a prognosis different from that
of their sporadic counterparts.
134 Tumours of the colon and rectum
Table 6.05
International Cowden Consortium diagnostic criteria for CS.
Diagnostic criteria Operational diagnosis in an individual Operational diagnosis in a family where one
individual is diagnostic for Cowden
Pathognomonic Criteria
Mucocutanous lesions:
Trichilemmomas, facial
Acral keratoses
Papillomatous papules
Mucosal lesions
Major Criteria
Breast CA
Thyroid CA, esp. follicular carcinoma
Macrocephaly (Megencephaly) ( *97%ile)
Lhermitte-Duclos disease (LDD)
Minor Criteria
Other thyroid lesions
(e.g. adenoma or multinodular goiter)
Mental retardation (IQ )75)
Gastro-intestinal hamartomas
Fibrocystic disease of the breast
Lipomas
Fibromas
Genitourinary tumours (e.g. uterine fibroids) or
malformation
1. Mucocutanous lesions alone if:
a) there are 6 or more facial papules, of
which 3 or more must be trichilemmoma, or
b) cutaneous facial papules and oral mucos-al papillomatosis, or
c) oral mucosal papillomatosis and acral ker-atoses, or
d) palmoplantar keratoses, 6 or more
2. Two major criteria but one must include
macrocephaly or LDD
3. One major and three minor criteria
4. Four minor criteria
1. At least one pathognomonic criterion
2. Any one major criterion with or without
minor criteria
3. Two minor criteria
135Hyperplastic polyposis
Definition
Multiple or large hyperplastic (metaplas-tic) polyps of the large intestine, typically
located proximally, and often exhibiting
familial clustering.
Synonyms and historical annotation
The term metaplastic polyposis has been
used synonymously. Early descriptions
emphasized a multiplicity of hyperplastic
polyps throughout the colorectum and
caused diagnostic confusion with familial
adenomatous polyposis (FAP) {2114}.
The condition was also reported to occur
in young male subjects. These descrip-tions (predating the colonoscopic era)
were biased towards cases mimicking
FAP or showing unusual aspects such as
young age of onset. In the colonoscopic
era, the features of large polyp size
and/or distribution throughout the col-orectum serve to distinguish hyperplastic
polyposis from the far more common
occurrence of small hyperplastic polyps
in the distal colon and rectum.
Hyperplastic polyposis should be distin-guished from sporadic hyperplastic
polyps in view of its association with col-orectal neoplasia {1198, 126} and
reports of familial clustering {849}.
Diagnostic criteria
In the absence of generally accepted
guidelines on what would constitute the
minimum number of polyps or polyp size
to warrant a diagnosis of hyperplastic
polyposis, the following criteria are rec-ommended: (1) At least five histological-ly diagnosed hyperplastic polyps proxi-mal to the sigmoid colon of which two are
greater than 10 mm in diameter, or (2)
any number of hyperplastic polyps
occurring proximal to the sigmoid colon
in an individual who has a first degree
relative with hyperplastic polyposis, or
(3) more than 30 hyperplastic polyps of
any size, but distributed throughout the
colon.
Clinical features
Unless there is associated malignancy,
hyperplastic polyposis is generally
asymptomatic. Larger hyperplastic
polyps may occasionally present with
rectal bleeding. The condition may be
diagnosed in adults of all ages. Although
considered as rare, the condition is prob-ably under-reported.
Firm management guidelines have not
been developed. The rather frequently
observed association with adenomatous
polyps and colon carcinomas suggests
that some surveillance of patients is
required, with generous biopsy sampling
and polypectomy as appropriate, partic-ularly of larger polyps, to determine if
neoplasia is present. Subtotal colectomy
is occasionally necessary in patients with
multiple adenomatous polyps if there are
numerous and rapidly growing hyper-plastic polyps that make it nearly impos-sible to selectively eliminate neoplastic
lesions.
Imaging
Small polyps may be indistinguishable
from diminutive adenomas. High resolu-tion videoendoscopy, combined with dye
spraying, will demonstrate the diagnostic
star-shaped crypt opening {1191}.
Larger hyperplastic polyps may either
present as pale flat lesions on the crest of
a mucosal fold or may become protuber-ant. The head may darken and become
lobulated, simulating an adenoma. The
colonoscopic phenotype in some
patients simulates FAP with scores to
hundreds of 1mm to 5mm in diameter
polyps, while others exhibit a smaller
number of centimeter sized darker ses-sile lesions that grossly may be confused
with multiple villous adenomas. With
either phenotype, one or several adeno-mas may be found in addition to the
hyperplastic polyps. High resolution
videoendoscopy suggests that a mixed
hyperplastic and cerebriform pattern
may be indicative of serrated adenoma
{1191}.
Histopathology
Most hyperplastic polyps are indistin-guishable from their common counter-parts, apart from their large size. As in
the sporadic hyperplastic polyp, the pro-liferative zone is increased but remains
confined to the lower crypt. There is
abnormal retention of cells in the upper
maturation zone associated with the
characteristic appearance of serration. A
small proportion contains foci of intraep-ithelial neoplasia (dysplasia) that may
R. Burt
J.R. JassHyperplastic polyposis
Fig. 6.73  Hyperplastic polyp in a patient with hyper-plastic polyposis.
Fig. 6.75 Immunohistochemistry for the  hMLH1
gene product in a mixed hyperplastic polyp / ade-noma in a case of hyperplastic polyposis. Normal
expression (right) is lost in the glands with intraepi-thelial neoplasia (left).
Fig. 6.74 Colectomy specimen, hyperplastic polypo-sis.
136 Tumours of the colon and rectum
either resemble a tubular, tubulovillous,
or villous adenoma, or retain a serrated
architecture supporting a diagnosis of
serrated adenoma {1987, 1092,  337}.
Hyperplastic polyps and serrated adeno-mas show a similar mucinous phenotype
exemplified by upregulation of the goblet
cell mucin MUC2, reduction of the intes-tinal mucin MUC4 and neo-expression of
the gastric mucin MUC5AC. This sug-gests that hyperplastic polyps and ser-rated adenomas represent a histogenet-ic continuum {139}.
Unusual growth patterns, including inver-sion and pseudoinvasion, with associat-ed disorganization of the muscularis
mucosae, are more characteristic of
large polyps {1729, 1773} and will there-fore be over-represented in hyperplastic
polyposis.
It has been suggested that hyperplastic
polyposis be distinguished from ‘serrat-ed adenomatous polyposis’ {1944}.
However, the histological distinction
between a large hyperplastic polyp and
a serrated adenoma is not straightfor-ward and there is probably no sharp divi-sion between hyperplastic polyposis and
‘serrated adenomatous polyposis’.
Genetics
Despite being regarded as non-neoplas-tic, hyperplastic polyps may show clonal
genetic changes, including chromosomal
rearrangements at 1p,  KRAS mutation
and low levels of DNA microsatellite insta-bility {775}. Mutations of  TP53 and
increased immunoexpression of p53 are
limited to areas of high-grade intraepithe-lial neoplasia in serrated adenomas
{720}. In hyperplastic polyposis, micro-satellite instability is seen in areas of
intraepithelial neoplasia. High levels of
microsatellite instability (MSI-H) are asso-ciated with loss of expression of the DNA
mismatch repair protein hMLH1 in these
lesions {844}. This observation fits with
the suggestion that DNA microsatellite
instability may be caused by the silenc-ing of DNA mismatch repair genes by
methylation of the promoter region {361}.
A mutation affecting a gene that controls
methylation might account for familial and
non-familial cases of hyperplastic polypo-sis, placing this condition within the spec-trum of colorectal lesions showing mis-match repair deficiency {1950}. An epige-netic mechanism involving disordered
methylation would explain polyp multi-plicity and the tendency for hyperplastic
polyps to regress spontaneously {986}.
Prognosis
Sporadic hyperplastic polyps are gener-ally believed not to be associated with an
increased cancer risk. Evidence for
hyperplastic polyposis being a precan-cerous lesion includes the observation of
mixed hyperplastic/adenomatous polyps
in this condition and the synchronicity of
hyperplastic polyposis and colorectal
cancer {1198, 126}. The genetic
changes noted above offer further evi-dence for a direct relationship between
hyperplastic polyposis and colorectal
carcinoma, and support the concept of a
hyperplastic polyp-adenoma-carcinoma
sequence {775}.
Fig. 6.76 A Serrated adenoma in a patient with hyperplastic polyposis. B Mixed hyperplastic polyp / adeno-ma in a patient with hyperplastic polyposis.
AB
137Endocrine tumours
Definition
Endocrine tumours of the large intestine
are defined as in the small intestine.
Epidemiology
Incidence and time trends
Endocrine tumours of the colon have an
incidence of 0.07-0.11 up to 0.21 cases
per 100,000 population per year {1251}.
In a recent series, carcinoids from cae-cum to transverse colon (midgut) repre-sented about 8% and descending colon
and rectosigmoid (hindgut) carcinoids
about 20% of 5973 gastrointestinal carci-noids {1251}. Rectal carcinoids had a
reported incidence of 0.14-0.76 cases
per 100,000 population per year. In the
40-year time period (from 1950 to 1991)
the percentage of caecal carcinoids,
among carcinoids of all sites, nearly dou-bled, as did the percentage of rectosig-moid lesions {1251}.
Age and sex distribution
The reported average age at diagnosis is
58 years, for rectal, and 66 years, for
colonic carcinoids, and the M/F ratio is
1.06, for rectal, and 0.66, for colonic car-cinoids {1251}.
Aetiology
Some colorectal carcinoids have been
reported in the large bowel of patients
with ulcerative colitis {584, 622} or Crohn
disease {722, 622}. In association with
these conditions, the tumours tend to be
multiple {1208}. However, there appears
to be no evidence to substantiate a direct
association between inflammatory bowel
disease and carcinoid tumours, because
almost all cases were found incidentally
after surgery for inflammatory bowel dis-ease {622}.
Localization
Endocrine tumours are more common in
the rectum (54% of the cases), followed
by the caecum (20%), sigmoid colon
(7.5%), rectosigmoid colon (5.5%) and
ascending colon (5%) {1251, 1784}.
Clinical features
Patients with colonic carcinoid tumours
most commonly present in the seventh
decade with symptoms of abdominal pain
and weight loss, though some present
late with liver metastases {1616}. Less
than 5% of patients present with the carci-noid syndrome {1616, 128}. Carcinoids of
the colon are associated with metachro-nous or synchronous non-carcinoid neo-plasms in 13% of cases {1251}.
Half of rectal endocrine tumours are
asymptomatic and are discovered at rou-tine rectal examination or endoscopy,
while the other half give rise to symptoms,
typically rectal bleeding, pain or consti-pation {857, 1836}. Rectal carcinoids are
practically never associated with the car-cinoid syndrome {857, 1836, 212}.
Small cell carcinomas are aggressive
neoplasms and can present with symp-toms due to local disease or to wide-spread metastases.
Macroscopy
The majority of colonic carcinoids are
detected in the right colon {1616, 128}
and are larger than carcinoids of the
small intestine, appendix, and rectum.
The average size was 4.9 cm in cases
reviewed by Berardi {128}.
Rectal carcinoids appear as submucosal
nodules, sometimes polypoid, often with
apparently intact overlying epithelium
{968}. Larger lesions tend to be somewhat
fixed to the rectal wall. In the great major-ity of cases the tumour is found 4 to 13 cm
above the dentate line and on the anterior
or lateral rectal walls {222}. The majority of
rectal endocrine tumours are solitary and
measure less than 1 cm in diameter {222}.
Reviewing 356 cases reported in the liter-ature, Caldarola et al. {222} found that
only 13% of rectal carcinoids measured
more than 2 cm in diameter.
Histopathology
Carcinoid – well differentiated endocrine
neoplasm
Colonic serotonin-producing EC-cell
tumours show histological, cytological,
cytochemical, and ultrastructural fea-tures that are identical to those of jejuno-ileal EC-cell tumours, including the
absence of S100 protein positive susten-tacular cells {1784}.
L-cell, glucagon-like peptide and PP/PYY-producing tumours are characterized his-tologically by a predominance of a type B
{1775} ribbon pattern, often admixed with
type C (tubuloacini or broad, irregular tra-beculae with rosettes) and only occasion-ally with areas of type A solid nest struc-tures. These patterns are different from
C. Capella
E. Solcia
L.H. Sobin
R. Arnold
Endocrine tumours
of the colon and rectum
Fig. 6.77  Endoscopically resected carcinoid tumour
of rectum.
Fig. 6.78  A, B Carcinoid tumour of rectum. Trabecular pattern, typical of L-cell tumour.
BA
138 Tumours of the colon and rectum
those of EC-cell tumours, in which type A
structures prevail. The argentaffin reac-tion is usually negative {146}, while con-sistently positive results are obtained with
Grimelius stain {488}. Immunohisto-chemically, they stain for panendocrine
markers (neuron-specific enolase, synap-tophysin, chromogranins) and for a vari-ety of peptide hormones {488}. Among 62
rectal carcinoids derived from surgical
pathology files, about 80% displayed
more or less abundant glucagon-like
peptide (GLP-1, GLP-2, glicentin) and/or
PP/PYY immunoreactivities typical of
intestinal L-cells, whereas only 30%
showed serotonin immunoreactivity and
20% somatostatin immunoreactivity, usu-ally in only few cells {1780, 507}.
Although there is a prevalence of L-cells
in these tumours, minority populations of
substance P, insulin, enkephalin, beta-endorphin, neurotensin, and motilin
immunoreactive cells have also been
identified {1780, 488, 212}. The vast
majority (82%) of colorectal carcinoids
tested in one series of 84 cases showed
immunoreactivity for prostatic acid phos-phatase, a finding that is unusual in other
gut carcinoids and possibly is related to
the common origin of the rectum and
prostate from cloacal hindgut {488}.
Ultrastructurally, rectal L-cells show
round to slightly angular secretory gran-ules similar to those of L-cells of the nor-mal human intestine {506}.
Small ()2 cm) benign L-cell rectal carci-noids show an immunohistochemical
Ki-67 index  ) 1%, while large (> 2 cm)
L-cell carcinomas show a Ki-67 index
* 5% (La Rosa S, Capella C, Solcia E,
unpublished observations, 1999).
Small cell carcinoma (poorly differentiat-ed neuroendocrine neoplasm)
These are morphologically identical to
small cell carcinomas of the lung, and
correspond to grade 3 tumours accord-ing to Rindi et al. {1589}. They are usual-ly found in the right colon, and are fre-quently associated with an overlying
adenoma or adjacent adenocarcinoma
{2085}, but are not associated with carci-noid tumours. Small cell carcinomas typ-ically express neuroendocrine markers
(e.g. chromogranin, synaptophysin) by
immunohistochemistry. Patients usually
have liver metastases at the time of orig-inal surgery, and the prognosis is poor
{207}.
Large cell neuroendocrine carcinoma is a
malignant neoplasm composed of large
cells having organoid, nesting, trabecu-lar, rosette-like and palisading patterns
that suggest endocrine differentiation,
which can be confirmed by immunohis-tochemistry and electron microscopy. In
contrast to small cell carcinoma, cyto-plasm is more abundant, nuclei are more
vesicular and nucleoli are prominent
{1954}. These tumours have not been
well described in the gastrointestinal
tract because of their apparent low fre-quency.
Genetics
Loss of heterozygosity at  MEN-1 locus
has been reported in two sporadic
colonic and two sporadic rectosigmoidal
carcinoids {829}. However, this finding
has not been confirmed by more recent
studies {394, 1938}. Colorectal carci-noids do not represent an integral part of
MEN-1 {1444}. A case of rectal carcinoid
tumour associated with Peutz-Jeghers
syndrome has been reported {2032}.
Prognosis
Colonic EC-cell carcinoids are frequently
malignant, local spread of the tumours
was found in 36-44% of patients and dis-tant metastases in 38% {1251, 1616}.
The reported 5-year survival rate was
25-42% and the 10-year survival rate was
10% {1251, 1616}. Modlin found malig-Fig. 6.79 Rectal carcinoid showing prostatic acid
phosphatase immunoreactive cells.
Fig. 6.80 Small cell carcinoma arising in a tubulovil-lous adenoma of the sigmoid colon.
Fig. 6.81  Small cell carcinoma. A Typical oval or moulded nuclei with diffuse chromatin, scant cytoplasm and little stroma. B Neuroendocrine granules in elec-tronmicrograph.
AB
139B-cell lymphoma
Definition
Primary lymphoma of the colorectum is
defined as an extranodal lymphoma aris-ing in either the colon or rectum with the
bulk of disease localized to this site
{796}. Contiguous lymph node involve-ment and distal spread may be seen, but
the primary clinical presentation is the
colon and/or rectum.
Epidemiology
Primary lymphomas arising in the large
intestine are less frequent than either
gastric or small bowel lymphomas {792}.
Primary colorectal lymphomas account
for about 0.2% of all neoplasms at this
site. The lymphoma subtypes that pres-ent in the colorectum are similar to those
that involve the small intestine, with the
exception of immunoproliferative small
intestinal disease (IPSID). Mucosa-asso-ciated lymphoid tissue (MALT) lym-phomas of both small and large cell type
account for the majority of lymphomas of
the colorectum {1733}. Mantle cell lym-phoma (MCL), often in the form of multi-ple lymphomatous polyposis, is less fre-quent but accounts for a larger propor-tion of primary lymphomas in the
colorectum than in the small bowel
{1733}.
Most colorectal lymphomas occur in
older patients without a clear sex pre-dominance. Amongst aquired immuno-deficiency syndrome (AIDS) patients, the
median age is lower and the majority of
cases occur in homosexual men.
Involvement of the colorectum by Burkitt
lymphoma is distinctly uncommon in
immunocompetent individuals.
Aetiology
The factors involved in the aetiology of
colorectal lymphomas are similar to
those in the small intestine. Inflammatory
bowel disease, particularly ulcerative
colitis, is a recognized predisposing fac-tor {1733}. Diverticular disease does not
appear to be a risk factor for the devel-opment of lymphoma.
Immunodeficiency disorders giving rise
to lymphoma have a predilection for the
gastrointestinal tract. The frequency of
colorectal lymphomas has significantly
increased, partly due to the AIDS epi-demic.
Localization
Most colorectal lymphomas involve the
distal large bowel, rectum and anus.
There is a preference for rectal lym-phoma in patients infected with the
human immunodeficiency virus (HIV)
{787, 1057}. Multifocal involvement is
uncommon with the exception of multiple
lymphomatous polyposis {1733}.
Clinical features
The presenting features are very similar
to epithelial neoplasms at this site. Rectal
bleeding is the most common symptom,
followed by diarrhoea, abdominal pain,
passage of mucus per rectum, constipa-tion, abdominal mass, weight loss, irreg-ular bowel habit, anal pain and worsen-ing of ulcerative colitis symptoms.
Occasional cases are found incidentally,
while an acute presentation with rupture
of the colon is distinctly uncommon
{1733, 611}.
Similar to gastric lymphomas, colorectal
lymphomas can be diagnosed using
endoscopy and biopsy. Computerized
tomography and barium enema have a
role in diagnosis and determining the
H.K. Müller-Hermelink
A. Chott
R.D. Gascoyne
A. Wotherspoon
B-cell lymphoma
of the colon and rectum
nant (non-localized) tumours represent-ed 71% of the cases among colonic car-cinoids, and 14% of cases among rectal
carcinoids {1251}. The alleged poor
prognosis of colonic carcinoids has been
questioned as possibly the result of a
proportion actually being poorly differen-tiated adenocarcinomas with carcinoid-like growth patterns {1928}.
For rectal carcinoids, an overall malig-nancy rate of 11% to 14% has been cal-culated in some studies {1251, 488}.
Recognised malignancy criteria include:
a size of the tumour greater than 2 cm
{857, 1328, 930}, invasion of the muscu-laris propria {857, 212, 1328}, atypical
histology {964}, presence of more than 2
mitoses per 10 high power (X 400) micro-scopic fields, and DNA aneuploidy
{1963}. Patients with rectal carcinoids
generally have a good prognosis, show-ing a 5-year survival rate of 72%-89%
{1251, 1931}, which is better than the
5-year survival rate of 60% for patients
with jejuno-ileal carcinoids {211}. The
prognosis is excellent if the tumour diam-eter is 1 cm or less {294}.
140 Tumours of the colon and rectum
extent of disease. Multiple lymphoma-tous polyposis has a characteristic radio-logical picture with numerous polyps of
variable size throughout the colon.
Transrectal ultrasonography may also be
a useful adjunct for diagnosis.
Macroscopy
Most low-grade lymphomas present as
well defined protuberant growths that
deeply invade the bowel wall. Diffuse
large B-cell lymphoma (DLBCL) and
Burkitt lymphoma tend to form larger
masses with stricture and ulcer formation
involving long segments of the colorec-tum. Low-grade and aggressive MALT
lymphomas typically remain localized for
prolonged periods, but may spread to
involve loco-regional lymph nodes.
Mantle cell lymphoma (MCL) may
present as an isolated mass or as multi-ple polyps producing the clinical picture
of multiple lymphomatous polyposis
{2084}. In most cases, the colon is more
significantly involved than the small
bowel. Importantly, other histological
subtypes of lymphoma can produce this
clinicopathological entity (see below).
The polyps range in size from 0.5 cm to
2 cm with much larger polyps found in
the ileocaecal region {791, 1292}. MCL
frequently spreads to involve the spleen,
extra-abdominal lymph nodes, bone
marrow and peripheral blood.
Histopathology
MALT lymphoma
The majority of intestinal lymphomas
involving the large bowel are B-cell lym-phomas of MALT type, including both
low-grade and aggressive histologies
{796}. The histological and immunophe-notypic features are discussed in detail
in the section describing lymphomas of
the stomach. Colorectal low-grade MALT
lymphomas resemble those of the small
intestine in that lymphoepithelial lesions
are less prominent than in the stomach.
Precise criteria for defining a MALT lym-phoma of large cell type are lacking, as
are the criteria for distinguishing transfor-mation within a low-grade MALT lym-phoma. When both histologies are evi-dent, the neoplasm is best described as
composite. When small foci of large
transformed cells or early sheeting-out of
large cells are detected within a back-ground of low-grade intestinal MALT lym-phoma, their presence should be noted
{383}. Currently, the prognostic impact of
these findings and their effect on treat-ment are undetermined. DLBCLs arising
in the large bowel that lack a background
of low-grade MALT lymphoma are best
classified as extranodal diffuse large
B-cell lymphoma, not otherwise speci-fied, until such time as confirmatory tests
can be established to clearly determine
the histogenesis of these neoplasms
from the mucosal immune system.
Mantle cell lymphoma
The morphology of MCL involving the
large bowel is identical to MCL at nodal
sites {110}. The architecture is most
frequently diffuse, but a nodular pattern
and a less common true mantle-zone
pattern are also seen. Reactive germinal
centers may be found and are usually
compressed by the surrounding
lymphoma cells, imparting the appear-ance of replacing the normal mantle
zones. Intestinal glands may be
destroyed by the lymphoma, but typical
lymphoepithelial lesions are not seen.
The low power appearance is monoto-nous with frequent epithelioid histiocytes,
mitotic figures and fine sclerosis sur-rounding small blood vessels. The lym-phoma cells are small to medium sized
with irregular nuclear outlines, indistinct
nucleoli and scant amounts of cytoplasm.
Large transformed cells are typically not
present.
The lymphoma cells are mature B-cells
and express both CD19 and CD20.
Characteristically the cells co-express
CD5 and CD43. Surface immunoglobulin
is found including both IgM and IgD.
Light chain restriction is present in most
cases, with some studies demonstrating
a predominance of lambda. CD10 and
CD11c are virtually always negative.
Bcl-1 (cyclin D1) is found in virtually all
cases and can be demonstrated within
the nuclei of the neoplastic lymphocytes
in paraffin sections.
Burkitt lymphoma
The details of the histology, immunophe-notype, cytogenetics and molecular
genetics are described in detail in the
small intestinal lymphoma section
(Chapter 4).
Burkitt-like lymphoma
The histological and cytogenetic features
have been previously described in the
small intestinal lymphoma section. AIDS
patients have a preponderance of cases
with this histology. Many are of small non-cleaved cell type with the typical molec-ular and cytogenetic changes associat-ed with classical Burkitt lymphoma, and
Fig. 6.82 MALT lymphoma of rectum with lym-phoepithelial lesions.
Fig. 6.83 Malignant lymphoma of rectum.
Fig. 6.84  Burkitt lymphoma of colon. The malignant
cells infiltrate the lamina propria and produce lym-phoepithelial lesions.
141B-cell lymphoma
are best considered to be part of the
same biological entity {236}. However,
patients with AIDS have also been rec-ognized to have another lymphoma, with
features intermediate between small
non-cleaved cell lymphoma with plas-mablastic differentiation and immuno-blastic lymphoma, plasmacytoid type.
This latter lymphoma subtype is strongly
associated with EBV infection and  TP53
mutations {236}.
Other B-cell lymphomas
Any subtype of B-cell lymphoma can
arise in a colorectal site, including those
thought to arise from peripheral lymph
node equivalents.  De novo DLBCLs are
equal in frequency to low-grade MALT
lymphomas in the colorectum {1733},
and are particularly common in the set-ting of HIV infection. Rectal involvement
in AIDS patients typically demonstrates
DLBCL with either centroblastic or
immunoblastic cytomorphology. These
lymphoma subtypes can be distin-guished using phenotypic markers
including Bcl-6, CD138 (syndecan-1)
and EBV-related protein, latent mem-brane protein (LMP-1). Small non-cleaved and centroblastic lymphomas
express Bcl-6, but fail to express CD138
or LMP-1 in the majority of cases.
Immunoblastic lymphomas in the HIV
setting do not express Bcl-6, but are pos-itive for both CD138 and LMP-1, in keep-ing with a non-germinal center histogen-esis {237}.
Genetics
MALT lymphoma
Cytogenetic and molecular features of
intestinal low-grade MALT lymphomas
are incompletely understood. The pres-ence of either t(1;14)(p22;q32) or
t(11;18)(q21;q21) and the corresponding
molecular abnormalities, rearrangement
of bcl-10 or AP12-MLT, have not been
described at this site, thus the relationship
of these lesions to gastric MALT
lymphomas is unclear {2116, 412}.
Furthermore, trisomy 3 is common in gas-tric MALT lymphomas, but the frequency
of this cytogenetic abnormality in primary
intestinal lymphoma is unknown. Some of
these DLBCLs may have a low-grade
MALT component evident, providing com-pelling evidence that their histogenesis is
related to the mucosal immune system.
Mantle cell lymphoma
MCL is characterized by a recurrent
cytogenetic abnormality, the t(11;14)
(q13;q32). This translocation deregulates
expression of the  bcl-1 oncogene on
chromosome 11. Rearrangement can be
detected using Southern blot analysis,
PCR or fluorescent in situ hybridization
(FISH).
Prognosis
The relevant prognostic factors in col-orectal lymphomas are similar to those
for the small intestine, and have been
described in detail in that section. MCL is
an aggressive lymphoma, which typical-ly presents in advanced stage; there is
often involvement of mesenteric and
peripheral lymph nodes, spleen, bone
marrow and peripheral blood {670}.
Fig. 6.86 Mantle cell lymphoma.
Fig. 6.85 Mantle cell lymphoma infiltrating the submucosa predominantly , thereby causing a polypoid lesion.
142 Tumours of the colon and rectum
Definition
A variety of benign and malignant mes-enchymal tumours that arise in the large
intestine as a primary site.
Classification
The morphological definitions of these
lesions follow the WHO histological clas-sification of soft tissue tumours {2086}.
Stromal tumours are described in detail
in the chapter on gastric mesenchymal
tumours.
Epidemiology
Sarcomas accounted for 0.1% of malig-nant large intestinal tumours in SEER
data {1928}. Males were affected slightly
less than females. Adults between the 6th
and 8th decades were primarily affected.
Aetiology
Aetiological factors are poorly under-stood for most colorectal mesenchymal
tumours. Kaposi sarcoma usually occurs
in association with AIDS, but it has also
been described in connection with
inflammatory bowel disease, in one case
following immunosuppressive therapy
{1930, 1584}. Human herpesvirus 8 is
usually demonstrable by PCR in Kaposi
sarcoma cells. An angiosarcoma has
been reported in the colon, related to a
persistent foreign body {149}.
Pathological features
Lipomas are composed of mature adi-pose tissue and are surrounded by a
fibrotic capsule. They usually arise in the
submucosal layer of the caecum or the
sigmoid colon. When ulcerated, the
lipocytes may become irregular and
hyperchromatic. Lipomas should be dis-tinguished from lipohyperplasia of the
ileocaecal valve {1726}.
Neurofibromas and schwannomas occur
in the colorectum. Most patients with the
former have neurofibromatosis, and in
these cases plexiform neurofibromas are
common. Ganglioneuromas occur rarely
in the mucosa.
Vascular tumours are classified into
benign (such as haemangiomas, lym-phangiomas and angiomatosis) and
malignant (such as haemangioendothe-liomas and angiosarcomas). Kaposi sar-coma is mostly asymptomatic; a few
present with GI-bleeding {319}. Intestinal
lesions may be observed without cuta-neous disease {114}. The tumours are
often multiple mucosal or submucosal
nodules. Histologically typical are sheets
of spindle cells interspersed by clusters
of extravasated erythrocytes. Cytoplas-mic hyaline PAS-positive globules are
usually seen. The spindle cells are
generally positive for CD31 and CD34
and are negative for actin, desmin and
c-kit.
Leiomyomas usually are detected in the
rectum and colon as small polyps arising
from the muscularis mucosae, and con-sist of well-differentiated smooth muscle
cells with a similar immunohistochemical
profile as observed in oesophageal
leiomyomas {1227}. Leiomyomatosis has
been described in the colon with a cir-cumferential semiconstrictive growth in a
35 cm long segment {529}. It is not
known whether colorectal leiomyomas
and leiomyomatosis have the same colla-M. Miettinen
J.Y. Blay
L.G. Kindblom
L.H. Sobin
Mesenchymal tumours
of the colon and rectum
Fig. 6.88 Leiomyosarcoma. A Cigar-shaped nuclei. B Pleomorphic cells with atypical mitosis.
Fig. 6.87 Leiomyoma of rectum.
AB
143Mesenchymal tumours
gen type IV deletions as the oeso-phageal leiomyomas.
Gastrointestinal stromal tumours (GISTs)
of the colorectum are similar to those in
the stomach and small intestine and are
discussed in the section on gastric mes-enchymal neoplasms. Most reports ante-date the separation of GISTs and
leiomyosarcoma. GISTs occur mainly
between the 6th and 8th decades, and
most are malignant {89}. Many tumours
grow beyond the rectal wall making radi-cal surgery difficult and recurrences
common. Histologically, the examples
reviewed by us have all been of the spin-dle cell variety, all have been c-kit posi-tive, and most of them CD34-positive.
Actin-positivity occurs, but the tumours
are desmin-negative.  C-kit mutations
have been shown in rectal GISTs {1018}.
The survival from large bowel stromal/
smooth muscle sarcomas appears to be
slightly higher than that of the small
bowel and lower than that of the stomach
and oesophagus {461}.
Fig. 6.89 Colonic lipoma.
Fig. 6.91  Kaposi sarcoma. A Submucosal infiltrate. B Vascular slit pattern.
Fig. 6.90 Malignant stromal tumour.
AB

CHAPTER 7
Tumours of the Anal Canal
Although incidence rates are still low, there has been a signif-icant increase in squamous cell carcinoma over the last 50
years. HIV infected homosexual men appear particularly at
risk. HPV DNA is detectable in most anal squamous cell car-cinomas.
Despite its short length, the anal canal produces a variety of
tumour types reflecting its complex anatomic and histological
structure. Squamous, glandular, transitional, and melanocytic
components occur at this site, either alone, or in combination.
Epithelial tumours
Intraepithelial neoplasia1
(dysplasia)
Squamous or transitional epithelium
Glandular
Paget disease 8542/32
Carcinoma
Squamous cell carcinoma 8070/3
Adenocarcinoma 8140/3
Mucinous adenocarcinoma 8480/3
Small cell carcinoma 8041/3
Undifferentiated carcinoma 8020/3
Others
Carcinoid tumour 8240/3
Malignant melanoma 8720/3
Non-epithelial tumours
Secondary tumours
WHO histological classification of tumours of the anal canal
TNM classification1, 2
T – Primary Tumour
TX Primary tumour cannot be assessed
T0 No evidence of primary tumour
Tis Carcinoma in situ
T1 Tumour 2 cm or less in greatest dimension
T2 Tumour more than 2 cm but not more than 5 cm in greatest
dimension
T3 Tumour more than 5 cm in greatest dimension
T4 Tumour of any size invades adjacent organ(s), e.g., vagina, ure-thra, bladder (involvement of sphincter muscle(s) alone is not
classified as T4)
N – Regional Lymph Nodes
NX Regional lymph nodes cannot be assessed
N0 No regional lymph node metastasis
N1 Metastasis in perirectal lymph node(s)
N2 Metastasis in unilateral internal iliac and/or inguinal lymph
node(s)
N3 Metastasis in perirectal and inguinal lymph nodes and/or bilater-al internal iliac and/or inguinal lymph nodes
M – Distant Metastasis
MX Distant metastasis cannot be assessed
M0 No distant metastasis
M1 Distant metastasis
Stage Grouping
Stage 0 Tis N0 M0
Stage I T1 N0 M0
Stage II T2 N0 M0
T3 N0 M0
Stage IIIA T1 N1 M0
T2 N1 M0
T3 N1 M0
T4 N0 M0
Stage IIIB T4 N1 M0
Any T N2, N3 M0
Stage IV Any T Any N M1
_________
1
Behaviour is coded /0 for benign tumours, /3 for malignant tumours, /2 for in situ carcinomas and grade III intraepithelial neoplasia, and /1 for unspecified, borderline or uncertain
behaviour. Intraepithelial neoplasia does not have a generic code in ICD-O. ICD-O codes are available only for lesions categorized as squamous intraepithelial neoplasia, grade III
(8077/2), squamous cell carcinoma in situ (8070/2), transitional cell carcinoma in situ (8120/2), glandular intraepithelial neoplasia, grade III (8148/2), and adenocarcinoma in situ (8140/2).
2
Morphology code of the International Classification of Diseases for Oncology (ICD-O) {542} and the Systematized Nomenclature of Medicine (http://snomed.org).
TNM classification of tumours of the anal canal
146 Tumours of the anal canal and anal glands
_________
1
{1, 66}. This classification applies only to carcinomas.
2
A help desk for specific questions about the TNM classification is available at http://tnm.uicc.org.
3
This includes cancer cells confined within the glandular basement membrane (intraepithelial) or lamina propria (intramucosal) with no extension through muscularis mucosae into
submucosa.
147Squamous cell carcinoma
Tumours of the anal canal  C. Fenger
M. Frisch
M.C. Marti
R. Parc
Definition
Tumours that arise from or are predomi-nantly located in the anal canal. The
most frequent neoplams of this region
are human papilloma virus (HPV-)associ-ated squamous cell carcinomas and
adenocarcinomas.
Topographic definition of anal canal
and anal margin
The anal canal is defined as the terminal
part of the large intestine, beginning at
the upper surface of the anorectal ring
and passing through the pelvic floor to
end at the anus {68}. The most important
macroscopic landmark in the mucosa is
the dentate (pectinate) line composed of
the anal valves and the bases of the anal
columns. Histologically, the mucosa can
be divided into three zones. The upper
part is covered with colorectal type
mucosa. The middle part is the anal tran-sitional zone (ATZ), which is covered by a
specialized epithelium with varying
appearances; it extends from the dentate
line and on average 0.5-1.0 cm upwards
{490, 1929}. The lower part extends from
the dentate line and downwards to the
anal verge and has formerly been called
the pecten. It is covered by squamous
epithelium, which may be partly kera-tinized, particularly in case of mucosal
prolapse.
The perianal skin (the anal margin) is
defined by the appearance of skin
appendages. There exists no generally
accepted definition of its outer limit {62,
66, 845}. The term anus refers to the dis-tal external aperture of the alimentary
tract. Anal margin tumours are classified
according to the WHO histological typing
of skin tumours {682}.
Squamous cell carcinoma
Definition
Squamous cell carcinoma (SCC) of the
anal canal is a malignant epithelial neo-plasm that is frequently associated with
chronic HPV infection.
ICD-O code 8070/3
Epidemiology
SCC of the anal canal and anal margin
typically occurs among patients in their
6th or 7th decade of life {540}. However,
anal SCCs may occur in young adults,
particularly in patients with cellular
immune incompetence {1212}. Unselec-ted, population-based studies show an
approximate 2:1 female predominance
among patients with anal SCC {540, 600,
1213}.
There are few published, histologically
verified incidence rates of anal cancer
{540, 600, 1213}. Data from most popula-tion-based cancer registries worldwide
show age standardized incidence rates
of anal SCC of between 0.5 and 1.0 per
100,000 in women and between 0.3 and
0.8 per 100,000 in men {1471}. Still a rel-atively rare disease, anal SCC has shown
a remarkable increase in incidence dur-ing the past half century {540, 600, 1213}.
From being similar in the two sexes until
approximately 1960 at 0.2 per 100,000,
annual age-adjusted incidence rates in
Denmark rose 2.5-fold in men and 5-fold
in women during the period 1943-1994.
For both men and women, urban popula-tions are at higher risk than rural popula-tions {540, 600, 1213}, and there are con-siderable racial differences in incidence.
In the United States, blacks tend to have
higher incidence rates than whites
{1213}, while Asians and Pacific Islanders
appear to be at very low risk {70}.
Homosexual men appear to constitute a
group at particular risk {368, 538, 140,
96, 369, 540, 1213, 1690, 730}. In the
United States, the incidence of anal SCC
in homosexual men has been estimated
to be 11 to 34 times higher than in the
general male population and approxi-mately as high as the incidence of cervi-cal cancer before the introduction of cer-vical cytology screening {369, 1447}. HIV
infected homosexual men appear to be
at particularly risk {1212, 1449, 598}.
Other sexual factors strongly associated
with anal SCC include number of sexual
partner, receptive anal intercourse, and
co-existence of sexually transmitted dis-eases {368, 538, 730, 733}.
Aetiology
Sexually transmittable human papillo-maviruses (HPVs) are detected by PCR
in the majority of anal SCC {355, 367,
538, 704, 732, 1448}. One large study
showed that SCCs involving the anal
canal are more often high-risk HPV posi-tive (92%) than lesions confined to the
perianal skin (64%) {536}, suggesting
that HPV-unrelated pathways may apply
particularly to cancers of the perianal
skin. A strong association with tobacco
smoking has been established in women,
but the role of smoking in men is less
clear {367, 539, 730, 733}. States of cel-lular immunosuppression are associatedFig. 7.01 Anatomy of the anal canal. Printed with permission from ref 490.
Surgical anal canal
Histological anal canal
Anatomical anal canal
Anal verge, ‘anus’
Anorectal ring
Anal columns
Anal valves and sinuses
DENTATE LINE
Intersphincteric groove
148 Tumours of the anal canal
with increased risk of anal squamous cell
carcinoma. This has been observed for
renal transplant recipients {150, 1494}
and for patients with HIV infection and
AIDS {1212}.
Haemorrhoids and fissures, fistulae and
abscesses in the anal region were long
considered predisposing factors {192,
198, 1618}. However, three case-control
studies {368, 537, 733} and two cohort
studies {541, 1074} failed to support the
association. Crohn’s disease of long
duration, which has been implicated in
the aetiology of anal SCC based on case
reports {992, 1765}, was not associated
with risk in the only controlled study
addressing the issue {537}.
Oestrogen and androgen receptors have
been found in the anal mucosa and its
supportive tissue {1396}, suggesting a
physiological role of sex hormones in
their maintenance. Women who reach
menarche late and women with short fer-tile periods may be at elevated risk of
anal SCC {539}.
Clinical features
Symptoms and signs
Anal intraepithelial neoplasia is often an
unexpected finding in minor surgical
specimens. Clinical manifestations of
anal cancer are often late and non-spe-cific and are mainly related to tumour size
and extent of infiltration. They include
anal pruritus, discomfort in sitting posi-tion, sensation of a pelvic mass, pain,
change in bowel habit, incontinence due
to sphincter infiltration, discharge, bleed-ing, fissure, or fistula. The initial non-specificity of clinical features explains
why diagnosis can be delayed {855,
1621, 1719, 1835}.
The clinical diagnosis of an anal tumour
should always be confirmed by histolog-ical examination. A forceps or needle
biopsy is usually sufficient to establish
the diagnosis. The biopsy should be
accompanied by an exact description of
location and appearance of the biopsy
site. An excisional biopsy is inadvisable,
because wound healing delay would
postpone optimal chemo-radiotherapy
treatment. Enlarged lymph nodes may
be excised or biopsied with needle aspi-ration under radiological control.
Imaging
Computerised tomography (CT) scan,
magnetic resonance imaging (MRI), and
needle aspiration are used to detect
inguinal and pararectal node involve-ment. Endoanal ultrasonography (EUS)
enables assessment of spread in terms
of proximal and circumferential extension
and infiltration of deep layers. Further-more, EUS enables the follow-up of irra-diated carcinomas {703}. CT scan and
MRI allow detection of involved lymph
nodes and distant metastases {1835}.
Exfoliative cytology
In patients with increased risk such as
individuals with HIV or women with geni-tal tract SCC, the use of anal smears
taken with a cytology brush from the area
below the dentate line is recommended
{1689}.
Macroscopy
The tumour may present as a small ulcer-ation or fissure with slightly exophytic
and indurated margins, and irregular
thickening of the anoderm and anal mar-gin with chronic dermatitis. The lesion
may have a different colour from the sur-rounding tissue.
If ulceration and infiltration develop, the
lesion becomes fixed to the underlying
structures and may bleed. In advanced
stages, the sphincteric muscles are
deeply infiltrated although there may be
little mucosal ulceration.
Tumour spread and staging
Anal SCC should be staged according to
the TNM system {66}. Treatment for anal
SCC has now changed from surgery
alone to sphincter preserving procedures
including radiation and chemotherapy,
sometimes in combination with local exci-sion. Large surgical specimens are there-fore rare. The examination should include
resection lines in all directions and a
careful search for lymph nodes. Clinical
results of the combined treatment
regimes are comparable or even better
than those for surgery alone, but detec-tion of residual disease can be more diffi-cult by imaging techniques due to local
fibrosis. In such cases a transanal full
thickness tru-cut needle biopsy may be
helpful {785}. Identification of residual
Fig. 7.02 Normal histology of the anal transition
zone.
Fig. 7.04 Ulcerating nodular squamous cell carci-noma of anus.
Fig. 7.03 In situ hybridisation for HPV 16/18 is posi-tive in this anal carcinoma.
Fig. 7.05 Squamous cell carcinoma arising at den-tate line.
149Squamous cell carcinoma
tumour cells may be facilitated by
immunostaining for high molecular weight
cytokeratins (CKs).
In 15-20% of cases, the lesion may infil-trate the lower rectum and the neigh-bouring organs including the rectovagi-nal septum, bladder, prostate and poste-rior urethra, sometimes with suppuration
and fistulas. The vulva is usually spared.
Lymphatic spread occurs in up to 40 per-cent of cases {165, 1174, 1621, 1719,
2033}. Tumours proximal to the pectinate
line drain into the pelvis along the middle
rectal vessels to the pelvic side walls and
internal iliac chains and superiorly via the
superior rectal vessels to the periaortic
nodes. Tumours distal to the dentate line
drain along cutaneous pathways to the
inguinal and the femoral nodal chains.
Inguinal nodes are involved in about
10-20% of cases {230, 575, 1174, 1650,
1692}. Inguinal lymph nodes can be
involved bilaterally in a small number of
cases at time of presentation. Retrograde
lymphatic drainage occurs in advanced
cases when the lymphatics are obstruct-ed by malignant spread {1621, 1719}.
Histopathology
Squamous cell carcinoma of anal canal
Anal SCC may show a single predomi-nant line of differentiation, but most exhib-it a mixture of areas with different histo-logical features. One pattern is that of
large, pale eosinophilic cells and kera-tinization of either lamellar or single cell
type. Another is that of small cells with
palisading of the nuclei in the periphery
of tumour cell islands. The latter often
contain necrotic eosinophilic centres.
Intermediate stages between these two
extremes are often present. Differentia-tion into tubular or spindle cell configura-tion may be found. The invasive margin
can vary from well circumscribed to irreg-ular, and a lymphocytic infiltrate may be
pronounced or absent. None of these fea-tures have been shown to have any prog-nostic significance, but poor keratiniza-tion, prominent basaloid features and
small tumour cell size are related to infec-tion with ‘high risk’ HPV {536}. The keratin
profile of anal SCC is complex and vari-able {2112, 2113}. The usual immunoex-pression pattern is shown in Table 7.01.
The second edition of the WHO classifi-cation of SCC in the anal canal included
the large-cell keratinizing subtype, the
large-cell non-keratinizing subtype, and
the basaloid subtype {845}. The value of
this classification of anal SCC has been
questioned in recent years. Many
tumours show more than one subtype.
Thus in a study of 100 cases of anal car-cinomas, 99 showed some features of
squamous differentiation (keratinisation,
stratification and prickles), 65 showed
basaloid features (small cell change, pal-isading, retraction artefact and central
eosinophilic necrosis) and 26 showed
focal evidence of ductal proliferation and
occasionally positive staining for PAS
after diastase digestion {2111}. Further-more, the diagnostic reproducibility of
these subtypes is low {492}. This is prob-ably the reason that the proportion of
basaloid carcinoma in larger series has
varied from 10 to almost 70 %, and that
no significant correlation between histo-logical subtype and prognosis has been
established. In addition, the histological
diagnosis is nowadays nearly always per-formed on small biopsies, that may not be
representative for the whole tumour {492}.
Therefore, it is recommended that the
generic term ‘squamous carcinoma’ be
used for these tumours, accompanied by
a comment describing those histopatho-logical features that may possibly affect
the prognosis or reflect different aetiolo-gies, i.e. size of predominant neoplastic
cell, basaloid features, degree of keratin-isation, adjacent squamous intraepithe-lial neoplasia, or presence of mucinous
microcysts.
Apart from the verrucous carcinoma
mentioned below, only two rare histolog-ical subtypes seem to have a different
biological course, both having a less
favourable prognosis {1734}. One is
characterized by areas with well formed
acinar or cystic spaces containing mucin
that reacts with Alcian dyes or PAS after
diastase digestion. This is termed squa-mous cell carcinoma with mucinous
microcysts. The other is characterized
by a rather uniform pattern of small
tumour cells with nuclear moulding, high
mitotic rate, extensive apoptosis and dif-fuse infiltration in the surrounding stro-ma. This has been called  small cell
(anaplastic) carcinoma, but should not
be confused with small cell carcinoma
(poorly differentiated neuroendocrine
carcinoma).
Squamous cell carcinoma of anal margin
The distinction between anal canal and
anal margin SCC may be difficult, as
tumours often involve both areas at the
time of diagnosis. This may account for
the varying data on prognosis, but this is
generally better for anal margin SCC
than for anal canal SCC, in particular if
local resection is possible {392, 530,
1484}. Anal margin SCC is often of the
large cell variant {536, 1484}.
Verrucous carcinoma
In the anogenital area, this tumour is also
called giant (malignant) condyloma or
Buschke-Lowenstein tumour. It has a
cauliflower-like appearance, is larger
than the usual condyloma with a diame-ter up to 12 cm, and fails to respond to
Fig. 7.06  Well differentiated squamous cell carci-noma composed of large cells showing keratiniza-tion.
Fig. 7.07 Squamous cell carcinoma composed of
basaloid cells. Central necrosis (N) of tumour nests
is typical.
Fig. 7.08 Squamous cell carcinoma showing a
combination of basaloid and squamous features.
N
150 Tumours of the anal canal
conservative treatment. In contrast to an
ordinary condyloma, it is characterized
by a combination of exophytic and endo-phytic growth. Histologically, it shows
acanthosis and papillomatosis with
orderly arrangement of the epithelial lay-ers and an intact but often irregular base
with blunt downward projections and ker-atin-filled cysts. The endophytic growth
is accompanied by destruction of the
underlying tissues. Cytologically, the
epithelial cells appear benign. Large
nuclei with prominent nucleoli may be
present, but dysplasia is usually minimal
and mitoses are restricted to the basal
layers {162}.
Some verrucous carcinomas contain
HPV, the most common types being 6
and 11. They are regarded as an inter-mediate state between the ordinary
condyloma and SCC, and the clinical
course is typically that of local destruc-tive invasion without metastases. Among
33 published anorectal cases, 42 per
cent have shown malignant transforma-tion {133}. The presence of severe cyto-logical changes, unequivocal invasion or
metastases should lead to the diagnosis
of SCC and to the appropriate therapy.
Grading
Poor prognosis has been related to poor
differentiation {165}, especially if this was
defined only by the degree of dissocia-tion of tumour cells {599}. However, such
differences may be related to tumour
stage in multivariate analysis {1734}.
Grading on biopsies is not recommend-ed, as these may not be representative
for the tumour as a whole.
Precursor lesions and benign tumours
Chronic HPV infection
Warts in the perianal skin and lower anal
canal (condyloma acuminatum) show the
same histology as their genital counter-parts. Flat koilocytic lesions also occur.
They should always be totally embedded
and examined histologically for possible
presence of intraepithelial neoplasia.
Intraepithelial neoplasia
Precancerous anal intraepithelial neopla-sia (AIN) in the anal transition zone (ATZ)
and the squamous zone, has also been
termed dysplasia, carcinoma in-situ and
anal squamous intraepithelial lesion
(ASIL) {494, 1449}. The corresponding
lesions in the perianal skin are commonly
referred to as Bowen disease. This termi-nology is complicated by the fact that the
precancerous changes are not always
restricted to one area. Leukoplakia is a
clinical term and should not be used as a
histological diagnosis.
Anal intraepithelial neoplasia (squamous
cell dysplasia in the anal canal).  Most
cases of AIN are incidental findings in
minor surgical specimens for benign con-ditions. When macroscopically detected,
AIN may present as an eczematoid or
papillomatous area, or as papules or
plaques. The latter may be irregular,
raised, scaly, white, pigmented or erythe-matous and occasionally fissured. Indur-ation or ulceration may indicate invasion.
Histologically, AIN is characterized by
varying degrees of loss of stratification
and nuclear polarity, nuclear pleomor-phism and hyperchromatism, and in-creased mitotic activity with presence of
mitoses high in the epithelium. The sur-face may or may not be keratinized, and
koilocytic changes may be present.
AIN has been graded into I, II or III, or
into mild, moderate and severe dysplasia
{494}. Reproducibility studies have
shown considerable observer variation
{254}. A two grade system (low- and
high-grade) may be more appropriate.
Squamous dysplasia at the anal margin -Bowen disease.   Clinically, this presents
as a white or red area in the perianal skin
that may be in continuity with dysplastic
lesions in the anal canal. HPV DNA is
sometimes identified, including types 16
and 18, among others. Histologically it
shows full thickness dysplasia of the
squamous and sometimes the piloseba-ceous epithelium, with disorderly matura-tion, mitoses at all levels and dyskerato-sis. Occasionally, atypical keratinocytes
may resemble Paget cells, but are nega-tive for low molecular weight CKs and for
mucin. In pigmented Bowen disease the
neoplastic cells are invariably negative
Fig. 7.09  Squamous cell carcinoma of anus. A Combination of basaloid features and keratinization. B Large
cells, poorly differentiated.
Fig. 7.10 Mucinous carcinoma of anus. Tumour extends to anal sphincter.
BA
151Squamous cell carcinoma / Adenocarcimoma
for S-100 protein and HMB-45.
Bowen disease has a strong tendency to
recurrence after local treatment but only a
few percent will progress to SCC. It is
often associated with genital neoplasia
but not with internal malignancies {1161,
1668}.
Bowenoid papulosis. This condition
presents as multiple 2-10 mm reddish
brown papules or plaques, most com-monly in sexually active young adults.
Aetiologically it is related to HPV infec-tion, usually HPV 16. Bowenoid papulo-sis is similar histologically to Bowen dis-ease, and the distinction is made on a
combination of clinical and pathological
observations. Bowenoid papulosis tends
to resolve spontaneously, but can recur
{635}. It does not progress to carcinoma.
Genetic susceptibility
Human leukocyte antigens (HLAs) are
involved in the presentation of viral anti-gens to the immune system. Since the
aetiology of most anal SCCs involves
HPV infection {536}, susceptibility to can-cer development might be HLA type
dependent. However, no study has
addressed the association between spe-cific HLA class I or II alleles and the risk,
and attempts to identify other genetic
susceptibility markers for anal SCC have
so far been unsuccessful {286, 287}.
Genetics
HPV DNA is detectable in most anal
SCCs; in a large population-based series
of anal SCCs in Denmark and Sweden,
84% contained HPV DNA, with higher
proportions of HPV-DNA positive can-cers among women and homosexual
men than among non-homosexual men
{536}.
Loss of functional tumour suppressor
protein p53 appears to be centrally
involved in the development of anal and
anogenital SCCs {355, 356, 704, 1040}.
Inactivation of p53 may occur at the
gene level through point mutations lead-ing to the production of inactive p53 or,
less frequently, by means of deletions in
the relevant area of chromosome 17p
{704}. More typically, p53 inactivation
occurs at the protein level through forma-tion of a complex between the viral pro-tein E6 (expressed by ‘high-risk’ HPV
types) and a cellular protein, the
E6-associated protein, which when
bound to p53 leads to rapid proteolytic
degradation of p53 {2092}. The level of
p53 expression does not correlate with
HPV status {704}. The E7 protein of ‘high
risk’ HPV types binds to the retinoblas-toma protein, pRb {440}, disrupting sig-nals that normally restrict proliferation to
the basal epithelial layer. The resulting
increased proliferation increases the risk
of malignant transformation on exposure
to DNA damaging stimuli. The combina-tion of increased cell proliferation (pRb
inactivation) and impaired ability to
induce cell cycle arrest or apoptosis fol-lowing DNA damage (p53 inactivation)
are two central mechanisms through
which ‘high risk’ types of HPV increase
the risk of anogenital cancer.
Additional gene alterations appear to be
involved in malignant progression and
invasion. In one study, the  c-myc gene
was found to be amplified in 30% of anal
SCCs {355}, while other cellular onco-genes, including ras and cyclin D, do not
seem to be centrally involved {708,
1737}. Several chromosomal aberrations
have been observed in anal SCCs {704,
1294}. Using comparative genomic
hybridization, one study identified con-sistent gains in chromosomes 3q, 17,
and 19 as well as losses in chromosomes
4p, 11q, 13q, and 18q {704}.
Prognosis and predictive factors
The most important prognostic factors in
recent larger series of anal canal SCC are
tumour stage and nodal status {530,
1483, 1734}. SCC of the anal margin has
a slightly better prognosis, which
depends only on inguinal node involve-ment {1484}. DNA ploidy status has only
been shown to be of independent prog-nostic significance in one of three larger
series {599, 1702, 1734}. Expression of
p53, cathepsin D, c-erb B2 and retino-blastoma gene protein are not predictive
factors {169, 731, 784, 1901}.
Adenocarcinoma
Definition
Anal canal adenocarcinoma is an adeno-carcinoma arising in the anal canal
epithelium, including the mucosal sur-face, the anal glands and the lining of fis-tulous tracts.
ICD-O code 8140/3
Clinical features
The clinical features of anal adenocarci-noma of colorectal type do not differ from
those of anal SCC. Perianal adenocarci-nomas may present as submucosal
tumours, sometimes in combination with
fistulas. Occasionally, there may be
Fig. 7.14 Carcinoma of anal canal. Small neoplastic
glands simulate anal glands.
Fig. 7.11 Giant condyloma.
Fig. 7.13 In situ hybridisation (black stain) for HPV
6/11 in an anal condyloma.
Fig. 7.12  High-grade intraepithelial neoplasia  adja-cent to normal rectal epithelium.
152 Tumours of the anal canal
associated Paget disease of the anus
(see below). Tumour spread and staging
largely correspond to anal SCC.
Histopathology
Adenocarcinoma arising in anal mucosa
Most adenocarcinomas found in the anal
canal represent downward spread from
an adenocarcinoma in the rectum or
arise in colorectal type mucosa above
the dentate line. Macroscopically and
histologically, they are indistinguishable
from ordinary colorectal type adenocar-cinoma, and do not seem to represent a
special entity except for their low loca-tion. Adenocarcinoma in the anal transi-tional zone (ATZ) may develop after
restorative proctocolectomy for ulcera-tive colitis {1711}.
Extramucosal (perianal) adenocarcinoma
Approximately two hundred cases of
extramucosal adenocarcinoma have
been reported, the largest series unfortu-nately with insufficient histological data
{9}. A minimum criterion for the diagnosis
is an overlying non-neoplastic mucosa,
which may be ulcerated. Recent reports
indicate that about two thirds of these
tumours manifest in men with a mean age
about 60 years. Reliable data for the
prognosis for such patients have not
been identified. Difficulties in establishing
the correct diagnosis may delay proper
treatment.
Extramucosal adenocarcinoma seem to
fall into two groups, based on their asso-ciation with either fistulae or remnants of
anal glands. At present, no laboratory
methods can distinguish between these
two.
The epithelium of persistent anal fistulae
is most often of the same type as found
in the anal glands and ATZ {1117}, and
the epithelium in these two locations
show the same profile with regard to
mucin composition {491} and keratin
expression {2113}.
Adenocarcinoma within anorectal fistula.
These tumours develop in pre-existing
anal sinuses or in fistulae {74}. Some are
associated with Crohn disease {992}.
Others may contain epithelioid granulo-mas, often related to foci of inflammation
or extravasated mucin but without other
signs of inflammatory bowel disease
{863}.
Rarely, the tumours may be related to fis-tulae lined by normal rectal mucosa
including muscularis mucosae, most
likely representing adenocarcinomas
arising in congenital duplications {863}.
Histologically, carcinomas arising in fistu-lae usually are of the mucinous type, but
tubular adenocarcinomas and squamous
neoplasia can also be found {992, 2173}.
Adenocarcinoma of anal glands.  Only a
few cases have been reported in which
convincing evidence for origin in an anal
gland has been demonstrated by conti-nuity between anal gland epithelium and
tumour {118, 650, 1472, 2087, 2131}.
With a single exception {650}, these
patients have had no history of previous
or concomitant fistula. The tumours were
all characterized by a combination of
ductular and mucinous areas. Pagetoid
spread was present in at least one case
{2131}.
Fig. 7.15 Low-grade squamous intraepithelial neo-plasia with koilocytosis.
Fig. 7.16 High-grade squamous intraepithelial neo-plasia with hyperkeratosis.
Fig. 7.18 Adenocarcinoma arising in a fistula.
B
A
Fig. 7.17 A, B Inflammatory cloacogenic polyp.
Dilated elongated hyperplastic glands showing
regenerative atypia. Surface erosion is a constant
feature.
153
Fig. 7.19  Paget disease of the anal canal.
Adenocarcinoma
Grading
Anal adenocarcinomas are graded as
colorectal adenocarcinomas.
Precursor lesions
Anal adenocarcinomas are thought to
arise from glandular intraepithelial neo-plasia, which can be graded as in the
colorectum.
Prognosis and predictive factors
The prognosis for anal adenocarcinoma
seems to be related only to the stage at
diagnosis and is poorer than that for SCC
{118, 930, 1305}.
Basal cell carcinoma
of the anal margin
Basal cell carcinoma, the most common
skin cancer, is primarily found on sun-exposed areas, and only a few more than
a hundred cases have been reported in
the anal area. {1353}. The aetiology is
unknown and there is no evidence of
HPV infection {1332}. The tumour com-monly presents as an indurated area with
raised edges and central ulceration,
located in the perianal skin but occasion-ally involving the squamous zone below
the dentate line. Histologically, it can
show the same variability in morphology
as basal cell carcinoma elsewhere, most
reported cases having had a solid or
adenoid pattern.
Basal cell carcinoma is sufficiently treat-ed by local excision and metastases are
extremely rare. It is therefore important to
distinguish it from squamous carcinoma,
and this may be particularly difficult on
small biopsies. Both tumours can be
found in the squamous zone, and both
can show a combination of basaloid,
squamous and adenoid features and an
inflammatory infiltrate in the stroma {50}.
Numerous and even atypical mitoses
may be present in basal cell carcinomas
{1538}. However, basaloid areas in squa-mous carcinoma usually show less con-spicuous peripheral palisading, more cel-lular pleomorphism, and often large,
eosinophilic necrotic areas. Immunohisto-chemistry may be helpful in establishing
the diagnosis. Basal cell carcinoma is
positive for Ber-EP4 and negative for CKs
13, 19 and 22, and for CEA, EMA, AE 1
and UEA 1, while basaloid variants of
squamous cell carcinoma usually show
the opposite pattern {50, 1061}.
Paget Disease
Extramammary Paget disease usually
affects sites with a high density of apoc-rine glands, such as the anogenital
region, where it presents as a slowly
spreading, erythematous eczematoid
plaque that may extend up to the dentate
line {1667}. Histologically, the basal part
or whole thickness of the squamous
epithelium is infiltrated by large cells with
abundant pale cytoplasm and large
nuclei. Occasional cells have the appear-ance of signet-rings. Paget cells invari-ably react positively for mucin stains and
nearly always for CK 7, but Merkel cells
and Toker cells may also be positive for
the latter {120, 1112}.
Paget disease of the anus appears to
represent two entities. About half of the
cases are associated with a synchronous
or metachronous malignancy, most often
a colorectal adenocarcinoma. Such
cases can be regarded as a pagetoid
extension of the tumour. They usually
react positively for CK 20 and negatively
for gross cystic disease fluid protein-15,
a marker for apocrine cells. This is in
contrast to the other half, which are not
associated with internal malignancies
but have a high local recurrence rate and
may become invasive {1162}. Only this
latter entity can be regarded as a true
epidermotrophic apocrine neoplasm {85,
120, 595, 1374}.
Other lesions
Squamous cell papilloma
of the anal canal
Rarely, papillomatous processes cov-ered by normal, more or less keratinized
squamous epithelium can be found in the
anus. Such lesions should be tested for
the presence of HPV. Negative cases are
commonly regarded as ‘burned-out’
condylomas.
Papillary hidradenoma
This rare tumour arises in the perianal
apocrine glands, typically in middle
aged women and only exceedingly rarely
in men {1082}. It presents as a circum-scribed nodule approximately 1 cm in
diameter and may resemble a haemor-rhoid.
Histologically, it consists of a papillary
mass with a cyst-like capsule. The papil-lae are lined by a double layer of epithe-lial cells, the outer layer being composed
of cells containing mucin. The tumour
does not express the eccrine marker
IKH-4, but it must be remembered that
adenocarcinoma metastases also are
negative {811}. Convincing examples of
anal apocrine adenocarcinoma have not
been published.
Keratoacanthoma
There are a few reports on keratoacan-thoma arising in the perianal skin {454}.
Neuroendocrine tumours
Neuroendocrine tumours may arise in the
anus {493, 744}. They are, however, con-ventionally classified as rectal. An
immunohistochemical study of 17 rectal
neuroendocrine tumours showed that
most were of L-cell type {294}. For details,
see in chapter 5 the section on endocrine
tumours of the colon and rectum.
Fig. 7.20  Paget disease of the anal canal. Large
Paget cells are distributed throughout the non-neo-plastic squamous epithelium.
154 Tumours of the anal canal
Malignant melanoma
Anal melanoma is rare. It is a disease of
adults with a wide age range; most
patients are white {339, 182}. Presen-tation is usually with mass and rectal
bleeding, but tenesmus, pain and
change in bowel habit also occur {339}.
Macroscopy. Lesions may be sessile or
polypoid. Pigmentation of the lesion is
often appreciated. Satellite nodules may
occur.
Histopathology. The features resemble
those of cutaneous melanomas. The
majority shows a junctional component
adjacent to the invasive tumour, and this
finding is evidence that the lesion is pri-mary rather than metastatic. The tumour
cells express S-100 and HMB-45.
Prognosis.  Anal melanomas spread by
lymphatics to regional nodes, and
haematogenously to the liver and thence
to other organs. Metastases are frequent
at time of presentation, and the progno-sis is poor; the 5-year survival is less than
10% {339, 157}. The chances of long-term survival are increased if the lesion is
small.
Mesenchymal and neurogenic
tumours
These are all rare and the exact point of
origin may be difficult to establish.
Recent reports on tumours in the anorec-tal and perianal area include haeman-gioma, lymphangioma {372}, haeman-giopericytoma {478}, leiomyoma, malig-nant fibrous histiocytoma and leio-myosarcoma {1110}, rhabdomyoma in a
newborn {1014}, and rhabdomyosarco-ma in childhood {1560} and adulthood
{902}, fibrosarcoma, neurilemmoma and
neurofibroma {571}, granular cell tumour
(myoblastoma) {862}, spindle cell lipoma
and aggressive angiomyxoma {503} and
extraspinal ependymoma in a newborn
{2074}. HIV infected persons may, in
addition to the increased risk of squa-mous neoplasia, develop Kaposi sarco-ma in the perianal area {113}.
Malignant lymphoma
Primary lymphomas of the anorectal
region are rare in the general population,
but much more common in patients with
AIDS, particularly homosexual men. All
are of B-cell type, the most common
types being large cell immunoblastic or
pleomorphic {687, 786}. Langerhans cell
histiocytosis has been described in chil-dren {617, 874} and an adult {329}.
Fig. 7.23 Malignant melanoma of anus. A Polypoid growth is frequent. B Scattered tumour cells contain melanin. C Epitheloid melanoma cells with prominent nucleoli.
B CA
Fig. 7.21 Secondary Paget disease of the anus. A The underlying adenocarcinoma is present beneath the
squamous epithelium. High molecular weight keratin immunostain is largely restricted to normal squamous
epithelium. B Low molecular weight keratins 8 and 13 immunostaining of tumour cells.
BA
Fig. 7.22 Malignant melanoma of anus with typical
polypoid appearance.
155Miscellaneous tumours
Secondary tumours
Metastases to the anal canal and perianal
skin are rare. Most primaries are found in
the rectum or colon, but occasionally also
in the respiratory tract, breast and pan-creas {157, 182, 379, 888, 1767, 489}.
There are few reports of metastatic squa-mous cell carcinoma {574}. Malignant
lymphoma, leukaemia and myeloma may
infiltrate the anal canal, and eosinophilic
granuloma has also been described
{489}.
Clinically, anal metastases cause similar
symptoms to primary tumours at this site,
including pain, bleeding and inconti-nence.
Neoplasia-like lesions
Fibroepithelial polyp
Also called fibrous polyp or anal tag, this
is one of the most frequent anal lesions.
It may be found in the squamous zone or
the perianal skin in up to half of all indi-viduals {2101}. Grossly, the polyp is
spherical or elongated with a greater
diameter ranging from a few mm up to
4 cm. The surface is white or grey and
may show superficial ulceration. Histo-logically, it consists of a fibrous stroma
covered by squamous epithelium, which
usually is slightly hyperplastic and may
be keratinized. The stroma may be more
or less dense and often contains fibrob-lastic cells with two or more nuclei and a
considerable number of mast cells {630}.
Neuronal hyperplasia is a common fea-ture {495}.
Fibroepithelial polyps may be associated
with local inflammation such as fissure or
fistula {1084}.
Granulomas can be found in about one
third of skin tags in cases of Crohn’s dis-ease {1905}. Others may represent the
end stage of a thrombosed haemorrhoid,
but remnants of haemorrhoidal vessels
or signs of previous bleeding are rarely
found. Most are probably of idiopathic
nature as the incidence is rather similar
in patients with or without anal diseases
{2101}.
Inflammatory cloacogenic polyp
This polyp was first described in 1981
{1083}. It arises in the ATZ and forms a
rounded or irregular mass measuring
from 1 to 5 cm in diameter. Histologically,
it consists of hyperplastic rectal mucosa,
partly covered with ATZ type or squa-mous epithelium. The surface is typically
eroded and the stroma shows oedema,
vascular ectasia, inflammatory cells and
granulation tissue. Vertically oriented
smooth muscle fibres are found between
the elongated and tortuous crypts. The
inflammatory cloacogenic polyp is com-monly associated with mucosal prolapse,
sometimes in company with haemor-rhoids {296, 1052}.
Malacoplakia
Cutaneous malacoplakia may arise in
immunocompromised patients and pres-ent as perianal nodules {1102}.
CK CK CK
8+18 7/20 5+14 Mucin CEA Vim Special
Colorectal adenocarcinoma + –/+ –++–
Squamous cell variants – –/– +––– CK 13/19
Basal cell carcinoma – –/– +––– Ber EP4
Neuroendocrine tumour + –/– –––– Chrom/Synap
Malignant melanoma – –/– –––+ S–100,  HMB–45
Bowen (also pigmented) – –/– +–––
Paget cells local Paget + +/– –++– GCDFP–15
Paget cells, from CRC + +/+ –++–
Prostatic carcinoma + –/– –––– PSA, PSAP
Malignant lymphoma – –/– –––+ LCA and others
––––––––––
Chrom = Chromogranin A
CK = Cytokeratin
CRC = Colorectal carcinoma
GCDFP = Gross cystic disease fluid protein
Table 7.01
Anal tumours, immunoreactivity profile (exceptions occur, especially among CK and mucin)1
1
PSA = Prostate specific antigen
PSAP = Prostate specific acid phosphatase
Synap = Synaptophysin
Vim = Vimentin

CHAPTER 8
Tumours of the Liver
and Intrahepatic Bile Ducts
The most frequent and important hepatic neoplasm is the pri-mary hepatocellular carcinoma (HCC). In many parts of the
world, in particular Africa and Asia, it poses a significant dis-ease burden. In these high incidence regions, chronic infec-tion with hepatitis B virus (HBV) is the principal underlying
cause, with the exception of Japan which has a high preva-lence of hepatitis C infection. HBV vaccination has become a
powerful tool in reducing cirrhosis and HCC, but implementa-tion is still suboptimal in several high risk regions. In Western
countries, chronic alcohol abuse is a major aetiological factor.
Hepatic cholangiocarcinoma has a different geographical dis-tribution, with peak incidences in Northern Thailand. Here, it is
caused by chronic infection with the liver fluke,  Opisthorchis
Viverrini, which is ingested through infected raw fish.
WHO histological classification of tumours of the liver and intrahepatic bile ducts
TNM classification1, 2, 3
T Primary Tumour
TX Primary tumour cannot be assessed
T0 No evidence of primary tumour
T1 Solitary tumour 2 cm or less in greatest dimension without vas-cular invasion
T2 Solitary tumour 2 cm or less in greatest dimension with vascular
invasion; or multiple tumours limited to one lobe, none more than
2 cm in greatest dimension without vascular invasion; or solitary
tumour more than 2 cm in greatest dimension without vascular
invasion.
T3 Solitary tumour more than 2 cm in greatest dimension with vas-cular invasion; or multiple tumours limited to one lobe, none more
than 2 cm in greatest dimension with vascular invasion; or multi-ple tumours limited to one lobe, any more than 2 cm in greatest
dimension with or without vascular invasion.
T4 Multiple tumours in more than one lobe; or tumour(s) involve(s) a
major branch of the portal or hepatic vein(s); or tumour(s) with
direct invasion of adjacent organs other than gallbladder; or
tumour(s) with perforation of visceral peritoneum.
N – Regional Lymph Nodes
NX Regional lymph nodes cannot be assessed
N0 No regional lymph node metastasis
N1 Regional lymph node metastasis
M – Distant Metastasis
MX Distant metastasis cannot be assessed
M0 No distant metastasis
M1 Distant metastasis
Stage Grouping
Stage I T1 N0 M0
Stage II T2 N0 M0
Stage IIIA T3 N0 M0
Stage IIIB T1 N1 M0
T2 N1 M0
T3 N1 M0
Stage IVA T4 Any N M0
Stage IVB Any T Any N M1
TNM classification of tumours of the liver and intrahepatic bile ducts
158 Tumours of the liver and intrahepatic bile ducts
Epithelial tumours
Benign
Hepatocellular adenoma (liver cell adenoma) 8170/01
Focal nodular hyperplasia
Intrahepatic bile duct adenoma 8160/0
Intrahepatic bile duct cystadenoma 8161/0
Biliary papillomatosis 8264/0
Malignant
Hepatocellular carcinoma (liver cell carcinoma) 8170/3
Intrahepatic cholangiocarcinoma  8160/3
(peripheral bile duct carcinoma)
Bile duct cystadenocarcinoma 8161/3
Combined hepatocellular and cholangiocarcinoma 8180/3
Hepatoblastoma 8970/3
Undifferentiated carcinoma 8020/3
Non-epithelial tumours
Benign
Angiomyolipoma 8860/0
Lymphangioma and lymphangiomatosis 9170/0
Haemangioma 9120/0
Infantile haemangioendothelioma 9130/0
Malignant
Epithelioid haemangioendothelioma 9133/1
Angiosarcoma 9120/3
Embryonal sarcoma (undifferentiated sarcoma) 8991/3
Rhabdomyosarcoma 8900/3
Others
Miscellaneous Tumours
Solitary fibrous tumour  8815/0
Teratoma 9080/1
Yolk sac tumour (endodermal sinus tumour) 9071/3
Carcinosarcoma 8980/3
Kaposi sarcoma 9140/3
Rhabdoid tumour 8963/3
Others
Haemopoietic and lymphoid tumours
Secondary tumours
Epithelial abnormalities
Liver cell dysplasia (liver cell change)
Large cell type (large cell change)
Small cell type (small cell change)
Dysplastic nodules (adenomatous hyperplasia)
Low-grade
High-grade (atypical adenomatous hyperplasia)
Bile duct abnormalities
Hyperplasia (bile duct epithelium and peribiliary glands)
Dysplasia (bile duct epithelium and peribiliary glands)
Intraepithelial carcinoma (carcinoma in situ) 8500/211
Miscellaneous lesions
Mesenchymal hamartoma
Nodular transformation
(nodular regenerative hyperplasia)
Inflammatory pseudotumour
_________
1
Morphology code of the International Classification of Diseases for Oncology (ICD-O) {542} and the Systematized Nomenclature of Medicine (http://snomed.org). Behaviour is coded
/0 for benign tumours, /1 for unspecified, borderline or uncertain behaviour, /2 for in situ carcinomas and grade III intraepithelial neoplasia and /3 for malignant tumours.
_________
1
{1, 66}. This classification applies only to primary hepatocellular and cholangio-(intrahepatic bile duct) carcinomas of the liver.
2
A help desk for specific questions about the TNM classification is available at http://tnm.uicc.org.
3
For classification, the plane projecting between the bed of the gallbladder and the inferior vena cava divides the liver in two lobes.
159Hepatocellular carcinoma
Hepatocellular carcinoma  S. Hirohashi H.E. Blum
K.G. Ishak Y. Deugnier
M. Kojiro P. Laurent Puig
I.R. Wanless H.P. Fischer
N.D. Theise M. Sakamoto
H. Tsukuma
Fig. 8.01 Worldwide annual incidence (per 100,000) of liver cancer in males
(1995). Numbers on the map indicate regional average values.
Definition
A malignant tumour derived from hepato-cytes. Most common aetiological factors
are viral infections (HBV, HCV), dietary
aflatoxin B1 ingestion and chronic alco-hol abuse.
Epidemiology
Primary liver cancer (PLC) is a major
public health problem worldwide. In
1990, the global number of new cases
was estimated at 316,300 for males and
121,100 for females, accounting for 7.4%
(males) and 3.2% (females) of all malig-nancies, excluding skin cancer {1469}.
Hepatocellular carcinoma (HCC) is the
most common histological type of PLC.
Population-based cancer registries show
that HCC as a percentage of histologi-cally specified PLCs varies considerably
{1471} but in over half of the registries,
the fraction is above 70%.
Regions with percentages less than 40%
are exceptional, e.g., Khon Kaen (Thai-land), where intrahepatic cholangiocarci-noma is predominant, due to endemic
infection with liver flukes  (Opisthorchis
viverrini) {1470}. Owing to the limited
availability of histological data, the follow-ing epidemiological survey is based on
PLC but it can be assumed that it largely
reflects HCC incidence and mortality.
Geographical distribution
The estimated PLC incidence in 1990 for
23 areas of the world is shown in Figure
8.01 {1469}. High-risk areas with an age-standardized incidence rate (ASIR, stan-dardized to world population) of more
than 20.1 per 100,000 for males are Sub-Saharan and South Africa, East Asia,
and Melanesia. Low-risk areas with an
ASR < 3.2 are North and South America,
South-Central Asia, Northern Europe,
Australia and New Zealand. Thus, devel-oping countries carry the greatest dis-ease burden, with more than 80% of
accounted global cases. The geograph-ical distribution of PLC is similar for
males and females, although males have
a considerably higher risk of developing
PLC. Geographical variations in PLC risk
are present even in relatively homoge-nous populations and environments
{1471, 176}.
Geographical variations in HCC inci-dence and mortality can be ascribed to
different levels of exposure to HCC risk
factors: chronic infections with hepa-titis B virus (HBV) and aflatoxin expo-sure in developing countries, and smok-ing and alcohol abuse in developed
countries {1545, 1482, 1417}. In Japan,
local differences in the age-standardized
mortality rate (ASMR, standardized to
world population) reflect the sero-preva-lence of anti-hepatitis C virus (anti-HCV)
antibodies among blood donors {1973,
1893, 1471, 67}.
Time trends
In most countries, the incidence rates
stayed largely constant or have de-creased over the past two decades.
However, they have increased in Japan
and Italy, especially for males {982,
1522}. A changing prevalence of risk fac-tors among populations as well as
changes in diagnostic techniques and in
classification of the disease and appre-ciably affected the disease incidence.
Fig. 8.02 Geographic distribution of the prevalence of chronic HBV infection,
based on HBs Ag serology.
Fig. 8.03  Age-specific incidence rates of liver can-cer in males for selected populations 1992.
From: M. Parkin et al. {1471}.
> 8% = high
2-7% = intermediate
< 2% = low
3.6
6.6 35.8
28.4
3.1
4.1
< 3.6 < 5.4 < 10.8 < 20.9 < 48.9
160 Tumours of the liver and intrahepatic bile ducts
Age and sex distribution
Regional age-specific incidence rates
differ significantly (Fig. 8.03). Qidong
and Hong Kong (China) are high-risk
populations for HBV-related HCC.
Characteristics of their curves are a
steep increase in the ages 20-34 years;
in Qidong the curve levels off already at
the age of 40. Osaka (Japan) is a high-risk area, but Varese (Italy) is a low to
intermediate risk area; approximately
70% of HCC in these populations is relat-ed to chronic HCV infection {1417}. Their
rates increase at older ages and show
relatively high rates over age 55-59. The
curve for whites in the USA (SEER data)
is representative of both low-risk popula-tions. Males are always more frequently
affected than females but high male to
female ratios of > 3 in the age-specific
rates occur particularly in populations
with a high incidence of HCC {1534, 402,
1906, 391, 452}.
Aetiology
Chronic infection with HBV, HCV or both
is the most common cause of HCC
worldwide {889}. Among Western popu-lations, alcohol-induced liver injury is a
leading cause of liver cirrhosis and con-stitutes the most important HCC risk
{426}. In Southern China and sub-Saharan Africa, dietary ingestion of high
levels of aflatoxin may present a special
environmental hazard, particularly in indi-viduals chronically infected with HBV.
Other exogenous factors have also been
incriminated, including iron overload
{1155}, long-term use of oral contracep-tives {1158, 2034}, and high-dose ana-bolic steroids. The development of liver
cirrhosis, particularly in association with
inherited genetic diseases such as
alpha-1-antitrypsin deficiency or haemo-chromatosis, place the individual at a
greatly increased risk of HCC develop-ment.
HCC risk is increased if aetiological risk
factors exist in combination, e.g., HCV
infection and alcohol use {341} or HBV
infection and exposure to aflatoxin
{1864}.
Liver cirrhosis
The major clinical HCC risk factor is liver
cirrhosis, largely independent of its aeti-ology (Fig. 8.04). Approximately 70–90%
of HCCs develop in patients with
macronodular cirrhosis which is charac-terised by the presence of large nodules
of varying size (up to several centimeters
in diameter), containing portal fields and
efferent veins, separated by broad, irreg-ularly shaped connective tissue septae
and scars. Macronodular and mixed
macro-micro-nodular cirrhosis are typi-cally caused by or associated with viral
hepatitis, metabolic disorders, and toxic
liver injury. Micronodular cirrhosis is
characterised by uniform nodules of
approximately 3 mm that lack the typical
liver architecture and do not contain a
central vein. They are typically observed
as a consequence of alcoholic liver dis-ease, haemochromatosis, and biliary cir-rhosis.
Hepatitis B virus (HBV)
HBV is a small DNA virus belonging to
the group of hepatotropic DNA viruses
known as hepadnaviruses. HBV consists
of an outer envelope, composed mainly
of hepatitis B surface antigen (HBsAg),
and an internal core (nucleocapsid),
which contains hepatitis B core antigen
(HBcAg), a DNA polymerase/reverse
transcriptase, and the viral genome. The
genome consists of a partly double-stranded circular DNA molecule of about
3200 base pairs with known sequence
and genetic organisation. In recent
years, HBV variants with mutations in
viral genes and in some regulatory
genetic elements have been detected in
patients with HBV infection; these muta-tions can have biological consequences.
Epidemiological studies have convinc-ingly shown that HCC development is
closely associated with chronic HBV
infection. The incidence of HCC in chron-ically HBV-infected individuals is approx-imately 100 times higher than in the unin-fected population, and the lifetime HCC
risk of males infected at birth approach-es 50%. In the absence of a common
molecular mechanism for HBV-induced
hepatocarcinogenesis, definitive proof
for a direct oncogenic role of HBV is still
lacking. Nevertheless, at least three lines
of evidence support a direct oncogenic
role for HBV in the development of HCC:
(1) integration of HBV DNA into the chro-mosomal DNA of HCCs, (2) the role of
the HBV X gene in the pathogenesis of
HBV-associated HCCs, in particular its
binding to and inactivation of p53, and
(3) HCC development in animal models
of chronic hepadnavirus infection. In
addition, the declining HCC incidence
following HBV vaccination clearly sup-ports the aetiological contribution {275).
Chronic hepatitis D virus (HDV) infection
does not increase the risk of HCC devel-opment over that of HBV infection alone,
but the latency period between HDV
infection and HCC development is 30-40
Fig. 8.04 Overview of outcome of HBV infection.
Infection
Symptomatic
acute hepatitis B
Asymptomatic
acute hepatitis B
Fulminant hepatitis
Cirrhosis
Chronic infection
Death
Hepatocellular carcinoma
(Death)
(Death)
“Healthy” carrier
Fig. 8.05 Interactions between aflatoxin B1 (AFB1)
and HBV infection in liver cancer.
161Hepatocellular carcinoma
years, compared with 30-60 years for
HBV infection alone.
Hepatitis C virus (HCV)
HCV has a single-stranded RNA genome
of positive polarity, around 10 kb in
length, that codes for a single polypro-tein consisting of 3010-3033 amino
acids. Post-translational processing in
the 5′-3′ direction yields the structural
protein C (RNA-binding nucleocapsid
protein) and the E1 and E2 envelope pro-teins, and the non-structural proteins
NS1-NS5, including RNA-dependent
RNA polymerase {321}.
As soon as the HCV genome was cloned,
it became evident that viruses isolated
from various geographic regions have
marked genetic heterogeneity. Sequence
comparison shows at least 6 different
HCV genotypes. Although mutations
have been identified in all regions of the
HCV genome, the genes for the envelope
proteins E1 and E2 appear to be particu-larly variable. A mutation rate of 1 or 2
nucleotides per 1000 bases per infection-year appears to be characteristic of
chronic HCV infection. This mutation rate
is about 10 times higher than that of HBV.
Some HCV genotypes may be more fre-quently associated with HCC develop-ment than others {321}.
Anti-HCV antibodies are found in
15–80% of HCC patients, depending on
the patient population studied. HCV
appears to be a major cause of HCC in
Japan, Italy, and Spain, but it seems to
play a less important role in South Africa
and Taiwan {321}. HCV-associated HCCs
typically develop after 20-30 years of
infection and are generally preceded by
liver cirrhosis. Thus far, there is no evi-dence to suggest that HCV integrates
into the cellular genome or has another
direct role in the molecular pathogenesis
of HCC. Rather, HCC develops via HCV-induced chronic liver injury, progressing
to fibrosis and cirrhosis.
Alcohol
Among Western populations, alcohol-induced liver injury is the leading cause
of chronic liver disease and liver cirrhosis
and constitutes the most important HCC
risk factor {426}. Regular daily consump-tion of > 50g ethanol in females or
> 80g in males is generally considered
sufficient to induce liver cirrhosis,
although individual susceptibility can
vary considerably. Patients who abuse
alcohol and have coexisting liver disease
from other causes (such as chronic HCV
infection) have the highest risk for HCC
development {341, 1432, 1508, 2106}.
Aflatoxin B1 (AFB1)
AFB1 is a potent liver carcinogen in sev-eral animal species as well as in humans
{2128}. It is produced by the moulds
Aspergillus parasiticus and Aspergillus
flavus which under hot and humid condi-tions in tropical countries typically con-taminate grain, particularly ground nuts
(peanuts). Dietary ingestion of high lev-els of aflatoxins presents a significant
environmental hazard, particularly in the
context of coexisting chronic HBV infec-tion {1864, 1265} which leads to a more
than 50-fold increase in the risk of devel-oping HCC (Fig. 8.05).
AFB1 is metabolized by cytochrome
P450 enzymes to its reactive form,
AFB1-5,9-oxide, which covalently binds
to cellular macromolecules. Reaction
with DNA at the N7 position of guanine
preferentially causes a G:C > T:A muta-Fig. 8.06 Hepatocellular carcinoma. A Nodular type. B Massive type. C Diffuse type. D Multifocal type.
Fig. 8.07 Hepatocellular carcinoma, trabecular.
AB
CD
162 Tumours of the liver and intrahepatic bile ducts
tion in codon 249 of the  TP53 tumour
suppressor gene, leading to an amino
acid substitution of arginine to serine
{188}. In Southern China and
Subsaharan Africa, the two world regions
with the highest levels of food contami-nation with AFB1, this mutation is present
in > 40% of HCC {1265} and can be
detected in serum DNA of patients with
preneoplastic lesions and HCC {924}. In
regions where AFB1 levels in food are
very low or undetectable, codon 249
transversion mutations are either very
rare or absent.
Clinical features
Symptoms and signs
Most HCC patients have a past or current
history of chronic liver disease from dif-ferent causes {1681}. The major clinical
risk factor for HCC development is liver
cirrhosis; 70–90% of HCCs develop in a
macronodular cirrhosis {452}.
The presenting symptoms in patients
with HCC include abdominal pain, gen-eral malaise, anorexia or weight loss, and
nausea or vomiting. The symptoms are
caused by the underlying chronic liver
disease or cirrhosis and its clinical com-plications, or by the HCC itself. The most
common clinical signs in HCC patients
are hepatomegaly, ascites, fever, jaun-dice, and splenomegaly.
The laboratory findings are in part deter-mined by the underlying liver disease,
which results in elevations of various liver
enzymes, such as aspartate amino trans-ferase (AST), alanine aminotransferase
(ALT), alkaline phosphatase (AP),
gamma-glutamyl-transpeptidase (GGT),
and bilirubin. These laboratory parame-ters are not HCC-specific, however. A
significantly raised level of alpha-fetopro-tein (AFP) of > 500 ng/ml, or continuous-ly rising values even if less than 100
ng/ml, strongly suggest HCC. However,
not all cases of HCC are associated with
AFP elevation, and raised AFP may also
be found in liver disease without HCC.
Furthermore, in the early stages of HCC
development, AFP levels do not closely
correlate with clinical HCC stage. AFP
levels, therefore, have to be interpreted
individually in the context of other clinical
symptoms and signs as well as imaging
studies. Another HCC-specific marker is
des-gamma-carboxyprothrombin (DCP),
which is roughly equivalent to AFP.
Occasionally, HCC patients develop a
paraneoplastic syndrome, with erythrocy-tosis, hypoglycaemia or hypercalcaemia.
Imaging
Imaging studies are important in patient
management for the identification and
localization of HCC. Useful techniques
include ultrasonography of the liver and
the abdomen, colour Doppler ultra-sonography, computed tomography
(CT), lipiodol CT, magnetic resonance
imaging, angiography, and possibly
positron emission tomography. The stan-dard imaging techniques are ultrasonog-raphy and CT. In most cases, these allow
HCC detection and staging. In patients
Fig. 8.08 Histological subtypes of hepatocellular carcinoma.  A Pseudoglandular. B Clear cell. C Fatty change.  D Spindle cell. E Scirrhous type. F Scirrhous type,
Masson trichrome stain. G Poorly differentiated, with numerous mitotic figures. H Pleomorphic. I Multinucleated giant cell.
ABC
DE F
HGI
163Hepatocellular carcinoma
with suspected HCC metastases, a chest
X-ray, bone scan, or other imaging
modalities may be indicated.
Liver biopsy
The definitive diagnosis of HCC depends
on the histological examination of the
lesion, especially in AFP-negative
patients. Ultrasound- or CT-guided percu-taneous biopsy with a 22-gauge needle
usually provides sufficient tissue for diag-nosis with minimum risk of bleeding or
seeding of tumour cells along the needle
tract. However, in patients with signifi-cantly elevated AFP levels who are poten-tially eligible for HCC resection or liver
transplantation, liver biopsy is not recom-mended to eliminate the residual risk of
tumour cells spreading before surgery.
Macroscopy
Macroscopic features of HCCs vary
depending on the size of the tumour and
the presence or absence of liver cirrho-sis. In general, most HCCs associated
with liver cirrhosis tend to present as an
expansile tumour with a fibrous capsule
and intratumoural septa, while those
without cirrhosis tend to be massive and
non-encapsulated. Varying degrees of
infiltrative growth, tumour thrombi in the
portal veins, and intrahepatic metas-tases, which are common in advanced
tumours, modify the gross appearance.
Occasionally, numerous minute tumour
nodules are distributed throughout the
liver and may be difficult to be distin-guished from regenerative nodules in
liver cirrhosis.
Hepatocellular carcinomas are occasion-ally pedunculated. Patients are usually
females and the tumours are thought to
arise in accessory lobes of the liver.
Following surgical resection, the progno-sis is excellent.
Hepatocyte (Dako)
Polyclonal carcinoembryonic antigen
Alpha fetoprotein
Fibrinogen
Cytokeratins 8 and 18
Cytokeratins 7 and 19
Cytokeratin 20
Epithelial membrane antigen
BER EP4
Positive (most useful in diagnosis)
Positive (canalicular pattern)
Positive or negative
Positive or negative
Usually positive
Usually negative
Usually negative
Negative
Negative
Antigen Result
Table 8.01
Immunohistochemistry of HCC.
Fig. 8.10 Pale bodies in hepatocellular carcinoma. A Haematoxylin and eosin. B Immunoreactivity for fibrinogen.
Fig. 8.09 A Numerous Mallory bodies in a hepatocellular carcinoma (two examples indicated by arrows). B Hyaline inclusions in a hepatocellular carcinoma.
A B
A B
164 Tumours of the liver and intrahepatic bile ducts
Tumour spread
Invasion into the blood vessels, in partic-ular into the portal vein, is a characteris-tic of HCC. Tumour thrombi in the portal
veins are present in more than 70% of
autopsies of advanced HCCs. Intra-hepatic metastases is caused mostly by
tumour spread through the portal vein
branches. Tumour invasion into the major
bile ducts is infrequent clinically, but
found in about 6% of autopsy cases.
Extrahepatic metastasis is mostly
haematogenous, the lungs being the
most common target. Regional lymphatic
metastasis is frequent though distant
lymph nodes are rarely involved.
Histopathology
HCCs consist of tumour cells that resem-ble hepatocytes. The stroma is com-posed of sinusoid-like blood spaces lined
by a single layer of endothelial cells.
Unlike the sinusoidal endothelial cells in
normal liver tissue, those of HCC are
immunohistochemically positive for
CD34 and factor-VIII-related antigen.
Ultrastructural observation shows a base-ment-membrane-like structure between
the endothelial cells and tumour cell tra-beculae, and basement-membrane-like
materials are immunohistochemically
positive with antibodies for laminin and
type IV collagen. Thus, the sinusoid-like
blood spaces resemble capillary vessels.
This phenotypic change of sinusoids is
called ‘capillarization’ {472, 919, 917}.
In the sinusoidal blood spaces, varying
numbers of macrophages, which show
immunohistochemical positivity with anti-lysozyme and CD68, are also present
and resemble Kupffer cells in well differ-entiated tumours {1894}. HCCs vary
architecturally and cytologically. The dif-ferent architectural patterns and cytolog-ical variants frequently occur in combina-tion. Immunohistochemical features of
HCC are summarized in Table 8.01.
Architectural patterns
Trabecular (plate-like).  This pattern is the
most common in well and moderately dif-ferentiated HCCs. Tumour cells grow in
cords of variable thickness that are sep-arated by sinusoid-like blood spaces.
Well-differentiated tumours have a thin
trabecular pattern and trabeculae
become thicker with de-differentiation.
Sinusoid-like blood spaces often show
varying degrees of dilatation, and pelio-sis hepatis-like change are occasionally
observed in advanced HCCs.
Pseudoglandular and acinar.  HCC fre-quently has a glandular pattern, usually
admixed with the trabecular pattern. The
glandular structure is formed mostly by a
single layer of tumour cells, and some
glandular or acinar structures are formed
by dilatation of the bile canaliculus-like
structure between cancer cells. Pseudo-glands frequently contain proteinaceous
fluids, which often stain with PAS but do
not stain with mucicarmine or Alcian blue.
Bile may be present. Cystic dilatation of
the pseudoglands sometimes occurs,
such dilated glands are occasionally
formed by degeneration of thick trabecu-lae. Generally, the glandular structure is
smaller in well differentiated tumours than
in moderately differentiated tumours.
Compact. Sinusoid-like blood spaces
are inconspicuous and slit-like, giving
the tumour a solid appearance.
Scirrhous. This uncommon type is char-acterised by marked fibrosis along the
sinusoid-like blood spaces with varying
degrees of atrophy of tumour trabeculae.
It is observed even in small  tumours. The
scirrhous type should not be confused
with cholangiocarcinoma or fibrolamellar
carcinoma. Similar fibrotic changes
occur following chemotherapy, radiation,
and transchemo arterial embolization.
Such post-therapeutic fibrosis should be
distinguished from the scirrhous variant.
The term ‘sclerosing hepatic carcinoma’
Fig. 8.12 Immunostaining for polyclonal CEA
demonstrates canaliculi in a hepatocellular carci-noma.
Fig. 8.13 Bile production in a hepatocellular carci-noma.
Fig. 8.11 Hepatocellular carcinoma in a 17-year old patient with Fanconi anaemia. A Green bile staining and extensive necrosis and haemorrhage. B Trabecular and
pseudoglandular pattern with bile plugs.
AB
165Hepatocellular carcinoma
{1424}, which has been used to desig-nate a variety of tumours arising in non-cirrhotic livers and associated with
hypercalcemia, does not constitute a dis-tinct histopathological entity {806}, some
of these tumours appear to be hepato-cellular, but others are intrahepatic
(peripheral) cholangiocarcinomas.
Cytological variants
Pleomorphic cell. Tumour cells show
marked variation in cellular and nuclear
size, shape, and staining. Bizarre
multinucleated or mononuclear giant
cells are often present, and osteoclast-like giant cells may be seen rarely.
Generally, pleomorphic tumour cells lack
cohesiveness and do not show a distinct
trabecular pattern. Pleomorphic cells are
common in poorly differentiated tumours.
Clear cell. The tumour consists predom-inantly of cells with clear cytoplasm due
to the presence of abundant glycogen.
This type is sometimes difficult to distin-guish from metastatic renal cell carcino-ma of clear cell type.
Sarcomatous change. HCC occasionally
appears sarcomatous, characterised by
the proliferation of spindle cells or bizarre
giant cells. When the tumour consists
solely of sarcomatous cells, it is difficult
to distinguish from sarcomas such as
fibrosarcoma and myogenic sarcoma.
When sarcomatous features are predom-inant, the tumour is called sarcomatoid
HCC or sarcomatous HCC. In many
cases, however, the sarcomatous
change is present in a part of the tumour,
and transitional features between
trabecular HCC and sarcomatous com-ponents are frequent. Sarcomatous
change is more frequent in cases with
repeated chemo-therapy or transchemo
arterial embolization {953}, but it is also
seen in small tumours. Most sarcoma-tous cells are positive for vimentin or
desmin but negative for albumin and
alpha-fetoprotein. Some are also positive
for cytokeratin.
Fatty change.  Diffuse fatty change is
most frequent in small, early-stage
tumours less than 2 cm in diameter. Its
frequency declines as tumour size
increases, and fatty changes are rather
infrequent in advanced tumours. Meta-bolic disorders related to hepatocarcino-genesis and insufficient blood supply in
the early neoplastic stage have been
suggested as a possible mechanism for
the development of fatty change in small
tumours, but a definite mechanism has
not yet been determined.
Bile production.  Bile is occasionally
observed, usually as plugs in dilated
canaliculi or pseudoglands. When bile
production is prominent, the tumour is
yellowish in color and turns green after
formalin fixation.
Mallory hyaline bodies  are intracytoplas-mic, irregular in shape, eosinophilic and
PAS-negative. They consist of aggregat-ed intermediate filaments and show
immunohistochemical positivity with anti-ubiquitin antibodies.
Globular hyaline bodies are small, round,
homogeneous, and strongly acidophilic
intracytoplasmic bodies. They are
PAS-positive and stain orange to red with
Masson trichrome stain. Immunohisto-chemically, they are often positive for
alpha-1-antitrypsin.
Pale bodies  are intracytoplasmic, round
to ovoid, amorphous and lightly eosino-philic. They represent an accumulation
of amorphous materials in cystically
dilated endoplasmic reticulum, and
show distinct immunohistochemical pos-itivity with anti-fibrinogen {1846}. They
are commonly seen in the fibrolamellar
variant of HCC but are also found in the
common types of HCC, especially in
scirrhous HCC.
Ground glass inclusions are rarely
observed in tumours of HBsAg-positive
patients. They stain with modified orcein,
Victoria blue, or aldehyde fuchsin, and
show immunohistochemical positivity
with anti-HBsAg antibody. They are not
seen in tumour casts in the portal vein or
in extrahepatic metastases, and most are
thought to be HBsAg-positive hepato-cytes entrapped in a tumour.
Fibrolamellar HCC
This variant usually arises in non-cirrhotic
livers of adolescents or young adults
{353}. It is rare in Asian and African coun-tries but not so rare in Western countries.
The tumour cells grow in sheets or small
trabeculae that are separated by hyalin-ized collagen bundles with a character-istic lamellar pattern. They are large and
polygonal and have a deeply eosino-philic and coarsely granular cytoplasm
and distinct nucleoli. The eosinophilic
granularity is due to the presence of a
large number of mitochondria. Pale bod-ies are frequently present, and stainable
copper, usually in association with bile,
can occasionally be shown.
Undifferentiated carcinoma
Undifferentiated carcinoma is rare,
accounting for less than 2% of epithelial
liver tumours. There is male preponder-ance but data on geographical distribu-tion are not available. Localization, clini-cal features, symptoms and signs, and
diagnostic procedures display no differ-ence as compared to hepatocellular car-cinoma. Undifferentiated carcinomas are
postulated to have a worse prognosis
(compared to HCC), although greater
case numbers to support this are not
available {351, 806}.
Grading
According to histological grade, HCC is
classified into well differentiated, moder-ately differentiated, poorly differentiated,
and undifferentiated types.
Fig. 8.14 Nodule-in-nodule type of hepatocellular carcinoma. The border between early and advanced components is shown in C.
ABC
Well differentiated HCC.  This is most
commonly seen in small, early-stage
tumours less than 2 cm in diameter and
is rare in advanced tumours. The lesions
are composed of cells with minimal atyp-ia and increased nuclear/cytoplasmic
ratio in a thin trabecular pattern, with fre-quent pseudoglandular or acinar struc-tures and frequent fatty change. In most
tumours larger than 3 cm in diameter,
well-differentiated carcinoma is observed
only in the periphery if at all.
Moderately differentiated HCC. The mod-erately differentiated type is the common-est in tumours larger than 3 cm in diame-ter and is characterized by tumour cells
arranged in trabeculae of three or more
cells in thickness. Tumour cells have
abundant eosinophilic cytoplasm and
round nuclei with distinct nucleoli. A
pseudoglandular pattern is also frequent,
and pseudoglands frequently contain
bile or proteinaceous fluid.
Poorly differentiated HCC.  This prolifer-ates in a solid pattern without distinct
sinusoid-like blood spaces, and only -slitlike blood vessels are observed in
large tumour nests. Neoplastic cells
show an increased nuclear/cytoplasmic
ratio and frequent pleomorphism, includ-ing bizarre giant cells. Poorly differentiat-ed HCC is extremely rare in small early-stage tumours.
Malignant progression of HCC.  HCC is
known to vary histologically even within a
single nodule. From the viewpoint of his-tological grade, most cancer nodules
less than 1 cm in diameter have a uniform
distribution of well differentiated cancer-ous tissues, whereas approximately 40%
of cancer nodules 1.0-3.0 cm in diameter
consist of more than 2 types of tissue of
different histological grades {900}. Less
differentiated tissues are always located
inside, surrounded by well differentiated
tumour on the outside. The area of well
differentiated neoplasm diminishes as the
tumour size increases, and they are com-pletely replaced by less-well-differentiat-ed cancerous tissues when the tumour
size reaches a diameter of around 3 cm.
When less-well-differentiated areas within
a well differentiated tumour nodule are
growing expansively, the nodule often
has a ‘nodule-in-nodule’ appearance
{1275}.
Multicentric development of HCC
HCCs frequently occur as multiple intra-hepatic nodules. Genetic analysis of
HBV integration pattern, chromosomal
allele loss, and mutational inactivation of
tumour suppressor genes has indicated
multicentric independent development of
these nodules {1647, 1392}. These stud-ies have shown that nodules apparently
growing from portal vein tumour thrombi
or satellite nodules surrounding a large
main tumour represent intrahepatic
metastases, whereas other nodules can
be considered multicentric HCCs if they
satisfy any of the following three criteria:
(1) multiple, small early-stage HCCs or
concurrent small early-stage HCCs and
classical HCCs; (2) presence of periph-eral areas of well differentiated HCC in
both lesions or in the smaller ones; and
(3) multiple HCCs of obviously different
histology.
Multicentric HCCs are associated with a
high rate of tumour recurrence, even
after curative resection, making treat-ment difficult and the prognosis poor.
The presence of hyperplastic foci, small-cell dysplasia, an increase in the prolifer-ative activity of non-tumourous liver tis-sue, or the progression of background
liver disease are risk factors for multicen-tric HCC development {1902, 1859}.
166 Tumours of the liver and intrahepatic bile ducts
Fig. 8.15 A, B Fibrolamellar type of hepatocellular carcinoma.
Fig. 8.17 Adenomatous hyperplasia with minimal
nuclear atypia and without features of malignancy.
Fig. 8.16 Early hepatocellular carcinoma showing
well differentiated histological features.
AB
A
B
167Hepatocellular carcinoma
Precursor and benign lesions
Early stage HCC and precancerous
lesions
Because of remarkable advances in
imaging techniques and their wide-spread availability, increased numbers of
small HCCs are detected clinically. Liver
transplantation has become common
treatment for liver cirrhosis and HCC in
highly selected cases. Studies of resect-ed and explant livers have revealed new
information about the morphological
characteristics of small early-stage HCC
and equivocal nodular lesions. The most
striking information is that HCC associat-ed with cirrhosis probably evolves from
precancerous lesions, and well differenti-ated HCC further progresses to a less
differentiated form {952, 1646, 1882,
1645, 81}.
Histological features of small early-stage
HCC
Although some small HCCs show fea-tures of classical HCCs, most less than
1.5 cm in diameter are vaguely nodular
with indistinct margins macroscopically
and have a uniform distribution of well
differentiated cancerous tissues. They
are characterized by increased cell den-sity with increased nuclear/cytoplasmic
ratio, increased staining intensity
(eosinophilic or basophilic), irregular thin
trabecular pattern with a frequent acinar
or pseudoglandular pattern, and fatty
change {959, 1324}. Diffuse fatty change
of tumour cells is present in approxi-mately 40% of tumours less than 2 cm in
diameter. Many portal tracts are present
within the tumour nodule, and tumour cell
invasion into some portal tracts can be
seen. At the tumour boundary, neoplastic
cells proliferate as though they are
replacing normal hepatocytes (‘replacing
growth’), and there is no capsule forma-tion. These small tumours may corre-spond to ‘carcinoma in-situ’ or ‘microin-vasive carcinoma’ of the liver. They tend
to preserve the underlying liver struc-tures, including portal tracts, receive por-tal blood supply, and do not show tumour
blushing in angiographic examinations.
In contrast, classical HCCs, even if small
and well differentiated, show tumour
blushing without portal flow {1883}.
Invasion into the stromal tissue can be
sometimes identified, but vascular inva-sion and intrahepatic metastases are
exceptional {1942}. Moreover, these
lesions are locally curable, have a favor-able long-term outcome, and can be
defined clinically as ‘early HCC’.
Adenomatous hyperplasia (dysplastic
nodules)
This lesion is characterized by marked
enlargement of individual cirrhotic nod-ules that show thick liver cell plates.
Small nodular lesions, most of which are
below 1.5 cm in size, have been noticed
in the livers of patients with HCCs that
have been resected surgically and in
explant cirrhotic livers. The nodules show
variable atypia but lack features of defi-nite malignancy. Macroscopically, most
lesions are vaguely nodular and are not
much different from small, well differenti-ated HCC with indistinct margins; it is
almost impossible to distinguish them
from cancer on the one hand or from
large regenerative nodules on the other
hand. Microscopically, they are charac-terized by a moderate increase in cell
density with a slightly irregular trabecular
pattern. There are many portal tracts
within the nodules but no invasion into
the portal tracts. These nodules some-times contain distinct, well differentiated
cancer foci. Many of them gave rise to
distinct HCC in clinical follow-up studies
{1882, 1645} and are, therefore, consid-ered precancerous lesions. Some of
Fig. 8.19 A–C Atypical adenomatous hyperplasia
with mild atypia and extensive fatty change.
Fig. 8.18 Adenoma. A Extensive central haemorrhage. B Benign appearing hepatocytes arranged in plates, one or two cells thick.
1 cm
AB
A
B
C
168 Tumours of the liver and intrahepatic bile ducts
these nodules contain areas with a
marked increase in cell density, a more
irregular trabecular pattern, and frequent
fatty change, characteristic of well differ-entiated HCC but insufficient in extent to
warrant such a diagnosis.
These foci have been designated adeno-matous hyperplasia {1080, 806} or dys-plastic nodule {64}. Additional terms
used for these lesions include macrore-generative nodule, hyperplastic nodule
and borderline lesions.
Morphological criteria for the differential
diagnosis of adenomatous hyperplasia
(dysplastic nodule, low grade), atypical
adenomatous hyperplasia (dysplastic
nodule, high grade) and early-stage
HCC are still under discussion, mainly
due to the lack of objective phenotypic or
genotypic markers {1080, 64, 805}.
Focal liver cell dysplasia (LCD)
Large cell dysplasia.   The term liver cell
dysplasia (LCD) was first coined by
Anthony et al. {73} to describe a change
characterized by cellular enlargement,
nuclear pleomorphism and multinucle-ation of liver cells occurring in groups or
occupying whole cirrhotic nodules. The
change was found in only 1% of patients
with normal livers, in 7% of patients with
cirrhosis and in 65% of patients with cir-rhosis and HCC. There was a strong rela-tionship between LCD and HBsAg
seropositivity {73}. They concluded that
the presence of LCD identified a group of
patients at high risk for development of
HCC, and that such patients should be
followed by serial alpha-fetoprotein
determinations.
Small cell dysplasia.  Watanabe et al.
{2068} have expanded the original defi-nition of LCD to include a ‘small cell’ vari-ant. The nuclear/cytoplasmic ratio is
increased in small cell dysplasia, the
ratio being between that of liver cancer
and normal hepatocytes. This is in con-trast to large cell dysplasia that has nor-mal nuclear/cytoplasmic ratio. Also,
multinucleation and large nucleoli are
characteristic of large cell dysplasia but
not small cell dysplasia. The small dys-plastic cells have more of a tendency to
form small round foci than large dysplas-tic cells. On the basis of their morpho-logical and morphometric studies
Watanabe et al. {2068} proposed the
hypothesis that small cell dysplasia,
rather than large cell dysplasia, is the
precancerous lesion in man.
Hepatocellular adenoma
A benign tumour composed of cells
closely resembling normal hepatocytes,
which are arranged in plates separated
by sinusoids. On gross examination,
adenomas are soft, rounded, yellow or
tan masses, often with areas of necrosis,
haemorrhage, and fibrosis. A fibrous
capsule is uncommon. Lesions are soli-tary in two-thirds of cases {511}. When
more than 10 lesions are encountered, a
diagnosis of ‘adenomatosis’ has been
recommended {511}.
Adenoma is histologically composed of
benign-appearing hepatocytes arranged
in plates one or two cells in thickness
{64, 803, 351, 71}. Portal tracts are
absent; the lesion is supplied by arteries
and veins. In most cases, the tumour
cells are uniform in size and shape, but
occasionally, mild to moderate cytologi-cal variation may be seen. Mitotic activi-ty is almost never found. Lipofuscin, fat
and clear cell change (due to water or
glycogen accumulation) are often pres-ent in the cytoplasm. Haemorrhage,
infarction, fibrosis, and peliosis hepatis
may be seen.
The differential diagnosis may be difficult
with small biopsies. Features suggesting
hepatocellular carcinoma include mito-ses, high nuclear/cytoplasmic ratio, and
plates more than 2 cells in thickness.
Loss of a normal reticulin pattern is com-mon in HCC whereas it is preserved in
hepatocellular adenoma. HCC typically
also shows diffuse capillarization using
Fig. 8.20 Focal nodular hyperplasia. A Solitary lobulated nodule with typical central stellate scar. B Masson trichrome stain shows extensive blue connective tissue
component.
Fig. 8.21 Nodular regenerative hyperplasia.
A Multiple pale nodules of varying size. B Reticulin
stain showing mild distortion of liver architecture.
A B
A
B
169Hepatocellular carcinoma
CD34 immunostain in comparison with
hepatocellular adenoma, which is either
negative or shows only focal staining.
Any evidence of ductular differentiation
suggests a regenerative lesion such as
focal nodular hyperplasia (FNH). Portal
tracts within the peripheral portion of an
adenoma may cause confusion.
The clinical setting is an important con-sideration in differential diagnosis. Most
patients have a known risk factor, espe-cially the use of contraceptive or anabol-ic steroids. Glycogen storage disease
has also been associated. A diagnosis of
adenoma should be made with caution in
the absence of a known cause or in the
presence of cirrhosis, where dysplastic
nodules, carcinoma, and large regenera-tive nodules are far more frequent.
Focal nodular hyperplasia (FNH)
A lesion composed of hyperplastic hepa-tic parenchyma, subdivided into nodules
by fibrous septa which may form stellate
scars. The majority of FNH lesions are
asymptomatic. Infarction may lead to
abdominal pain but rupture is rare. When
more than one FNH lesion is present the
patient often has other features suggest-ing a systemic abnormality of angiogen-esis, including hepatic haemangioma,
intra-cranial lesions (vascular malforma-tions, meningeoma, astrocytoma), and
dysplasia of large muscular arteries
{2054, 2055}.
Most FNH lesions are solitary, firm, and
lobulated nodules (Fig. 8.20). Lesions on
the surface of the liver may protrude
above the capsule. On cut section, they
are circumscribed but not encapsulated,
and paler than the surrounding liver.
They typically consist of a central stellate
scar surrounded by parenchymal
nodules. Although most lesions are paler
than the surrounding liver, a less
common telangiectatic type has promi-nent blood-filled vascular spaces {64,
2055}.
Histologically, FNH has a regular hierar-chical structure defined by the arterial
supply, which is usually a single artery
with several orders of branching. Each
terminal branch is located in the center
of a 1 mm nodule. The large arteries
often have degenerative changes in the
media and eccentric intimal fibrosis. The
arteries are found in a fibrous stroma
without portal veins and usually without
ducts. Proliferating ductules are usually
present and may be prominent, com-monly with visible features of chronic
cholestasis (cholate stasis, copper accu-mulation) and neutrophil infiltration.
Nascent FNH is a small region of hyper-plasia or dilated sinusoids, recognised in
the context of more definite FNH lesions.
The rare telangiectatic type of FNH has a
similar arterial supply but with markedly
dilated sinusoids comprising at least a
quarter of the lesion.
The histological differential diagnosis of
FNH includes cirrhosis, in which septa
contain portal areas, and hepatocellular
adenoma. If the ductular component is
not sampled, an unequivocal diagnosis
may not be possible.
Nodular regenerative hyperplasia (NRH)
This condition is characterized by small
regenerative nodules dispersed through-out the liver, associated with acinar atro-phy with occlusive portal vascular
lesions.
The liver has a normal weight and shape
with a fine granularity of the capsular sur-face. The cut surface demonstrates a dif-fuse nodularity with most nodules meas-uring 1-2 mm. Occasionally, there are
clusters of nodules up to several cm in
diameter {64, 2056, 2053}. The nodules
are paler than the atrophic hepatic
parenchyma which surrounds them.
Microscopically, the normal architecture
is mildly distorted by widespread atrophy
admixed with numerous monoacinar
regenerative nodules. The nodules are
composed of normal-appearing hepato-cytes in plates 1-2 cells wide centered
on portal tracts. The atrophic regions
have small hepatocytes in thin trabecu-lae with dilated sinusoids. No significant
paren-chymal fibrosis is present but
numerous small portal veins are obliter-ated.
Histological diagnosis of NRH depends
on the recognition of a nodular architec-ture in the absence of parenchymal
fibrosis. Nodularity may be suspected
when there are two adjacent populations
of hepatocytes that are normal and
atrophic, respectively. This pattern is
best appreciated on a reticulin stain.
Macro-nodular, incomplete septal, or
regressed cirrhosis commonly have
regions with this configuration, especial-ly in livers with healed portal vein throm-bosis {1742}. These forms of cirrhosis
are difficult to exclude in a small biopsy.
Genetic susceptibility
Several rare inherited disorders of
metabolism are associated with an
increased risk of developing HCC.
Carbohydrate metabolism disorders
In glycogen storage disease (GSD),
especially type 1 {323}, HCC can devel-op within preexisting adenomatous
lesions {137}. Distinction between
benign and malignant tumours is difficult,
since GSD-associated HCCs are well dif-ferentiated, and atypical lesions (‘nodule
within nodule’ pattern and Mallory bod-ies) are found commonly in GSD-related
adenomas {137, 1527}. Cirrhosis is never
present.
Fig. 8.22 Multicentric, independent development of two HCC (T1 and T2), indicated by differences in their
HBV DNA integration pattern. (N, normal tissue)
(kb)
23.1
9.4
6.6
4.4
2.3
2.0
HindIII BamHI
T1 T2 N T1 T2 N
T1
T2
170 Tumours of the liver and intrahepatic bile ducts
Protein metabolism disorders
In alpha-1-antitrypsin deficiency (A1ATD)
{1501}, only male A1ATD homozygotes
are at high risk for HCC, even in the
absence of cirrhosis {473}. Further-more,
cholangiocarcinomas and combined
hepatocellular and cholangiocarcinomas
in non-cirrhotic livers of adult patients
with heterozygous A1ATD of PiZ type are
well documented {2207}. HCC occurs in
18%-35% of patients with hereditary
tyrosinaemia {2082, 1996}. The non-tumourous liver is cirrhotic and often dys-plastic {808}. HCC has further been
reported in 14% of adult-onset cases of
hypercitrullinaemia in the absence of cir-rhosis {1324A}.
Disorders of porphyrin metabolism.   The
prevalence of HCC in porphyria cutanea
tarda (PCT) ranges from 7% to 47%
{1755, 1073}. Almost all HCCs occur in
male patients older than 50 years with
preexisting cirrhosis and a long-standing
history of symptomatic PCT. The involve-ment of additional risk factors is likely
{396}. Rarely, PCT evolves as a para-neoplastic syndrome associated with
HCC {1389}. Other hepatic porphyrias
are occasionally associated with HCC
{1073, 53}.
Chronic cholestatic syndromes.
HCC may complicate paucity of intra-hepatic bile ducts {1028, 99, 898},
biliary atresia {2082}, congenital hepatic
fibrosis {2082}, and Byler syndrome
{1550}.
Metal-storage diseases.
The relative risk for the development of
primary liver cancer in inherited
haemochromatosis has been calculated
as being greater than 200 {181, 1351,
487}. HCC develops usually in patients
with cirrhosis {403, 951}, even after iron
depletion {403}. Iron-free foci (defined as
clear-cut, sublobular, hepatocytic nod-ules free of iron or having significantly
less iron than the surrounding parenchy-ma) may represent an early step of HCC
in genetic haemochromatosis {403}. In
Wilson’s disease, HCC is present only
exceptionally {293}.
Hepatic vascular anomalies.
Cases of HCC have been occasionally
reported in hereditary haemorrhagic
telangiectasia {831} and ataxia-telang-iectasia {2083}.
Extrahepatic inherited conditions.
Several cases of HCC have been report-ed in familial adenomatous polyposis of
the colon {1000}. Occasional cases have
also been described in neurofibromato-sis, Soto syndrome, and situs inversus
{2082}. Cases of hepatocellular adeno-mas and HCC in young patients with
Fanconi anaemia have been also
described {1033}.
Genetics
Clonal expansion and subclonal progres-sion during multistage carcinogenesis
Most HCCs are associated with HBV or
HCV infection. Clonal expansion of hepa-tocytes is initiated during regeneration in
damaged livers; a clonal integration pat-tern of HBV was identified in cirrhotic
nodules {2170}. Advanced HCCs often
emerge as ‘nodule-in-nodule’ HCCs; the
early and advanced HCC components of
a ‘nodule-in-nodule’ type HCC showed
identical integration patterns of HBV
{1968, 1647}. Ordinary HCCs with in-creased cell proliferation and neovascu-larization are subsequently formed.
TP53 mutations
Point and frameshift mutations of the
TP53 tumour suppressor gene are fre-quent in areas with low exposure to afla-toxin B1 {1393}. TP53 mutations were
most frequent and were clustered in
domains IV and V in poorly differentiated
HCCs, but were less frequent and equal-ly distributed in domains II to V in well or
moderately differentiated HCCs in one
study {1393}. Analysis of ‘nodule-in-nod-ule’ type HCC shows that TP53 mutation
is associated with the progression of
HCC from an early to a more advanced
stage {1392, 1391}.
In areas with high exposure to AFB1,
mutation of the third nucleotide in codon
249 of TP53 is frequent {758, 188}, sug-gesting that some TP53 mutations can be
fingerprints of past exposure to a given
carcinogen (see ‘Aetiology’, above).
HBV X
The HBV X open reading frame is fre-quently integrated and expressed. HBV
X [MLS1] can bind to the C terminus of
p53, inhibits its sequence-specific DNA
binding and transcriptional activation
and suppresses p53-induced apoptosis
Fig. 8.23 CpG methylation around E-cadherin promoter in HCCs and non-tumorous liver showing chronic
hepatitis or cirrhosis. CpG methylation was detected in 46% of liver tissues showing chronic hepatitis or cir-rhosis and 67% of HCCs. Heterogenous E-cadherin expression was detected in hepatocytes in 7 (41%) of the
17 liver tissues showing chronic hepatitis or cirrhosis; small focal areas of hepatocytes showed only slight
E-cadherin immunoreactivity. Reduced E-cadherin expression was observed in 10 (59%), in which over 50%
of the HCC cells in each patient lacked or showed only slight E-cadherin immunoreactivity, of the 17 HCCs.
Chronic hepatitis HCC HCC
C1 C2 H99N H99T H103N H103T
EB
EBM
EBH
EB
EBM
EBH
EBM
EBH
EBM
EBH
EBM
EBH
EBM
EBH
E, EcoRI; B; BamHI; M, Mspl; H, Hpall; C1 and 2, cases with liver metastatic lesions
of primary colonic cancer; H99 and 103, HCC cases.
= normal liver tissue  = cirrhotic liver tissue  = HCC
2.6 kb
171Hepatocellular carcinoma
{2050, 2051, 457}. HBV  X may affect a
wide range of p53 functions and thereby
contribute to the molecular pathogenesis
of HCCs. HBV  X further inhibits nucleo-tide excision repair {858}.
Oncogenes
Mutational activation of known onco-genes is rare. Point mutations of the
c-KRAS gene and coamplification of the
cyclin D1 gene were detected in only 3%
{1967} and 11% {1355} of HCCs, respec-tively.
Recent findings, obtained by compara-tive genomic hybridization of amplified
sequences mapped to 11q12, 12p11,
and 14q12, may lead to the characteri-zation of new genes involved in hepato-carcinogenesis {1163}.
Wnt pathway and beta-catenin
In the wingless/Wnt pathway, mutations
of the  β-catenin gene were detected in
26-41% of HCCs {386, 760}. Nuclear
accumulation of β-catenin was observed
by immunohistochemistry in all HCCs
with β-catenin mutations {760}. No muta-tion was detected in mutation cluster
region of the  APC gene in any of 22
HCCs analysed {760}. Deletions on chro-mosomes 1p, 4q, and 16p were
significantly associated with the absence
of β-catenin mutation, which suggests
that a  β-catenin-activating mutation is
involved in cases without chromosomal
instability {1041}.
Genetic instability and allelic loss
Frequent allelic losses have been found
at loci on 1p, 4q, 5q, 8p, 11p, 13q, 16p,
16q, and 17p by restriction fragment
length polymorphism analysis {2046,
200, 1970, 2203, 546, 1759, 459, 460}.
Loss of heterozygosity (LOH) on chromo-some 16 was detected in 52% of inform-ative cases {1970}. The common deleted
region lay between HP (16q22.1) and
CTRB (16q22.3-q23.3) loci {1970}.
These losses occurred more frequently
in HCCs with poor differentiation, of large
size, and with metastasis, and were not
detected in early-stage HCCs {1970}.
LOH on chromosome 16 may be
involved in enhancement of tumour
aggressiveness. Recent development of
microsatellite markers allows an exten-sive allelotypic analysis {2171, 163,
1307, 1515, 659, 108}. Detailed deletion
mapping revealed that allelic loss at a
1-cM-interval flanked by D4S2921 and
D4S2930 loci on 4q35 was frequent in
HCCs with poor differentiation and of
large size {108}. Inactivation of unidenti-fied tumour suppressor genes within this
region may contribute to progression of
HCCs.
Microsatellite instability is another path-way for genetic instability other than
chromosomal instability. Only 11% of
HCCs had replication errors in one study,
and the incidence of replication errors
correlated significantly with poor differ-entiation and portal vein involvement of
HCCs {961}.
Cell cycle regulators
The gene product of  p16INK4
binds to
cyclin-dependent kinase (CDK) 4 and
prevents CDK4 from forming an active
complex with cyclin D. p16 protein loss
may contribute to both early- and late-stage hepatocarcinogenesis, because it
was observed in 22% of early-stage
HCCs and occurred approximately twice
as often in advanced HCCs as in early-stage HCCs {763}. Neither p16 homozy-gous deletion/mutation nor loss of p16
mRNA expression was observed in
HCCs lacking p16 protein {763}, sug-gesting post-transcriptional inactivation.
DNA methylation around the promoter
region of the p16 gene has been
observed in HCC {1187}.
Expression of  p21WAF1/CIP1 mRNA, a
universal CDK inhibitor, was reduced
markedly in 38% of HCCs {762}. p21
mRNA expression of HCCs with  TP53
mutations was significantly lower than
that of HCCs with wild-type TP533 {762}.
p21 expression is regulated predomi-nantly by dependence on TP53 in HCCs.
mRNA expression of p27Kip1
, another uni-versal CDK inhibitor, was reduced in
52% of HCCs {764}.
Fig. 8.24 Correlation between TP53 mutation at codon 249, dietary exposure to aflatoxin B1, and regional inci-dence of hepatocellular carcinoma (HCC).
Senegal (10/15)
Mozambique (8/15)
China (Quidong, Quanxi; 38/73)
Thailand (1/15) Japan (1/274)
Sth. Africa (Transkei, Natal; 3/48)
China (Shanghai; 3/52)
Europe/USA (0/107)
Prevalence of TP53 mutation
(codon 249; AGG > AGT);
% of total HCC
Average range of aflatoxin
B1 intake (ng/kg body weight
per day)
Age standardized incidence
of hepatocellular carcinoma
(males/105
)
70
60
50
40
30
20
10
0
200
100
50
150
100
80
60
40
20
Fig. 8.25 DNA sequencing autoradiographs of
β-catenin mutations in HCC {760}.
Fig. 8.26 Nuclear accumulation of β-catenin protein
in neoplastic hepatocytes in a HCC associated with
HCV infection {760}.
172 Tumours of the liver and intrahepatic bile ducts
Growth factors
Transforming growth factor-beta (TGF-β)
was expressed at a high level in 82% of
HCCs and was associated with HBV
infection {756}. TGF-β expression could
be part of a chain of events by which HBV
contributes to the development of HCCs.
TGF-β1, TGF-β2, and TGF-β3 showed
marked mRNA overexpression in HCCs
{818, 12}. TGF-β was expressed in both
tumour and stroma cells; this suggests
that TGF-β may play a role in hepatocar-cinogenesis through both autocrine and
paracrine pathways {12}. The mannose-6-phosphate / insulin-like growth factor-II
receptor (M6P/IGF2R) regulates cell pro-liferation through interactions with TGF-β
and IGF II. A study from the U.S.A. report-ed LOH at the M6P/IGF2R locus and
mutations of the remaining allele were
identified in 61% and 55% of HCCs,
respectively {2149}, while no M6P/IGF2R
mutations were detected in HCCs from
Japanese patients {2031}.
Angiogenic growth factors. mRNA
expression of basic fibroblast growth fac-tor (bFGF) was high in HCCs {1746}.
Strong immunoreactivity for bFGF was
localised in the progressed HCC compo-nent but not in the early-stage compo-nent of a nodule-in-nodule HCC {712}.
Acquisition by cancer cells of the capac-ity to produce bFGF could be an impor-tant event in the stepwise progression of
HCC. Greater mRNA expression of vas-cular endothelial growth factor (VEGF)
was found in 60% of HCCs and was sig-nificantly correlated with the intensity of
tumour staining in angio-grams. This
suggests that VEGF contributes signifi-cantly to angiogenesis during hepatocar-cinogenesis {1239, 1869}.
DNA methylation
DNA methyltransferase  (DNMT1) mRNA
expression was significantly higher in
chronic hepatitis and cirrhotic nodules
than in normal livers, and was even high-er in HCCs {1863}. Indeed, DNA hyper-methylation at D16S32, TAT, and D16S7
loci on chromosome 16 is frequently
present even in chronic hepatitis and cir-rhotic nodules {885}. The incidence and
degree of aberrant DNA methylation
increased in HCCs compared with
chronic hepatitis and cirrhotic nodules
{885}. Aberrant DNA methylation may
participate even in the early develop-mental stages of HCCs by predisposing
some loci to allelic loss or silencing spe-cific genes {885}.
DNA methylation around the promoter
region of the E-cadherin tumour suppres-sor gene, which is located on 16q22.1,
was detected in 46% of chronic hepatitis
and cirrhotic nodules and in 67% of
HCCs {884}. DNA hypermethylation
around the promoter region correlated
significantly with reduced E-cadherin
expression in HCCs {884}. The HIC-1
(hypermethylated-in-cancer) tumour sup-pressor gene was identified at the D17S5
locus. DNA hypermethylation at the
D17S5 locus was detected in 44% of
chronic hepatitis and cirrhotic nodules
and in 90% of HCCs {883}. LOH at this
locus, which was preceded by DNA
hypermethylation, was detected in 54%
of HCCs {883}. The HIC-1 mRNA expres-sion level of chronic hepatitis and cirrhot-ic nodules was significantly lower than
that of normal livers, and that of HCCs
was even lower {883}. Thus, silencing of
tumour suppressor genes by aberrant
DNA methylation is a significant event
during hepatocarcinogenesis.
Prognosis and predictive factors
The prognosis of patients with HCC is
generally very poor, particularly in cases
with AFP levels greater than 100 ng/ml at
the time of diagnosis, partial or complete
portal vein thrombosis, and presence of
a TP53 mutation {45, 1861}. Sponta-neous regression has been reported
rarely. Most studies report a five-year sur-vival rate of less than 5% in symptomatic
HCC patients. HCCs are largely resistant
to radio- and chemotherapy. Long-term
survival is likely only in patients with
small, asymptomatic HCC that can be
treated by surgical resection, including
liver transplantation, or non-surgical
methods, including percutaneous etha-nol or acetic acid injection and percuta-neous radiofrequency thermal ablation.
Fig. 8.27  Malignant progression in a HCC (T1) with new tumour clones (T2, T3). Only T3 shows a mutation in
TP53. Macroscopy shows typical ‘nodule-in-nodule’ pattern. Neo-angiogenesis (arrow) is restricted to one
of the nodules.
TP53 mutations
PCR-SSCP
analysis
Angiogenesis
173Intrahepatic cholangiocarcinoma
Definition
An intrahepatic malignant tumour com-posed of cells resembling those of bile
ducts. Intrahepatic (or peripheral) cholan-giocarcinoma (ICC) arises from any por-tion of the intrahepatic bile duct epitheli-um, i.e. from intrahepatic large bile ducts
(the segmental and area ducts and their
finer branches) or intrahepatic small bile
ducts. Cholangiocarcinoma arising from
the right and left hepatic ducts at or near
their junction is called hilar cholangiocar-cinoma and is considered an extrahepat-ic lesion.
Epidemiology
Incidence and geographical distribution
ICC is a relatively rare tumour in most
populations but second among primary
malignant liver tumours; about 15% of
liver cancers are estimated to be ICC
{61, 2162, 1467}. The frequency of ICC
among all liver cancers ranges from 5%
in males and 12% in females in Osaka,
Japan, to 90% in males and 94% in
females in Khon Kaen, Thailand {1467,
1471} (Fig. 8.29).
The highest incidence of ICC is found in
areas of Laos and North and Northeast
Thailand suffering from endemic infec-tion with the liver fluke, Opisthorchis
viverrini. In 1997, the age standardized
incidence of ICC in Khon Kaen
(Thailand) was 88 per 100,000 in males
and 37/105
in females {1467, 1471}.
About 90% of the histologically con-firmed cases of liver cancer in Khon
Kaen are ICC, and almost all the ICC
cases were found to be related to
chronic O. viverrini infection {2006,
2007}. In the Clonorchis sinensis endem-ic area in Korea, there is also a high
incidence of liver cancer with truncate
incidence rates (35-64 years group) of
75 per 100,000 in males and 16 per
100,000 in females {23}. About 20%
of liver cancers in Pusan, Korea, are
ICC {871}.
Time trends
In both endemic and non-endemic
areas, there have been no significant
changes in the incidence of ICC in recent
years {61}. It is less than 10 years since
O. viverrini drug therapy was initiated;
since it probably takes 30 years for ICC
to complicate opisthorchiasis, the trends
of ICC are probably not likely to change
in the next decade {2007, 2009}.
Age and sex distribution
Patients with ICC are elderly, with no
clear sex differences. ICC occurs at
rather older ages than hepatocellular
carcinoma (HCC) in most clinical series
{1419}.
Aetiology
Although many aetiological factors have
been characterized, the cause of ICC
remains speculative in many cases.
Parasites
Clonorchis sinensis parasitizes the bile
ducts of millions of individuals in the Far
East, particularly China and Korea
{1467}. Early reports from Hong Kong
have shown that 65% of patients with
ICC were infected by C. sinensis {747}.
However, the incidence of C. sinensis
infection in the general population was
also similarly high at that time {308}. ICC
from this cause appears to less frequent
in recent years.
By contrast, infection of O. viverrini is
continuing in Northeast Thailand, and
Y. Nakanuma A.S.-Y Leong
B. Sripa T. Ponchon
V. Vatanasapt K.G. Ishak
Intrahepatic cholangiocarcinoma
Fig. 8.28 Histology of the liver fluke, Opisthorchis
viverrini, in a hepatic bile duct.
010 2030 4085 95
Thailand, Khon Kaen
Japan, Osaka
Hong Kong
Japan, Hiroshima
Singapore, Chinese
Philippines, Manila
Thailand, Chiang Mai
Singapore, Malay
Italy, Varese
France, Bas-Rhin
Switzerland, Zurich
Spain (6 registries)
Finland
USA, SEER, Black
Denmark
Slovakia
Scotland
Israel, Jews
Canada
USA, SEER, White
New Zealand, non Maori
Australia (4 states)
= CCA
= HCC
= All
CCA
84.6
2.8
5.4
1.0
1.0
1.4
6.1
1.9
0.9
1.0
0.4
0.5
1.2
0.6
1.1
0.8
0.7
0.3
0.4
0.4
0.4
0.2
HCC
6.8
37.9
27.9
24.6
24.2
18.2
11.3
11.5
8.6
7.8
5.1
4.1
2.9
3.3
2.1
1.9
1.7
2.2
1.8
1.6
1.3
1.7
All
94.2
41.6
39.2
28.5
27.2
23.5
19.7
14.3
10.6
9.1
6.0
5.8
4.7
4.2
4.0
2.9
2.9
2.8
2.5
2.4
2.1
2.0
Fig. 8.29 Age-standardized incidence of liver cancer, per 100,000, in males, 1992 . Rates for cholangiocarci-noma and hepatocellular carcinoma are estimates. From: M. Parkin et al. {1468}
174 Tumours of the liver and intrahepatic bile ducts
the evidence for the role of opisthorchia-sis in the induction of ICC is compelling
{2009, 2008}. Carcinogenesis is proba-bly related to the length and severity of
infection, the host’s immune response,
and other variables such as ingestion of
dietary carcinogens, for example nitro-samines. In northeast Thailand, several
carcinogenic N-nitroso compounds and
their precursors exist at low levels in the
daily diet {1230}. In addition, endo-genous nitrosamine formation by liver
fluke infection has been reported {1673}.
Both exogeneous and in situ nitrosamine
formation may lead to DNA alkylation
and deamination {1346}. It seems that
the presence of parasites induces DNA
damage and mutations as a conse-quence of the formation of carcino-gens/free radicals and of cellular prolif-eration of the intrahepatic bile duct
epithelium.
Hepatolithiasis
Hepatolithiasis (recurrent pyogenic
cholangitis), which is not uncommon in
the Far East, is also associated with ICC
{1857, 1321}. It is frequently observed in
clonorchiasis {746} but not in opisthor-chiasis. Most of these cases are associ-ated with calcium bilirubinate stones; a
few cases with cholesterol stones have
also been reported. Patients with intra-hepatic stones and ICC have a signifi-cantly longer duration of symptoms and
a higher frequency of previous biliary
surgery.
Inflammatory bowel disease and primary
sclerosing cholangitis
Patients with primary sclerosing cholan-gitis (PSC) and ulcerative colitis (UC)
have a predisposition to develop col-orectal neoplasia and also bile duct
carcinoma, including ICC {672, 1993,
194, 2078}.
Epstein-Barr virus (EBV) infection
Rare examples of ICC have a lymphoep-itheliomatous, undifferentiated pattern.
Clonal EBV has been found in such
cases {757, 2025}.
Non-biliary cirrhosis
There are several reports of ICC arising in
non-biliary cirrhosis, particularly hepatitis
virus-related liver cirrhosis {2159, 1940}.
HCV is frequent in such cases and ICC is
usually of a smaller, mass-forming type.
Such ICC and combined hepatocellular-cholangiocarcinomas share apomucin
profiles {1669}, suggesting that these two
tumours have a similar or common histo-genesis, or that ICC associated with cir-rhosis might be the result of exclusive
proliferation of the cholangiocellular com-ponent of the combined type. Genotypes
of hepatitis B and C viruses have been
shown in cholangiocarcinoma cells
{2049, 1787}.
Deposition of Thorotrast
Thorotrast is a radioactive  α-particle
emitter that was widely used as a radio-opaque intra-arterial contrast medium
between 1930 and 1955. ICC has been
recorded in many patients with prior
exposure to Thorotrast. The data suggest
that the chronic alpha-irradiation may be
the causative factor, with latent periods
ranging from 25 to 48 years.
Biliary malformations and other lesions
ICC may arise rarely in solitary unilocular
or multiple liver cysts, congenital seg-mental or multiple dilatation of the bile
ducts (Caroli disease), congenital hepat-ic fibrosis, and von Meyenburg complex-es {736, 2165}.
Clinical features
The site of the tumour, its growth pattern
and the presence or absence of stricture
or obstruction of the biliary tree are
responsible for the variable clinical fea-tures of ICC.
Symptoms and signs
General malaise, mild abdominal pain
and weight loss are frequent clinical
symptoms. When the carcinoma infil-trates the hilar region, jaundice and
cholangitis become manifest. ICCs, par-ticularly those arising from the small bile
ducts, may go unnoticed until they
have attained a large size. The liver is
enlarged to a lesser extent, ascites
is less common, and signs of portal
hypertension are absent or minimal.
Patients with unrelieved obstruction of
the intrahepatic large bile ducts may die
from complications, e.g. liver failure or
sepsis.
Imaging
Advanced cases of ICC show mixed
growth and spreading patterns with
intrahepatic metastases. Computerized
tomography (CT) images of ICC usually
show a lobulated or fused hypodense
space-occupying lesion with peripheral
enhancement, probably due to central
hypocellular dense fibrosis. Secondary
dilated ducts around the tumour are
detectable by CT and ultrasonography. A
focal area of carcinoma involving the bile
duct wall is identifiable by spiral CT.
Endoscopic retrograde, transhepatic or
magnetic resonance cholangiography is
a useful adjunct for the identification of
the level of biliary obstruction and sec-ondary bile duct dilatation.
ICCs at relatively early and surgically
resectable stages are classifiable into
three representative types of growth pat-terns {1080}, and these patterns, which
are evaluable by imaging studies, can be
useful for the preoperative staging of
Fig. 8.30 Ultrasonography of an intrahepatic
cholangiocarcinoma. A hyperechoic mass is pres-ent in a dilated bile duct.
Fig. 8.31  Cholangiocarcinoma, CT images. A The right lobe contains a mass and shows peripheral bile duct
dilation. B Arrows indicate a peribiliary spreading type.
AB
tumour extent and for designing the sur-gical procedure. The mass forming type
is an expansile nodule and is the most
common. The tumour borders between
the cancerous and noncancerous por-tions are relatively clear. The contrast
enhanced CT scan shows a low-density tumour with peripheral ring-like
increased density. The periductal-infiltrat-ing type, which is usually associated with
biliary stricture, is relatively common. The
tumour exhibits diffuse infiltration along
the portal pedicle. This type resembles
hilar or extrahepatic bile duct carcinoma.
The contrast enhanced CT demonstrates
a small cancerous enlargement of the
portal pedicle, or a mass central to the
dilated peripheral ducts. The anatomical
location of the involved ducts can be
evaluated by caliber changes or the
rigidity of the bile duct on high-quality
cholangiographic images. The intraduc-tal growth type (intraductal papillary
cholangiocarcinoma) is less common
{351}. These tumours are confined within
the dilated part of an intrahepatic large
bile duct, with no or mild extension
beyond the bile duct walls. Some
tumours of this type of ICC might have
arisen from biliary papillomatosis after
malignant transformation. Marked local-ized dilatation of the affected duct is
detectable by ultrasound or CT. Cholan-giography shows filling defects in the bil-iary tract, due to polypoid tumours and
mucin.
Macroscopy
ICC can arise from any portion of the
intrahepatic bile duct epithelium {61,
1418}. Lesions are  gray to gray-white,
firm and solid, although some tumours
show intraductal growth, sometimes with
polyp formation. Typical tumours consist
of variably sized nodules, usually coales-cent. Portal tract infiltration is also seen.
Central necrosis or scarring are common,
and mucin may be visible on the cut sur-faces. ICC cases involving the hepatic
hilum are hardly distinguishable from hilar
cholangiocarcinoma, and such cases
show cholestasis, biliary fibrosis, and
cholangitis with abscess formation. ICC
is not often noted in a non-cirrhotic liver.
ICC in endemic areas of liver fluke infec-tion is similar to that described in non-endemic regions; liver flukes are rarely
seen nowadays due to mass treatment.
In hepatolithiasis-associated ICC, the
tumour tends to proliferate and spread
along the stone-containing ducts. The
liver lobe or segments containing stones
involved by ICC are atrophic in some
cases.
Tumour spread
ICC shows direct spread into the sur-rounding hepatic parenchyma, portal
pedicle and bile duct. Intrahepatic
metastases develop in nearly all cases at
a relatively advanced stage.
Vascular invasion is a frequent histologi-cal finding relatively early, suggesting the
development of early metastasis. The
incidence of metastases in regional
lymph nodes is higher than in HCC.
Blood-borne spread occurs later, to the
lungs in particular; other sites include
bone, adrenals, kidneys, spleen, and
pancreas.
175Intrahepatic cholangiocarcinoma
Fig. 8.32  Macroscopic features of intrahepatic cholangiocarcinoma.  A Cut surface shows massive tumour and multiple intrahepatic metastatic nodules.
Surrounding liver is non-cirrhotic. B White, scar-like mass in a normal liver (mass forming types) together with dilated peripheral bile ducts. C Intraductal growth
type of intrahepatic cholangiocarcinoma.
Fig. 8.33  Intrahepatic cholangiocarcinoma. A Well differentiated tubular adenocarcinoma. B Moderately differentiated tubular adenocarcinoma.
AB C
AB
176 Tumours of the liver and intrahepatic bile ducts
On rare occasions, the tumour shows
extensive intraluminal spread of bile
ducts throughout the liver. The tumour
cells can also infiltrate into the peribiliary
glands of the intrahepatic large bile
ducts and their conduits. It may be diffi-cult to distinguish this lesion from reac-tive proliferated peribiliary glands histo-logically.
Histopathology
Most ICCs are adenocarcinomas show-ing tubular and/or papillary structures
with a variable fibrous stroma {326}.
There is no dominant histological type of
ICC in cases associated with liver flukes
or hepatolithiasis when compared to
those in non-endemic areas.
Adenocarcinoma
This common type of ICC growing in the
hepatic parenchyma and portal pedicle
reveals a significant heterogeneity of his-tological features and degree of differen-tiation. At an early stage, a tubular pat-tern with a relatively uniform histological
picture is frequent. Cord-like or micro-papillary patterns are also seen. The
cells are small or large, cuboidal or
columnar, and can be pleomorphic. The
nucleus is small and the nucleolus is
usually less prominent than that of HCC.
The majority of cells have a pale,
eosinophilic or vacuolated cytoplasm;
sometimes, the cells have a clear and
abundant cytoplasm or resemble goblet
cells.
ICC arising from the large intrahepatic
bile ducts shows intraductal micropapil-lary carcinoma and in situ like spread
along the biliary lumen. Once there is
invasion through the periductal tissue,
the lesion may be well, moderately, or
poorly differentiated adenocarcinoma,
with considerable desmoplasia and
stenosis or obliteration of the bile duct
lumen.
Infrequently, a papillary tumour growing
in the duct lumen is supported by fine
fibrovascular cores. Cholangio-carcino-ma arising from the intrahepatic peribil-iary glands {1914} mainly involves these
glands, sparing the lining epithelial cells
at an early stage.
An abundant fibrous stroma is an impor-tant characteristic of ICC. Activated
perisinusoidal cells (myofibroblasts) are
incorporated into the tumour, producing
extracellular matrix proteins that lead to
fibrosis {1913}. Usually, the central parts
of the tumour are more sclerotic and
hypocellular, while the peripheral parts
show more actively proliferating carcino-ma cells. On rare occasions, the tumour
cells are lost in a massive hyaline stroma,
which may be focally calcified.
The secretion of mucus in one form or
another can be demonstrated in the
majority of tumours by mucicarmine, dia-stase-PAS and Alcian blue staining.
Mucus core (MUC) proteins 1, 2, and 3
are detectable in the carcinoma cells
{1264, 1670}. ICC cells can immunoex-press cytokeratins 7 and 19, CEA, epithe-lial membrane antigen, and blood group
antigens. Bile may be present occasion-ally in ICC as a result of destruction of the
bile ducts or entrapment of non-neoplas-Fig. 8.34 A Intrahepatic cholangiocarcinoma showing papillary growth pattern involving the peribiliary glands . The bile duct lumen (top and center) is free of car-cinoma. B Papillary cholangiocarcinoma invading the bile duct wall.
Fig. 8.35  High-grade intraepithelial neoplasia of a peribiliary gland in a patient with hepatolithiasis.
A B
177Intrahepatic cholangiocarcinoma
tic hepatocytes or bile ductules contain-ing bile. It is always seen at the periphery
of the tumour. Bile production by tumour
cells is never found.
Carcinoma cell nests with small tubular
or cord-like patterns extend by com-pressing the hepatocytes or infiltrating
along the sinusoids. Occasionally, carci-noma cells abut directly on to hepato-cytes. As a result, the portal tracts are
incorporated within the tumour and
appear as tracts of elastic fibre-rich con-nective tissue. Fibrous encapsulation is
not seen.
ICC frequently infiltrates portal tracts, and
invades portal vessels (lymphatics, portal
venules); there is also perineural inva-sion, particularly in the large portal tracts.
Infiltrating, well-differentiated tubular car-cinoma must be differentiated from the
non-neoplastic pre-existing small bile
ducts. The carcinoma cells infiltrate
around nerve fibres and have variably-sized cancerous lumens.
Adenosquamous and squamous carcino-ma. The former is an adenocarcinoma
containing significant amounts of unequi-vocal squamous carcinomatous ele-ments, i.e. keratin and/or intercellular
bridges. The latter is entirely composed of
squamous cell carcinoma. They are occa-sionally seen at advanced stages of ICC.
Cholangiolocellular carcinoma. The car-cinoma cells are arranged as small, regu-lar, narrow tubular structures resembling
ductules or canals of Hering {1828}. The
cells are larger than the usual ICC.
Mucinous carcinoma.  A predominant
component of extracellular mucus
(mucus lakes), usually visible to the
naked eye, is present in the stroma.
Carcinoma cells distended with mucus
are seen floating in the mucus lakes. The
histology is similar to that seen in other
organs. These tumours show rapid pro-gression clinically {1671}.
Signet-ring cell carcinoma.  A malignant
tumour in which there is a predominance
of discrete cells distended with mucus.
ICC composed only of signet ring cells is
extremely rare.
Sarcomatous ICC. A cholangiocarcino-ma with spindle cell areas resembling
spindle cell sarcoma or fibrosarcoma or
with features of malignant fibrous histio-cytoma. This variant may have a more
aggressive behaviour. Carcinomatous
foci, including squamous cell carcinoma,
are scattered focally.
Lymphoepithelioma-like carcinoma.  Two
cases of undifferentiated lymphoepithe-liomatous lesions with adenocarcinoma
have been reported {757, 2025}. In these
cases, EBV-coded nuclear RNAs were
demonstrable.
Clear cell variant.  This lesion is charac-terized by distinct overgrowth of clear
cells in an acinar or tubular pattern. The
tumour cells are PAS reactive and dia-stase resistant, indicating the presence
of mucin.
Mucoepidermoid carcinoma. This variant
resembles the tumour arising in salivary
glands.
Differential diagnosis
Hepatocellular carcinoma.  Some ICCs
grow in a cord-like pattern reminiscent of
the trabeculae of HCC. The cords are
always separated by a connective tissue
stroma rather than by sinusoids; canali-culi and bile are also absent. Almost all
Fig. 8.36  Intrahepatic cholangiocarcinoma.  A Clear cell type.  B Mucinous type.  C Pleomorphic type.  D
Spindle cell type.
Fig. 8.37 Intrahepatic cholangiocarcinoma. In situ hybridisation for human telomerase mRNA shows signal
in carcinoma cells (left). Non-neoplastic bile duct is negative (right).
AB
CD
178 Tumours of the liver and intrahepatic bile ducts
ICCs are diffusely positive for cytokeratin
7 and 19, whereas only a few cases of
HCC are positive. The hepatocyte anti-gen (Dako) is expressed by HCC but not
by ICC.
Metastatic carcinoma.  ICC cannot be
distinguished histologically from meta-static adenocarcinoma of biliary tract or
pancreatic origin. Occasionally, dysplas-tic changes in neighbouring bile ducts
suggest intrahepatic origin. In addition,
diffuse expression of cytokeratin 20
favours metastatic adenocarcinoma, par-ticularly from colon {1141}. While cyto-keratin 7 is common in ICC, it is not so
common in metastatic carcinoma.
Sclerosing cholangitis. Periductal
spread of ICC may be difficult to distin-guish from sclerosing cholangitis, partic-ularly when only biopsy material is
available. The most important criteria for
the diagnosis of malignancy are severe
cytological atypia, random and diffuse
infiltration of the duct wall by the
neoplastic cells, and perineural invasion.
Grading
ICCs can be graded into well, moderate-ly, and poorly differentiated adenocarci-noma according to their morphology. In
the case of the common type of adeno-carcinoma, well-differentiated lesions
form relatively uniform tubular or papil-lary structures, moderately differentiated
tumours show moderately distorted tubu-lar patterns with cribriform formations
and/or a cord-like pattern, while the poor-ly differentiated show severely distorted
tubular structures with marked cellular
pleomorphism.
Precursor and benign lesions
Biliary intraepithelial neoplasia (dysplasia)
This is characterized by abnormal
epithelial cells with multilayering of nuclei
and micropapillary projections into the
duct lumen {2078, 1322}. The abnormal
cells have an increased nuclear/cyto-plasmic ratio, a partial loss of nuclear
polarity, and nuclear hyperchromasia.
They are divisible into low-grade and
high-grade lesions. Some peribiliary
glands may also be dysplastic.
Cell kinetic studies have disclosed prolif-erative activity of intraepithelial neoplasia
between that of hyperplasia and ICC,
and telomerase activity is demonstrable
in both intraepithelial and invasive carci-noma {1915, 1440}. Carcinoembryonic
antigen (CEA) is focally detectable in bil-iary intraepithelial neoplasia and more so
in carcinoma {1322}. These findings sup-port the concept of a hyperplasia-dys-plasia-carcinoma sequence in the biliary
tree {1989}.
In liver fluke infestations, the bile ducts
first show desquamation of the epithelial
lining with subsequent hyperplasia,
periductal fibrosis, inflammation and
goblet cell metaplasia {2008, 913}. The
neoplastic transformation from hyperpla-sia in bile ducts to ICC through dysplas-tic changes is demonstrable in opisthor-chiasis. In hepatolithiasis, the findings
are those of cholangitis, with proliferation
of the biliary epithelial lining and peri-biliary glandular cells, and multiple foci
of biliary intraepithelial neoplasia {1323}.
Hyperplasia and intraepithelial neoplasia
of the duct epithelium in livers with
Thorotrast-deposition and congenital bil-iary anomalies may be also related to the
development of ICC {1626, 2165}.
It has been reported in patients with PSC
that biliary intraepithelial neoplasia could
evolve from papillary hyperplasia {2078,
1107}. However, recent experience at
orthotopic liver transplantation of PSC
has detected hardly any in situ or inva-sive neoplastic foci.
Biliary papillomatosis
Dilated intrahepatic and extrahepatic bile
ducts are filled with papillary or villous
excrescences, which microscopically are
papillary or villous adenomas with deli-cate fibrovascular stalks covered with a
columnar or glandular epithelium {806,
351}. They are soft and white, red or tan.
In some cases, there are variable degrees
of cellular atypia and multilayering of
nuclei. Occasionally, foci of in situ or inva-sive carcinoma are encountered {1340}.
Von Meyenburg complex (biliary micro-hamartoma)
The lesions are small, up to several mm
in diameter. They are usually multiple and
Fig. 8.38  Intrahepatic cholangiocarcinoma, in a patient with heterozygous alpha-1 antitrypsin deficiency of the Piz type. A Tubular adenocarcinoma. B Cytokeratin 7
immunohistochemistry demonstrates tumour cells spreading along bile ducts and infiltrating liver tissue.
Fig. 8.39 Immunoexpression of atz11 demonstrates
alpha-1 antitrypsin deficiency of piz type.
A B
179Intrahepatic cholangiocarcinoma
are adjacent to a portal area. Within a
fibrous or hyalinized stroma, they present
as irregular or round ductal structures
that appear somewhat dilated and have
a flattened or cuboidal epithelium. The
lumina contain proteinaceous or bile-stained secretion. These lesions carry lit-tle or no malignant potential {736, 673}.
Bile duct adenoma (BDA)
BDA is usually single and subcapsular,
and is white and well circumscribed but
non-encapsulated. BDA is usually less
than 1 cm in size, and is composed of a
proliferation of small, normal appearing
ducts with cuboidal cells that have regu-lar nuclei and lack dysplasia {44}. These
ducts have no or little lumen and can
elaborate mucin. Their fibrous stroma
shows varying degrees of chronic inflam-mation and collagenization. Enclosed in
the lesion are normally spaced portal
tracts. They are considered to be a focal
reaction to injury.
BDA and peribiliary glands share com-mon antigens, suggesting a common line
of differentiation {136}. Occasionally, BDA
contains periductular endocrine cell clus-ters {1384}.
In addition, there are several atypical
BDA with a neoplastic nature. Biliary
adenofibroma is characterized by a com-plex tubulocystic biliary epithelium with-out mucin production, together with
abundant fibroblastic stromal compo-nents {1972}. Its expansive growth, and
foci of epithelial tufting, cellular atypia
and mitoses favor a neoplastic process.
Intrahepatic peribiliary cysts
In chronic advanced liver disease and
biliary anomalies, and also in normal liv-ers, multiple cysts may be seen around
the intrahepatic large bile ducts {1319,
1320}. They are visible by ultrasound or
CT. These cysts are derived from peribil-iary glands and should be differentiated
from ICC clinically and histologically.
Diffuse and multifocal hyperplasia of peri-biliary glands
Diffuse, severe, macroscopically recog-nizable dilatation and hyperplasia of the
peribiliary glands of intrahepatic and
extrahepatic bile ducts is a rare condition
{1319, 437}. Some ducts may be cysti-cally dilated. Lack of familiarity with this
lesion could lead to an erroneous diag-nosis of a well-differentiated cholangio-carcinoma. It occurs in apparently nor-mal livers and also in acquired liver dis-eases.
Molecular genetics and genetic sus-ceptibility
Mutations of the RAS and TP53 genes are
the most common genetic abnormalities
identified in ICC. The incidence of KRAS
mutations ranges from 100% and 60%
among British {1054} and Japanese
patients respectively {1878, 1402}, to 4%
among Thai patients {1510}. Taiwanese
and Korean patients show an intermedi-ate frequency {1037, 887}. The most fre-quently mutated position in the  KRAS
Fig. 8.40 Bile duct adenoma. A Frozen section. B Cytokeratin immunostain showing characteristic branching pattern of bile ducts.
Fig. 8.41 Bile duct adenoma. Small, normal appearing proliferating bile ducts associated with a small con-nective tissue component and lymphocytic infiltration.
AB
180 Tumours of the liver and intrahepatic bile ducts
gene is codon 12 involving GGT (glycine)
to GAT (aspartic acid). Less frequent
mutations have been identified in codon
13, involving GGT (glycine) to GAT
(aspartic acid) and codon 61, involving
CAA (glutamine) to CAC (histidine) {1402,
1969, 1511}.
TP53 mutations occur between exons 5
to 8, the most common change being G
to A transitions {887, 1511, 907, 1848}.
The mutations are random with no spe-cific hot spot, being mostly missense
mutations and less frequently nonsense
mutations {887}. p53 protein is immuno-histochemically detectable in carcinoma
cells in more that 70% of ICC cases.
KRAS and TP53 mutations correlate with
the gross morphology of ICC {1969,
1401}; a higher prevalence of  KRAS
gene alterations is found in the periduc-tal and spicular forming infiltrating sub-type compared to the slower growing,
non-invasive mass-forming type.  TP53
mutations are prominent in the mass-forming type of ICC.
The variable incidence of  KRAS muta-tions in different populations of ICC may
reflect different aetiologies.  O. viverrini
infection and increased consumption of
nitrates and nitrites are contributing fac-tors in Thailand where the incidence of
KRAS abnormalities is low {2025, 1446}.
Overexpression of c-erbB-2 occurs in one
fourth to about two thirds of carcinoma of
the biliary tract, and may be used as a
phenotypic marker for neoplastic transfor-mation {1912}. Membranous expression
of E-cadherin, alpha-catenin, and beta-catenin is reduced in a majority of ICC
and this down-regulation correlates with
ICC at high-grade {91}.
Overexpession of MET, the receptor for
hepatocytes growth factor, occurs in ICC
and correlates with tumour differentia-tion, being poorly expressed in poorly
differentiated tumours {1912}. It also cor-relates with the markedly increased pro-liferation indices seen in precancerous
glands and cholangiocarcinoma. Biliary
epithelial cells are continuously exposed
to genotoxic insults such as chronic
inflammation and hydrophobic bile
acids, predisposing to oncogenic muta-tions. Progression to malignancy may be
due, in part, to failure in activating apop-tosis and deleting cells with genetic
damages {263}. The anti-apoptotic pro-tein bcl-2, is overexpressed in ICC {281}
and telomerase activity is detectable in
carcinoma cells of almost all ICC cases.
Prognosis and predictive factors
Early detection of ICC is difficult, and the
overall prognosis after resection is poor
compared with that of HCC. Lymph node
spread, vascular invasion, positive mar-gins and bilobar distribution are associ-ated with a high recurrence rate and a
poor prognosis. One study found the
5-year survival rate was 39% in patients
with mass-forming tumours and 69% for
intraductal tumours while no patients with
mass-forming plus periductal-infiltrating
tumours survived > 5 years {2161}.
Histologically, squamous cell or sarco-matous elements and mucinous variants
confer a poor prognosis {1312, 1313}.
Patients with well differentiated ICC seem
to survive longer than those with moder-ately or poorly differentiated ones. A few
cases of well differentiated ICC with
bland features resembling bile duct ade-noma show a good prognosis {522}.
MUC 2 protein expression is relatively
frequent in well differentiated ICC, sug-gesting a somewhat more favourable
prognosis {1915}.
Lymph node metastasis is a significant
prognostic factor {2160}. The 5-year sur-vival rate in patients with lymph node
metastases is significantly lower than
that in patients without lymph node
metastasis (51%).
In liver fluke-associated ICC, survival
after right hepatectomy is better than
after left hepatectomy, and is not associ-ated with tumour size {1990}. In addition,
multiple tumour masses have a poor
prognosis. Concomitant hepatolithiasis
prevents precise diagnosis preoperative-ly, and precipitates biliary sepsis. Long-term post-surgical survival of patients
with stone-containing ICC compared to
ICC alone is controversial {291, 1849}.
ICC found in non-biliary cirrhosis is usual-ly detectable as a small nodule during fol-low-up of hepatitis virus-related cirrhosis,
and is treatable with hepatectomy {2159}.
181Combined hepatocellular and cholangiocarcinoma
Definition
A rare tumour containing unequivocal
elements of both hepatocellular and
cholangiocarcinoma that are intimately
admixed.
This tumour should be distinguished
from separate hepatocellular carcinoma
and cholangiocarcinoma arising in the
same liver {605}. Such tumours may be
widely separated or close to each other
(‘collision tumour’).
Epidemiology
This tumour type comprises less than 1%
of all liver carcinomas. There are similar
geographical distribution differences as
for hepatocellular carcinoma and a simi-lar age and sex distribution.
Tumour spread and staging
Some studies have found a higher fre-quency of lymph node metastasis com-pared with HCC.
Macroscopy
Gross inspection does not show signifi-cantly different morphology compared to
hepatocellular carcinoma. In tumours
with a major cholangiocarcinomatous
component with fibrous stroma, the cut
surface is firm.
Histopathology
Combined hepatocellular and cholangio-carcinoma is the term preferred for a
tumour containing both hepatocellular
and distinct or separate cholangiocarci-noma. The presence of both bile and
mucus should be sought in the com-bined tumour. This category should not
be used for tumours in which either form
of growth is insufficiently differentiated
for positive identification.
Hepatocytes preferentially express cytok-eratins 8 and 18 and, like duct epithelial
cells, cytokeratins 7 and 19. However, the
different patterns of expression are not as
clear-cut in these tumours. For practical
purposes, demonstration of bile canaliculi
by polyclonal CEA (mixed biliary glyco-proteins) combined with Hep Par immu-noexpression is sufficient for the diagno-sis of a hepatocellular carcinomatous
component, and that of neutral epithelial
mucin by the PAS-diastase reaction for
the diagnosis of a cholangiocarcinoma-tous component {1046, 1456, 667}.
Prognostic factors
Some authors have reported patients
with combined hepatocellular and
cholangiocarcinoma having a worse
prognosis as compared with patients
with HCC.
C. Wittekind
H.P. Fischer
T. Ponchon
Combined hepatocellular
and cholangiocarcinoma
Fig. 8.42  Combined hepatocellular carcinoma and
cholangiocarcinoma arising in non-cirrhotic liver
tissue in a patient with heterozygous Piz type alpha-1 antitrypsin deficiency.  A Pale, homogeneous cut
surface. B Microscopic, showing glandular areas.
Fig. 8.43 Combined hepatocellular and cholangio-cellular carcinoma.  A Microtrabecular HCC and
cholangiocarcinoma with desmoplastic response.
B Border zone between HCC and cholangiocarci-noma.
A
B
A
B
182 Tumours of the liver and intrahepatic bile ducts
Definition
A cystic tumour either benign (cystade-noma) or malignant (cystadenocarcino-ma), lined by epithelium with papillary
infoldings that may be mucus-secreting
or, less frequently, serous. Lesions arise
from ducts proximal to the hilum of the
liver. They differ from tumours that arise
in cystic congenital malformation and in
parasitic infections and hepatolithiasis.
Epidemiology
Bile duct cystadenoma and cystadeno-carcinoma are rare {809}. Cystadenoma
is seen almost exclusively in females,
with cystadenocarcinoma appearing
equally in males and females. The aver-age age of patients is 50-60 years.
Clinical features
Patients often present with abdominal
pain and mass. A few patients have jaun-dice. Elevated serum levels of tumour
marker CA 19-9 may occur. Imaging
techniques show multilocular cystic
tumour(s), occasionally with tiny papillary
folds in the cystic wall.
Macroscopy
The cysts are usually multilocular and
typically range from 5 to 15 cm diameter
{809}. In cystadenocarcinoma, a large
papillary mass may occur as well as
solid areas of grey-white tumour in a
thickened wall.
Tumour spread and staging
Cystadenocarcinomas show intrahepatic
spread and metastasis to regional lymph
nodes in the hepatoduodenal ligament.
Distant metastases occur most frequent in
the lungs, the pleura and the peritoneum.
Staging is performed according to the
TNM Classification of liver tumours {66}.
Histopathology
Cystadenomas are usually multilocular
and are well defined by a fibrous cap-sule, which may contain smooth muscle
fibres. The contents of the locules are
either thin, opalescent or glairy fluid, or
mucinous semisolid material.
Two histological variants are recognized.
The mucinous type is more common and
is lined by columnar, cuboidal, or flat-tened mucus-secreting epithelial cells
resting on a basement membrane; poly-poid or papillary projections may be pres-ent. About 5% of the tumours reveal neu-roendocrine differentiation, as identified
by expression of chromogranin and
synaptophysin. Subjacent to the base-ment membrane is a cellular, compacted
mesenchymal stroma, which in turn is
surrounded by looser fibrous tissue. This
mesenchymal component is seen only in
females and has been likened to ovarian
stroma. The stromal cells express
vimentin, and there are many cells that
express smooth muscle actin. A xan-C. Wittekind
H.P. Fischer
T. Ponchon
Bile duct cystadenoma
and cystadenocarcinoma
Fig. 8.46  Bile duct cystadenoma. A Large peribiliary cysts in the connective tissue of the hilus; the background liver shows advanced cirrhosis. B Variably sized cysts
are intermingled with peribiliary glands.
BA
Fig. 8.44 Biliary cystadenoma. The lining epithelium
is cuboidal and lies on ovarian-like stroma, beneath
which is a band of dense tissue.
Fig. 8.45 Severe dysplasia in the epithelium of an
intrahepatic large bile duct in a case of hepatolithi-asis.
183Bile duct cystadenoma and cystadenocarcinoma
thogranulomatous reaction, with foam
cells, cholesterol clefts and pigmented
lipofuscin-containing macrophages, may
be present in the cyst wall. The  serous
type consists of multiple, small locules
lined by a single layer of cuboidal cells
with clear cytoplasm containing glyco-gen. The cells rest on a basement mem-brane but are not surrounded by the
mesenchymal stroma typical of the muci-nous variety. Squamous metaplasia may
also occur.
Cystadenocarcinomas are usually multi-locular and contain mucoid fluid. Malig-nant change may not involve all of the
epithelium lining the cyst; it is usually mul-tifocal. The tumours are so well defined
that complete removal can usually be
achieved with good prognosis. Differenti-ation from intrahepatic bile duct cystade-noma depends on the demonstration of
cytological (particularly nuclear) atypia,
mitosis, and invasion of the underlying
stroma.
Some bile duct cystadenocarcinomas
may be misdiagnosed as bile duct cys-tadenomas because insufficient sam-pling results in tumour morphology
showing no cytological features of malig-nancy or invasion of the underlying stro-ma {351, 809, 1268, 2096}.
Prognostic factors
The prognosis of patients with biliary
duct cystadenocarcinomas is good if a
curative resection is possible. The
course of patients with unresectable
tumours seems to be better than of
patients with cholangiocarcinoma {71}.
Fig. 8.47 Bile duct cystadenocarcinoma. Papillary
folding with serous and mucinous neoplastic
epithelium.
184 Tumours of the liver and intrahepatic bile ducts
Definition
A malignant embryonal tumour with
divergent patterns of differentiation,
ranging from cells resembling fetal epi-thelial hepatocytes, to embryonal cells,
and differentiated tissues including
osteoid-like material, fibrous connective
tissue and striated muscle fibers.
Epidemiology
Hepatoblastoma is the most frequent
liver tumour in children. Four percent of
hepatoblastomas are present at birth,
68% in the first two years of life and 90%
by five years of age. Only 3% are seen in
patients over 15 years of age. A recent
increase in the incidence of tumours in
infants with birth weights below 1500
grams has been reported {776, 777,
1899}. There is a male predominance of
1.5:1 to 2:1, but no racial predilection.
Localization
Hepatoblastomas occur as a single
mass in 80% of cases, involving the right
lobe in 57%, the left lobe in 15% and
both lobes in 27% of patients {1838}.
Multiple masses, seen in the other 20%
of cases, may occur in either or both
lobes.
Clinical features
Hepatoblastomas are often noted by a
parent or physician as an enlarging
abdomen in the infant that may be
accompanied by weight loss or anorexia.
Less frequently nausea, vomiting, and
abdominal pain are present. Jaundice is
seen in 5% of cases. Rarely, tumour cells
may produce human chorionic gona-dotrophin, leading to precocious puberty
with pubic hair, genital enlargement and
deepening voice, noted most prominent-ly in young boys.
Hepatoblastoma is accompanied by ane-mia in 70% of cases and by thrombocy-tosis in 50%, with platelet counts exceed-ing 800 x 109
/L in nearly 30% of cases
{1717}. Alpha fetoprotein (AFP) is elevat-ed in about 90% of patients at the time of
diagnosis. The levels of AFP parallel the
course of the disease, falling to normal
levels after complete removal of the
tumour and rising with recurrence of the
lesion. AFP levels may be normal or only
slightly elevated with small cell undiffer-entiated hepatoblastoma. Caution must
be taken in evaluating the levels of AFP in
younger infants since the ‘adult’ level of
AFP (< 25ng/mL) is not reached until
approximately six months of age.
Other laboratory abnormalities can
include elevated levels of serum choles-terol, bilirubin, alkaline phosphatase, and
aspartate aminotransferase {10}.
Imaging
Computed tomography (CT) shows sin-gle or multiple masses within the liver,
which in 50% of cases display calcifica-tion {1233}. Magnetic resonance imaging
(MRI) along with CT can help differentiate
hepatoblastoma from infantile haeman-gioendothelioma, mesenchymal hamar-toma, and hepatocellular carcinoma by
demonstrating cystic or vascular features
peculiar to each lesion {1999}. MRI may
also be used to characterize epithelial
and mesenchymal components of hepa-toblastoma {1533}.
Macroscopy
Hepatoblastomas vary in size from 5 to
22 cm in diameter and from 150 to 1,400
g in weight. Single and multiple lesions
may be well circumscribed, the edge of
the lesion being separated from the nor-mal liver by an irregular pseudocapsule.
Pure fetal hepatoblastomas have the tan-brown colour of normal liver, while mixed
hepatoblastomas display a variety of
colours from brown to green to white. The
lesions are often nodular and bulge from
the cut surface. Areas of necrosis and
haemorrhage are usually present and
may appear as soft or gelatinous, brown
to red tissue {1837}.
Tumour spread
At clinical manifestation, 40-60% of
hepatoblastomas are either very large or
involve both lobes to the extent that they
are considered unresectable {1839}.
Preoperative chemotherapy, however,
reduces the size of the lesion in nearly
85% of these patients to a size that ren-ders it resectable. Tumour spread
includes local extension into the hepatic
J.T. Stocker
D. Schmidt
Hepatoblastoma
Hepatoblastoma 43.5 27.6
Infantile haemangioendothelioma 36.1 16.5
Mesenchymal hamartoma 13.3 8.0
Hepatocellular carcinoma 1.4 18.9
Focal nodular hyperplasia 1.1 10.1
Undifferentiated “embryonal” sarcoma 1.1 7.2
Nodular regenerative hyperplasia 2.1 4.5
Hepatocellular adenoma 0.0 3.8
Angiosarcoma 1.4 2.4
Embryonal rhabdomyosarcoma 0.0 1.0
Birth to  Birth to
2 years (%) 20 years (%)
Type of Tumour (285 cases) (716 cases)
Fig. 8.48  Hepatoblastoma in a patient 3 years of
age. The T2 weighted MRI shows a liver mass that
histologically corresponds to fetal epithelial hepa-toblastoma.
Table 8.02
Age distribution of hepatic tumours in young patients. Data are from the Armed Forces Institute of Pathology
(AFIP), Washington, DC (U.S.A.)
185Hepatoblastoma
veins and inferior vena cava. The lung is
the most frequent site of metastases;
approximately 10-20% of patients have
pulmonary metastases when first diag-nosed. Hepatoblastomas also spread to
bone, brain, ovaries, and the eye {179,
1600, 619, 463}.
Histopathology
Hepatoblastomas display a distinct vari-ety of histological patterns that may be
present in varying proportions. Some
tumours are composed entirely of uni-form fetal epithelial cells or small undif-ferentiated cells, while others contain a
variety of tissue types including hepatic
fetal epithelial and embryonal cells,
fibrous connective tissue, osteoid-like
material, skeletal muscle fibers, nests of
squamous epithelial cells, and cells with
melanin pigment.
Pure fetal epithelial differentiation
Accounting for nearly one third of cases,
the fetal epithelial pattern is composed of
thin trabeculae of small cuboidal cells
resembling the hepatocytes of the devel-oping fetal liver. These cells contain a
small round nucleus with fine nuclear
chromatin and an indistinct nucleolus.
The cytoplasm varies from finely granular
to clear, reflecting variable amounts of
glycogen and lipid which can impart a
‘light and dark’ pattern to the lesion when
viewed at lower magnifications. Cana-liculi may be seen between hepatocytes
of the 2-3 cell layer trabeculae, but only
rarely is bile stasis present. In biopsies
taken before preoperative chemothera-py, foci of extramedullary haemato-poiesis (EMH) composed of clusters of
erythroid and myeloid precursors may be
present in the sinusoids {2023}.
Sinusoids are lined by endothelial and
Kupffer cells which show a more diffuse
staining with UEA-1 and anti-CD34 than
the focal staining of the sinusoidal
endothelial cells of normal liver {1630}.
The fetal phenotype has been signifi-cantly associated with both diploid DNA
nuclear content and low proliferative
activity assessed by flow cytometry and
PCNA labeling index {1640}.
Combined fetal and embryonal epithelial
Approximately 20% of cases display a
pattern combining fetal epithelial cells
and sheets or clusters of small, ovoid to
angulated cells with scant amounts of
dark granular cytoplasm surrounding a
nucleus with increased nuclear chro-matin. The cells display little cohesive-ness but may cluster into pseudorosette,
glandular or acinar structures. These
small, round, blue cells resemble the
blastemal cells seen in nephroblastomas,
neuroblastomas and other ’embryonal’
tumours in children. While often inter-mixed with the fetal epithelial cells, the
foci of embryonal cells, which are devoid
of glycogen and lipid, can be identified
by their absence of staining with PAS or
oil red-O stains. Mitotic activity is more
pronounced in the embryonal areas, and
associated with a low TGF-alpha expres-sion. EMH, in the absence of preopera-tive chemotherapy, may also be noted
{925}.
Macrotrabecular
In about 3% of cases of fetal or fetal and
embryonal epithelial hepatoblastomas,
areas containing broad trabeculae (6-12
or more cells in thickness) are present.
These macrotrabeculae are composed
of fetal and embryonal epithelial cells
and a third, larger cell type characterized
by more abundant cytoplasm and larger
nuclei. Although the trabeculae resemble
those seen in the pseudoglandular type
of hepatocellular carcinoma, the cells
display only mild hyperchromasia and
anisocytosis, and mitotic activity is low.
The term ‘macrotrabecular’ is applied to
only those cases in which macrotrabecu-lae are a prominent feature of the lesion.
If only an isolated focus is present, the
Stage I Complete resection
Stage II Microscopic residual
Negative nodal
involvement
No spilled tumour
Stage III Gross residual or
Nodal involvement or
Spilled tumour
Stage IV Metastatic disease
Table 8.03
Staging of Hepatoblastoma according to the
Children’s Cancer Study Group (CCSG) classifica-tion.
Absence of left adrenal gland
Acardia syndrome
Alcohol embryopathy
Beckwith-Wiedemann syndrome
Beckwith-Wiedemann syndrome with opso-clonus, myoclonus
Bilateral talipes
Budd-Chiari syndrome
Cleft palate, macroglossia, dysplasia of ear
lobes
Cystothioninuria
Down syndrome, malrotation of colon, Meckel
diverticulum, pectum excavatum, intrathoracic
kidney, single coronary artery
Duplicated ureters
Fetal hydrops
Gardner syndrome
Goldenhar syndrome – oculoauriculovertebral
dysplasia, absence of portal vein
Hemihypertrophy
Heterotopic lung tissue
Heterozygous α1-antitrypsin deficiency
HIV or HBV infection
Horseshoe kidney
Hypoglycemia
Inguinal hernia
Isosexual precocity
Maternal clomiphene citrate and Pergonal
Meckel diverticulum
Oral contraceptive, mother
Oral contraceptive, patient
Osteoporosis
Persistent ductus arteriosus
Polyposis coli families
Prader-Willi syndrome
Renal dysplasia
Right-sided diaphragmatic hernia
Schinzel-Geidion syndrome
Synchronous Wilms tumour
Trisomy 18
Type 1a glycogen storage disease
Umbilical hernia
Very low birth weight
Table 8.04
Clinical syndromes, congenital malformations and
other conditions that have been associated with
hepatoblastoma.
Fig. 8.49 Epithelial hepatoblastoma presenting as a
large, well demarcated lesion with central haemor-rhage.
186 Tumours of the liver and intrahepatic bile ducts
classification is based on the epithelial or
mixed epithelial/mesenchymal compo-nents present.
Small cell undifferentiated
Hepatoblastomas composed entirely of
noncohesive sheets of small cells resem-bling the small blue cells of neuroblas-toma, Ewing sarcoma, lymphoma, and
rhabdomyosarcoma are called small cell
undifferentiated hepatoblastomas and
amount to about 3% of the tumours. This
type is believed to represent the least dif-ferentiated form of hepatoblastoma
{602}.
While often difficult to identify as hepatic
in origin, the presence of small amounts
of glycogen, lipid and bile pigment,
along with cytoplasmic cytokeratin, helps
separate this lesion from metastatic small
cell tumours. The cells are arranged as
solid masses with areas of cellular
pyknosis and necrosis and high mitotic
activity. Sinusoids are present but
decreased in amount compared to the
fetal epithelial pattern, and there is pro-nounced intracellular expression of
extracellular matrix proteins and large
numbers of fibers immunoreactive for
collagen type III {1629}.
Mixed epithelial and mesenchymal
The largest number of hepatoblastomas
(44%) display a pattern combining fetal
and embryonal epithelial elements with
primitive mesenchyme and mesenchy-mally derived tissues. Of these mixed
tumours, 80% have only immature and
BA
Fig. 8.51  Pure fetal hepatoblastoma.  A Cuboidal cells form trabeculae.  B Immunoreactivity for alpha-fetoprotein is present in most tumour cells. A cluster of
hematopoietic cells is present at lower center.
BA
Fig. 8.53 Fetal and embryonal hepatoblastoma.
Embryonal epithelial cells occur singly and in gland-like structures.
Fig. 8.52 Fetal and embryonal epithelial hepatoblas-toma. Fetal epithelial cells with a high cytoplasmic
lipid concentration are separated by a band of
fibrous connective tissue from a vascular mass of
embryonal cells.
Fig. 8.50  Pure fetal epithelial hepatoblastoma. Variable concentrations of glycogen and lipid within tumour cells create dark and light areas.
187Hepatoblastoma
mature fibrous tissue, osteoid-like tissue
and cartilaginous tissue, in addition to
the epithelial cells. The other 20% con-tain additional elements.
The mesenchymal elements of the ‘sim-ple’ mixed tumour are interspersed with
the fetal and embryonal epithelial ele-ments. The primitive mesenchymal tissue
consists of a light myxomatous stroma
containing large numbers of spindle-shaped cells with elongate nuclei. The
cells may display a parallel orientation
with collagen fibers and cells resembling
young fibroblasts. More mature fibrous
septa with well differentiated fibroblasts
and collagen may also be seen.
Islands of osteoid-like tissue composed of
a smooth eosinophilic matrix containing
lacunae filled with one or more cells are
the hallmark of the mixed lesion. Rarely,
they are the only ‘mesenchymal’ compo-nent noted in a predominantly fetal
epithelial hepatoblastoma. In fact, the
‘osteoid’ material is positive for alpha
1-antitrypsin, alpha 1-antichymotrypsin,
alpha fetoprotein, carcinoembryonic anti-gen, chromogranin A, epithelial mem-brane antigen, vimentin and S-100 pro-tein, suggesting an origin from epithelial
cells {10, 2058, 1629}. The cells within the
lacunae, while ‘osteoblast-like’ with angu-lated borders, abundant eosino-philic
cytoplasm and one or more round or oval
nuclei, may in some areas blend with
adjacent areas of embryonal epithelial
cells, further supporting their epithelial
origin. Cartilaginous material may also be
present.
Mixed with teratoid features
In addition to the features noted in the
‘simple’ mixed epithelial/mesenchymal
hepatoblastoma, about 20% of lesions
will display additional features, including
striated muscle, bone, mucinous epitheli-um, stratified squamous epithelium, and
melanin pigment {1839}. These tissues
may occur separately or be admixed with
others. It is important to differentiate
these teratoid features from a true ter-atoma, which does not contain fetal and
embryonal epithelial hepatoblastoma
areas. There is, however, a single case
report of a discrete cystic teratoma con-tiguous to a hepatoblastoma {331}.
Staging
These is no official TNM classification for
hepatoblastoma but a TNM-type system
has been proposed {332}. The Children’s
Cancer Study Group (CCSG) classifica-tion is widely used. While 40-60% of
patients are considered inoperable at the
time they are first seen and 10-20% have
pulmonary metastases, preoperative
chemotherapy and transplantation for the
more extensive lesions have resulted in
resectability for nearly 90% of cases.
Precursor lesions and benign tumours
Precursor lesions of hepatoblastoma
have not been identified, but hepatoblas-toma must be differentiated from other
liver tumours and pseudotumours that
occur in the same age period. Infantile
haemangioendothelioma, the most com-monly occurring benign tumour of the
liver, is seen almost exclusively in the first
year of life and presents as an asympto-matic mass or, less frequently, as con-gestive heart failure due to rapid shunt-ing of blood through the liver {1708}. MRI
and arteriography are helpful in estab-lishing the diagnosis.
Mesenchymal hamartoma, another
benign lesion, occurs during the first 2-3
Fig. 8.54  Pure fetal epithelial hepatoblastoma. Clusters of small, dark haematopoietic cells are present.
Fig. 8.55  Fetal and embryonal hepatoblastoma. The embryonal cells may resemble other blastemal cells, e.g.
those encountered in nephroblastoma or neuroblastoma.
188 Tumours of the liver and intrahepatic bile ducts
years of life and presents as a rapidly
enlarging mass due to accumulation of
fluid within cysts formed in the mes-enchymal portion of the lesion {1841}. CT
and MRI are useful in defining the cystic
nature of the lesion. Focal nodular hyper-plasia and nodular regenerative hyper-plasia may be seen in the first few years
of life but are more common in older chil-dren {1839}. Hepatocellular adenoma is
rarely seen in the first 5-10 years of life,
but may be difficult to differentiate from a
pure fetal epithelial hepatoblastoma.
Genetic susceptibility
Congenital anomalies are noted in
approximately 5% of patients (Table 8.04)
and include renal malformations such as
horseshoe kidney, renal dysplasia and
duplicated ureters, gastrointestinal mal-formations such as Meckel diverticulum,
inguinal hernia and diaphragmatic her-nia, and other disparate malformations
such as absent adrenal gland and het-erotopic lung tissue. Other syndromes
with an increased incidence of hepato-blastoma include Beckwith-Wiedemann
syndrome, trisomy 18, trisomy 21,
Acardia syndrome, Goldenhar syndrome,
Prader Willi syndrome, and type 1a glyco-gen storage disease {1585}.
Hepatoblastoma and familial adenoma-tous polyposis (FAP) are associated due
to germline mutation of the adenomatous
polyposis coli (APC) gene. FAP kindreds
include patients with hepatoblastoma
who have an  APC gene mutation at the
5′ end of the gene {267, 578}. Alterations
in APC have also been noted in cases of
hepatoblastoma in non-familial adeno-matous polyposis patients {1390}.
Molecular genetics
Cytogenetic abnormalities include tri-somy for all or parts of chromosome 2,
trisomy for chromosome 20 and loss of
heterozygosity (LOH) for the telomeric
portion of 11p (11p15.5). The material
lost on 11p is always of maternal origin
{43}. LOH has also been observed on the
short and long arms of chromosome 1
with a random distribution of parental ori-gin for chromosome arm 1p and a pater-nal origin for chromosome arm 1q {970}.
TP53 overexpression has been
described in several cases, but  TP53
mutations in exons 5 to 9 are infrequent
{1406}. Increased copy numbers of c-met
and K-sam proto-oncogenes and cyclin
D1 genes have been described in a case
of hepatoblastoma in an adult patient
{977}.
The presence of oval cell antigen has
been demonstrated in hepatoblastomas,
which supports the stem cell origin of
these tumours {1631}.
Fig. 8.57  Mixed epithelial and mesenchymal hepatoblastoma. Areas showing
mesenchymal tissue and foci of osteoid-like material are present, together with
areas of epithelial hepatoblastoma.
Fig. 8.56  Macrotrabecular hepatoblastoma. On the left, the tumour consists of
macrotrabeculae. The one to two-cell thick trabeculae of fetal epithelial hepa-toblastoma pattern are seen on the right.
Fig. 8.58 Mixed epithelial and mesenchymal hepatoblastoma with teratoid features. A Squamous differentiation. B Skeletal muscle fibres.
BA
189Hepatoblastoma
Prognosis and predictive factors
Prognosis is directly affected by the abil-ity to resect the lesion entirely, i.e. to
attain Stage I or II following the initial sur-gery {332, 446, 648, 2024}. Chemo-therapy and transplantation have
allowed resectability in 90% of cases,
increasing the overall survival to 65-70%.
Survival in Stage I is nearly 100% and
Stage II survival approaches 80%.
AFP levels are useful in predicting out-come by observing their response to sur-gery and chemotherapy {1997}. AFP lev-els of 100 to 1,000,000 ng/mL at initial
diagnosis are associated with a better
prognosis than if they are < 100 or
> 1,000,000ng/mL. Other factors posi-tively influencing prognosis include
tumour confined to one lobe, fetal epithe-lial growth pattern, and multifocal dis-semination (rather than unifocal growth
pattern in the liver with distant metas-tases and vascular invasion) {2022}.
Fig. 8.59  Mixed epithelial and mesenchymal hepatoblastoma. Fetal epithelial
cells upper left and embryonal epithelial cells upper right lie adjacent to a focus
of osteoid-like material.
Fig. 8.60 Mixed epithelial and mesenchymal hepatoblastoma with teratoid fea-tures. This area resembling fetal hepatoblastoma contains black melanin pig-ment.
190 Tumours of the liver and intrahepatic bile ducts
Definition
Primary lymphoma of the liver is defined
as an extranodal lymphoma arising in the
liver with the bulk of the disease localized
to this site. Contiguous lymph node
involvement and distant spread may be
seen but the primary clinical presentation
is in the liver, with therapy directed to this
site.
Epidemiology
Primary lymphoma of the liver is rare
{796}. It is mainly a disease of white mid-dle aged males {1043, 1217} although an
occasional case has been reported in
childhood {1557}. Most are B-cell lym-phomas. Primary hepatosplenic T-cell
lymphomas have a different distribution.
Patients are almost always male (M:F
approximately 5:1) but are usually
younger with a mean age of 20 years
(range 8-68 years) {334}.
In contrast to primary lymphoma, sec-ondary liver infiltration is a frequent
occurrence, being present in 80-100% of
cases of chronic leukaemia, 50-60% of
cases of non-Hodgkin lymphoma and
approximately 30% of cases of multiple
myeloma {2042, 261}.
Aetiology
A proportion of cases are associated
with hepatitis C virus infection with and
without mixed cryoglobulinaemia {390,
56, 1257, 90, 371, 1625, 311}. Other lym-phomas have been reported arising with-in a background of hepatitis B virus
infection {1441, 1183}, HIV infection
{1680, 1516} and primary biliary cirrhosis
{1535}.
Clinical features
The most frequent presenting symptoms
are right upper abdominal/epigastric
pain or discomfort, weight loss and fever
{1043, 1217}. Most cases are solitary or
multiple masses within the liver which
may be misdiagnosed as a primary liver
tumour or metastatic cancer {1043,
1217}. Some cases have been reported
with diffuse infiltration of the liver associ-ated with hepatomegaly but without a
discrete mass, simulating hepatic inflam-mation {668}.
Hepatosplenic T-cell lymphomas present
with hepatosplenomegaly, usually without
peripheral lymphadenopathy and without
lymphocytosis. There is almost always
thrombocytopenia and most patients are
anaemic. Liver function tests are usually
abnormal with moderate elevation of lev-els of transaminases and alkaline phos-phatase. Serum lactate dehydrogenase
level may be very high {334}.
Histopathology
B-cell lymphoma
The majority of primary hepatic lym-phomas are of diffuse large B-cell type
with sheets of large cells with large nuclei
and prominent nucleoli. Phenotypically
these characteristically express the pan
B-cell markers CD20 and CD79a.
Occasional cases of Burkitt lymphoma
have been described {759} in which the
morphology is typical of Burkitt lym-phoma encountered elsewhere in the
digestive tract. Immunophenotypically
the cells express CD20, CD79a and
CD10. They are generally negative with
antibodies to bcl-2 protein.
Low-grade B-cell lymphomas of MALT
type have also been described. These
are characterized by a dense lymphoid
infiltrate within the portal tracts. The atyp-ical lymphoid cells have centrocyte-like
cell morphology and surround reactive
germinal centres. Lymphoepithelial
lesions are formed by the centrocyte-like
cells and the bile duct epithelium, and
these may be highlighted by staining with
anti-cytokeratin antibodies. Nodules of
normal liver may be entrapped within the
tumour. The cells express pan-B-cell
markers CD20 and CD79a and are nega-tive for CD5, CD10 and CD23. There is no
expression of cyclinD1 {797, 1143, 923}.
Secondary involvement of the liver by
chronic lymphocytic leukaemia and
B-cell non-Hodgkin lymphoma tends to
show a distribution involving the portal
triads although nodular infiltration may
also be seen with non-Hodgkin lym-phoma and multiple myeloma {2042}.
Hepatosplenic T-cell lymphoma
This is characterized by infiltration of the
sinusoids by a monomorphic population
of medium sized cells with a moderate
amount of eosinophilic cytoplasm. The
nuclei are round or slightly indented with
moderately dispersed chromatin and
contain small, usually basophilic, nucle-oli. There may be mild sinusoidal dilation
and there are occasional pseudo-peliotic
lesions. Perisinusoidal fibrosis may be
present. Portal infiltration is variable. A
similar sinusoidal pattern of infiltration is
seen in the spleen and bone marrow
both of which are usually involved by the
lymphoma at diagnosis {486, 334}.
The cells are usually immunoreactive for
CD2, CD3, CD7 and the cytotoxic gran-ule related protein TIA-1. There is usually
no expression of CD5. The majority of
cases are CD4-/CD8+ although some
are CD4-/CD8- {486, 334}. A CD4+ vari-ant has been described very infrequent-ly {771}. There is variable expression of
CD16 and CD56. All cases are negative
for βF1 and positive with antibodies for
the T-cell receptor δ.
Genetics
Hepatosplenic T-cell lymphoma exhibits
rearrangement of the T-cell receptor  γ
gene. EBV sequences have not been
detected {334}. Cytogenetic studies
have shown isochromosome 7q in a
number of cases and in some this has
been present as the sole cytogenetic
abnormality {524, 48}
Prognosis
The prognosis of primary hepatic lym-phoma is generally poor. Chemotherapy
or radiotherapy alone has been reported
to be ineffective but combination modali-ties, including surgery in resectable
cases, can give relatively good results.
{1043, 1217}. Hepatosplenic T-cell lym-phomas are very aggressive, with a
mean survival of 1 year {334} although
the CD4+ subtype may be associated
with a slightly longer survival {771}.
A. Wotherspoon
Lymphoma of the liver
191Mesenchymal tumours
Definition
Benign and malignant tumours arising in
the liver, with vascular, fibrous, adipose
and other mesenchymal tissue differenti-ation.
ICD-O codes
ICD-O codes, terminology, and defini-tions largely follow the WHO ‘Histological
Typing of Soft Tissue Tumours’ {2086}.
Imaging
Imaging studies establish the presence
of a space-occupying lesion or lesions in
the liver, and may provide a diagnosis or
differential diagnosis {1565}. Biopsy of a
mass is, however, needed for a definitive
diagnosis {806}.
Mesenchymal hamartoma
Mesenchymal hamartoma is a ‘tumour
malformation’ that develops  in utero. It
accounts for 8% of all liver tumours and
pseudotumours from birth to 21 years of
age, but during the first two years of life
it represents 12% of all hepatic tumours
and pseudotumours, and for 22% of the
benign neoplasms {1839}. It usually
manifests in the first two years of life and
there is a slight male predominance.
Lesions involve the right lobe in 75% of
cases, the left lobe in 22% and both
lobes in 3%.
Presentation is typically with abdominal
swelling, but rapid accumulation of fluid
in the tumour can cause sudden enlarge-ment of the abdomen {1841}. Macrosco-pically, it is usually a single mass that can
attain a large size (up to 30 cm or more).
Mesenchymal hamartoma has an excel-lent prognosis after resection. The fate of
untreated lesions is not known but there
is no convincing evidence of malignant
transformation.
Histopathology.  This tumour-like lesion is
composed of loose connective tissue and
epithelial ductal elements in varying pro-portions. Grossly, the cut surfaces exhib-it solid, pink-tan areas and cysts contain-ing a clear fluid. Histologically, the con-nective tissue is typically loose and oede-matous with a matrix of acid mucopoly-K.G. Ishak
P.P. Anthony
C. Niederau
Y. Nakanuma
Mesenchymal tumours of the liver
DC
Fig. 8.61  Mesenchymal hamartoma. A Cut surface shows cysts and tan-white tissue. B Mixture of bile ducts,
mesenchymal tissue and blood vessels. C Bile ducts display a ductal plate malformation; the primitive mes-enchymal tissue consists of loosely arranged stellate cells. In addition to blood vessels, the tumour also con-tains liver cells (top). D Fluid accumulation in the mesenchyme mimics lymphangioma, but the spaces lack
an endothelial lining.
BA
Asymptomatic (incidental finding) Any
Upper abdominal mass +/- hepatomegaly Any
Sudden increase in size of tumour Mesenchymal hamartoma,
cavernous haemangioma
Febrile illness with weight loss Inflammatory pseudotumour,
embryonal sarcoma, angiosarcoma
Acute abdominal crisis from rupture Cavernous haemangioma, angiosarcoma,
epithelioid haemangioendothelioma
Budd-Chiari syndrome Epithelioid haemangioendothelioma
Congestive heart failure Infantile haemangioendothelioma
Cardiac tumour syndrome Embryonal sarcoma
Consumption coagulopathy Cavernous haemangioma,
infantile haemangioendothelioma
Hypoglycaemia Solitary fibrous tumour
Portal hypertension Epithelioid haemangioendothelioma,
inflammatory pseudotumour
Liver failure Epithelioid haemangioendothelioma,
angiosarcoma
Obstructive jaundice Inflammatory pseudotumour
Lung metastases Epithelioid haemangioendothelioma,
angiosarcoma
Mode of Presentation Examples
Table 8.05
Presentation of mesenchymal tumours of the liver.
192 Tumours of the liver and intrahepatic bile ducts
saccharide, or it is collagenous and
arranged concentrically around the
ducts. Fluid accumulation leads to sepa-ration of the fibres with formation of lym-phangioma-like areas and larger cavities.
The epithelial component consists of bile
ducts that may be tortuous and occa-sionally dilated. The ducts often are
arranged in a ductal-plate-malformation
pattern. Islets of liver cells without an aci-nar architecture may be present.
Numerous arteries and veins are scat-tered throughout, as are foci of extra-medullary haematopoiesis.
Infantile haemangioendothelioma
This lesion is defined as a benign tumour
composed of vessels lined by plump
endothelial cells, intermingled with bile
ducts, that are set in a fibrous stroma.
Infantile haemangioendothelioma ac-counts for about one fifth of all liver
tumours and pseudotumours from birth to
21 years of age. It usually presents in the
first two years of life, when it represents
40% of all tumours and pseudotumours
and 70% of the benign ones {1839}. It
occurs more frequently in females (63%)
than in males. Infantile haemangioen-dothelioma is a localized ‘tumour malfor-mation’ that develops in utero. There may
be a variety of associated congenital
anomalies, including hemihypertrophy
and Cornelia de Lange syndrome.
Patients may develop congestive heart
failure or consumption coagulopathy, with
or without an abdominal mass {397,
1708}, and about 10% have haeman-giomas of the skin.
Grossly, infantile haemangioendothe-lioma forms a single large mass (55%) or
involves the entire liver by multiple
lesions (45%). The single tumours have a
maximum diameter up to 14 cm while the
multiple lesions are often less than a cen-timeter. The large, single lesions are red-brown or red-tan, often with haemorrhag-ic or fibrotic centers and focal calcifica-tion. The small lesions appear spongy
and red-brown on sectioning.
Histopathology.  Lesions are composed
of numerous small vascular channels
lined by plump endothelial cells usually
arranged in a single layer, but multilayer-ing and tufting can occur. The vessels
are supported by a scanty fibrous stroma
that may be loose or compact. Larger
cavernous vessels with a single layer of
flat endothelial cells are often present in
the centre of the larger lesions; these
vessels may undergo thrombosis with
infarction, secondary fibrosis and calcifi-cation. Other characteristic features of
infantile haemangioendothelioma are
small bile ducts scattered between the
vessels, and foci of extramedullary
haematopoiesis. Endothelial cells in the
tumour express Factor VIII-related anti-gen and CD34.
Prognosis.  Infantile haemangioendothe-lioma has an overall survival of 70%;
adverse risk factors include congestive
heart failure, jaundice and the presence
of multiple tumours {1708}. Single
tumours are generally resected although
some 5-10% undergo spontaneous re-gression. Hepatic artery ligation or trans-arterial embolization are other therapeu-tic modalities. There are occasional
reports of transformation of infantile hae-mangioendothelioma to angiosarcoma
{1708}.
Cavernous haemangioma
This is the most frequently occurring
benign tumour of the liver. The reported
incidence varies from 0.4 to 20%, the
highest figure being the result of a thor-ough prospective search {892}. It is more
frequent in females, and occurs at all
ages but is least common in the paedi-atric age group. Although it usually pres-ents in adults, it is thought to be a hamar-tomatous lesion. It is known to increase in
size or even rupture during pregnancy,
and also may enlarge or recur in patients
on oestrogen therapy. Consumption
coagulopathy may occur. Cavernous
Fig. 8.62  Infantile haemangioendothelioma.  A Red and brown tumour with focal hemorrhage.  B Multiple
brown cavitary lesions. C The tumour is well circumscribed but not encapsulated, and consists of small ves-sels. D Masson trichrome stain shows vessels lined by a single layer of plump endothelial cells surrounded
by a scant fibrous stroma. Note the scattered bile ducts.
BA
DC
BA
Fig. 8.63 Cavernous haemangioma. A Multilocular blood-filled structures with pale solid areas. B Large thin-walled vascular spaces.
193Mesenchymal tumours
haemangiomas are not known to under-go malignant change. Only large symp-tomatic tumours require surgical exci-sion.
Macroscopically, cavernous haeman-giomas vary from a few millimeters to
huge tumours (‘giant’ haemangiomas)
that can replace most of the liver. They
are usually single, and soft or fluctuant.
When sectioned they partially collapse
due to the escape of blood and have a
spongy appearance. Recent haemor-rhages, organized thrombi, fibrosis and
calcification may be seen.
Histopathology.  Lesions are typically
composed of blood-filled vascular chan-nels of varied size lined by a single layer
of flat endothelial cells supported by
fibrous tissue. Thrombi in various stages
of organization with areas of infarction
may be present, and older lesions show
dense fibrosis and calcification. In scle-rosed haemangiomas, most or all of the
vessels are occluded and sometimes are
only demonstrable by stains for elastic
tissue.
Angiomyolipoma
The lesion is defined as a benign tumour
composed of variable admixtures of adi-pose tissue, smooth muscle (spindled or
epithelioid), and thick-walled blood ves-sels. The age range of angiomyolipoma
is from 30-72 years, with a mean of 50
years {1373}. It is seen equally in males
and females {604}. A small number are
associated with tuberous sclerosis.
Angiomyolipomas are usually single, with
60% located in the right lobe, 30% in the
left lobe, 20% in both lobes and 8% in the
caudate lobe {1373}. They are sharply
demarcated but not encapsulated, fleshy
or firm and, when sectioned, with a
homogeneous yellow, yellow-tan or tan
appearance, depending on their content
of fat.
Histopathology. Angiomyolipomas are
composed of adipose tissue, smooth
muscle and thick-walled, sometimes
hyalinized blood vessels in varying pro-portions. Morphologically and phenotyp-ically they are believed to belong to a
family of lesions characterized by prolif-eration of perivascular epithelioid cells
{2197}. The smooth muscle is composed
of spindle-shaped cells arranged in bun-dles, or larger more rounded cells with
an ‘empty’ (glycogen-rich) cytoplasm or
an eosinophilic, epithelioid appearance.
The nuclei of the spindle cells are elon-gated with blunt ends, but the larger
smooth muscle cells can have large,
hyperchromatic nuclei with prominent
nucleoli. The microscopic appearances
are extensively varied and may imitate
several malignant tumours, e.g. leio-myosarcoma, malignant fibrous histiocy-toma and hepatocellular carcinoma
{1971}. A characteristic feature of angio-myolipoma is the presence of extra-medullary haematopoiesis. The smooth
muscle cells contain variable quantities
of melanin and express the melanoma
markers HMB-45 and Melan-A. They also
express muscle specific actin and
smooth muscle actin.
Fig. 8.64 Sclerosed haemangioma. Pale hyalinized
nodule with remnants of obliterated vessels.
Fig. 8.65 Lymphangioma. Lymphatic channels of
variable size contain clear pink fluid.
DC
Fig. 8.66  Angiomyolipoma. A Fat within the tumour imparts a yellow colour. B Fat and smooth muscle are
present. C Two characteristically thick-walled arteries are surrounded by fat. D This tumour is composed
predominantly of smooth muscle. The clear cytoplasm is due to glycogen that was lost during processing.
E Large smooth muscle cells show perinuclear condensation of cytoplasm.  F Marked extramedullary
haematopoiesis.
BA
FE
194 Tumours of the liver and intrahepatic bile ducts
Solitary fibrous tumour
Solitary fibrous tumour has an age range
from 32-83 years (mean, 57 years)
{1270}. Its aetiology is unknown. Lesions
vary considerably in size, from 2-20 cm in
diameter {1270}. They arise in either lobe
and are occasionally pedunculated. The
external surface is smooth and the con-sistency firm. They are sharply demarcat-ed but not encapsulated. Gross sections
show a light tan to almost white colour
with a whorled texture.
Histopathology. Solitary fibrous tumour
often shows alternating cellular and rela-tively acellular areas. The cellular areas
consist of bundles of spindle cells
arranged haphazardly or in a storiform
pattern. There is a well-developed retic-ulin network. In some cases the cells are
arranged around ectatic vessels in a hae-mangiopericytoma-like pattern. Nuclei of
the spindle cells are uniform and lack
pleomorphism, but these tumours may
undergo malignant change as evidenced
by the presence of foci of necrosis,
prominent cellular atypia, and mitotic
activity in the range of 2-4 mitoses/10 hpf
{1270, 514}. The relatively acellular areas
of solitary fibrous tumour contain abun-dant collagen bundles with thin,
stretched-out tumour cells. The tumour
cells characteristically express CD34.
Inflammatory pseudotumour
This lesion is defined as a benign, non-neoplastic, non-metastasizing mass
composed of fibrous tissue and prolifer-ated myofibroblasts, with a marked
inflammatory infiltration, predominantly
plasma cells {318}.
The mean age at presentation of inflam-matory pseudotumour of the liver is 56
years (range, 3-77) {438}; it is commoner
in males (70%) than in females {1270}.
Inflammatory pseudotumours are solitary
(81%) or less often multiple (19%) {1275}
and usually intrahepatic, but some can
involve the hepatic hilum. About half of the
solitary tumours are located in the right
lobe. They vary in size from 1 cm to large
masses involving an entire lobe, and are
firm, tan, yellow-white or white. Some
inflammatory pseudotumours are proba-bly the residuum of a resolved bacterial
abscess, while others may be related to
Epstein-Barr virus infection {82, 318}.
Histopathology.  The lesions are similar to
those occurring in other sites. They are
composed of inflammatory cells in a stro-ma of interlacing bundles of myofibro-blasts, fibroblasts, and collagen bundles.
The majority of inflammatory cells are
mature plasma cells, but lymphocytes
(and occasional lymphoid aggregates or
follicles), as well as eosinophils and neu-trophils, may be present. Macrophages,
sometimes showing xanthomatous
changes, occasional granulomas and,
rarely, phlebitis involving portal vein
branches or outflow veins, may be seen.
Lymphangioma and
lymphangiomatosis
Lymphangioma is a benign tumour char-acterized by multiple endothelial-lined
spaces that vary in size from capillary
channels to large, cystic spaces contain-ing lymph. The vascular spaces are lined
by a single layer of endothelial cells,
though papillary projections or tufting
may be seen.
The cells rest on a basement membrane
and the supporting stroma is usually
scanty. Clear, pink-staining lymph fills the
lymphatic channels.
Hepatic lymphangiomatosis, often ac-companied by lymphangiomatosis of the
spleen, skeleton, and other tissues, may
represent a malformation syndrome.
Diffuse lymphangiomatosis involving the
liver and multiple organs is associated
with a poor prognosis. Single lesions have
been successfully resected.
Pseudolipoma
Pseudolipoma is believed to represent an
appendix epiploica attached to the
Glisson capsule after becoming detached
from the large bowel {1609}. Lesions are
usually a small, encapsulated mass of fat
located in a concavity on the surface of
the liver, the fat typically showing necrosis
and calcification {891}.
Focal fatty change
Focal fatty change of the liver is charac-terized by multiple, contiguous acini
showing macrovesicular steatosis of
hepatocytes, with preservation of acinar
architecture {804}. About 45% of cases
of a series of focal fatty change occurred
in patients with diabetes mellitus {632}.
Embryonal sarcoma
A malignant tumour composed of mes-enchymal cells that, by light microscopy,
are undifferentiated.
Embryonal sarcoma (‘undifferentiated’
sarcoma) comprises 6% of all primary
hepatic tumours  in childhood {2082}. It
usually occurs between 5 and 20 years
of age {1840}. Rarely, cases have
occurred in middle and even old age.
The incidence in males and females is
equal {1840}. Embryonal sarcoma is of
unknown aetiology, although one patient
had a past history of prenatal exposure
DC
Fig. 8.67 Embryonal sarcoma. A Yellow and brown tumour with necrotic and haemorrhagic areas. B Small
nodule in the pseudocapsule and a tumour thrombus in a vessel. Multiple bile ducts are entrapped in the sar-comatous tissue.  C Spindle and stellate cells together with giant cells in a loose myxoid stroma.
D Pleomorphic cells with eosinophillic cytoplasmic globules.
BA
195Mesenchymal tumours
to phenytoin {148}. Symptoms include
abdominal enlargement, fever, weight
loss, and nonspecific gastrointestinal
complaints {1840}. Rarely, the tumour
invades the vena cava and grows into
the right atrium, mimicking a cardiac
tumour {561}.
Macroscopy.  Embryonal sarcoma is
usually located in the right lobe of
the liver, and varies from 10-20 cm in
diameter. It is typically well-demarcated
but not encapsulated. Gross sections
reveal a variegated surface with glisten-ing, solid, grey-white tumour tissue alter-nating with cystic, gelatinous areas
and/or red and yellow foci of haemor-rhage or necrosis.
Histopathology.  Embryonal sarcoma is
composed of malignant stellate or spin-dle cells that are compactly or loosely
arranged in a myxoid stroma. Tumour
cells often show prominent anisonucleo-sis with hyperchromasia; giant cells that
may be multinucleated are seen in many
cases. A characteristic feature is the
presence of eosinophilic globules of var-ied size, sometimes many per cell, in the
cytoplasm. They are PAS-positive, resist
diastase digestion, and express alpha-1
antitrypsin, though the larger globules
may only be immunoreactive at the
periphery. Entrapped bile ducts and
hepatocellular elements are often pres-ent in the peripheral areas of these
tumours. The spindle, stellate and giant
cells typically show no morphological
evidence of differentiation, but immuno-histochemical studies in a few cases
have demonstrated widely divergent dif-ferentiation into both mesenchymal and
epithelial phenotypes, probably from a
primitive stem cell {1460}.
Prognosis.  Until recently the prognosis
of embryonal sarcoma has been very
poor, with a median survival of less than
one year after diagnosis {1840}. The sur-vival has greatly improved in the last sev-eral years with some patients living five
or more years after combined modality
therapy (surgical resection, radiothera-py, and chemotherapy).
Kaposi sarcoma
This lesion is defined as a tumour com-posed of slit-like vascular channels, spin-dle cells, mononuclear inflammatory
cells, with an admixture of haemosiderin-laden macrophages.
Kaposi sarcoma involves the liver in
12-25% of fatal cases of the acquired
immunodeficiency syndrome (AIDS), but
is not known to contribute significantly to
its morbidity and mortality. In patients
with AIDS, it is aetiologically related to
HHV-8 infection {276, 1367}. It involves
portal areas but can infiltrate the adja-cent parenchyma for short distances,
and is characterized grossly by irregular,
variably-sized, red-brown lesions scat-tered throughout the liver.
Histologically, lesions resemble those
occurring in other sites with spindle cells
showing elongated or ovoid, vesicular
nuclei with rounded ends and inconspic-uous nucleoli. Eosinophilic, PAS-positive
globules may be seen in the cytoplasm.
The tumour cells are separated by slit-like vascular spaces . Aggregates of
haemosiderin granules may be present.
The spindle cells express endothelial cell
markers (CD31, CD34).
Epithelioid haemangioendothelioma
A tumour of variable malignant potential
that is composed of epithelioid or spindle
cells growing along preformed vessels or
forming new vessels.
Epithelioid haemangioendothelioma pre-sents between 12 and 86 years (mean 47
years) {807, 1150}. Its overall incidence is
unknown, but more are reported in
females (61%) than in males (39%) {807,
1150}. Risk factors are not known; the
Fig. 8.69 Epithelioid haemangioendothelioma. There is extensive destruction of liver cell plates. Note the
intracellular vascular lumina (arrow).
B CA
Fig. 8.68  Kaposi sarcoma. A Multiple dark brown lesions centered in large portal areas. B, C Spindle cells and slit-like vascular spaces.
196 Tumours of the liver and intrahepatic bile ducts
suggestion of a relationship to oral con-traceptive use has not been validated
{1270}. Epithelioid haemangioendothe-lioma causes systemic symptoms (weak-ness, malaise, anorexia, episodic vomit-ing, upper abdominal pain, and weight
loss) and hepato-splenomegaly {807,
1150}. Some patients develop jaundice
and liver failure. Uncommon modes of
presentation include the Budd-Chiari syn-drome {2040} or portal hypertension.
Macroscopy. Macroscopically, lesions
are usually multifocal; ill-defined lesions
scattered throughout the liver vary from a
few millimeters to several centimeters in
greatest dimension. They are firm, tan to
white on sectioning, and often have a
hyperaemic periphery; calcification may
be evident grossly.
Histopathology.  The tumour nodules are
ill-defined, and often involve multiple
contiguous acini. In actively proliferating
lesions the acinar landmarks, such as
terminal hepatic venules (THV) and por-tal areas, can be recognized despite
extensive infiltration by the tumour. The
cells grow along preexisting sinusoids,
THV, and portal vein branches, and often
invade Glisson capsule. Growth within
the acini is associated with gradual atro-phy and eventual disappearance of liver
cell plates. Intravascular growth may be
in the form of a solid plug, or a polypoid
or tuft-like projection.
Neoplastic cell are either ‘dendritic’, with
spindle or irregular shapes and multiple
interdigitating processes, ‘epithelioid’,
with a more rounded shape and an abun-dant cytoplasm, or ‘intermediate’.
Nuclear atypia and mitoses are mainly
observed in the epithelioid cells. Cyto-plasmic vacuoles, representing intracel-lular vascular lumens, are often identified
and may contain erythrocytes. The
tumour cells synthesize factor VIII-related
antigen (von Willebrand factor), which
can be demonstrated in the cytoplasm or
in the neoplastic vascular lumens. Other
endothelial cell markers, such as CD31
and CD34, are also positive.
The stroma can have a myxoid appear-ance due to an abundance of sulphated
mucopolysaccharide. Reticulin fibres sur-round nests of tumour cells. Basement
membrane can be demonstrated around
the cells by the PAS stain, as well as ultra-structurally and immunohistochemically.
Variable numbers of smooth muscle cells
surround the basement membrane.
As the lesions evolve they are associated
with progressive fibrosis and calcification.
Eventually, tumour cells (and indeed, the
vascular nature of the lesion) may be diffi-cult if not impossible to recognize in the
densely sclerosed areas. Needle biopsy
specimens taken from such areas often
pose diagnostic problems. The histopa-thological differential diagnosis includes
angiosarcoma and cholangiocarcinoma.
Angiosarcoma is much more destructive
than epithelioid haemangioendothelioma,
obliterates acinar landmarks and results
in cavity formation. Cells of cholangiocar-cinoma are arranged in a tubular or glan-dular pattern, and often produce mucin;
the cells are cytokeratin positive and do
not express endothelial cell markers.
Prognosis. The clinical outcome of
epithelioid haemangioendothelioma is
unpredictable, with some patients having
a fulminant course and others surviving
many years with no therapy. A recent
study {1150} showed a correlation
between high cellularity of the tumour
with a poor clinical outcome. Successful
treatment includes resection, when feasi-ble, and liver transplantation.
Angiosarcoma
A malignant tumour composed of spindle
or pleomorphic cells that line, or grow
into, the lumina of preexisting vascular
spaces, such as liver sinusoids and
small veins.
Worldwide, about 200 cases of angiosar-coma are diagnosed annually {848, 59}.
During the period 1973-87, the SEER
database of the US National Cancer
Institute contained 6,391 histologically-confirmed primary liver cancers; of these
only 65 (1%) were angiosarcomas {252}.
The peak incidence is in the 6th and 7th
decades of life. The male to female ratio
is 3:1 {1085}.
75% of angiosarcomas of the liver have
no known aetiology {484}. The remainder
have been linked to prior administration
of Thorotrast (a radioactive material con-taining thorium dioxide, that was used as
an angiography contrast medium from
the 1930s to the early 1950s), exposure
to vinyl chloride monomer (VCM) or inor-ganic arsenic, and the use of andro-genic-anabolic steroids {484}.
Patients with angiosarcoma present in
one of several ways: 61% have symp-toms referable to the liver (e.g. hepato-megaly, abdominal pain, ascites); 15%
have an acute abdominal crisis due to
haemoperitoneum from rupture of the
tumour; 15% have splenomegaly, often
with pancytopenia; and 9% present due
to distant metastases {804}. The progno-sis of angiosarcoma is very poor, with
most patients dying within 6 months of
diagnosis.
Macroscopy.  Angiosarcoma typically
affects the entire liver. Grayish-white
BA
DC
Fig. 8.70 Epithelioid haemangioendothelioma.  A, B  Tumour cells form polypoid projections in dilated peri-portal sinusoids. C Dendritic tumour cells, some having intracellular vascular lumina appearing as small vac-uoles. A terminal hepatic venule is infiltrated by tumour. D Tumour cells express factor VIII-related antigen.
197Mesenchymal tumours
tumour alternates with red-brown haem-orrhagic areas. Large cavities with
ragged edges, filled with liquid or clotted
blood, may be present. A reticular pat-tern of fibrosis is seen in cases related to
prior exposure to Thorotrast.
Histopathology.  Tumour cells grow along
preformed vascular channels (sinusoids,
THV and portal vein branches). Sinus-oidal growth is associated with progres-sive atrophy of liver cells and disruption
of the plates, with formation of larger vas-cular channels and eventually the devel-opment of cavities of varied size. These
cavities have ragged walls lined by
tumour cells, sometimes with polypoid or
papillary projections, and are filled with
clotted blood and tumour debris. Reti-BA
Fig. 8.71 Angiosarcoma. A Multiple dark brown tumour foci scattered throughout the liver.  B Solid portion showing spindle cells and numerous small vascular
channels. C Intravascular papillary structure covered by neoplastic endothelial cells. D Tumour cells express CD34.
DC
Fig. 8.72 Angiosarcoma. A Sinusoidal spread of tumour cells with destruction of hepatocyte plates. B Disrupted liver cells act as scaffolding for the tumour cells.
BA
198 Tumours of the liver and intrahepatic bile ducts
culin fibres and, less often, collagen
fibres support the tumour cells. Perithelial
cells, reactive for alpha-smooth muscle
actin, may also be present. The tumour
cells are sometimes packed solidly in
nodules that resemble fibrosarcoma.
The cells of angiosarcoma are spindle-shaped, rounded or irregular in outline,
and often have ill-defined borders. The
cytoplasm is lightly eosinophilic, and
nuclei are hyperchromatic and elongated
or irregular in shape. Nucleoli can be
small, or large and eosinophilic. Large,
bizarre nuclei and multinucleated cells
may be seen, and mitotic figures are fre-quently identified. The spindled cells
have ill-defined outlines, a lightly eosino-philic cytoplasm, and vesicular nuclei
with blunt ends. Factor VIII-related anti-gen can be identified in tumour cells
immunohistochemically. Other useful
markers include CD31 and CD34; the for-mer is believed to be the most sensitive
immunostain {1224}.
Invasion of THV and portal vein branch-es leads to progressive obstruction of the
lumen, and readily explains the frequent-ly encountered areas of haemorrhage,
infarction, and necrosis. Haematopoietic
activity is observed in the majority of
tumours.
Cases related to Thorotrast and vinyl
chloride monomer are often associated
with considerable periportal and sub-capsular fibrosis. Thorotrast deposits are
readily recognized in reticuloendothelial
cells, in connective tissue of portal areas,
in Glisson capsule, or in the walls of THV.
The deposits are coarsely granular and
refractile, and in an H&E-stained section
they have a pink-brown hue. They are
readily visualized by scanning electron
microscopy, and thorium can be defini-tively identified by energy dispersive
X-ray microanalysis {804}.
Genetics. Analysis of six hepatic angio-sarcomas associated with VCM expo-sure found three  TP53 mutations, all
A:T→T:A transversions, which are other-wise uncommon in human cancers {728}.
Another study of 21 sporadic angiosar-comas not associated with vinyl chloride
exposure found  TP53 mutations to be
uncommon, thus supporting previous
evidence of the carcinogenic potential of
chloroethylene oxide, a metabolite of
VCM {1776}. A high rate of KRAS-2 muta-tions has been found in both sporadic
and Thorotrast-induced angiosarcomas
of the liver {1542}.
Malignant mesenchymal tumours other
than angiosarcoma may have cytogenet-ic aberrations similar to those of soft tis-sue tumours {513, 1812}.
Carcinosarcoma
This neoplasm is defined as a malignant
tumour containing an intimate mixture of
carcinomatous (either hepatocellular or
cholangiocellular) and sarcomatous ele-ments; such lesions have also been
called ‘malignant mixed tumour’ of the
liver. Carcinosarcoma should be distin-guished from carcinomas with foci of
spindled epithelial cells and from the rare
true ‘collision’ tumours.
Fig. 8.73  Angiosarcoma. A Closely packed elongated tumour cells. B Pink-brown granular deposits of Thorotrast in a portal area adjacent to an angiosarcoma.
BA
199Secondary tumours
Definition
Malignant neoplasms metastasized to
the liver from extrahepatic primary
tumours.
Epidemiology
In Europe and North America, metas-tases predominate over primary hepatic
tumours in a ratio of 40:1 {130, 1517}. In
Japan the ratio is 2.6:1 {1517}. In South-East Asia and sub-Saharan Africa, pri-mary hepatic tumours are more common
than metastases {1909} owing to the high
incidence of hepatocellular carcinoma, a
shorter life span (common extrahepatic
carcinomas affect older age groups) and
the low incidence of certain tumour types
(e.g. carcinomas of the lung and col-orectum). Autopsy studies in the USA
and Japan have shown that about 40%
of patients with extrahepatic cancer have
hepatic metastases {351, 1517}.
Aetiopathogenesis
The liver has a rich systemic (arterial)
and portal (venous) blood supply, pro-viding a potentially abundant source of
circulating neoplastic cells. Circulating
tumour cell arrest is controlled by Kupffer
cells in the sinusoids {881, 121} and may
be enhanced by growth factors such as
transforming growth factor alpha (TGFα)
{385}, tumour necrosis factor (TNF)
{1431}, and insulin-like growth factor-1
(IGF-1) {1091}. As tumour deposits
enlarge, they induce angiogenesis using
native sinusoidal endothelium; this
enhances their chances of survival and is
often macroscopically evident {1919}.
Most metastases from unpaired abdomi-nal organs reach the liver via the portal
vein, and from other sites via the systemic
arterial circulation. Lymphatic spread is
less common and extension to the liver
via the peritoneal fluid is rare {351}.
Cirrhosis provides some relative protec-tion against seeding by secondary
tumours {1983, 1211}. It has also been
suggested that metastasis is rare in fatty
livers {676}, but excess alcohol con-sumption apparently enhances hepatic
metastases {1140}.
In the majority of cases, metastases to
the liver are a manifestation of systemic,
disseminated disease. Colorectal carci-noma, neuroendocrine tumours, and
renal cell carcinoma are exceptions as
these neoplasms sometimes produce
isolated, even solitary deposits {1517}.
Origin of metastases
The majority of secondary liver neo-plasms are carcinomas, involvement by
lymphomas is next and sarcomas are
uncommon. The order of frequency by
primary site in Western populations is:
upper gastrointestinal tract (stomach,
gallbladder, pancreas): 44-78%; colon:
56-58%; lung 42-43%; breast 52-53%;
oesophagus 30-32% and genito-urinary
organs 24-38% {130, 1517, 351}.
Carcinomas of the prostate and the
ovaries preferentially spread to the lymph
nodes and the spine, and to the peri-toneal cavity, respectively.
Hodgkin and non-Hodgkin lymphomas
may involve the liver in up to 20% of
cases on presentation and 55% at autop-sy {1620, 826}. Sarcomas are much less
common but 6% had hepatic metastases
at presentation (mostly intra-abdominal
leiomyosarcomas) in one study {833},
P.P. Anthony
P. DeMatosSecondary tumours of the liver
BA
DC
FE
Fig. 8.74 Secondary tumours in the liver. A Metastatic colon carcinoma showing umbilication and hyper-emic borders. B Metastatic small cell carcinoma of lung forming inumerable small nodules. C, D Metastatic
large intestinal carcinoma, cut surfaces. E Metastatic gastric adenocarcinoma, cut surface. F A metastasis
lies adjacent to a Zahn infarct.
200 Tumours of the liver and intrahepatic bile ducts
while 34% had hepatic metastases at
autopsy in another {1517}.
In a study of randomly selected liver
biopsies from England and Wales {852},
the commonest histological type of
metastasis was adenocarcinoma (39%),
followed by carcinoma not otherwise
specified (36%); the rest were undifferen-tiated small cell carcinoma, other special
types of carcinoma, and lymphomas.
Clinical features
Symptoms and signs
Hepatic metastases produce clinical
manifestations in about two-thirds of
cases and they generally reveal them-selves through symptoms referable to the
liver. Afflicted patients often present with
ascites, hepatomegaly or abdominal full-ness, hepatic pain, jaundice, anorexia,
and weight loss. Constitutional symp-toms, such as malaise, fatigue, and fever
may be present. On examination, nod-ules or a mass are felt in up to 50% of the
cases, and a friction bruit may be heard
on auscultation. Unfortunately, sympto-matic presentation is associated with
bulky, rapidly progressive tumours with a
poor prognosis {2035}.
Rarely, patients present with fulminant
hepatic failure, obstructive jaundice, or
intraperitoneal haemorrhage. Function-ing neuroendocrine tumours produce syn-dromes of hormonal excess. ‘Carcino-matous cirrhosis’ with jaundice, ascites,
and bleeding varices due to diffuse infil-tration of the liver, usually by metastatic
breast carcinoma, has been described
{174}.
Laboratory studies
The alkaline phosphatase (ALP) and
serum glutamic-oxaloacetic transami-nase (SGOT) levels, although non-spe-cific, are elevated in approximately 80%
and 67% of patients respectively, and
most likely represent the effects of hepat-ic parenchymal infiltration by tumour and
of generalized wasting. Elevated lactic
dehydrogenase (LDH) levels are relative-ly specific for the presence of metastatic
melanoma. Tests of synthetic function,
e.g. serum albumin levels and the pro-thrombin time, may be normal despite
extensive metastatic involvement. Alpha-fetoprotein (AFP) levels may be slightly to
moderately elevated but very high con-centrations are more consistent with a
diagnosis of hepatocellular carcinoma
{904}. Carcinoembryonic antigen (CEA)
levels, which are raised in as many as
90% of patients with metastases from
colorectal carcinoma, can be useful in
monitoring patients after primary tumour
resection. However, CEA levels do not
correlate well with prognosis {2043,
1821}.
Imaging
Ultrasound (US) can identify tumours
measuring 1-2 cm in size, can differenti-ate solid from cystic lesions, and provide
guidance for percutaneous needle biop-sy. However, it provides poor anatomical
definition and frequently misses smaller
lesions.
Computed tomography (CT), using both
contrasted and non-contrasted images,
can also serve as a screening tool. The
administration of intravenous contrast
permits the detection of tumours as small
as 0.5 cm in diameter {1763}. Most meta-stases display decreased vascularity in
comparison to the surrounding hepatic
parenchyma and appear as hypodense
defects. Tumours that are hypervascular
(e.g. melanoma, carcinoids and some
breast cancers) or calcified (e.g. colorec-tal carcinoma) are better delineated by
noncontrast views.
Magnetic resonance imaging (MRI) is
more sensitive than CT in the detection of
hepatic tumours and can demonstrate
additional lesions, too small to be seen
on CT.
Positron emission tomography (PET) can
detect metastatic disease in the liver and
elsewhere. Using 2-(18)fluoro-2-deoxy-D-glucose (F-18 FDG), a radiolabeled
glucose analogue, PET highlights meta-bolically active tissues. Through co-reg-istration with anatomical studies like CT
or MRI, viable malignant tumours can be
differentiated from benign or necrotic
lesions {54}.
CT arterial portography performed pre-operatively, and intraoperative ultra-sound are associated with the highest
sensitivities {1796}. The former is capa-ble of detecting lesions as small as
15 mm, although a false positive rate of
BA
Fig. 8.75  Metastatic tubular adenocarcinoma from the stomach. A Haematoxylin and eosin. B Intraluminal
diastase-resistant PAS positive mucin.
BA
Fig. 8.76 Metastatic colorectal carcinoma. A Tumour is necrotic and cell type is typically columnar.
B Necrosis may result in calcification.
Fig. 8.77 Metastatic breast carcinoma.
201Secondary tumours
17% has been reported {1795}. Its suc-cess relies on the fact that tumours are
not fed by portal vein blood, so that
metastases appear as filling defects. The
latter, capable of detecting lesions 2-4
mm in diameter delineates the anatomi-cal location of tumours in relationship to
major vascular and biliary structures and
provides guidance for intraoperative
needle biopsies. It is the definitive step in
determining resectability at the time of
exploratory laparotomy or laparoscopy.
Angiography use has declined in recent
years. It remains useful for defining vas-cular anatomy for planned hepatic resec-tions, selective chemotherapy, chemo-embolization, or devascularization pro-cedures, for assessing whether there is
metastatic involvement of the portal
venous system and/or hepatic veins, and
for differentiating between benign vascu-lar lesions, such as haemangiomas and
metastases, when other imaging studies
have yielded equivocal results.
Macroscopy
The distribution of metastases from col-orectal carcinoma was found to be
homogenous, regardless of the primary
site of origin {1695} but in another study,
it was suggested that right sided cancers
predominantly metastasize to the right
lobe of the liver and left sided cancers to
both lobes {1749}.
Metastases are nearly always multinodu-lar or diffusely infiltrative, but may rarely
be solitary and massive (e.g. from colo-rectal and renal cell carcinomas).
Umbilication (a central depression on the
surface of a metastatic deposit) is due to
necrosis or scarring and is typical of an
adenocarcinoma from stomach, pan-creas or colorectum. A vascular rim
around the periphery is often seen.
Highly mucin secreting adenocarcino-mas appear as glistening, gelatinous
masses whilst well differentiated kera-tinizing squamous cell carcinomas are
granular. Metastatic carcinoid tumours
can form pseudocysts {401}. Haemor-rhagic secondary deposits suggest
angiosarcoma, choriocarcinoma, carci-noma of thyroid or kidney, neuroen-docrine tumour, or vascular leiomyosar-coma. Some diffusely infiltrating carcino-mas (e.g. small cell carcinoma), lym-phomas and sarcomas may have a soft,
opaque ‘fish flesh’ appearance. Meta-static breast carcinoma in particular can
produce an intensely fibrous, granular
liver (‘carcinomatous cirrhosis’) either
before {174} or after {1693} treatment.
Calcification of secondary deposits is a
feature of colorectal carcinoma but it is
seldom excessive and has no effect on
prognosis {653}. Metastatic melanoma is
often, but not always, of a brown-black
colour. Secondary tumours may appear
in the liver long after the removal of the
primary.
Histopathology
Liver biopsy samples can be obtained by
percutaneous or transjugular routes with
or without imaging techniques for guid-ance, as a wedge during laparotomy, or
a fine needle can be used to aspirate
material for cytology. Each of these meth-ods has advantages and drawbacks but
a guided percutaneous needle biopsy
producing a core of liver for histology is
the one most frequently used. It pro-duces a tissue sample that is usually
adequate for all purposes, including the
use of special stains, immunohistochem-istry and molecular biological tech-niques. Touch preparations for cytology
can also be prepared from needle cores
before fixation and may provide an
instant diagnosis {1523}.
Differential diagnosis
Hepatocellular carcinoma can usually be
distinguished from metastatic tumours by
its trabecular structure, sinusoids, lack of
stroma, bile production, absence of
mucin secretion, and the demonstration
of bile canaliculi by polyclonal CEA anti-sera, which is specific for a liver cell ori-gin. Other useful immunophenotypic fea-tures in this differentiation are the pres-ence of liver export proteins (albumin,
fibrinogen, alpha-1-antitrypsin), the cyto-keratin pattern, and the expression of
Hep Par 1 antigen {1046}. Metastatic
tumours that often mimic hepatocellular
carcinoma are adrenal cortical and renal
cell carcinomas. Amelanotic melanoma
may also cause difficulties but it is easily
identified by positive immunostaining for
S100 protein and HMB45 .
The distinction between primary cholan-giocarcinoma and metastatic adenocar-Fig. 8.79 Systemic non-Hodgkin lymphoma involv-ing the liver.
Fig. 8.78  Metastatic islet cell carcinoma of pancreas. A Haematoxylin and eosin. B Somatostatin immunoreactivity.
BA
202 Tumours of the liver and intrahepatic bile ducts
cinomas is much more difficult and may
be impossible {351}. Cholangiocarcino-ma may take on any of the histological
patterns of an adenocarcinoma; it is usu-ally tubular but may be mucinous, signet-ring, papillary, cystic, or undifferentiated.
Mucin secretion and production of CEA
are nearly always demonstrable in both
primary and secondary adenocarcino-mas. Metastases from many sites form
similar patterns. However, small tubular
or tubulo-papillary glands frequently
derive from the stomach, gallbladder
and extrahepatic biliary tree, and a
signet-ring cell appearance suggests a
gastric primary. Perhaps the easiest pat-tern to recognize as metastatic in origin
is that exhibited by adenocarcinomas of
the colon and rectum, which nearly
always show glands of variable size and
shape that are lined by tall columnar
cells and contain debris within the lumi-na. Metastases from the colorectum fre-quently have well defined edges where-as those from other glandular sites tend
to be more diffuse. Colorectal metas-tases are also frequently necrotic and
may show calcification {653}.
The presence of carcinoma-in-situ in
intrahepatic bile ducts in the vicinity of an
adenocarcinoma is evidence that it is a
cholangiocarcinoma. However, this may
be mimicked by intrabiliary ductal growth
of metastatic colonic adenocarcinoma
{1593}. Analysis of cytokeratin expres-sion may be useful in the distinction of
primary and metastatic gastrointestinal
adenocarcinomas. The former express
cytokeratins 7 and 19 but not 20, where-as the latter are negative for 7 and posi-tive for 20 {1141}.
Carcinoma of the breast often produces
a diffuse sinusoidal infiltrate that on
imaging studies may mimic cirrhosis
and, indeed, may be associated with
splenomegaly, ascites and oesophageal
varices {174}; sclerosis following sys-temic chemotherapy may exaggerate
this effect. Metastases from the breast
may be identified by the combined use of
zinc-α2-glycoprotein, gross cystic dis-ease fluid protein 15 and oestrogen
receptor {283}. However, occult breast
carcinoma presenting with metastases is
rare and most patients with liver involve-ment have a past history of a primary
tumour.
Most hepatic metastases from the lung in
clinical practice are undifferentiated
small cell carcinomas, characteristically
producing an enlarged liver due to dif-fuse or miliary spread. The primary
tumour may still be small, asymptomatic
and undetected. Squamous cell and
adenocarcinomas will metastasize to the
liver but their existence is usually known
already. The same applies to squamous
cell carcinomas of the oesophagus and
cervix. Squamous cell carcinomas of the
head and neck seldom involve the liver.
Neuroendocrine/islet cell/carcinoid tu-mours are easily identified by their
organoid nesting pattern, uniform cytol-ogy and vascularity, and positive
immunostaining for chromogranin, syn-aptophysin and neuron specific enolase;
islet cell tumours also produce specific
hormones such as insulin, glucagon,
gastrin, vasoactive intestinal peptide and
somatostatin, which either give rise to
clinical syndromes or can be demon-strated in the blood or tumour tissue.
Most sarcomas that metastasize to the
liver are gastrointestinal stromal tumours
that are positive for CD34 and c-kit, or
leiomyosarcomas of the uterus that may
be positive for desmin or muscle-specif-ic actin. Some carcinomas, notably of the
kidney, may be sarcomatoid in their mor-phology.
Many haematological malignancies, e.g.
leukaemias, myeloproliferative disorders
and both Hodgkin and non-Hodgkin lym-phomas, involve the liver. Leukaemias
tend to produce diffuse sinusoidal
infiltrates. Hodgkin and high-grade non-Hodgkin lymphomas produce tumour-like masses, while low-grade non-Hodgkin lymphomas produce diffuse
portal infiltrates.
Rare secondary tumours include those
from the thyroid, prostate, and gonads.
The diagnosis can be confirmed by the
immunohistochemical demonstration of
thyroglobulin, prostate specific antigen
and AFP and βHCG, respectively.
A triad of histological features, namely
proliferating bile ducts, leukocytes and
focal sinusoidal dilatation, is found in the
liver adjacent to space-occupying le-sions. Their presence in a core biopsy
suggests the possibility of a metastatic
deposit missed by the biopsy needle.
Three lesions, bile duct adenoma, scle-rosed haemangioma, and larval granulo-ma may resemble metastatic tumours at
laparotomy.
Prognosis
In most cases, disseminated disease is
present which precludes surgical inter-vention. Due to recent improvements in
imaging techniques, more metastatic
carcinomas are being diagnosed early,
providing the possibility of surgical
resection in a greater number of patients.
When curative resection is feasible,
5-year survival can be as high as 40%;
without surgical therapy, median sur-vivals of less than 12 months should be
expected {1817}.
Fig. 8.80  Typical histological changes adjacent to space occupying liver lesions: sinusoidal dilatation, leuko-cyte infiltration, and bile-ductular proliferation.
CHAPTER 9
Tumours of the Gallbladder
and Extrahepatic Bile Ducts
These two closely related tumour sites show remarkable
differences in terms of epidemiology, aetiology, and clinical
presentation. The incidence of gallbladder carcinoma shows
prominent geographic, gender, and racial differences, while
extrahepatic bile duct carcinomas show none of these varia-tions. Aetiologic associations include gall stones, sclerosing
cholangitis, ulcerative colitis, abnormal choledochopancreatic
junction, choledochal cysts, and infestation with liver flukes.
Epithelial tumours
Benign
Adenoma 8140/01
Tubular 8211/0
Papillary 8260/0
Tubulopapillary 8263/0
Biliary cystadenoma 8161/0
Papillomatosis (adenomatosis) 8264/0
Intraepithelial neoplasia (dysplasia and carcinoma in situ)
Malignant
Carcinoma
Adenocarcinoma 8140/3
Papillary adenocarcinoma 8260/3
Adenocarcinoma, intestinal type 8144/3
Adenocarcinoma, gastric foveolar type
Mucinous adenocarcinoma 8480/3
Clear cell adenocarcinoma 8310/3
Signet-ring cell carcinoma 8490/3
Adenosquamous carcinoma 8560/3
Squamous cell carcinoma 8070/3
Small cell carcinoma 8041/3
Large cell neuroendocrine carcinoma 8013/3
Undifferentiated carcinoma 8020/3
Biliary cystadenocarcinoma 8161/3
Carcinoid tumour 8240/3
Goblet cell carcinoid  8243/3
Tubular carcinoid 8245/1
Mixed carcinoid-adenocarcinoma 8244/3
Others
Non-epithelial tumours
Granular cell tumour  9580/0
Leiomyoma 8890/0
Leiomyosarcoma 8890/3
Rhabdomyosarcoma 8900/3
Kaposi sarcoma 9140/3
Others
Malignant lymphoma
Secondary tumours
WHO histological classification
of tumours of the gallbladder and extrahepatic bile ducts
_________
1
Morphology code of the International Classification of Diseases for Oncology (ICD-O) {542} and the Systematized Nomenclature of Medicine (http://snomed.org). Behaviour is coded
/0 for benign tumours, /1 for unspecified, borderline, or uncertain behaviour, /2 for in situ carcinomas and grade III intraepithelial neoplasia and /3 for malignant tumours.
TNM classification1, 2
T – Primary Tumour
TX Primary tumour cannot be assessed
T0 No evidence of primary tumour
Tis  Carcinoma in situ
T1 Tumour invades lamina propria or muscle layer
T1a Tumour invades lamina propria
T1b Tumour invades muscle layer
T2 Tumour invades perimuscular connective tissue, no extension
beyond serosa or into liver
T3 Tumour perforates serosa (visceral peritoneum) or directly
invades into one adjacent organ or both (extension 2 cm or less
into liver)
T4 Tumour extends more than 2 cm into liver and/or into two or
more adjacent organs (stomach, duodenum, colon, pancreas,
omentum, extrahepatic bile ducts, any involvement of liver)
N – Regional Lymph Nodes
NX Regional lymph nodes cannot be assessed
N0 No regional lymph node metastasis
N1 Metastasis in cystic duct, pericholedochal, and/or hilar lymph
nodes (i.e., in the hepatoduodenal ligament)
N2 Metastasis in peripancreatic (head only), periduodenal, peripor-tal, coeliac, and/or superior mesenteric lymph nodes
M – Distant Metastasis
MX Distant metastasis cannot be assessed
M0 No distant metastasis
M1 Distant metastasis
Stage Grouping
Stage 0 Tis N0 M0
Stage I T1 N0 M0
Stage II T2 N0 M0
Stage III T1 N1 M0
T2 N1 M0
T3 N0, N1 M0
Stage IVA T4 N0, N1 M0
Stage IVB Any T N2 M0
Any T Any N M1
TNM classification of tumours of the gallbladder
_________
1
{1, 66}. The classification applies only to carcinomas.
2
A help desk for specific questions about the TNM classification is available at http://tnm.uicc.org.
204 Tumours of the gallbladder and extrahepatic bile ducts
205
TNM classification1, 2
T – Primary Tumour
TX Primary tumour cannot be assessed
T0 No evidence of primary tumour
Tis Carcinoma in situ
T1 Tumour invades subepithelial connective tissue or fibromuscular
layer
T1a Tumour invades subepithelial connective tissue
T1b Tumour invades fibromuscular layer
T2 Tumour invades perifibromuscular connective tissue
T3 Tumour invades adjacent structures: liver, pancreas, duodenum,
gallbladder, colon, stomach
N – Regional Lymph Nodes
NX Regional lymph nodes cannot be assessed
N0 No regional lymph node metastasis
N1 Metastasis in cystic duct, pericholedochal, and/or hilar lymph
nodes (i.e., in the hepatoduodenal ligament)
N2 Metastasis in peripancreatic (head only), periduodenal, peripor-tal, coeliac, superior mesenteric, posterior peripancreatico-duo-denal lymph nodes
M – Distant Metastasis
MX Distant metastasis cannot be assessed
M0 No distant metastasis
M1 Distant metastasis
Stage Grouping
Stage 0 Tis N0 M0
Stage I T1 N0 M0
Stage II T2 N0 M0
Stage III T1 N1, N2 M0
T2 N1, N2 M0
Stage IVA T3 Any N M0
Stage IVB Any T Any N M1
TNM classification1, 2
T – Primary Tumour
TX Primary tumour cannot be assessed
T0 No evidence of primary tumour
Tis Carcinoma in situ
T1 Tumour limited to ampulla of Vater or sphincter of Oddi
T2 Tumour invades duodenal wall
T3 Tumour invades 2 cm or less into pancreas
T4 Tumour invades more than 2 cm into pancreas and/or
into other adjacent organs
N – Regional Lymph Nodes
NX Regional lymph nodes cannot be assessed
N0 No regional lymph node metastasis
N1 Regional lymph node metastasis
M – Distant Metastasis
MX Distant metastasis cannot be assessed
M0 No distant metastasis
M1 Distant metastasis
Stage Grouping
Stage 0 Tis N0 M0
Stage I T1 N0 M0
Stage II T2 N0 M0
T3 N0 M0
Stage III T1 N1 M0
T2 N1 M0
T3 N1 M0
Stage IV T4 Any N M0
Any T Any N M1
TNM classification of tumours of the extrahepatic bile ducts
TNM classification of tumours of the Ampulla of Vater
_________
1
{1, 66}. The classification applies to carcinomas of extrahepatic bile ducts and those of choledochal cysts.
2
A help desk for specific questions about the TNM classification is available at http://tnm.uicc.org.
_________
1
{ 1, 66}. The classification applies only to carcinomas.
2
A help desk for specific questions about the TNM classification is available at http://tnm.uicc.org.
206 Tumours of the gallbladder and extrahepatic bile ducts
Carcinoma of the gallbladder and
extrahepatic bile ducts
J. Albores-Saavedra H.R. Menck
J.C. Scoazec N. Soehendra
C. Wittekind P.V.J. Sriram
B. Sripa
Definition
A malignant epithelial tumour with glan-dular differentiation, arising in the gall-bladder or extrahepatic biliary system.
Epidemiology
Most tumours of the gallbladder and
extrahepatic bile ducts are carcinomas.
Only a small proportion are adenomas,
carcinoid and stromal tumours {35}.
Geographic distribution
The incidence of carcinoma of the gall-bladder varies in different parts of the
world and also differs among different
ethnic groups within the same country. In
the United States, carcinoma of the gall-bladder is more common in Native
Americans and Hispanic Americans than
in whites or blacks; the rate among
female Native Americans is 21 per
100,000 compared with 1.4 per 100,000
among white females. In Latin American
countries, the highest rates are found in
Chile, Mexico and Bolivia. In Japan, the
incidence rates are intermediate. In the
general population of the United States
cancer of the gallbladder accounts for
0.17% for all cancers in males and
0.49% in females.
There are no geographic variations in the
incidence of extrahepatic bile duct carci-noma which accounts for 0.16% of all
invasive cancers in males and 0.15% in
females in the general population of the
United States {35}.
Age and sex distribution
Carcinomas of the gallbladder and extra-hepatic bile ducts are diseases of older
age groups. Most patients are in the 6th
or 7th decades of life. Gallbladder carci-nomas have a strong female predomi-nance, whereas extrahepatic bile duct
carcinomas occur more frequently in
males.
Aetiology
Unlike carcinoma of the extrahepatic bile
ducts, gallbladder carcinomas are not
associated with primary sclerosing
cholangitis or ulcerative colitis.
Gallbladder carcinoma
Gallstones. The incidence of gallbladder
cancer is higher in patients with gall-stones than in patients without stones
{35}, and stones are present in over 80%
of gallbladder carcinomas. The inci-dence of gallbladder carcinoma paral-lels that of gallstones, being more fre-quent in females and in certain ethnic
groups, e.g. Native Americans, who
have a high incidence of stones.
Nevertheless, although gall stones are
considered a risk factor, the overall inci-dence of carcinoma of the gallbladder in
patients with cholelithiasis is less than
0.2%; this percentage varies with race,
sex, and length of exposure to the stones
{35}. While some authors have reported
a correlation between gallstone size and
the risk of cancer, others have not found
such a correlation {35}.
Abnormal choledochopancreatic junc-tion. Data largely reported from Japan
indicate an association between gall-bladder cancer and an abnormal junc-tion of the pancreatic and common bile
ducts {1248}. Normally, the main pancre-atic duct and the common bile duct unite
within the sphincter to form the pancre-aticobiliary duct. The abnormal junction
is defined as the union of the pancreatic
and common bile ducts outside the wall
of the duodenum beyond the influence of
the sphincter of Oddi. As a result, pan-creatic juice can reflux into the common
bile duct, resulting in hyperplastic, meta-Fig. 9.02 Carcinoma of the gallbladder involving the
fundus (arrow). Bile ducts are normal.
Fig. 9.03 Hilar cholangiocarcinoma extending
beyond both the right and left hepatic bile ducts
(Klatskin type III) (arrows).
Fig. 9.01 Gallbladder carcinoma with a white, irreg-ular cut surface next to a large gall stone.
207Carcinoma
plastic, and neoplastic changes in the
gallbladder epithelium.
Porcelain gallbladder. Diffuse calcifica-tion of the gallbladder wall (porcelain
gallbladder) is associated with carcino-ma in 10-25% of cases.
Genetic susceptibility. As discussed
above, carcinoma of the gallbladder is
concentrated in certain racial and ethnic
groups. Familial aggregation of gallblad-der cancer has been recorded in the US
and in other countries {35}.
Carcinoma of extrahepatic bile ducts
Well established risk factors for carcino-mas of the extrahepatic bile ducts are
sclerosing cholangitis, ulcerative colitis,
abnormal choledochopancreatic junc-tion, choledochal cysts and infestation
with the liver flukes  C. sinensis and
O. viverrini. Choledocholithiasis does not
seem to play a role in the pathogenesis
of carcinomas of the extrahepatic bile
ducts.
Clinical features
Cancer of the gallbladder usually pres-ents late in its course. The signs and
symptoms are not specific, often resem-bling those of chronic cholecystitis. Right
upper quadrant pain is common.
Computed tomography and ultrasonog-raphy can be used to demonstrate the
lesion.
Carcinomas of the extrahepatic bile
ducts usually present relatively early with
obstructive jaundice, which can rapidly
progress or fluctuate. Jaundice usually
appears while the tumour is relatively
small before widespread dissemination
has occurred. Other symptoms include
right upper quadrant pain, malaise,
weight loss, pruritus, anorexia, nausea,
and vomiting. If cholangitis develops,
chills and fever appear. In patients with
carcinoma of the proximal bile ducts
(right and left hepatic ducts, common
hepatic duct), the intrahepatic bile ducts
are dilated, the gallbladder is not palpa-ble and the common duct often collaps-es. Patients with carcinoma in the com-mon or cystic ducts have a distended
and palpable gallbladder as well as a
markedly dilated proximal duct system,
as may be shown by ultrasonography
and computerised tomography. Trans-hepatic cholangiograms and endoscopic
retrograde cholangiopancreatography
are essential for exact localization of car-cinomas of the extrahepatic bile ducts.
Macroscopy
Carcinoma of the gallbladder appears as
an infiltrating grey white mass. Some car-cinomas may cause diffuse thickening
and induration of the entire gallbladder
wall. The gallbladder may be distended
by the tumour, or collapsed due to
obstruction of the neck or cystic duct. It
can also assume an hourglass deformity
when the tumour arises in the body and
constricts the lateral walls. Papillary car-cinomas are usually sessile and exhibit a
polypoid or cauliflower-like appearance.
Mucinous and signet ring cell carcino-mas have a mucoid or gelatinous cut sur-face. Although any type of gallbladder
cancer may show necrosis, undifferenti-ated giant cell and small cell carcinomas
are usually the most necrotic. Submu-cosal growth is an important feature of
signet ring and small cell carcinomas.
Carcinomas of the extrahepatic bile
ducts have been divided into polypoid,
nodular, scirrhous constricting, and dif-fusely infiltrating types. This separation
can provide a guide to the operative pro-cedure, extent of resection, and progno-sis. However, except for the polypoid
tumours, this separation is rarely possi-ble in practice because of overlapping
gross features. The nodular and scir-rhous types tend to infiltrate surrounding
tissues and are difficult to resect. The dif-fusely infiltrating types tend to spread lin-early along the ducts.
Tumour staging
There are separate TNM classifications
for carcinomas of the gallbladder, extra-hepatic bile ducts, and the ampulla of
Vater.
Histopathology
The histological classification of tumours
of the gallbladder and extrahepatic bile
ducts is essentially similar to the previ-ous WHO classification published in
1991 {1774} and to the classification
adopted by the AFIP fascicle published
in 2000 {35}.
Adenocarcinoma
Well to moderately differentiated adeno-carcinomas are the most common malig-nant epithelial tumours of the gallbladder
and extrahepatic bile ducts. They are
composed of short or long tubular glands
lined by cells that vary in height from low
cuboidal to tall columnar, superficially
resembling biliary epithelium. Mucin is fre-quently present in the cells and glands.
Rarely, the extracellular mucin may
Fig. 9.05  Intestinal type adenocarcinoma. A Tubular glands similar to colonic adenocarcinoma. B Goblet cell type of adenocarcinoma. C Numerous serotonin con-taining cells in a neoplastic gland.
Fig. 9.04  Papillary adenocarcinoma, non-invasive.
The tumour projects into the lumen, but does not
invade the wall of the gallbladder.
ABC
208 Tumours of the gallbladder and extrahepatic bile ducts
become calcified {1465, 1606}. About
one-third of the well differentiated tumours
show focal intestinal differentiation and
contain goblet and endocrine cells {36,
2152, 2158}. The endocrine cells may be
numerous and show immunoreactivity for
serotonin and peptide hormones, but a
diagnosis of neuroendocrine neoplasm is
not warranted. Paneth cells may rarely be
seen. An extremely well differentiated
adenocarcinoma with gastric foveolar
phenotype that simulates adenoma has
been described in the extrahepatic bile
ducts {39}. Adenocarcinomas may show
cribriform or angiosarcomatous patterns.
They may also contain cyto- and synctio-trophoblast cells.
Extrahepatic bile duct adenocarcinomas
tend to be better differentiated than their
gallbladder counterparts. Many gallblad-der carcinomas are immunoreactive for
TP53 {1907, 2125}
Histological variants of adenocarcinoma
Papillary adenocarcinoma. This malig-nant tumour is composed predominantly
of papillary structures lined by cuboidal
or columnar epithelial cells often contain-ing variable amounts of mucin. Some
tumours show intestinal differentiation
with collections of goblet, endocrine, and
Paneth cells. Papillary adenocarcinomas
may fill the lumen before invading the
wall. Papillary adenocarcinomas appear
to be more frequent in the gallbladder
than in the extrahepatic biliary tree
{2150}. In addition, skip lesions may be
observed in approximately 10% of cases
{1989}.
Adenocarcinoma, intestinal type. This
unusual variant of adenocarcinoma is
composed of tubular glands or papillary
structures lined predominantly by cells
with an intestinal phenotype, namely
goblet cells or colonic-type epithelium or
both, with or without a variable number of
endocrine and Paneth cells {41}.
Mucinous adenocarcinoma. Mucinous
adenocarcinomas of the biliary tree are
similar to those that arise in other
anatomic sites. By definition, more than
50% of the tumour contains extracellular
mucin {1774}. There are two histological
variants of mucinous adenocarcinomas
of the gallbladder and extrahepatic bile
ducts: one variant is characterized by
neoplastic glands distended with mucin
and lined by columnar cells with mild to
moderate nuclear atypia, and the second
variant is characterized by small groups
or clusters of cells surrounded by abun-dant mucin. Some tumours show both
growth patterns. The abundant mucin
makes the tumour appear hypocellular.
Cystadenocarcinoma refers to a unilocu-lar or multilocular glandular tumour that
may be the result of malignant transfor-mation of a cystadenoma.
Clear cell adenocarcinoma. This rare
malignant tumour is composed predomi-nantly of glycogen-rich clear cells having
well-defined cytoplasmic borders and
hyperchromatic nuclei. In addition to
clear cells, a variable number of cells
contain eosinophilic granular cytoplasm.
The clear cells line glands or are
arranged in nests, sheets, cords, trabec-ulae or papillary structures {40, 145,
1856}. Foci of conventional adenocarci-noma with focal mucin production are
usually found and are useful in separating
primary from metastatic clear cell carci-nomas. In some clear cell adenocarcino-mas of the biliary tree the columnar cells
contain subnuclear and supranuclear
vacuoles similar to those seen in secreto-ry endometrium. Focal hepatoid differen-tiation with production of alpha-fetopro-tein has been documented in clear cell
carcinomas of the gallbladder {2000}.
Signet-ring cell carcinoma. Cells contain-ing intracytoplasmic mucin displacing
the nuclei toward the periphery predomi-nate in this variant of adenocarcinoma. A
variable amount of extracellular mucin is
usually present. Lateral spread through
the lamina propria is a common feature.
Fig. 9.09 Adenosquamous carcinoma of gallbladder.
Fig. 9.06 Well differentiated adenocarcinoma infil-trating gallbladder wall.
Fig. 9.07 Mucinous adenocarcinoma of gallbladder.
Fig. 9.08 Signet-ring cell carcinoma of gallbladder.
Fig. 9.11 Undifferentiated carcinoma of gallbladder,
spindle and giant cell type. No glandular differenti-ation.
Fig. 9.10 Squamous cell carcinoma of gallbladder.
209Carcinoma
A diffusely infiltrating linear pattern
resembling linitis plastica of the stomach
is observed in some cases.
Adenosquamous carcinoma
This tumour consists of two malignant
components, one glandular and the
other squamous. The extent of differenti-ation of the two components varies, but
in general they tend to be moderately dif-ferentiated {1357, 1867}. Keratin pearls
are often present in the squamous com-ponent, and mucin is usually demonstra-ble in the neoplastic glands.
Squamous cell carcinoma
This malignant epithelial tumour is com-posed entirely of squamous cells. The
extent of differentiation varies consider-ably. Keratinizing and non-keratinizing
types exist. Spindle cells predominate in
some poorly differentiated tumours,
which may be confused with sarcomas.
Immunostains for cytokeratin may clarify
the diagnosis in these spindle cell cases.
The tumour may arise from areas of
squamous metaplasia. Intraepithelial
neoplasia can be found in the metaplas-tic squamous mucosa {35}.
Small cell carcinoma
This lesion is covered in the chapter on
endocrine tumours of the gallbladder
and extrahepatic bile ducts.
Undifferentiated carcinoma
Undifferentiated carcinomas are more
common in the gallbladder than in the
extrahepatic bile ducts. Characteristically,
glandular structures are absent in undiffer-entiated carcinomas. There are four histo-logical variants {40, 411, 643, 1360}.
Undifferentiated carcinoma, spindle and
giant cell type.  The spindle and giant
cell type is the most common and resem-bles a sarcoma. These tumours have
been referred to as pleomorphic spindle
and giant cell adenocarcinomas or sar-comatoid carcinomas. They consist of
variable proportions of spindle, giant and
polygonal cells, but foci of well-differenti-ated neoplastic glands are usually found
in some of these tumours after extensive
sampling. Areas of squamoid differentia-tion may also be seen. Rarely, foci of
osteoclast-like multinucleated giant cells
are present. The presence of cytokeratin
in the spindle cells may help to distin-guish this tumour from carcinosarcoma.
Undifferentiated carcinoma with osteo-clast-like giant cells. This variant con-tains mononuclear cells and numerous
evenly spaced osteoclast-like giant cells
resembling giant cell tumour of bone.
The mononuclear cells show immunore-activity for cytokeratin and epithelial
membrane antigen while the osteoclast-like giant cells are positive for histiocytic
markers such as CD68.
Undifferentiated carcinoma, small cell
type. The tumour is composed of sheets
of round cells with vesicular nuclei and
prominent nucleoli that occasionally con-tain cytoplasmic mucin.
Undifferentiated carcinoma, nodular or
lobular type. The fourth variant consists
of well defined nodules or lobules of neo-plastic cells superficially resembling
breast carcinoma.
Carcinosarcoma
This malignant tumour consists of a mix-ture of two components: carcinomatous
and sarcomatous. The epithelial ele-ments usually predominate in the form of
glands but may be arranged in cords or
sheets. Foci of malignant squamous cells
are occasionally seen. The mesenchymal
component includes foci of heterologous
elements such as chondrosarcoma,
osteosarcoma, and rhabdomyosarcoma.
Cytokeratin and carcinoembryonic anti-gen are absent from the mesenchymal
Fig. 9.13 Adenocarcinoma (CA) of the distal common bile duct, infiltrating the duodenal wall.
Fig. 9.14  Clear cell carcinoma of extrahepatic bile
duct. The overlying biliary epithelium is non-neo-plastic.
Fig. 9.12  Carcinosarcoma of gallbladder. The
tumour shows malignant glandular elements and a
sarcomatous component with osteoid formation.
CA
210 Tumours of the gallbladder and extrahepatic bile ducts
component, which helps to distinguish
carcinosarcomas from spindle and giant
cell carcinomas.
Grading
Adenocarcinomas can be divided into
well, moderately, or poorly differentiated
types. The diagnosis of well differentiat-ed adenocarcinoma requires that 95% of
the tumour contains glands. For moder-ately differentiated adenocarcinoma 40
to 94% of the tumour should be com-posed of glands and for poorly differenti-ated adenocarcinomas 5 to 39% of the
tumour should contain glands. Undiffer-entiated carcinomas display less than
5% of glandular structures.
Precursor lesions
Adenoma
Adenomas are benign neoplasms of
glandular epithelium (intraepithelial neo-plasia) that are typically polypoid, single
and well-demarcated. They are more
common in women than in men {42}.
There is a wide age range; although
mostly a disease of adults rare gallblad-der adenomas occur in children {1256,
2126}. They are more common in the
gallbladder than in the extrahepatic bile
ducts, and are found in 0.3-0.5% of gall-bladders removed for cholelithiasis or
chronic cholecystitis. A small proportion
of adenomas progress to carcinoma {42,
909, 967}.
Adenomas are often small, asympto-matic, and usually discovered incidental-ly during cholecystectomy, but they can
be multiple, fill the lumen of the gallblad-der and be symptomatic. Occasionally,
adenomas of the gallbladder occur in
association with the Peutz-Jeghers syn-drome {521} or with Gardner syndrome
{1900, 2041}. Adenomas of the extrahep-atic bile ducts are usually symptomatic
and cause biliary obstruction. These
benign tumours are not associated with
lithiasis.
According to their pattern of growth, they
are divided into three types: tubular, pap-illary, and tubulopapillary. Cytologically,
they are classified as: pyloric gland type,
intestinal type, and biliary type. Tubular
adenomas of pyloric gland type are more
common in the gallbladder while intestin-al type adenomas are more common in
the extrahepatic bile ducts {42}.
Tubular adenoma, pyloric-gland type. A
benign tumour composed of closely
packed short tubular glands that are sim-ilar to pyloric glands. Early lesions
appear as well demarcated nodules
embedded in the lamina propria and
covered with normal biliary epithelium.
They are composed of lobules that con-tain closely packed pyloric-type glands,
some of which may be cystically dilated.
The epithelial cells are columnar or
cuboidal with vesicular or hyperchromat-ic nuclei and small nucleoli and variable
amounts of cytoplasmic mucin. Nodular
aggregates of cytologically bland spin-dle cells with eosinophilic cytoplasm but
without keratinization or intercellular
bridges known as squamoid morules
{984, 1361} are present in about 10% of
the cases, whereas frank squamous
metaplasia is exceedingly rare. Paneth
cells and  endocrine cells are often pres-ent. By immunohistochemistry, serotonin
and a variety of peptide hormones
including somatostatin, pancreatic
polypeptide, and gastrin have been
detected in the cytoplasm of these cells.
Smaller lesions show low-grade intraep-ithelial neoplasia, but larger adenomas
may have high-grade changes or foci of
invasive carcinoma. As they enlarge,
most adenomas develop a pedicle and
project into the lumen. Rarely, they
extend into or arise from Rokitansky-Aschoff sinuses, a finding that should not
be mistaken for carcinoma {42}.
Tubular adenoma, intestinal type. This
benign tumour is composed of tubular
glands lined by cells with an intestinal
phenotype, and closely resembles
colonic adenomas. It consists of tubular
glands lined by pseudostratified colum-nar cells with elongated hyperchromatic
nuclei, and high-grade dysplastic
changes are frequent. The glands lack
invasive properties and focally are
arranged in well defined lobules. The
adenomatous epithelium may extend into
the Rokitansky-Aschoff sinuses, a finding
that should not be confused with stromal
invasion. Clusters of goblet, Paneth, and
endocrine cells are usually mixed with
the columnar cells. Serotonin and, less
frequently, peptide hormones have been
identified in the endocrine cells by
immunohistochemistry. Hyperplasia of
metaplastic pyloric type glands is often
seen at the base of the adenomas.
Papillary adenoma, intestinal type.  This
benign tumour consists predominantly of
papillary structures lined by dysplastic
cells with an intestinal phenotype. These
adenomas, which usually arise in a back-ground of pyloric gland metaplasia, may
Fig. 9.15 Papillary adenoma of gallbladder, intestinal type. A Numerous papillary structures project into lumen. B Pseudostratified columnar cells with scattered gob-let and Paneth cells.
A
B
211Carcinoma
occur in the gallbladder or the extrahep-atic bile ducts. In a series of five intestin-al type papillary adenomas of the gall-bladder, one progressed to invasive car-cinoma {42}. The predominant cell is
columnar with elongated hyperchromatic
nuclei and little or no cytoplasmic mucin.
The cells are pseudostratified, mitotically
active, and indistinguishable from those
of villous adenomas arising in the large
intestine. Tubular glands lined by the
same type of epithelium, but represent-ing less than 20% of the tumour, may also
be found. Dysplastic changes are more
extensive than in pyloric-gland type ade-nomas. Also present are goblet, Paneth,
and serotonin-containing cells. Some of
the endocrine cells are immunoreactive
for peptide hormones.
Papillary adenoma, biliary type.  This
lesion consists predominantly of papil-lary structures lined by cells with a biliary
phenotype. It is well demarcated and
consists of papillary structures lined by
tall columnar cells, which except for the
presence of more cytoplasmic mucin
show minimal variation from normal gall-bladder epithelium. Endocrine or Paneth
cells are not found. Only mild dysplastic
changes are noted. In situ or invasive
carcinoma has not been reported in
association with these adenomas. This is
the rarest form of adenoma of the gall-bladder; we have seen only one case.
Most papillary lesions composed of nor-mal-appearing gallbladder epithelium
are examples of hyperplasia secondary
to chronic cholecystitis.
Tubulo-papillary adenoma. When tubular
glands and papillary structures each
comprise more than 20% of the tumour,
the term tubulo-papillary adenoma is
applied. Two subtypes are recognized:
one is composed of tubular glands and
papillary structures similar to those of
tubulovillous intestinal adenomas; the
other subtype consists of tubular glands
similar to pyloric glands and papillary
structures often lined by foveolar epithe-lium. Paneth and endocrine cells are
present in some. Rarely, tubulo-papillary
adenomas arise from the epithelial
invaginations of adenomyomatous hyper-plasia.
Other benign biliary lesions
Biliary cystadenoma. These lesions
resemble their intrahepatic counterparts
(see chapter on bile duct cystadenoma
and cystadenocarcinoma). Cystadeno-mas are seen predominantly among
adult females and are usually sympto-matic. Some of the tumours may meas-ure up to 20 cm in diameter leading to
obstructive jaundice or cholecystitis-like
symptoms. More common in the extra-hepatic bile ducts than in the gallblad-der, cystadenomas are multiloculated
neoplasms that contain mucinous or
serous fluid and are lined by columnar
epithelium reminiscent of bile duct
or foveolar gastric epithelium {404}.
Occasionally endocrine cells are pres-ent. The cellular subepithelial stroma
resembles ovarian stroma and shows
immunoreactivity for estrogen and prog-esterone receptors {2029}. The stroma
also shows variable fibrosis. Malignant
transformation (cystadenocarcinoma)
can occur {404}.
Papillomatosis (adenomatosis).   Papillo-matosis is a clinicopathological condition
characterized by multiple recurring papil-lary adenomas, that may involve exten-sive areas of the extrahepatic bile ducts
and even extend into the gallbladder and
intrahepatic bile ducts. The disease
affects both sexes equally. Most patients
are adults between 50 and 60 years.
Complete excision of the multicentric
lesions is difficult and local recurrence is
common. The lesion consists of numer-ous papillary structures as well as com-plex glandular formations. Because
severe dysplasia is often present, papillo-matosis is difficult to distinguish from
papillary carcinoma. Some regard this
lesion as a form of low-grade multicentric
intraductal papillary carcinoma. Papil-lomatosis has a greater potential for
malignant transformation than solitary
adenomas.
Intraepithelial neoplasia (dysplasia)
If intraepithelial neoplasia is found, multi-ple sections should be taken to exclude
invasive cancer. Cholecystectomy is a
curative surgical procedure for patients
with in situ carcinoma or with carcinoma
extending into the lamina propria {35}.
Epidemiology. The rate of intraepithelial
neoplasia of the gallbladder reflects that
of invasive carcinoma. In countries in
which carcinoma of the gallbladder is
endemic, the prevalence is higher than in
countries in which this tumour is spo-radic. Studies from different countries
have shown that the incidence of high-grade dysplasia or carcinoma in situ in
gallbladders with lithiasis has varied from
0.5-3% {35}. This variation in the inci-dence of intraepithelial neoplasia is also
attributable to other factors such as lack
of uniformity in morphological criteria
and sampling methods.
Fig. 9.16  A, B Tubular adenoma of gallbladder, pyloric gland type.
AB
212 Tumours of the gallbladder and extrahepatic bile ducts
Macroscopic features.  Intraepithelial
neoplasia is usually not recognized on
macroscopic examination because it
often occurs in association with chronic
cholecystitis. The mucosa may appear
granular, nodular, plaque-like, or trabec-ulated. The papillary type of intraepithe-lial neoplasia usually appears as a small,
cauliflower-like excrescence that projects
into the lumen and can be recognized on
close inspection. However, in most
cases, the gallbladder shows only a
thickened and indurated wall, the result
of chronic inflammation and fibrosis.
Microscopic features.  Microscopically
two types of intraepithelial neoplasia are
recognized: papillary and flat, the latter
being more common. The papillary type
is characterized by short fibrovascular
stalks that are covered by dysplastic or
neoplastic cells.
Intraepithelial neoplasia usually begins
on the surface epithelium and subse-quently extends downward into the
Rokitansky-Aschoff sinuses and into
metaplastic pyloric glands. Columnar,
cuboidal, and elongated cells with vari-able degrees of nuclear atypia, loss of
polarity, and occasional mitotic figures
are characteristic. The dysplastic cells
are usually arranged in a single layer, but
can be pseudostratified. Later, papillary
structures covered by dysplastic epitheli-um may form. The large nuclei of dys-plastic cells may be round, oval, or
fusiform, with one or two nucleoli that are
more prominent than those of normal
cells.
The cytoplasm is usually eosino-philic
and contains non-sulphated acid and
neutral mucin. Goblet cells are found in
one third of cases. An abrupt transition
between normal-appearing columnar
cells and intraepithelial neoplasia is seen
in nearly all cases. In general, the cell
population of dysplasia is homogeneous,
unlike the heterogeneous cell population
of the epithelial atypia of repair. Wide-spread involvement of the mucosa by
intraepithelial neoplasia often occurs. For
this reason, we have suggested that
some, if not most, invasive carcinomas of
the gallbladder arise from a field change
within the epithelium.
The cells of intraepithelial neoplasia are
reactive for CEA and for the carbohy-drate antigen CA19-9 {35}. Expression of
p53 occurs in some lesions {2125}.
Differential diagnosis. Reactive epithelial
changes (‘atypia of repair’) differs from
intraepithelial neoplasia in consisting of a
heterogeneous cell population in which
columnar mucus-secreting cells, low
cuboidal cells, atrophic-appearing epithe-lium, and pencil-like cells are present. In
addition, there is a gradual transition of
the cellular abnormalities, in contrast with
the abrupt transition seen in intraepithelial
neoplasia. The extent of nuclear atypia is
less pronounced in reactive changes and
immunoreactivity for p53 protein is
absent, while usually positive in intraep-ithelial neoplasia.
High-grade intraepithelial neoplasia and
carcinoma in situ
In cases where the cells have all the
cytological features of malignancy with
frequent mitotic figures, nuclear crowd-ing and prominent pseudostratification,
the term carcinoma in situ may be used.
Neoplastic cells first appear along the
surface epithelium and later spread into
the epithelial invaginations and antral-type metaplastic glands. In the late
stages of carcinoma in situ, the histolog-ical picture is that of back-to-back glands
located in the lamina propria but often
connected with the surface epithelium.
However, not all in situ carcinomas exhib-it this type of growth pattern. Some show
distinctive papillary features with small
fibrovascular stalks lined by neoplastic
cells. Not infrequently, a combination of
these growth patterns is seen.
The differential diagnosis between high-grade intraepithelial neoplasia (severe
dysplasia) and carcinoma in situ is diffi-cult and often impossible in many cases.
This is not important because the two
lesions, which vary only in degree histo-logically, are closely related biologically
Histological variants of carcinoma in situ.
An in situ carcinoma composed of goblet
cells, columnar cells, Paneth cells, and
endocrine cells, has been described,
which may represent an in situ phase of
intestinal-type adenocarcinoma {35, 41}.
Another type of in situ intestinal-type car-cinoma is composed of cells closely
resembling those of colonic carcinomas
at the light and electron microscopic lev-Fig. 9.18  High-grade intraepithelial neoplasia adja-cent to intestinal metaplasia with numerous mature
goblet cells.
Fig. 9.17 High-grade intraepithelial neoplasia (carcinoma in situ) of gallbladder.
AB
213Carcinoma
els. The neoplastic columnar cells
extend into the epithelial invaginations
and the antral-type glands. Formation of
cribriform structures in the lamina propria
occurs. This tumour also has scattered
endocrine cells, most of which are
immunoreactive for serotonin.
Two examples of in situ signet-ring cell
carcinoma confined to the surface
epithelium and to the epithelial invagina-tions of the gallbladder have been
reported {40}. These in situ signet ring
cell carcinomas represented incidental
findings in cholecystectomy specimens
and were cytologically similar to those
reported in the stomach. This unusual
form of carcinoma in situ should be dis-tinguished from epithelial cells which
acquire signet-ring cell morphology
when desquamated within the lumen of
dilated metaplastic pyloric glands in
cases of chronic cholecystitis and from
mucin-containing histiocytes (muci-phages).
The morphological type of in situ carci-noma does not always correspond with
that of the invasive carcinoma. For exam-ple, we have seen conventional adeno-carcinoma in situ in the mucosa adjacent
to invasive squamous, small cell, and
undifferentiated carcinomas.
The wall of the gallbladder with dysplasia
or carcinoma in situ usually shows vari-able inflammatory changes, typically with
a predominance of lymphocytes and
plasma cells, although lymphoid follicles
with germinal centers, xanthogranuloma-tous inflammation or an acute inflamma-tory reaction may be present.
Molecular pathology
Mutations of  TP53 are found in the vast
majority of invasive gallbladder carcino-mas {2124, 2127}. Loss of heterozygosi-ty (LOH) at chromosomal loci 8p (44%),
9p (50%) and 18q (31%) are also fre-quently detected {2127}. These genetic
alterations are considered early events,
while RAS mutations and LOH at 3p, RB,
and 5q occur less frequently and are
considered late events, probably related
to tumour progression. Amplification of
the c-erbB-2 gene, that codes for a gly-coprotein structurally similar to the epi-dermal growth factor receptor was
detected in 30 of 43 invasive gallbladder
carcinomas {1036}. However, no correla-tion between  c-erbB-2 gene amplifica-tion and prognosis was found.
In contrast to lesions of the gallbladder,
the incidence of TP53 mutations in extra-hepatic bile duct carcinomas is lower
and appears to be a late molecular
event.
Although the frequency of  KRAS muta-tions in gallbladder carcinomas has
ranged from 0%-34% in different studies,
most investigators have found these
mutations to be significantly higher in
extrahepatic bile duct tumours than in
gallbladder carcinomas {2067}. Depend-ing on the study, the incidence of  KRAS
mutations in extrahepatic bile duct carci-nomas has varied from 0-100% {1586},
but most likely, the true incidence is
around 56% {2067}. However, the inci-dence of  KRAS mutations is greater in
gallbladder carcinomas associated with
an anomalous junction of the pancreati-cobiliary duct than in carcinomas not
associated with this congenital anomaly
{661}. These molecular pathology find-ings support the concept that gallbladder
carcinogenesis requires a number of
genetic alterations involving activation of
oncogenes or inactivation of tumour sup-pressor genes.
The molecular pathology of adenomas of
the gallbladder differs from that of carci-nomas. None of 16 adenomas showed
TP53 or p16  Ink4/CDKN2a gene muta-tions, which are common in carcinomas
{2126}. Four adenomas had KRAS muta-tions (2 in codon 12 and 2 in codon 61)
which are considered rare and late
Fig. 9.19  Biliary papillomatosis. A Large, thickened intrahepatic and extrahepatic bile ducts. B Villous pattern. C There is no invasion by tumour cells.
Fig. 9.20 Papillomatosis of extrahepatic bile duct.
ABC
214 Tumours of the gallbladder and extrahepatic bile ducts
events in the pathogenesis of carcino-mas of the gallbladder. Only one adeno-ma of intestinal type showed loss of het-erozygosity at 5q22 {2126}.
Intraepithelial neoplasia (both dysplasia
and carcinoma in situ) shows a high inci-dence of loss of heterozygosity at the
TP53 gene locus. Other molecular abnor-malities include loss of heterozygosity at
9p and 8p loci and the 18q gene. These
abnormalities are also early events and
most likely contributing factors in the
pathogenesis of gallbladder carcinoma.
However,  KRAS mutations were not
detected in intraepithelial neoplasia
{2125}.
Prognosis and predictive factors
The prognosis of tumours of the extra-hepatic biliary tract depends primarily on
the extent of disease and histological
type {694, 695}. Polypoid tumours (which
histologically often prove to be papillary
carcinomas) have the best prognosis.
Non-invasive papillary carcinomas are
associated with a better prognosis than
other types of invasive carcinomas.
Perineural invasion and lymphatic per-meation are common in the extrahepatic
bile duct carcinoma and are significant
prognostic factors {2150, 376}.
Definition
Tumours with endocrine differentiation
arising from the extrahepatic bile ducts
and gallbladder.
Epidemiology
In an analysis of 8305 cases of carcinoids
of all sites, 19 cases of gallbladder and
one case of biliary tract carcinoids were
recorded, representing 0.2% and 0.01%
of cases {1251}. The average age of
presentation (60 years) is lower than the
average age of presentation of non-carci-noid neoplasms (71 years). The reported
male/female ratio is 1:1.2 {1251}. Small
cell carcinomas of the gallbladder, like
other carcinomas, are more common in
females (M/F ratio: 1:1.8) {1359}. The
reported average age of presentation is
65 years (range, 43-83 years) {1359}.
Small cell carcinomas represent about
4% of all malignant tumours of the gall-bladder {1359, 37}.
Aetiology
Small cell carcinomas are more common
in females and are almost always associ-ated with stones {34, 1524}. There is no
available information on the aetiology of
the very rare carcinoid tumours of the
extrahepatic biliary tree.
Localization
All types of endocrine tumours are more
often located in the gallbladder than in
extrahepatic bile ducts {1251, 2157,
1639, 34}.
Clinical features
Gallbladder carcinoids can cause recur-rent upper quadrant pain. Carcinoids of
extrahepatic bile ducts typically produce
the sudden onset of biliary colic and/or
sometimes painless jaundice {1639}.
In the majority of cases of small cell car-cinoma, the chief complaint is abdominal
pain. Other clinical features include
abdominal mass, jaundice, and ascites
{1359}. A case of primary gastrinoma of
the common hepatic duct with Zollinger-Ellison syndrome {1175}, and a patient
with Cushing syndrome due to an ACTH-secreting small cell carcinoma have
been reported {1801}.
Macroscopy
Carcinoids are usually small grey-white
or yellow submucosal nodules or polyps,
sometimes infiltrating the muscular wall,
that may be located in any part of the
gallbladder or the extrahepatic biliary
tree {1639, 34}. Small cell carcinomas
appear as a nodular mass or diffusely
invade the gallbladder wall {1359}. A sig-nificant proportion of mixed endocrine-exocrine carcinomas have a polypoid or
protruding aspect {2157, 2030}.
Histopathology
Carcinoid (well differentiated endocrine
tumour)
The cells forming this tumour are uniform
in size, with round or oval nuclei, incon-spicuous nucleolus, and eosino-philic
cytoplasm. Neoplastic cells are arranged
in combined patterns with trabecular
anastomosing structures, tubular struc-tures and solid nests {1639, 299, 603,
177}. Tumour cells show positive staining
for Grimelius silver {1639, 195, 115, 926,
1205}, chromogranin {1639, 57}, neuron-specific enolase {195, 115, 57}, and sev-C. Capella
E. Solcia
L.H. Sobin
R. Arnold
Endocrine tumours of the gallbladder
and extrahepatic bile ducts
215Endocrine tumours
eral hormones including serotonin {115,
57}, gastrin {1175, 1156}, and somato-statin {603, 57}.
Cases showing regional or distant
metastases {177, 926, 1205, 57} or signs
of local aggressive growth, including
invasion of the entire wall {1205, 57} and
neural invasion {1205}, should be con-sidered as well differentiated endocrine
carcinomas (malignant carcinoids).
Small cell carcinoma (poorly differentiat-ed endocrine carcinoma)
The cell population and growth patterns
of this tumour are similar to those of small
cell carcinoma of the lung {38, 40, 1359}.
Small cell carcinomas appear to be more
common in the gallbladder than in the
extrahepatic bile ducts. Some mimic car-cinoid tumours.
Most tumours are composed of round or
fusiform cells arranged in sheets, nests,
cords, and festoons. Rosette-like struc-tures and tubules are occasionally pres-ent. Extensive necrosis and subepithelial
growth are constant features. In necrotic
areas, intense basophilic staining of the
blood vessels occurs. The tumour cells
have round or ovoid hyperchromatic
nuclei with inconspicuous nucleoli. A few
tumour giant cells can be observed in
some cases {1359, 34}. Occasionally,
focal glandular configurations similar to
those of adenocarcinomas, and foci of
squamous differentiation are seen {40,
774, 40, 1359}. Mitotic figures are fre-quently observed and they are reported
to range from 15 to 206 (mean 75) per 10
high power fields {1359}.
Most small cell carcinomas show scat-tered Grimelius positive cells. In addition,
tumour cells immunoexpress epithelial
markers such as EMA, AE1/AE3 and
CEA, and endocrine markers such as
NSE, chromogranin A, Leu7, serotonin,
somatostatin, and ACTH {1359, 34}.
Ultrastructurally, a small number of
dense core secretory granules can be
found {34, 37}.
Mixed endocrine-exocrine carcinoma
A significant number of cases reported in
the older literature as carcinoids, includ-ing the cases reviewed by Yamamoto et
al. {2157}, are in fact mixed endocrine-exocrine carcinomas. These are com-posite tumours in which areas of adeno-carcinoma intermingle with areas of
endocrine cell carcinoma formed by
solid and/or trabecular structures with
cells which are argyrophylic and
immunoreactive for endocrine markers,
including NSE, chromogranin, serotonin
and gastrin {2157, 2030, 1405, 1575}.
The adenocarcinoma component is usu-ally tubular or papillary, formed by
columnar cells, goblet cells and some-times Paneth cells, but a case of a com-bined diffuse type tumour in which
mucin-containing signet-ring cells were
admixed with clear endocrine cells has
also been reported {1455}.
These tumours behave as adenocarcino-mas and, therefore, are clinically more
aggressive than carcinoids. Adenocar-cinoma with endocrine cells should not
be included in this category.
Genetic susceptibility
Carcinoids of the gallbladder and extra-hepatic bile ducts are infrequently asso-ciated with the Zollinger-Ellison, MEN I,
or the carcinoid syndromes. One patient
with von Hippel-Lindau syndrome and a
carcinoid tumour of the extrahepatic bile
ducts has been reported.
Fig. 9.22 Small cell carcinoma lying below normal
gallbladder epithelium.
Fig. 9.21 Carcinoid tumour of common bile duct. A A band of fibrous tissue separates the tumour from normal bile duct epithelium. B Carcinoid cells with round nuclei
and eosinophilic cytoplasm. C The tumour cells are immunoreactive for serotonin.
AB C
216 Tumours of the gallbladder and extrahepatic bile ducts
Genetics
Overexpression of TP53 has been found
in 64% of small cell carcinomas of the
gallbladder {1359}, compared with a fre-quency of 44% in small cell carcinomas
of the lung {773} and 75% in small cell
carcinomas of the stomach {1589}.
Prognostic factors
The percentage of gallbladder carci-noids showing regional and distant
metastases has been estimated as
approximately 44% and 11%, respective-ly {1251}. The 5-year survival rate was
41% in SEER data. Carcinoid tumours
larger than 2 cm often extend into the
liver or metastasize. Complete excision
of small tumours is usually curative. The
prognosis of small cell carcinoma of the
gallbladder is poor, with only one of 18
patients {34} surviving 11 months follow-ing cholecystectomy, radiotherapy, and
chemotherapy. In one study, the survival
rates differed significantly between
stages I, II, III and stage IV {1359}. The
survival of patients with small cell carci-noma of the gallbladder appears to be
shorter than that of patients with papillary
adenocarcinoma {1359}.
Neural and mesenchymal tumours
Paraganglioma
This benign tumour is composed of chief
cells and sustentacular cells arranged in
a nesting or zellballen pattern. The chief
cells are argyrophilic and stain for neu-ron-specific enolase and chromogranin.
The sustentacular cells are S-100 protein
positive. The tumour is located in either
the subserosa or muscular wall of the
gallbladder and apparently arises from
normal paraganglia. This rare and small
tumour is usually an incidental finding in
cholecystectomy specimens. Paragan-gliomas also occur in the extrahepatic
bile ducts, where they may be sympto-matic.
Granular cell tumour
Granular cell tumours are the most com-mon benign non-epithelial tumours of the
extrahepatic biliary tract. They are more
common in the bile ducts than in the gall-bladder. Although usually single, granu-lar cell tumours may be multicentric or
may coexist with one or more granular
cell tumours in other sites, especially the
skin.
Ganglioneuromatosis
Ganglioneuromatosis of the gallbladder
is a component of the type Ilb multiple
endocrine neoplasia syndrome. The his-tological changes consist of Schwann
cell and ganglion cell proliferation in the
lamina propria as well as enlarged and
distorted nerves in the muscle layer and
subserosa. Neurofibromatosis is exceed-ingly rare in the gallbladder but has been
reported in association with multiple neu-rofibromatosis.
Embryonal rhabdomyosarcoma (‘sarco-ma botryoides’) is the most common
malignant neoplasm of the biliary tract in
childhood. It occurs more frequently in
the bile ducts than in the gallbladder.
Kaposi sarcoma of the extrahepatic bil-iary tract is an incidental autopsy finding
in the acquired immune deficiency syn-drome. The haemorrhagic lesions are
usually located in the subserosa or mus-cular wall of the gallbladder or in the
periductal connective tissue of the bile
ducts. Other malignant non-epithelial
tumours are leiomyosarcoma, malignant
fibrous histiocytoma and angiosarcoma.
Leiomyoma, lipoma, haemangioma, and
lymphangioma have been described. A
benign stromal tumour of the gallbladder
with interstitial cells of Cajal phenotype
has been reported recently {35}.
J. Albores-Saavedra H.R. Menck
J.C. Scoazec N. Soehendra
C. Wittekind P.V.J. Sriram
B. Sripa
217Lymphoma / Secondary tumours
Incidence and origins
Although rare in clinical practice, gall-bladder and extrahepatic bile duct
metastases were encountered in 15%
and 6% of cases respectively in an
autopsy study of melanoma patients
{373}. Indeed, malignant melanoma
accounts for more than 50% of all report-ed cases of gallbladder and intrabiliary
metastases {100}. Other metastatic
lesions include carcinomas of the kidney,
lung, breast, ovary and oesophagus {35,
1674, 2085}; some examples result from
transcoelomic spread in the setting of
peritoneal carcinomatosis. The gallblad-der and extrahepatic bile ducts may also
be involved by direct extension from car-cinomas of the pancreas, stomach, colon
and liver.
Metastatic infiltration of the common bile
duct by carcinoma of the breast, giving
rise to obstructive jaundice, has been
reported {471}. Certain types of non-Hodgkin lymphoma (e.g. mantle cell lym-phoma) may also involve the common
bile duct.
Malignant melanoma
Primary malignant melanoma is exceed-ingly rare in the gallbladder. Junctional
activity in the epithelium adjacent to the
tumour, absence of a primary melanoma
elsewhere in the body and long term sur-vival are important features to distinguish
primary from the more commonly occur-ring metastatic melanoma. However,
junctional activity has been reported in
metastatic melanoma in the gallbladder.
Clinical features
Involvement of the gallbladder by
metastatic tumour rarely produces symp-toms, which could explain the paucity of
clinical reports published in the literature
{373, 427}. When symptoms are present,
they are usually those of acute cholecys-titis {1433, 1013, 427}. Patients with bile
duct metastases may present with
obstructive jaundice {180}.
Ultrasound may be used to evaluate
metastatic lesions within the gallbladder.
Computed tomography is also helpful
especially for assessing the extent of
tumour when therapeutic intervention is
contemplated {1013}. The common bile
duct is best imaged through the use of
ultrasound, endoscopic retrograde
cholangiography, and percutaneous
transhepatic cholangiography.
Macroscopy
Intraluminal metastases of melanoma
tend to be polypoid whilst metastatic car-cinoma of the breast and lymphoma pro-duce diffuse infiltrates and strictures.
Histopathology
The features are similar to those
observed in other organs.
P. DeMatos
P.P. AnthonySecondary tumours and melanoma
In common with lymphoma elsewhere in
the digestive system, primary lymphoma
of the gallbladder is defined as an extra-nodal lymphoma arising in the gallblad-der with the bulk of the disease localized
to this site {796}. Contiguous lymph node
involvement and distant spread may be
seen but the primary clinical presenta-tion is in the gallbladder with therapy
directed at this site.
Primary lymphoma of the gallbladder is
extremely rare, with only about 13 cases
reported {282, 1201, 94, 138}. Two cases
of low-grade B-cell MALT lymphoma
have been described {1201, 138}, while
the majority of the remainder have been
large B-cell lymphomas. MALT lym-phomas may arise within acquired MALT
that is frequently encountered within gall-bladders associated with chronic chole-cystitis {1943}. The morphology of pri-mary MALT lymphoma of the gallbladder
resembles that seen elsewhere in the
digestive tract. Lymphoid follicles are
surrounded by an infiltrate of centrocyte-like (CCL) cells showing variable plasma
cell differentiation. Infiltration of the
epithelium with the formation of lym-phoepithelial lesions is a typical feature.
Characteristically, the CCL cells show
expression of the pan-B-cell markers
CD20 and CD79a, and there is frequent
expression of bcl-2 protein. Tumour cells
are usually negative for CD5 and CD10
but there may be expression of CD43.
A. Wotherspoon
Lymphoma of the gallbladder

CHAPTER 10
Tumours of the Exocrine Pancreas
Pancreatic carcinoma is a highly malignant neoplasm that still
carries a very poor prognosis. Ductal adenocarcinoma is the
most frequent type. Although cigarette smoking has been
established as a causative factor, the risk attributable to
tobacco abuse amounting to approximately 30%. An increased
risk is also associated with hereditary pancreatitis, but addi-tional aetiological factors remain to be identified.
Significant progress has been made in the understanding of
the molecular basis of ductal carcinomas.  KRAS point muta-tions and inactivation of the tumour suppressor genes  p16,
TP53 and DPC4 have been identified as most frequent genetic
alterations.
Non-ductal pancreatic neoplasms span a wide range of histo-logical features that need to be recognized by pathologists as
several entities are associated with distinct opportunities for
therapy.
Epithelial tumours
Benign
Serous cystadenoma 8441/01
Mucinous cystadenoma 8470/0
Intraductal papillary-mucinous adenoma 8453/0
Mature teratoma 9080/0
Borderline (uncertain malignant potential)
Mucinous cystic neoplasm with moderate dysplasia 8470/1
Intraductal papillary-mucinous neoplasm with moderate dysplasia 8453/1
Solid-pseudopapillary neoplasm 8452/1
Malignant
Ductal adenocarcinoma 8500/3
Mucinous noncystic carcinoma 8480/3
Signet ring cell carcinoma 8490/3
Adenosquamous carcinoma 8560/3
Undifferentiated (anaplastic) carcinoma 8020/3
Undifferentiated carcinoma with osteoclast-like giant cells 8035/3
Mixed ductal-endocrine carcinoma 8154/3
Serous cystadenocarcinoma 8441/3
Mucinous cystadenocarcinoma 8470/3
– non-invasive 8470/2
– invasive 8470/3
Intraductal papillary-mucinous carcinoma 8453/3
– non-invasive 8453/2
– invasive (papillary-mucinous carcinoma) 8453/3
Acinar cell carcinoma 8550/3
Acinar cell cystadenocarcinoma 8551/3
Mixed acinar-endocrine carcinoma 8154/3
Pancreatoblastoma 8971/3
Solid-pseudopapillary carcinoma 8452/3
Others
Non-epithelial tumours
Secondary tumours
WHO histological classification of tumours of the exocrine pancreas
TNM classification1, 2
Primary Tumour (T)
TX Primary tumour cannot be assessed
T0 No evidence of primary tumour
Tis Carcinoma in situ
T1 Tumour limited to the pancreas, 2 cm or less in greatest dimen-sion
T2 Tumour limited to the pancreas, more than 2 cm in greatest
dimension
T3 Tumour extends directly into any of the following: duodenum, bile
duct, peripancreatic tissues3
T4 Tumour extends directly into any of the following: stomach,
spleen, colon, adjacent large vessels4
Regional Lymph Nodes (N)
NX Regional lymph nodes cannot be assessed
N0 No regional lymph node metastasis
N1 Regional lymph node metastasis
N1a Metastasis in a single regional lymph node
N1b Metastasis in multiple regional lymph nodes
Distant Metastasis (M)
MX Distant metastasis cannot be assessed
M0 No distant metastasis
MI Distant metastasis
Stage grouping
Stage 0 Tis N0 M0
Stage I T1 N0 M0
T2 N0 M0
Stage II T3 N0 M0
Stage III T1 N1 M0
T2 N1 M0
T3 N1 M0
Stage IVA T4 Any N M0
Stage IVB Any T Any N M1
_________
1
Morphology code of the International Classification of Diseases for Oncology (ICD-O) {542} and the Systematized Nomenclature of Medicine (http://snomed.org). Behaviour is coded
/0 for benign tumours, /1 for unspecified, borderline or uncertain behaviour, (/2 for in situ carcinomas) and /3 for malignant tumours.
TNM classification of tumours of the exocrine pancreas
220 Tumours of the exocrine pancreas
_________
1
{1, 66}. This classification applies only to carcinomas of the exocrine pancreas.
2
A help desk for specific questions about the TNM classification is available at http://tnm.uicc.org.
3
Peripancreatic tissues include the surrounding retroperitoneal fat (retroperitoneal soft tissue or retroperitoneal space), including mesentery (mesenteric fat), mesocolon, greater and
lesser omentum, and peritoneum. Direct invasion to bile ducts and duodenum includes involvement of ampulla of Vater.
4
Adjacent large vessels are the portal vein, coeliac artery, and superior mesenteric and common hepatic arteries and veins (not splenic vessels).
221Ductal adenocarcinoma
Ductal adenocarcinoma of the pancreas G. Klöppel G. Adler
R.H. Hruban S.E. Kern
D.S. Longnecker T.J. Partanen
Definition
A carcinoma occurring almost exclusive-ly in adults that probably arises from and
is phenotypically similar to, pancreatic
duct epithelia, with mucin production
and expression of a characteristic cyto-keratin pattern.
ICD-O codes
Ductal adenocarcinoma 8500/3
Mucinous noncystic carcinoma 8480/3
Signet ring cell carcinoma 8490/3
Adenosquamous carcinoma 8560/3
Undifferentiated (anaplastic)
carcinoma 8020/3
Undifferentiated carcinoma
with osteoclast-like giant cells 8035/3
Mixed ductal-endocrine
carcinoma 8154/3
Epidemiology
Incidence and geographical distribution
Ductal adenocarcinoma and its variants
are the most common neoplasms in the
pancreas, representing 85-90% of all
pancreatic neoplasms {359, 941, 1781}.
In developed countries, the annual age-adjusted incidence rates (world standard
population) range from 3.1 (Herault,
France) to 20.8 (central Louisiana, USA,
blacks) per 100,000 males and from 2.0
(Herault, France) to 11.0 (San Francisco,
CA, USA, blacks) per 100,000 females
{1471}. Rates from most developing
countries range from 1.0 to close to 10
per 100,000. Incidence and mortality
rates are almost identical, since survival
rates for pancreatic carcinoma are very
low.
Time trends
After a steady increase between 1930
and 1980, the incidence rates have
levelled off {593}. It is currently the fifth
leading cause of cancer death in
Western countries, second only to colon
cancer among malignancies of the
digestive tract.
Age and sex distribution
Approximately 80% of cases manifest
clinically in patients 60-80 years; cases
below the age of 40 years are rare {1781}.
The incidence of pancreatic carcinoma is
slightly higher among men than women,
with a male/female ratio of 1.6 in devel-oped nations and 1.1 in developing coun-tries. Blacks have distinctly higher rates
than whites {593}.
Aetiology
The development of pancreatic carcino-ma is strongly related to cigarette smok-ing, which carries a 2-3 fold relative risk
(RR) that increases with the number of
pack-years of smoking {21}. Although the
association between cigarette smoking
and pancreatic carcinoma is not as strong
as that between cigarette smoking and
lung cancer (RR > 20), it has been esti-mated that a substantial reduction of the
number of smokers in the European Union
could save as many as 68,000 lives that
would otherwise be lost to pancreatic
cancer during the next 20 years {1293}.
Chronic pancreatitis, past gastric sur-gery, occupational exposure to chemi-cals such as chlorinated hydrocarbon
solvents, radiation exposure, and dia-betes mellitus have also been associated
with the development of pancreatic car-cinoma {593, 1100, 2080}. A markedly
increased risk has been observed in
hereditary pancreatitis {1101}.
A number of dietary factors have been
putatively connected with pancreatic can-cer, including a diet low in fibre and high
in meat and fat {593}. Coffee consumption
was once thought to be a risk factor for
pancreatic carcinoma, but recent studies
showed no significant associations {593}.
Localization
60-70% of pancreatic ductal adenocarci-nomas are found in the head of the
gland, the remainder occur in the body
and/or tail. Pancreatic head tumours are
mainly localized in the upper half, rarely
in the uncinate process {1781}. Rarely,
heterotopic pancreatic tissue gives rise
to a carcinoma {596, 1898}.
Clinical features
Symptoms and signs
Clinical features include abdominal pain,
unexplained weight loss, jaundice and
pruritus. Diabetes mellitus is present in
Fig. 10.01 Global distribution of pancreatic cancer (2000). Note the high incidence areas in North America,
Europe, and the Russian Federation.
7.8
2.8
8.9
1.5
6.1
5.7
< 1.8 < 2.9 < 5.4 < 7.7 < 11.7
7.0
222 Tumours of the exocrine pancreas
70% of patients, usually with a diabetes
history of less than 2 years. Later symp-toms are related to liver metastasis and/or
invasion of adjacent organs (stomach,
colon) or of the peritoneal cavity (ascites).
Occasionally, patients present with acute
pancreatitis {621}, migratory throm-bophlebitis, hypoglycaemia, or hypercal-caemia {1261}.
Imaging and laboratory tests
Currently, the most important tests for
establishing the diagnosis of pancreatic
carcinoma are ultrasonography (US) and
computerised tomography (CT) or mag-netic resonance imaging (MRI), with or
without guided percutaneous fine-needle
biopsy, endoscopic retrograde cholan-giography (ERCP), endoscopic ultra-sonography (EUS) and tumour marker
determination (CA 19-9, Du-Pan 2, CEA,
Span-1). The sensitivity and specificity of
any of these tests alone ranges between
55 and 95%. By applying combinations
of these tests, accuracy rates of more
than 95% have been achieved {2061}.
On transabdominal US and on EUS, pan-creatic ductal adenocarcinomas are
characterised as echo-poor and inhomo-geneous mass lesions in about 80% of
cases. About 10% of the tumours appear
echo-rich. With increasing size, tumours
tend to become inhomogeneous, with
cystic and echo-rich areas. Indirect signs
of a pancreatic tumour (dilatation of pan-creatic and/or common bile duct) are
usually found proximal to tumours larger
than 3 cm. On EUS lymph node metas-tases appear as enlarged echo-poor
nodes. ERPC may demonstrate dis-placement, narrowing, or obstruction of
the pancreatic duct. Angiography is
helpful in preoperative management.
CT shows pancreatic adenocarcinomas
as hypodense masses in up to 92% of
cases {528}. Diffuse tumour involvement
of the pancreas is found in about 4%. In
up to 4% the pancreatic and common
bile duct are dilated without an identifi-able mass.
KRAS mutations.  Mutations in codon 12
of the KRAS gene have been detected in
the stool, in pancreatic juice and/or
blood samples from patients with proven
ductal adenocarcinoma of the pancreas
{224, 960, 1876}, but their diagnostic
value in is still controversial.
Fine needle aspiration (FNA)
FNA can be performed percutaneously
with guidance by imaging techniques or
under direct visualisation at surgery.
Aspirates from a typical, well to moder-ately differentiated ductal adenocarcino-ma show a cellular aspirate {32, 940}.
Pancreatic juice cytology obtained from
ERCP is less sensitive than percuta-neous or intraoperative FNA (76 versus
90 to 100%) {32, 1242, 1311}.
Macroscopy
Ductal adenocarcinomas are firm and
poorly defined masses. The cut surfaces
are yellow to white. Haemorrhage and
necrosis are uncommon, but microcystic
areas may occur. In surgical series, the
size of most carcinomas of the head of
the pancreas ranges from 1.5 to 5 cm,
with a mean diameter between 2.5 and
3.5 cm. Carcinomas of the body/tail are
usually somewhat larger at diagnosis.
Tumours with a diameter less than 2 cm
are infrequent {697} and may be difficult
to recognise by gross inspection.
Carcinomas of the head of the pancreas
usually invade the common bile duct
and/or the main pancreatic duct and pro-duce stenosis that results in proximal
dilatation of both duct systems.
Complete obstruction of the main pan-creatic duct leads to extreme prestenotic
duct dilatation with duct haustration and
fibrous atrophy of the parenchyma
(i.e. obstructive chronic pancreatitis).
More advanced pancreatic head carci-nomas involve the ampulla of Vater
and/or the duodenal wall, causing ulcer-ations. Carcinomas in the pancreatic
body or tail obstruct the main pancreatic
duct, but typically do not involve the
common bile duct.
Tumour spread and staging
It is an exception to find a resected car-cinoma that is still limited to the pancreas
{1414}. In head carcinomas, peripancre-Fig. 10.02 Ductal adenocarcinoma. An ill-defined
pale carcinoma in the head of the pancreas.
Fig. 10.03 Ductal adenocarcinoma. A Well differentiated tumour with desmoplasia and irregular gland formation. B Well differentiated neoplasm involving a normal
duct (right part).
AB
223Ductal adenocarcinoma
atic tumour invasion, often via perineural
sheaths, primarily involves the retroperi-toneal fatty tissue. Subsequently, retro-peritoneal veins and nerves are invaded.
Direct extension into neighbouring or-gans and/or the peritoneum is seen in
advanced cases. In carcinomas of the
body and tail, local extension is usually
greater, because of delayed tumour
detection, and includes invasion of the
spleen, stomach, left adrenal gland,
colon, and peritoneum {359, 941}.
Lymphatic spread of pancreatic head
carcinomas involves, in descending order
of frequency, the retroduodenal (posterior
pancreaticoduodenal) and the superior
pancreatic head groups, the inferior head
and the superior body groups, and the
anterior pancreaticoduodenal and the
inferior body groups {359}. This lymph
node compartment is usually resected
together with the head of the pancreas,
using a standard Whipple procedure
{1955}. More distal nodal metastases may
occur in the ligamentum hepatoduode-nale, at the coeliac trunk, the root of the
superior mesenteric artery, and in para-aortic nodes at the level of the renal arter-ies. These lymph node compartments are
only removed if an extended Whipple pro-cedure is performed. Carcinomas of the
body and tail metastasise especially to
the superior and inferior body and tail
lymph node groups and the splenic hilus
lymph nodes. They may also spread via
lymphatic channels to pleura and lung.
Haematogenous metastasis occurs, in
approximate order of frequency, to the
liver, lungs, adrenals, kidneys, bones,
brain, and skin {359, 941, 1231}.
Staging
The 1997 TNM classification {66} is pre-sented on page 220. Another staging
system has been published by the Japan
Pancreas Society {832}.
Histopathology
Most ductal adenocarcinomas are well to
moderately differentiated. They are char-acterized by well-developed glandular
structures, which more or less imitate
normal pancreatic ducts, embedded in
desmoplastic stroma. The large amount
of fibrous stroma accounts for their firm
consistency. Variations in the degree of
differentiation within the same neoplasm
are frequent, but well differentiated carci-nomas with foci of poor differentiation are
uncommon.
Well differentiated carcinomas consist of
large duct-like structures, combined with
medium-sized neoplastic glands. Tubular
or cribriform patterns are typical; there
may also be small irregular papillary pro-jections without a distinct fibrovascular
stalk, particularly in large duct-like struc-tures. Mitotic activity is low. In between
the neoplastic glands there may be a few
non-neoplastic ducts as well as remnants
of acini and individual islets.
Sometimes, the neoplastic duct-like
glands are so well differentiated that they
are difficult to distinguish from non-neo-plastic ducts. However, the mucin-con-taining neoplastic glands may be rup-tured or incompletely formed, a feature
that is not seen in normal ducts. The
mucin-producing neoplastic cells tend to
be columnar, have eosinophilic and
occasionally pale or even clear cyto-plasm, and are usually larger than those
of non-neoplastic ducts. They contain
large round to ovoid nuclei which may
vary in size, with sharp nuclear mem-branes and distinct nucleoli that are not
found in normal duct cells. Moreover,
although the neoplastic cell nuclei tend
to be situated at the base of the cell, they
always show some loss of polarity.
Moderately differentiated carcinomas
predominantly show a mixture of medi-um-sized duct-like and tubular structures
of variable shape, embedded in desmo-plastic stroma. Incompletely formed
glands are common. Compared with the
well differentiated carcinoma, there is a
greater variation in nuclear size, chro-matin structure and prominence of nucle-oli. Mitotic figures are rather frequent. The
cytoplasm is usually slightly eosinophilic,
but clear cells are occasionally abun-dant. Mucin production appears to be
decreased and intraductal in situ compo-nents are somewhat less frequent than in
well differentiated carcinomas. Foci of
poor and irregular glandular differentia-tion are often found at the leading edge
of the neoplasm, particularly where it
invades the peripancreatic tissue.
Poorly differentiated ductal carcinomas
are infrequent. They are composed of a
mixture of densely packed, small irregular
glands as well as solid tumour cell sheets
and nests, which entirely replace the aci-nar tissue. While typical large, duct-like
structures and intraductal tumour compo-nents are absent, there may be small
squamoid, spindle cell, or anaplastic foci
(comprising by definition less than 20% of
the tumour tissue). There may be some
scattered inflammatory cells. Foci of
necrosis and haemorrhage occur. The
neoplastic cells show marked pleomor-phism, little or no mucin production, and
brisk mitotic activity. At the advancing
edge of the carcinoma, the gland and the
peripancreatic tissue are infiltrated by
small clusters of neoplastic cells.
Changes in non-neoplastic pancreas
All ductal adenocarcinomas are associ-ated with more or less developed
fibrosclerotic and inflammatory changes
Fig. 10.04 Poorly differentiated ductal adenocarcinoma.
224 Tumours of the exocrine pancreas
in the adjoining non-neoplastic pan-creas, due to carcinomatous duct
obstructions (obstructive chronic pan-creatitis). In cases of complete occlusion
of the main duct, there is marked
upstream dilatation of the duct and
almost complete fibrotic atrophy of the
parenchyma. In contrast to chronic pan-creatitis due to alcoholism, intraductal
calcifications are generally absent.
Poorly differentiated carcinomas usually
destroy the islets. In the well and moder-ately differentiated neoplasms, however,
islets may be found entrapped in neo-plastic tissue. In addition, scattered
endocrine cells occur attached to or
intermingled between neoplastic colum-nar cells. Only in exceptional cases do
the endocrine cells constitute a second
cell component of the ductal carcinoma
(see mixed ductal-endocrine carcinoma).
Histochemistry and immunohistochem-istry
Although no histochemical or immuno-histochemical marker is able to unequiv-ocally distinguish pancreatic from extra-pancreatic adenocarcinoma, some
markers are useful in separating ductal
adenocarcinoma of the pancreas from
non duct-type tumours or other gastroin-testinal carcinomas.
Mucin.  Ductal adenocarcinomas mainly
stain for sulphated acid mucins but focal-ly also for neutral mucins {1714}.
Immunohistochemically, most ductal
adenocarcinomas express MUC1, MUC3
and MUC5/6 (but not MUC2) {1918,
2179}, CA 19-9, Du-Pan 2, Span-1,
CA 125 and TAG72 {1714, 1884}. The
expression patterns of CA 19-9, Du-Pan
2, Span-1, CA 125 and TAG 72 are large-ly comparable in their immunoreactivity
and specificity. These markers also label
the epithelium of normal pancreatic ducts
to some extent, particularly in chronic
pancreatitis, and the tumour cells of
some serous cystadenomas and acinar
cell carcinomas {1282}.
Carcinoembryonic antigen (CEA).
Monospecific antibodies against CEA that
do not recognise other members of the
CEA family are capable of discriminating
between non-neoplastic duct changes,
such as ductal papillary hyperplasia, and
a variety of neoplasms {119}. CEA is neg-ative in serous cystadenoma.
Cytokeratins, vimentin, endocrine mark-ers and enzymes. Normal pancreatic
and biliary ductal cells and pancreatic
centroacinar cells express the cytoker-atins (CK) 7, 8, 18, 19 and occasionally
also 4 {1696}. Acinar cells contain only
CK 8 and 18, and islet cells 8, 18 and
occasionally also 19. Ductal adenocarci-nomas express the same set of cytoker-atins as the normal duct epithelium,
i.e. CK 7, 8, 18 and 19. More than 50% of
the carcinomas also express CK 4
{1696}, but are usually negative for CK 20
{1259}. As the usual keratin patterns of
non-duct-type pancreatic neoplasms
(i.e. acinar carcinomas and endocrine
tumours, CK 8, 18 and 19) and gut carci-nomas (i.e. CK 8, 18, 19 and 20) differ
from that of ductal carcinoma, it is possi-ble to distinguish these tumours on the
basis of their CK profile.
Ductal adenocarcinomas are usually
negative for vimentin {1696}. With rare
exceptions (see mixed ductal-endocrine
carcinoma), they also fail to label with
endocrine markers such as synapto-physin and the chromogranins, but may
contain, particularly if well differentiated,
some scattered (possibly non-neoplas-tic) endocrine cells in close association
with the neoplastic cells {167}. They are
generally negative for pancreatic
enzymes such as trypsin, chymotrypsin
and lipase {739, 1282}.
Growth factors and adhesion molecules.
Pancreatic carcinomas overexpress epi-dermal growth factor and its receptor,
c-erbB-2, transforming growth factor
alpha {380, 1676, 2163}, metallothionein
{1409}, CD44v6 {259, 1880} and mem-branous E-cadherin {1519}.
Ultrastructure
Ductal adenocarcinoma cells are charac-terized by mucin granules in the apical
cytoplasm, irregular microvilli on the lumi-nal surface, and a more or less polarised
arrangement of the differently sized
nuclei {359, 901, 1714}. The content of
the mucin granules (0.4-2.0 μm) varies
from solid-electron dense to filamentous
and punctate; often there is a dense
Fig. 10.06  Undifferentiated carcinoma with osteoclast-like giant cells. A The carcinoma is in the uncinate process and shows haemorrhagic necrosis. B There is
marked cellular pleomorphism with scattered osteoclast-like giant cells and a well-differentiated ductal carcinoma component (left upper corner).
Fig. 10.05 Undifferentiated carcinoma exhibiting
extreme pleomorphism with giant cells.
AB
225Ductal adenocarcinoma
eccentric core. Some cells have features
of gastric foveolar cells, showing gran-ules with a punctate-cerebroid structure
{1714}. Loss of tumour differentiation is
characterized by loss of cell polarity, dis-appearance of a basal lamina, appear-ance of irregular luminal spaces, and
loss of mucin granules {901}.
Histological variants
Adenosquamous carcinoma and undif-ferentiated (anaplastic) carcinoma
(including osteoclast-like giant cell
tumours), mucinous noncystic adenocar-cinoma and signet-ring cell carcinoma
are considered variants of ductal adeno-carcinoma because most of these carci-nomas, even if poorly differentiated, con-tain some foci showing neoplastic glands
with ductal differentiation {288, 359, 941,
947, 1781}.
Adenosquamous carcinoma
This rare neoplasm, relative frequency
3-4% {941, 359, 813, 1415}, is character-ized by the presence of variable propor-tions of mucin-producing glandular ele-ments and squamous components. The
squamous component should account
for at least 30% of the tumour tissue. In
addition, there may be anaplastic and
spindle cell foci. Pure squamous carci-nomas are very rare.
Undifferentiated (anaplastic) carcinoma
Also called giant cell carcinoma, pleo-morphic large cell carcinoma, and sarco-matoid carcinoma, these tumours have a
relative frequency of 2-7%. They are
composed of large eosinophilic pleomor-phic cells and/or ovoid to spindle-shaped cells that grow in poorly cohe-sive formations supported by scanty
fibrous stroma. Commonly the carcino-mas contain small foci of atypical glan-dular elements {359, 941, 1786, 1962}.
Carcinomas consisting predominantly of
spindle cells may also contain areas of
squamoid differentiation. High mitotic
activity as well as perineural, lymphatic,
and blood vessel invasion is found in
almost all cases. Immunohistochemical-ly, some or most tumour cells express
cytokeratins and usually also vimentin
{740}. Electron microscopy reveals
microvilli and mucin granules in some
cases {359}. Undifferentiated carcino-mas with a neoplastic mesenchymal
component (carcinosarcoma) have so far
not been described.
Undifferentiated carcinoma with osteo-clast-like giant cells
This rare neoplasm is composed of pleo-morphic to spindle-shaped cells and
scattered non-neoplastic osteoclast-like
giant cells with usually more than 20 uni-formly small nuclei. In many cases there
is an associated in situ or invasive ade-nocarcinoma {359}. The osteoclast-like
giant cells are often concentrated near
areas of haemorrhage and may contain
haemosiderin and, occasionally, phago-cytosed mononuclear cells. Osteoid for-mation may also be found.
Immunohistochemically, at least some of
the neoplastic cells express cytokeratin,
vimentin and p53 {740, 2095}. The osteo-clast-like giant cells, in contrast, are neg-ative for cytokeratin and p53, but positive
for vimentin, leukocyte common antigen
(CD56) and macrophage markers such
as KP1 {740, 1258, 2095}.
The mean age of patients with osteo-clast-like giant cell tumours is 60 years
but there is a wide age range from 32 to
82 years {1370}. Some tumours are
found in association with mucinous cys-tic neoplasms {1258, 2095, 2198}. In the
early reports on this tumour it was sug-gested that they may have a more
favourable prognosis than the usual duc-tal adenocarcinoma {359}. More recently
a mean survival of 12 months has been
reported.
Mucinous noncystic carcinoma
This uncommon carcinoma (relative fre-quency: 1-3%) {941} has also been
called ‘colloid’ or gelatinous carcinoma.
Mucin accounts for > 50% of the tumour.
The large pools of mucin are partially
lined by well-differentiated cuboidal cells
and contain clumps or strands of tumour
cells. Some floating cells may be of the
signet-ring cell type.
Sex and age distribution are similar to
those of ductal adenocarcinoma. The
tumours may be very large and are usu-ally well demarcated. The development
of pseudomyxoma peritonei has been
described {285}. It is of interest that the
invasive component of some of the intra-ductal papillary-mucinous tumours re-sembles mucinous noncystic carcinoma.
Mucinous noncystic carcinoma should
not be confused with mucinous cystic
tumour because of the much better prog-nosis of the latter (see chapter on muci-nous cystic neoplasms).
Signet-ring cell carcinoma
The extremely rare signet-ring cell carci-noma is an adenocarcinoma composed
almost exclusively of cells filled with
mucin {1781, 1951}. The prognosis is
extremely poor; a gastric primary should
always be excluded before making this
diagnosis.
Fig. 10.07 Adenosquamous carcinoma. Note the glandular component on the left and the squamous differ-entiation on the right (arrowheads).
226 Tumours of the exocrine pancreas
Mixed ductal-endocrine carcinoma
Mixed ductal-endocrine carcinoma {947}
has also been referred to as mixed carci-noid-adenocarcinoma, mucinous carci-noid tumour {359}, or simply mixed
exocrine-endocrine tumour. This neo-plasm is characterized by an intimate
admixture of ductal and endocrine cells
in the primary tumour as well as in its
metastases. By definition, the endocrine
cells should comprise at least one third
to one half of the tumour tissue. The duc-tal differentiation is defined by mucin pro-duction and the presence of a duct type
marker such as CEA. The endocrine cells
are characterized by the presence of
neuroendocrine markers and/or hormon-al products; immunoexpression of all four
islet hormones, amylin (IAPP), serotonin,
pancreatic polypeptide (PP), and occa-sionally gastrin have been described
{167}.
Mixed ductal-endocrine carcinomas, as
defined above, seem to be exceptionally
rare in the pancreas {1714, 1781}.
Biologically, the mixed carcinoma
behaves like the usual ductal adenocar-cinoma.
Acinar cell carcinomas {739, 1694, 1985}
and pancreatoblastomas {741} with
some endocrine and ductal elements,
and endocrine tumours with ductal com-ponents {1372, 1941} are not discussed
here, because their behaviour is dictated
by their acinar and endocrine elements.
Mixed ductal-endocrine carcinomas
should also be distinguished from ductal
adenocarcinomas with scattered endo-crine cells, since scattered endocrine
cells are found in 40-80% of ductal ade-nocarcinomas {167, 289} and seem to
be particularly frequent in the well differ-entiated tumours, where they are either
lined up along the base of the neoplastic
ductal structures or lie between the
neoplastic columnar cells. ‘Collision
tumours’ composed of two topographi-cally separate components are not inclu-ded in the mixed ductal-endocrine cate-gory.
Other rare carcinomas
Other very rare carcinomas of probable
ductal phenotype include  clear cell car-cinoma {359, 882, 1908, 1121} and ciliat-ed cell carcinoma (see chapter on mis-cellaneous carcinomas) {1276, 1786}.
Carcinomas with ‘medullary’ histology
have recently been described {590};
these lesions are associated with wild-type KRAS status and microsatellite
instability.
The so-called  microglandular carcino-mas {359} or microadenocarcinomas are
distinguished by a microglandular to
solid-cribriform pattern. They most likely
do not form an entity of their own but
belong to either the ductal, endocrine, or
acinar carcinomas.
Grading
A few formal grading systems have been
described. Miller et al. graded pancreat-ic tumours using the system of Broder,
which distinguishes four grades of cellu-lar atypia. High-grade carcinomas
(Broder grades 3 and 4) were larger and
the frequency of venous thrombosis and
metastasis higher than in low-grade
tumours.
A more recent grading system is based
on combined assessment of histological
and cytological features and mitotic
activity {944, 1119}. If there is intratumour
heterogeneity, i.e. a variation in the
degree of differentiation and mitotic
activity, the higher grade and mitotic
activity is assigned. This rule also applies
if only a minor component (less than half
of the tumour) was of lower grade. Using
this system, there is a correlation
between grade and survival and grade is
an independent prognostic variable
{944, 1119}.
Precursor lesions
Pancreatic neoplasms
Mucinous cystic neoplasms and intra-ductal papillary mucinous neoplasms
may progress to invasive cancer. In the
case of mucinous cystic neoplasms, the
invasive component usually resembles
ductal adenocarcinoma {1781}. In the
case of intraductal papillary-mucinousFig. 10.09 Pancreatic duct showing high-grade intraepithelial neoplasia (PanIN III).
Fig. 10.08  Mucinous non-cystic adenocarcinoma.  A A mucinous carcinoma in the head of the pancreas
obstructs the main pancreatic duct and impinges on the bile duct (BD). B The neoplastic cells float in pools
of mucin.
AB
BD
227Ductal adenocarcinoma
carcinoma, the invasive component
either corresponds to a usual ductal ade-nocarcinoma or to mucinous noncystic
carcinoma {1781}.
Severe ductal dysplasia – carcinoma
in situ
This change of the ductal epithelium is
characterized by irregular epithelial bud-ding and bridging, small papillae lacking
fibrovascular stalks, and severe nuclear
abnormalities such as loss of polarity,
pleomorphism, coarse chromatin, dense
nucleoli and mitotic figures. The lesion is
often surrounded by one or two layers of
fibrosclerotic tissue. Here, no attempt is
made to distinguish between severe dys-plasia and carcinoma in situ, since it is
very difficult, if not impossible, to draw a
clear distinction between these two
changes, which both represent high-grade intraepithelial neoplasia. The
lesion corresponds to PanIN III in the
proposed terminology of pancreatic
intraepithelial neoplasia (Table 10.01).
High-grade intraepithelial neoplasia is
commonly found in association with an
invasive ductal adenocarcinoma {358,
555, 943}, and may represent either a
precursor to invasive carcinoma or con-tinuous intraductal extensions of the
invasive tumour. Similar duct changes
have also been described remote from
the macroscopic tumour {1781} or years
before the development of an invasive
ductal carcinoma {185, 191}.
Duct changes
With the exception of high-grade intraepi-thelial neoplasia, the precursors to infil-trating ductal adenocarcinomas are still ill-defined. Putative precursor lesions (Table
10.01) include mucinous cell hypertrophy,
ductal papillary hyperplasia with muci-nous cell hypertrophy (papillary duct
lesion without atypia), adenomatoid (ade-nomatous) ductal hyperplasia, and squa-mous metaplasia {1781, 947}. All these
lesions may show mild nuclear atypia.
The evidence that some of these duct
lesions (i.e. mucinous cell hypertrophy
and papillary hyperplasia) may be pre-cursors to invasive carcinoma comes
from three areas: morphological studies,
clinical reports, and genetic analyses. At
the light microscopic level, ductal papil-lary hyperplasia was found adjacent to
invasive carcinomas more frequently
than it was in pancreases without cancer
{290, 358, 943, 965}. It was also noted
Grade 1 Well differentiated  Intensive  )5  Little polymorphism, polar arrangement
Grade 2 Moderately differentiated  Irregular 6-10 Moderate polymorphism
duct like structures
and tubular glands
Grade 3 Poorly differentiated glands, Abortive > 10 Marked polymorphism and increased size
mucoepidermoid and
pleomorphic structures
Tumour grade Glandular differentiation Mucin production Mitoses (per 10 HPF) Nuclear features
Squamous metaplasia Squamous metaplasia Epidermoid metaplasia, multilayered metaplasia
Incomplete squamous metaplasia Incomplete squamous metaplasia focal epithelial hyperplasia, focal atypical
epithelial hyperplasia, multilayered metaplasia
PanIN-IA Mucinous cell hypertrophy Mucinous cell hyperplasia, mucinous ductal
hyperplasia, mucoid transformation, simple
hyperplasia, flat ductal hyperplasia, mucous
hypertrophy, hyperplasia with pyloric gland
metaplasia, ductal hyperplasia grade 1, non-papillary
epithelial hypertrophy, nonpapillary ductal hyperplasia
PanIN-IB Ductal papillary hyperplasia Papillary ductal hyperplasia, ductal hyperplasia grade 2
Adenomatoid ductal hyperplasia Adenomatous hyperplasia, ductular cell hyperplasia
PanIN-II Any PanIN-I lesion with moderate dysplasia
as defined in the text
PanIN-III Severe ductal dysplasia Ductal hyperplasia grade 3, atypical hyperplasia
Carcinoma in situ
Recommended WHO term Previous WHO classification {947} Other synonyms
Table 10.01
List of recommended terms with synonyms for focal hyperplastic and metaplastic duct lesions in the human exocrine pancreas.
Table 10.02
Histopathological grading of pancreatic ductal adenocarcinoma {1119}.
228 Tumours of the exocrine pancreas
that ductal papillary hyperplasia is simi-lar to severe dysplasia-carcinoma in situ
lesions seen in the vicinity of invasive
ductal carcinomas {358}. Clinically, Brat
et al. {185} and Brockie et al. {191} have
reported a total of five patients who
developed infiltrating ductal adenocarci-nomas years after the identification of
atypical duct lesions in their pancreas.
Finally, molecular genetic analyses of
duct lesions have demonstrated that they
contain some of the same genetic alter-ations seen in infiltrating ductal carcino-mas. For example, activating point muta-tions in codon 12 of the  KRAS geneal-terations of the  p16 and TP53 tumour
suppressor genes and loss of BRCA2
and DPC4 have all been reported in duct
lesions {1286, 1875, 2166, 2105, 589}.
Duct lesions and infiltrating cancers from
the same pancreas may harbour identi-cal mutations {1120, 1286}.
Only a minority of duct lesions may
progress to invasive cancer, as demon-strated by recent data from a study on
normal pancreases, which showed that
all types of duct lesions and even normal
epithelium may harbour KRAS mutations,
and that the lesions are evenly distributed
in the pancreas and do not concentrate in
the head region where the carcinoma is
most frequent {647}. It has recently been
suggested that the term ‘Pancreatic
Intraepithelial Neoplasia (PanIN)’ be
adopted for these duct lesions (see
http://pathology.jhu.edu/ pancreas.panin)
{937}. Table 10.01 indicates the general
relationship between the previous WHO
terminology and this new proposed
PanIN terminology.
Genetic susceptibility
Between 3% and 10% of cases of pan-creatic cancer are familial {754, 1125,
1126, 499}. Some arise in patients with
recognized genetic syndromes, as dis-cussed below, but in most instances the
genetic basis for the familial aggregation
of pancreatic carcinomas has not been
identified. A confounding factor is the
possibility of shared environmental fac-tors, such as tobacco use. Nevertheless,
some studies show familial aggregations
suggestive of a genetic aetiology {485,
577, 499, 1207} Studies of extended fam-ilies have shown a pattern suggestive of
an autosomal dominant mode of inheri-tance.
Hereditary pancreatitis
This disease is caused by germline
mutations in the cationic trypsinogen
gene on 7q35 {2098}. This syndrome is
characterized by the early onset of
severe recurrent bouts of acute pancrea-titis, and affected individuals have as
high as a 40% lifetime risk of developing
pancreatic carcinoma {1101}.
FAMMM syndrome
Familial atypical multiple mole melanoma
(FAMMM) is associated with germline
mutations in the  p16 tumour suppressor
gene on 9p. Affected individuals have
an increased risk of developing both
melanoma and pancreatic carcinoma
{601, 1127, 1285, 2097}. The lifetime risk
for developing pancreatic carcinoma is
about 10%.
BRCA2
The discovery of the second breast can-cer gene  (BRCA2) on 13q was made
possible in large part by the discovery of
a homozygous deletion in a pancreatic
carcinoma {1697}. Pancreatic carcino-mas have been reported in some kindred
with BRCA2 mutations and familial breast
Oncogenes
KRAS 12p Point mutation > 90
MYB, AKT2, AIB1 6q, 19q, 20q Amplification1
10-20
HER/2-neu 17q Overexpression 70
Tumor suppressor genes
p16 9p Homozygous deletion 40
Loss of heterozygosity  40
and intragenic mutation
Promotor 15
hypermethylation
TP53 17p Loss of heterozygosity  50-70
and intragenic mutation
DPC4 18q Homozygous deletion 35
Loss of heterozygosity  20
and intragenic mutation
BRCA2 13q Inherited intragenic mutation  7
and loss of heterozygosity
MKK4 17p Homozygous deletion, 4
loss of heterozygosity
and intragenic mutation
LKB1/STK11 19p Loss of heterozygosity  5
and intragenic mutation,
homozygous deletion
ALK5 and TGF βR2 9q, 3p Homozygous deletion 4
DNA Mismatch Repair
MSH2, MLH1, others 2p, 3p, others Unknown < 5
___________________
1
In cases of amplification, it is generally not possible to unambiguously identify the key oncogene due to the participa-tion of multiple genes in an amplicon.
Gene Chromosome Mechanism of alteration % of cancers
Table 10.03
Genetic alterations in pancreatic ductal carcinoma.
229Ductal adenocarcinoma
cancer {1514, 1934, 591, 479} identified
germline mutations in  BRCA2 in about
7% of patients with pancreatic carcino-ma. Remarkably, most pancreatic ductal
carcinoma patients with such mutations
do not have a strong family history of
breast or pancreatic carcinoma. A num-ber of them are, however, of Ashkenazi
Jewish ancestry {591, 1442}.
Peutz-Jeghers syndrome
Patients with the Peutz-Jeghers syndrome
have an increased risk of developing pan-creatic carcinoma, and recently the bi-allelic inactivation of the  LKB1/STK11
gene has been demonstrated in a pan-creatic carcinoma which arose in a
patient with the Peutz-Jeghers syndrome
{579, 1851}.
Hereditary nonpolyposis colon cancer
(HNPCC)
This syndrome is associated with an
increased risk of developing carcinoma
of the colon, endometrium, stomach, and
ovary {2071}. It can be caused by
germline mutations in any one of a num-ber of DNA mismatch repair genes,
including MSH2 on 2p and MLH1 on 3p
{1029, 1078, 2071}. Lynch et al. have
reported pancreatic carcinomas in some
kindred with HNPCC, and Goggins et al.
have recently reported microsatellite
instability, a genetic change associated
with defects in DNA mismatch repair
genes, in about 4% of pancreatic carci-nomas {590, 1130, 1487}.
Genetics
Genetic alterations are listed in Table
10.03. At the chromosome level, they
include losses and gains of genetic
material as well as generalised chromo-some instability {608, 625, 626}. The
most frequent gains identified cytogenet-ically include those of chromosomes 12
and 7; the most common recurrent struc-tural abnormalities involve chromosome
arms 1p, 6q, 7q, 17p, 1q, 3p, 11p, and
19q, and the most frequent losses
involve chromosomes 18, 13, 12, 17, and
6 {626, 625}. Similar patterns of loss have
been identified at the molecular level
{184, 1716}, using highly polymorphic
microsatellite markers. These include
very high rates of loss at chromosomes
18q (90%), 17p (90%), 1p (60%), and 9p
(85%) and moderately frequent losses at
3p, 6p, 8p, 10q, 12q, 13q, 18p, 21q, and
22q (25-50% of cases).
Recurrent losses of genetic material at
specific loci in a carcinoma suggest that
these loci harbour tumour suppressor
genes which are inactivated in the carci-noma, and, indeed, the p16 gene on 9p,
the Tp53 gene on 17p, and the  DPC4
gene on 18q are all frequently inactivat-ed in pancreatic carcinoma {1716}. The
p16 tumour suppressor gene is inacti-vated in 40% of pancreatic carcinomas
by homozygous deletion, in 40% by loss
of one allele coupled with an intragenic
mutation in the second, and by hyperme-thylation of the p16 promoter in an addi-tional 15% {223, 1698, 2104}. The  Tp53
is inactivated in 75% of pancreatic carci-nomas by loss of one allele coupled with
an intragenic mutation in the second
allele {1570, 1624}. The  DPC4 tumour
suppressor gene is inactivated in 55% of
pancreatic carcinomas {651}, in 35% of
the carcinomas by homozygous deletion
and in 20% by loss of one allele coupled
with an intragenic mutation in the second
allele. The  BRCA2 tumour suppressor
gene on 13q is inactivated in about 7% of
pancreatic carcinomas {591, 1442,
1697}. Remarkably, in almost all of these
cases one allele of BRCA2 is inactivated
by a germline (inherited) mutation in the
gene {591}. Other tumour suppressor
genes which have been shown to be
occasionally inactivated in pancreatic
carcinoma include the genes  MKK4,
RB1, LKB1/STK11, and the transforming
growth factor  β receptors I and II {592,
761, 1850, 1851}.
Several oncogenes have been shown to
be activated in ductal adenocarcinomas
of the pancreas. These include the KRAS
gene on chromosome 12p, which is acti-vated by point mutations in over 90% of
the carcinomas, overexpression of the
HER2-neu gene on 17q in 70% of the car-cinomas, and amplification of the  AKT2
gene on chromosome 19q in 10–20% of
the carcinomas, the nuclear receptor
coactivator gene  AIB1 on chromosome
20q, and the MYB gene on chromosome
6q {47, 292, 380, 576, 761, 1242, 2039}.
Compared to normal pancreas,  Smad2
mRNA levels are increased in pancreatic
carcinoma, which might lead to the
over-expression of components of the
TGF-beta signalling pathway that is
observed in these lesions {931}.
DNA mismatch repair genes, such as
MLH1 and MSH2, can also play a role.
Microsatellite instability resulting from the
inactivation of both alleles of a DNA mis-match repair gene has been identified in
4% of pancreatic carcinomas {590}. They
had wild-type  KRAS genes and a char-acteristic ‘medullary’ histological appear-ance, forming a distinct subset of pan-creatic adenocarcinomas (see section
on other rare carcinomas).
Prognosis and predictive factors
Ductal adenocarcinoma is fatal in most
cases {639}. The mean survival time of
the untreated patient is 3 months, while
the mean survival after radical resection
varies from 10-20 months {560, 692, 814,
1955}. The overall 5-year survival rate of
patients treated by resection is 3-4%
{639}, although in selected and stage-stratified series survival figures approach-ing 25 or even 46% have been reported
{560, 1955, 1966, 1976}. Unresectable
carcinomas are treated with palliative
bypass operations. Response to chemo-therapy with 5-fluorouracil or gemcitabine
may be seen in up to approximately 10%
of patients. Radiotherapy alone is largely
ineffective {2061}.
Site, size, and stage
The survival time is longer in patients with
carcinomas confined to the pancreas
and less than 3 cm in diameter (17-29
months) than in patients with tumours of
greater size or retroperitoneal invasion
(6-15 months) {2172}. Carcinomas of the
body or the tail of the pancreas tend to
present at a more advanced stage than
those of the head {560, 1955, 1966,
1976}. Some have found that lymph node
metastases significantly worsen progno-sis, while others have not {710, 1955,
2172}.
Residual tumour tissue
Patients with no residual tumour following
resection (R0) have the most favourable
prognosis of all patients undergoing sur-gical resection {2108}. This implies that
local spread to peripancreatic tissues,
i.e. the retroperitoneal resection margin,
is of utmost importance in terms of prog-nosis {1122}.
Recurrence
Local recurrence seems to be the major
factor determining survival after resection
of pancreatic ductal carcinoma. The most
common sites of recurrences are the tis-sues surrounding the large mesenteric
vessels {646}. Clear retroperitoneal resec-tion margin or margins are therefore
230 Tumours of the exocrine pancreas
required, if a ‘curative’ resection (R0) is to
be achieved {1122}. Second in frequency
are recurrences arising from lymph node
or liver metastases that were too small to
be detected during surgery. The peri-toneum and the bone marrow are rare
sites of recurrence, although malignant
cells are detected cytologically in one
quarter of the patients during laparoscopy
and one half of the patients when bone
marrow trepanation is performed during a
Whipple procedure {870}.
Grading
Based on the criteria of the grading sys-tem summarised in Table 10.02, it was
found that median postoperative survival
correlated significantly with tumour
grade {944}, mitotic index, and severity
of cellular atypia. As grading systems
are, however, to a great extent subjec-tive, reproducibility may be low {1119}.
Other studies found no relationship
between grade and survival {2079}.
Nuclear parameters such as median
nuclear size, nuclear area, and nuclear
perimeter have been shown to be of
prognostic value for ductal adenocarci-noma {477, 944}.
DNA content and proliferation
Nondiploid and/or aneuploid DNA content
is associated with advanced tumour stage
and shorter survival {46, 105, 476, 2079}.
Tumours with low argyrophylic nucleolar
organizer region (AgNOR) counts per
cell (< 3.25) have been reported to have
a better prognosis than tumours with a
high AgNOR count {1413}. High Ki-67
labeling index is an indicator of poor
prognosis, but does not seem to be an
independent prognostic parameter
{1111, 1119}
The immunohistochemical expression of
a number of growth factors has shown
weak association with survival {21, 535}.
Early onset familial pancreatic  Autosomal dominant Unknown About 30%; 100-fold increased risk
adenocarcinoma associated with diabetes of pancreatic cancer;
(Seattle family) {479} high risk of diabetes and pancreatitis
Hereditary pancreatitis (167800) Autosomal dominant  Cationic trypsinogen (7q35)  30%; 50-fold increased risk of
pancreatic cancer {1101, 499}
FAMMM: familial atypical multiple  Autosomal dominant p16/CMM2 (9p21) 10% {601, 1127, 2097}
mole melanoma (155600)
Familial breast cancer (600185) Autosomal dominant  BRCA2 (13q12-q13)  5-10%; 6174delT in Ashkenazi Jews
{1442}, 999del5 in Iceland {1934}
Ataxia-telangiectasia (208900) Autosomal recessive ATM, ATB, others (11q22-q23) Unknown; somewhat increased
(heterozygote state)
Peutz-Jeghers (175200) Autosomal dominant STK11/LKB1 (19p) Unknown; somewhat increased
{579}
HNPCC: hereditary non-polyposis Autosomal dominant MSH2 (2p), MLH1 (3p), others Unknown; somewhat increased
colorectal cancer (120435) {1130, 2071}
Familial pancreatic cancer  Possibly autosomal dominant Unknown Unknown; 5-10fold increased risk
if a first-degree relative has
________ pancreatic cancer {499, 1128, 755}
1
Mendelian Inheritance in Man: http://www.ncbi.nlm.nih.gov/omim
Syndrome (MIM No)1
Mode of inheritance Gene (chromosomal location) Lifetime risk of pancreatic cancer
Table 10.04
Genetic syndromes with an increased risk of pancreatic cancer.
231Serous cystic neoplasms
Serous cystic neoplasms
of the pancreas
C. Capella
E. Solcia
G. Klöppel
R.H. Hruban
Serous cystic pancreatic tumours are
cystic epithelial neoplasms composed of
glycogen-rich, ductular-type epithelial
cells that produce a watery fluid similar to
serum. Most are benign (serous cystade-nomas), either serous microcystic adeno-ma or serous oligocystic adenoma. Only
very rare cases exhibit signs of malig-nancy (serous cystadenocarcinoma).
A solid variant of serous cystadenoma
(solid serous cystadenoma) has been
described {1499} but remains to be
established as a separate disease entity.
ICD-O codes
Serous cystadenoma 8441/0
Serous cystdenocarcinoma 8441/3
Serous microcystic adenoma
Definition
A benign neoplasm composed of numer-ous small cysts lined by uniform glyco-gen-rich cuboidal epithelial cells, dis-posed around a central stellate scar.
Epidemiology
This is a rare neoplasm, accounting for 1
to 2% of all exocrine pancreatic tumours
{1280}. The mean age at presentation is
66 years (range, 34-91 years), with a pre-dominance in women (70%) {1781}. It
has been reported in patients with differ-ent ethnicity {327, 2151}.
Aetiology
The aetiology and pathogenesis of the
neoplasm are unknown. The striking
predilection for women suggests that sex
hormones or genetic factors may play a
role. An association with Von Hippel-Lindau disease has been reported {327,
2026} and confirmed by recent genetic
molecular investigations {2026}.
Localization
The neoplasms occur most frequently
(50-75%) in the body or tail; the remain-ing tumours involve the head of the pan-creas {49, 327}.
Clinical features
About one third of the neoplasms pres-ent as an incidental finding at routine
physical examination or at autopsy {445}.
Approximately two thirds of patients
exhibit symptoms related to local mass
effects, including abdominal pain, palpa-ble mass, nausea and vomiting, and
weight loss {1544}. Jaundice due to
obstruction of the common bile duct is
unusual, even in neoplasms originating
from the head of the pancreas.
Pancreatic serum tumour markers are
generally normal. Calcifications are
found in a few patients on plain abdomi-nal roentgenograms. Ultrasonography
(US) and computed tomography (CT)
reveal a well circumscribed, multilocular
cyst, occasionally with an evident central
stellate scar and a sunburst type calcifi-cation {532, 817, 1544}. On angiography,
the tumours are usually hypervascular.
Macroscopy
Serous microcystic adenomas are sin-gle, well-circumscribed, slightly bosse-lated, round lesions, with diameters
ranging from 1-25 cm in greatest dimen-sion (average, 6-10 cm). On section, the
neoplasms are sponge-like and are
made up of numerous tiny cysts filled
with serous (clear watery) fluid. The
cysts range from 0.01-0.5 cm, with a few
larger cysts of up to 2 cm in diameter.
Often, the cysts are arranged around a
more or less centrally located, dense
fibronodular core from which thin fibrous
septa radiate to the periphery (central
stellate scar).
Histopathology
At low magnification, the pattern of the
cysts is similar to a sponge. The cysts
contain proteinaceous fluid and are lined
by a single layer of cuboidal or flattened
epithelial cells. Their cytoplasm is clear
and only rarely eosinophilic and granular.
The nuclei are centrally located, round to
oval in shape, uniform, and have an
inconspicuous nucleolus. Due to the
presence of abundant intracytoplasmic
glycogen, the periodic acid-Schiff (PAS)
stain without diastase digestion is posi-tive, whereas PAS-diastase and Alcian
blue stains are negative {160}. Mitoses
are practically absent and there is no
cytological atypia. Occasionally, the neo-plastic cells form intracystic papillary
projections, usually without a fibrovascu-lar stalk. The central fibrous stellate core
is formed of hyalinized tissue with a few
clusters of tiny cysts.
Immunohistochemistry
The epithelial nature of these neoplasms
is reflected in their immunoreactivity for
epithelial membrane antigen and cytok-eratins 7, 8, 18, and 19. In addition, the
neoplastic cells may focally express
CA19-9 and B72.3 {815, 1752}. They are
uniformly negative for carcinoembryonic
Fig. 10.10 Microcystic serous cystadenoma. A CT
scan showing a well demarcated, spongy lesion in
the head of the pancreas. B Cut surface showing a
typical honeycomb appearance and a (para-)cen-tral stellate scar (arrowhead).
A
B
232 Tumours of the exocrine pancreas
antigen (CEA), trypsin, chromogranin A,
synaptophysin, S-100 protein, desmin,
vimentin, factor VIII-related antigen and
actin {49, 119, 445, 689, 815, 1752,
1781, 2151}.
Ultrastructure
Electron microscopy shows a single row
of uniform epithelial cells lining the cysts
and resting on a basal lamina {49, 160,
915}. The apical surfaces have poorly
developed or no microvilli. The cyto-plasm contains numerous glycogen
granules but only a few mitochondria,
short profiles of endoplasmic reticulum,
lipid droplets, and multivesicular bodies.
Golgi complexes are rarely identified.
Zymogen granules and neurosecretory
granules are absent.
Genetics
Loss of heterozygosity at the von Hippel-Lindau (VHL) gene locus, mapped to
chromosome 3p25, was found in 2/2
serous microcystic adenomas associat-ed with VHL disease and in 7/10 spo-radic cases {2026}. In contrast to ductal
adenocarcinomas, serous microcystic
adenomas have wild-type  KRAS and
lack immunoreactivity for TP53 {815}.
Prognosis
The prognosis of patients with this neo-plasm is excellent, since there is only a
minimal risk of malignant transformation
{1159}.
Serous oligocystic adenoma
Definition
A benign neoplasm composed of few,
relatively large cysts, lined by uniform
glycogen-rich cuboidal epithelial cells.
Synonyms
This tumour category includes macro-cystic serous cystadenoma {257, 1062},
serous oligocystic and ill-demarcated
adenoma {445}, and some cystade-nomas observed in children {2057}.
Whether these neoplasms form a homo-geneous group remains to be estab-lished.
Epidemiology
Serous oligocystic adenomas are much
less common than serous microcystic
adenomas {445, 1062}. There is no sex
predilection. Adults are usually 60 years
and over (age range, 30-69 years; mean,
65 years); the tumour has been
described in two male and two female
infants, aged between 2 and 16 months
{1781}.
Aetiology
The aetiology of this neoplasm is not
known. In children, it has been suggest-ed that the lesions may be of malforma-tive origin and not true neoplasms since
in two cases there was a cytomegalo-virus infection in the adjacent pancreas
{52, 273}.
Localization
Most serous oligocystic adenomas are
located in the head and body of the pan-creas {1781}. In the head, they may
obstruct the periampullary portion of the
common bile duct.
Clinical features
In most cases reported in adult patients,
the neoplasms caused symptoms that
led to their discovery and removal. The
most common symptom was upper
abdominal discomfort or pain {1781}.
Other symptoms included jaundice and
steatorrhoea. In infants, the tumours pre-sented as a palpable abdominal mass
{52, 273}.
Macroscopy
These neoplasms typically appear as a
cystic mass with a diameter of 4-10 cm
(mean, 6 cm) {1781}. On cut surface,
Fig. 10.13  Serous cystadenoma. A cystic neoplasm
replaces the head of the pancreas; a portion of duo-denum is on the right.
Fig. 10.11 Serous oligocystic adenoma. This CT
scan shows a macrocystic neoplasm in the head of
the pancreas.
Fig. 10.12 Serous microcystic cystadenoma. A The lesion is well demarcated from the adjacent pancreas. B Cysts of varying size. C The epithelium is cuboidal and
focally PAS-positive.
ABC
233Serous cystic neoplasms
there are few (occasionally only one)
macroscopically visible cysts filled with
watery clear or brown fluid. The cysts
usually vary between 1 and 2 cm in
diameter, but cysts as large as 8 cm
have been reported {1062}. The irregu-larly arranged cysts, sometimes separat-ed by broad septa, lie within a fibrous
stroma that lacks a central stellate scar.
The cysts and the supporting fibrous tis-sue may extend into the adjoining pan-creatic tissue so that the tumours are
poorly demarcated.
Histopathology
Serous oligocystic adenoma has gener-ally the same histological features as
serous microcystic adenoma. Occasion-ally, however, the lining epithelium may
be more cuboidal and less flattened, and
the nuclei are generally larger. The cyto-plasm is either clear, due to the presence
of glycogen, or eosinophilic. The stromal
framework is well developed and often
hyalinized. The tumour border is not well
defined and small cysts often extend into
the adjoining pancreatic tissue. The
immunohistochemical and ultrastructural
features are the same as for serous
microcystic adenoma {445, 2057}.
Prognosis
There is no evidence of malignant poten-tial {445}.
Serous cystadenocarcinoma
Definition
A malignant cystic epithelial neoplasm
composed of glycogen-rich cells.
Epidemiology
So far, only eight cases have been report-ed {573, 815, 1781}. These patients were
between 63 and 72 years of age; there
were four women and four men. Three
patients were Caucasian and four were
from Japan {8, 815, 1781}.
Clinical features
Clinical symptoms reported in the cases
so far observed include bleeding from
gastric varices due to tumour invasion of
the wall of the stomach and the splenic
vein, a palpable upper abdominal mass,
and jaundice. Ultrasonography and CT
revealed a hyperechoic mass. CEA and
CA19-9 were normal or slightly increased.
Macroscopy
These neoplasms have a spongy appear-ance {573, 879, 2182}. Their reported
size has varied between 2.5 and 12 cm.
Liver and lymph node metastases have
been reported {573, 815, 1781, 2182}.
Invasion of the spleen and metastasis to
the gastric wall were found in one case.
Histopathology
The histological features in the primary
tumour as well as in the metastases are
remarkably similar to those of serous
microcystic adenoma, although focal
mild nuclear pleomorphism can be found
{573, 2182}. One carcinoma reported
showed neural invasion and aneuploid
nuclear DNA content {879}, while other
cases showed vascular and perivascular
invasion {1412} or involvement of a
lymph node and adipose tissue {8}.
Prognosis
Serous cystadenocarcinomas are slowly
growing neoplasms and palliative resec-tion may be helpful even in advanced
stages {2182}.
Fig. 10.14 Serous cystadenoma. Characteristic cuboidal epithelium forms intracystic papillary structures in
this field.
234 Tumours of the exocrine pancreas
Definition
Cystic epithelial neoplasms occurring
almost exclusively in women, showing no
communication with the pancreatic duc-tal system and composed of columnar,
mucin-producing epithelium, supported
by ovarian-type stroma. According to the
grade of intraepithelial neoplasia (dys-plasia), tumours may be classified as
adenoma, borderline (low-grade malig-nant) and non-invasive or invasive carci-noma.
ICD-O codes
Mucinous cystadenoma 8470/0
Mucinous cystic neoplasm
with moderate dysplasia 8470/1
Mucinous cystadenocarcinoma
non-invasive 8470/2
invasive 8470/3
Epidemiology
Although more than 500 cases have
been reported in the literature {328,
2198}, mucinous cystic neoplasm (MCN)
is still considered a rare lesion, repre-senting approximately 2-5% of all exo-crine pancreatic tumours {1781, 1932}.
Changes in diagnostic criteria over the
years and the high resectability rate
compared to that of ductal adenocarci-noma may have led to an overrepresen-tation of MCNs in histopathology series.
The increasing number of these lesions
seen in recent years is most likely due to
advances in diagnostic techniques,
allowing early and correct recognition of
MCN.
In a recent study, in which MCNs were
defined by the lack of a communication
with the pancreatic duct system and the
presence of an ovarian type stroma, all
occurred in women {2198}. It is likely that
many of the cases reported in men in the
early literature were intraductal papillary
mucinous neoplasms (IPMNs) {328,
1932, 2198}.
The mean age at diagnosis is 49 years
(range, 20-82 years) {1781}. Patients with
mucinous cystadenocarcinomas are
about 10 years older than patients with
adenomatous or borderline tumours
(54 versus 44 years), suggesting an ade-noma – carcinoma sequence {2198}.
MCTNs seem to occur in patients with
different ethnic background {1781}.
Aetiology
Pancreatic MCNs share many features
with their counterparts in the liver and
retroperitoneum, including their morphol-ogy and their almost exclusive occur-rence in women {328, 2139, 404, 2198}.
The possible derivation of the stromal
component of MCNs from the ovarian pri-mordium is supported by morphology,
tendency to undergo luteinization, pres-ence of hilar-like cells, and immunophe-notypic sex cord-stromal differentiation. It
has been hypothesized that ectopic
ovarian stroma incorporated during
embryogenesis in the pancreas, along
the biliary tree or in the retroperitoneum
may release hormones and growth fac-tors causing nearby epithelium to prolif-erate and form cystic tumours {2198}.
Since the left primordial gonad and the
dorsal pancreatic anlage lie side by side
during the fourth and fifth weeks of devel-opment, this hypothesis could explain
the predilection of MCN for the body-tail
region of the pancreas {1977}.
Localization
The overwhelming majority of cases
occur in the body-tail of the pancreas
{328, 1932, 2148, 2198}. The head is
only rarely involved, with a predilection
for mucinous cystadenocarcinomas
{1932, 2198}.
G. Zamboni D.S. Longnecker
G. Klöppel G. Adler
R.H. Hruban
Mucinous cystic neoplasms
of the pancreas
Fig. 10.16 Mucinous cystic neoplasm in the tail of
the pancreas. The thick wall shows focal calcifica-tion.
Fig. 10.15 Mucinous cystic neoplasm. The pancreatic duct, which does not communicate with the cyst
lumen, has been opened over the surface of the tumour (left, arrowheads). The thick wall and irregular lin-ing of the bisected neoplasm are shown on the right.
235Mucinous cystic neoplasms
Clinical features
Symptoms and signs
The clinical presentation depends on the
size of the tumour. Small tumours
(< 3 cm) are usually found incidentally.
Larger tumours may produce symptoms
that are usually due to compression
of adjacent structures, and are often
accompanied by a palpable abdominal
mass. An association with diabetes mel-litus is relatively frequent, whereas jaun-dice is uncommon {1781}.
Serum tumour markers
An increase in the peripheral blood serum
tumour markers CEA, CA 19-9, or high
cyst fluid levels of CEA, CA 19-9, TAG-72,
CA-15-3 or MCA (mucin-like carcinoma-associated antigen) together with a low
amylase level is suggestive of MCN. The
highest levels of these markers are seen
in cystadenocarcinoma {1063, 1804}.
Imaging
Abdominal X-ray may demonstrate nodu-lar calcifications in the tumour capsule
and compression or displacement of the
stomach, duodenum or colon. US and
CT reveal a sharply demarcated hypoe-choic or low density mass with one or
more large loculations {1461}. Features
suggestive of malignant transformation
include an irregular thickening of the cyst
wall and/or papillary excrescences pro-jecting into the cystic cavity {201, 2060}.
Magnetic resonance imaging may have
a complementary role. Endoscopic retro-grade cholangiography (RCP) shows a
displacement of the main pancreatic
duct and the absence of communication
with the cystic cavity, a very important
finding for the differential diagnosis with
IPMN.
Fine needle aspiration cytology (FNAC)
can be performed percutaneously with
CT or US guidance, or intraoperatively
{1019}.
Preoperative diagnosis of MCN is impor-tant, since other types of cystic neo-plasm may be treated differently.
Furthermore, MCNs must be distin-guished from an inflammatory pseudo-cyst, because drainage may be appro-priate for patients with a pseudocyst, but
is disastrous for patients with MCN, since
apparently histologically benign muci-nous cystic tumours can recur after
drainage as invasive cystadenocarcino-mas {328, 2194}. The best approach to
obtain an exact preoperative diagnosis is
the combined evaluation of all available
clinical, serological, radiological, and
biopsy findings.
Macroscopy
MCNs typically present as a round mass
with a smooth surface and a fibrous
pseudocapsule with variable thickness
and frequent calcifications. The size of
the tumour ranges from 2-35 cm in great-est dimension, with an average size
between 6 and 10 cm. The cut surfaces
demonstrate a unilocular or multilocular
tumour with cystic spaces ranging from a
few millimetres to several centimeters in
diameter, containing either thick mucin or
a mixture of mucin and haemorrhagic-necrotic material. The internal surface of
unilocular tumours is usually smooth and
glistening, whereas the multilocular
tumours often show papillary projections
and mural nodules. Malignant tumours
are likely to show papillary projections
and/or mural nodules and multilocularity
{2198}. As a rule, there is no communi-cation of the tumour with the pancreatic
duct system, but exceptions have been
reported {2148}.
Tumour spread and staging
Invasive mucinous cystadenocarcinoma
follows the same pathways of local
spread as ductal adenocarcinoma. The
first metastases are typically found in the
regional peripancreatic lymph nodes and
the liver {1781}. Staging follows the pro-tocol for ductal adenocarcinomas.
Histopathology
MCNs show two distinct components: an
inner epithelial layer and an outer dense-ly cellular ovarian-type stromal layer.
Large locules can be extensively denud-ed and many sections are often needed
to demonstrate the epithelial lining. The
epithelium may be flat or it may form
papillary or polypoid projections, pseu-dostratifications and crypt-like invagina-tions. The columnar cells are character-ized by basally located nuclei and abun-dant intracellular mucin which is dia-stase-PAS and Alcian blue positive.
Pseudopyloric, gastric foveolar, small
and large intestinal, and squamous dif-ferentiation can also be found. About half
of the tumours contain scattered argy-rophil and argentaffin endocrine cells at
the bases of the columnar cells {33, 36,
328, 2151}.
Spectrum of differentiation
This ranges from histologically benign
appearing columnar epithelium to
severely atypical epithelium. According
to the grade of intraepithelial neoplasia
(dysplasia), tumours may be classified
as adenoma, borderline (low-grade
malignant) and non-invasive or invasive
carcinoma {947}.
Mucinous cystadenomas show only a
slight increase in the size of the basally
located nuclei and the absence of mitosis.
Mucinous cystic neoplasms of borderline
malignant potential exhibit papillary pro-jections or crypt-like invaginations, cellu-lar pseudostratification with crowding of
slightly enlarged nuclei, and mitoses.
Mucinous cystadenocarcinomas may be
invasive or non-invasive. They show
changes of high-grade intraepithelial
neoplasia which are usually focal and
may be detected only after careful
search of multiple sections from different
regions. The epithelial cells, which often
form papillae with irregular branching
and budding, show nuclear stratification,
severe nuclear atypia and frequent
mitoses.
Invasive mucinous cystadenocarcinoma
is characterized by invasion of the malig-nant epithelium into the stroma. The inva-sive component usually resembles the
common ductal adenocarcinoma. How-Fig. 10.18 Mucinous cystic neoplasm presenting as
multiloculated cystic mass in the tail of the pan-creas.
Fig. 10.17  Well differentiated columnar epithelium
supported by ovarian-like stroma.
236 Tumours of the exocrine pancreas
ever, mucinous cystadenocarcinomas
with invasive adenosquamous carcino-ma, osteoclast-like giant cell or chorio-carcinoma have been reported {328,
1530, 1571, 2194}. Invasive foci may be
focal and require careful search.
Stroma
The ovarian-type stroma consists of
densely packed spindle-shaped cells
with round or elongated nuclei and
sparse cytoplasm. It frequently displays
a variable degree of luteinization, char-acterized by the presence of single or
clusters of epithelioid cells with round to
oval nuclei and abundant clear or
eosinophilic cytoplasm. Occasionally,
these cells, resembling ovarian hilar
cells, can be found associated with (or
present in) nerve trunks. Stromal luteini-zation is found in decreasing order of fre-quency from adenomatous to carcinoma-tous cases {2194}. The stroma of large
MCNs may become fibrotic and hypocel-lular. Rare MCNs show mural nodules
with a sarcomatous stroma or an associ-ated sarcoma {1932, 2088, 2198}.
Immunohistochemistry
The epithelial component is immunoreac-tive with epithelial markers including
EMA, CEA, cytokeratins 7, 8, 18 and 19
{2151}, and it may show gastroen-teropancreatic differentiation, as is also
observed in ovarian and retroperitoneal
MCN {1714, 1910}. With increasing
degrees of epithelial atypia the character
of mucin production changes from sul-phated to sialated or neutral mucin
{1932}. The neoplastic cells express gas-tric type mucin marker M1 and PGII, the
intestinal mucin markers CAR-5 and
M3SI, and the pancreatic type mucin
marker DUPAN-2 and CA19-9 {119,
1714, 2151, 2190}. Furthermore, pancre-atic, hepatobiliary, and retroperitoneal
MCNs share the same types of intraep-ithelial endocrine cells {613, 1911, 1910}.
p-53 nuclear positivity in more than 10%
of neoplastic cells, found in 20% of MCN,
strongly correlates with mucinous cys-tadenocarcinoma {2198}.
The stromal component expresses
vimentin, alpha smooth muscle actin,
desmin and, in a high proportion, prog-esterone and estrogen receptors {2198}.
The luteinized cells are labeled with anti-bodies against tyrosine hydroxylase, cal-retinin, which have been shown to recog-nize testicular Leydig cells and hilar
ovarian cells, and the sex cord-stromal
differentiation marker inhibin {2198,
2206}.
Ultrastructure
Electron microscopy of tumours with only
mild to moderate dysplasia demon-strates columnar epithelial cells resting
on a thin basement membrane. The cells
may have well-developed microvilli and
mucin granules {33}.
Genetics
Activating point mutations in codon 12 of
KRAS were found in invasive mucinous
cystic neoplasms (MCNs) {117} and
mucinous cystic neoplasms associated
with osteoclast-like giant cells {1485}.
Mutations of  KRAS and allelic losses of
6q, 9p, 8p have been reported in MCNs
with sarcomatous stroma {1998}.
Prognosis and predictive factors
The prognosis of MCN, regardless of the
degree of cellular atypia, is excellent if
the tumour is completely removed {328,
410, 2060, 2198}. The prognosis of inva-sive mucinous cystadenocarcinoma
depends on the extent of tumour inva-sion. Tumour recurrence and poor out-come correlate with invasion of the
tumour wall and peritumoural tissues
{2198}. Patients older than 50 years
appear to have a lower survival rate
{2198}. Other variables such as site,
tumour size, macroscopic appearance,
grade of differentiation, luteinization of
the stroma and p53 positivity have no
prognostic significance.
Aneuploidy is a rare event in MCNs, is
largely restricted to mucinous cystade-nocarcinomas and carries a worse prog-nosis {1792, 1932, 512}.
Fig. 10.20 Mucinous cystadenocarcinoma. The
thick wall of this cystic neoplasm is invaded by
mucinous carcinoma at upper left.
Fig. 10.19  Mucinous cystadenocarcinoma. The neoplasm exhibits well differentiated and poorly differenti-ated mucinoius epithelium.
237Intraductal papillary-mucinous neoplasms
Definition
An intraductal papillary mucin-producing
neoplasm, arises in the main pancreatic
duct or its major branches. The papillary
epithelium component, and the degree
of mucin secretion, cystic duct dilatation,
and invasiveness are variable. Intra-ductal papillary-mucin neoplasms are
divided into benign, borderline, and
malignant non-invasive or invasive
lesions.
ICD-O codes
Intraductal papillary-mucinous adenoma
8453/0
Intraductal papillary-mucinous neoplasm
with moderate dysplasia 8453/1
Intraductal papillary-mucinous carcinoma
non-invasive 8453/2
invasive 8453/3
Synonyms and historical annotation
Papillary pancreatic neoplasms have
been recognized for many years {247,
1532}, but the distinction between muci-nous cystic neoplasms and intraductal
papillary neoplasms was not made until
the last two decades {947, 1781, 65,
1404}. Interest in IPMNs was first stimu-lated when they were recognized clini-cally {1281}, and pathological descrip-tions quickly followed {2164, 1093}. The
incidence appears to have risen since
the first reports, but this may reflect the
combined effects of new diagnostic
techniques, and progress in recognition
and classification of IPMNs {1138, 918}.
It is likely that many IPMNs were classi-fied among the mucinous cystic neo-plasms as recently as a decade ago.
Epidemiology
The incidence is low and not precisely
known because IPMNs are not accurately
identified in large population-based reg-istries. Nomenclature and classification
have been highly variable until recently,
and are not yet standardized worldwide.
IPMNs have been estimated to amount to
1-3% of exocrine pancreatic neoplasms,
with an incidence rate well below 1 per
100,000 per year {1280, 1095}.
IPMNs are found in a broad age range
(30-94) with a median age of diagnosis in
the 6-7th decade {1443, 2148, 556}.
They occur more frequently in males than
in females {1138, 2148}. IPMNs were first
reported from France and Japan, but
subsequent reports have come from all
parts of the world. Two studies provide
some evidence that the incidence may
be higher among Asians than among
whites, but issues of consistency of clas-sification require that this be further eval-uated {1095, 941}.
Aetiology
The low incidence and imprecise identifi-cation of IPMN in large databases has
hindered recognition of aetiological fac-tors. In one series, most patients with
IPMNs were cigarette smokers {550}.
There is no consistent association with
other types of pancreatic neoplasm
{2198}.
Localization
The majority of these neoplasms occur in
the main pancreatic duct and its branch-es in the head of the pancreas {1781,
330, 97}. A single cystic mass or seg-mental involvement of the duct is usual,
but diffuse involvement is also described
{1093, 1751, 1953}. Multicentric origin is
suspected because of recurrence in
pancreatic remnants following surgical
removal of IPMNs {1088}. IPMNs may
extend to the ampulla of Vater, common-ly in association with involvement of the
duct of Wirsung or the common bile duct
{1781}.
Clinical features
Clinical presentation includes epigastric
pain, pancreatitis, weight loss, diabetes,
and jaundice {2169, 1953, 942}; some
patients have no symptoms. Some cases
are detected because of dilatation of the
pancreatic duct seen incidentally in
imaging studies. Serum amylase and
lipase are commonly elevated.
Endoscopic ultrasound, ERCP, and
endoscopic examination of the pancreat-ic duct {1596} may all contribute to pre-operative diagnosis. Endoscopic biopsy
or cytology may provide histological con-firmation, but definitive diagnosis
requires surgical removal and extensive
histological sampling. Serum markers
such as CEA and CA19-9 are too insen-sitive to be of value {2148, 1953}.
Macroscopy
Depending on the degree of ductal
dilatation, IPMNs vary in size from 1 to 8
cm in maximum dimension {17}. They are
cystic and may appear multiloculated if
branch ducts are involved. The mucin
found in IPMN is viscous or sticky and
can dilate parts of the duct that are lined
by normal appearing epithelium. The lin-ing of cystic spaces may be smooth and
glistening, granular, or velvet-like, the lat-ter reflecting papillary growth. When
D.S. Longnecker R.H. Hruban
G. Adler G. KlöppelIntraductal papillary-mucinous
neoplasms of the pancreas
Fig. 10.21 Intraductal papillary-mucinous neoplasm.
A Large neoplasm in the head of the pancreas con-taining multiple cystic spaces.  B The lesion illus-trated in A sectioned to demonstrate the dilated,
mucin-filled main pancreatic duct (arrowheads).
A
B
238 Tumours of the exocrine pancreas
papillary growths are large, the dilated
ducts may show localized excrescences
or be filled with soft papillary masses of
tissue.
The pancreatic parenchyma surrounding
and retrograde to the tumour is often
pale and firm, reflecting changes of
chronic obstructive pancreatitis. When
there is invasion, gelatinous areas may
be identified in fibrotic tissue.
Tumour spread and staging
Adenomas, borderline tumours and non-invasive carcinomas may extend intra-ductally into adjacent portions of the duct
system, and evidence of such extension
is often encountered adjacent to IPMNs.
Recurrence following surgical resection
has been reported in patients that had
IPMNs extending into the margin of
resection {1953}. Invasive neoplasms are
staged as ductal adenocarcinomas.
Histopathology
IPMN tumour cells are usually tall colum-nar mucin-containing epithelial cells that
line dilated ducts or cystic spaces aris-ing from dilated branch ducts. The
epithelium typically forms papillary or
pseudopapillary structures, but portions
of the neoplasm may be lined by non-papillary epithelium or be denuded of
epithelium. The amount of mucin produc-tion varies widely, as does the degree of
duct dilatation {97, 872}. Goblet or
Paneth cells may be present as a mani-festation of intestinal metaplasia in the
neoplastic epithelium, and neuroen-docrine cells have also been demon-strated.
The recently described intraductal onco-cytic papillary neoplasm probably repre-sents a rare related phenotype that is
similar macroscopically {1244, 1860}.
Oncocytic IPMNs are composed of strat-ified oncocytic cells with pale pink cyto-plasmic granules that are much finer
than those seen in Paneth cells. Goblet
cells may be interspersed among the
oncocytic cells. A characteristic feature
of the oncocytic papillary neoplasms is
the formation of ‘intraepithelial lumina’,
which are spaces in the epithelium about
one quarter the size of the cells.
Histochemistry and immunohistochemistry
A variety of abnormalities have been
demonstrated in IPMNs using mucin and
immunohistochemical stains.
Most IPMNs express epithelial mem-brane antigen (EMA) as well as several
cytokeratins {1917}. A variety of
endocrine cell types occur in most
tumours but account for fewer than 5 per
cent of the tumour cells {1676}.
A change in type of mucin has been sug-gested as a marker of progression since
normal duct cells characteristically
secrete sulfated mucin, intraductal papil-lary-mucinous adenomas characteristi-cally secrete neutral mucin, and dysplas-tic epithelium secretes predominantly
sialomucin {1138, 1916, 1186}. Nearly all
IPMNs express MUC2 {2179}.
Overexpression of c-erbB-2 protein
occurs in a high fraction of IPMNs {1939,
1675, 1877, 380}.
A study of cell proliferation, as shown by
PCNA and Ki67 labelling indices,
demonstrated a progressive increase in
cell proliferation from normal duct epithe-lium, to adenomas, to borderline
tumours, to carcinomas {1917}. The
labeling index in IPM carcinomas was
lower than in ductal adenocarcinomas.
Although immunostaining of p53 protein
was detected in a lower fraction of IPMN
(31%) than is usually seen in solid ductal
adenocarcinomas, it was found only in
borderline and malignant IPMN and
therefore may be a marker of progression
{1939}.
Failure of IPMN to elicit the production of
a collagenase that mediates invasion
was reported {2193}.
Fig. 10.22 Intraductal papillary mucinous neoplasm
in the main pancreatic duct (arrowhead).
Fig. 10.23 Intraductal papillary mucinous neoplasms with (A) columnar epithelium and (B) oncocytic epithe-lium.
Fig. 10.24 Intraductal papillary-mucinous neoplasm
within the dilated main pancreatic duct and branch
ducts.
AB
239Intraductal papillary-mucinous neoplasms
Classification and grading of IPMNs
IPMNs have been the source of great
confusion that is reflected in a diverse
nomenclature found in case and series
reports and in standard references
{1781}. Because of the variability within a
tumour, it is important to sample IPMNs
well, giving special emphasis to papillary
areas because this is where the highest
degree of intraepithelial neoplasia (dys-plasia) is likely to occur, and to sclerotic
areas that may reflect invasion.
IPMNs are classified as benign, border-line, or malignant on the basis of the
greatest degree of dysplasia present. In
accordance with the previous WHO clas-sification, lesions are specifically desig-nated as intraductal papillary-mucinous
adenoma, borderline intraductal papil-lary-mucinous neoplasm, and intraductal
papillary-mucinous carcinoma, with or
without invasion {947, 1781}.
A slightly different histopathological clas-sification has been proposed by the
Japan Pancreas Society (JPS) {65}, intra-ductal tumours are designated as intra-ductal papillary adenoma or adenocarci-noma. The degree of cellular atypia in
adenomas is designated as slight, mod-erate, or severe. The JPS category of
adenoma with severe atypia corre-sponds to the WHO borderline lesion,
although some authors also utilize a bor-derline category {2148}
Intraductal papillary-mucinous adenoma
The epithelium is comprised of tall
columnar mucin-containing cells that
show slight or no dysplasia, i.e. the
epithelium maintains a high degree of
differentiation in adenomas.
Borderline intraductal papillary-mucinous
neoplasm
IPMNs with moderate dysplasia are
placed in the borderline category. The
epithelium shows no more than moderate
loss of polarity, nuclear crowding,
nuclear enlargement, pseudostratifica-tion, and nuclear hyperchromatism.
Papillary areas maintain identifiable stro-mal cores, but pseudopapillary struc-tures may be present.
Intraductal papillary-mucinous carcinoma
IPMNs with severe dysplastic epithelial
change are designated as carcinoma
even in the absence of invasion.
Carcinomas are papillary or micropapil-lary. Cribriform growth and budding of
small clusters of epithelial cells into the
lumen support the diagnosis of carcino-ma. Severe dysplasia is manifest cyto-logically as loss of polarity, loss of differ-entiated cytoplasmic features including
diminished mucin content, cellular and
nuclear pleomorphism, nuclear enlarge-ment, and the presence of mitoses
(especially if suprabasal or luminal in
location). Severely dysplastic cells may
lack mucin. Non-invasive lesions are
termed non-invasive intraductal papil-lary-mucinous carcinoma. When inva-sive, an IPMN may be called a papillary-mucinous carcinoma since it is no longer
only intraductal. When IPMNs become
invasive, the invasive component may
assume the appearance of a tubular
ductal adenocarcinoma or a mucinous
noncystic carcinoma {17}. If the invasive
component is dominant, and is a ductal
or mucinous noncystic carcinoma, then
that diagnosis may be used, descriptive-ly noting the association with an IPMN
component.
Differential diagnosis
Historically, IPMNs and mucinous cystic
neoplasms (MCNs) have been confused
because they are both cystic and have a
similar epithelial component. However,
IPMNs and MCNs are distinct entities
and can be separated easily, because
MCNs typically occur in women with a
median age in the fifth decade, almost
always are located in the tail or body of
the pancreas, typically exhibit a thick
wall with a cellular ‘ovarian’ stroma, and
typically fail to communicate with the
pancreatic duct system.
Precursor lesions
The criteria for classifying pancreatic
intraepithelial neoplasia (PanIN) lesions
(including papillary hyperplasia, see
chapter on ductal adenocarcinoma of
the pancreas) in IPMNs are not well
established {1144, 1744}, and need to be
defined. PanIN lesions characteristically
occur in intralobular ducts, are not
detected macroscopically, and are clini-cally silent {17}. It seems likely that the
earliest stage of development of the
IPMN would involve the progression from
a flat area of mucous metaplasia to a
papillary lesion in a main or branch pan-creatic duct as suggested by Nagai et al.
Fig. 10.25 Intraductal papillary-mucinous carcinoma. Intraductal papillary neoplasm (left), invasive mucin
secreting carcinoma (right).
Fig. 10.26 Intraductal papillary-mucinous carcino-ma. This tumour shows moderately differentiated
(left) and well differentiated (right) areas.
240 Tumours of the exocrine pancreas
{1306}. Thus, it will be difficult to recog-nize the initial stage of an intraductal
papillary-mucinous adenoma unless a
distinctive molecular marker is identified.
Genetic susceptibility
Excessive rates of colonic and gastric
epithelial neoplasms were reported in a
group of 42 patients with IPMNs {106}.
This suggests the possibility of a predis-posing genetic susceptibility, but no spe-cific hereditary syndrome was identified.
Genetics
Activating point mutations in codon 12 of
the KRAS gene have been reported in
40-60% of intraductal papillary mucinous
neoplasms {1939, 544}. Fujii et al. exam-ined a series of IPMNs using polymorphic
microsatellite markers and found allelic
loss at 9p in 62% of the cases and at 17p
and at 18q in ~40% {544}. These allelic
losses include the loci of the p16, TP53,
and DPC4 tumour-suppressor genes. In
addition to immunohistochemical evi-dence of p53 abnormality in IPMN {544},
mutations have been demonstrated in
two adenomas {876}. Overexpression of
anti-apoptotic genes in IPMN is reported
{1247}.
Mutations of KRAS and TP53 genes have
been detected in DNA from pancreatic
juice of patients with IPMN {875}.
Prognosis and predictive factors
The overall 5-year survival rate for a com-posite series was 83% {2148}. The prog-nosis is excellent for adenomas and bor-derline tumours with 3 and 5-year sur-vivals approaching 100%. The survival
rates are high for non-invasive carcino-mas, and survival rates for patients with
invasive IPMNs may also be higher than
for patients with typical ductal adenocar-cinomas {2148, 97, 2169}. The histologi-cal classification, with major emphasis
on the presence or absence of invasion,
and stage remain the best predictors for
survival.
As the distinction between IPMNs and
MCNs has been refined, some authors
report that MCNs are more often malig-nant than IPMNs and that the latter have
a better prognosis following treatment
{97}, but this was not confirmed in other
series {1953, 551}. Expression of MUC2
and MUC5AC mucins are associated
with a good prognosis relative to ductal
adenocarcinomas that do not express
these mucins {2179, 2178}.
Differentiation markers
Alcian blue stain Adenomas contain neutral mucin, {1138, 1916}
carcinomas contain sialomucin
MUC1 Negative>>positive (2179}
MUC2 Positive>>negative {2179}
Endocrine markers < 5% of cells positive in most IPMN  {1676}
Epithelial membrane antigen Positive  {1917}
Cytokeratins 7, 8, 18, 19 Positive  {1917}
CEA Positive {1939}
CA-19-9 Positive {1939}
B72.3 Positive {1939}
DUPAN-2 Seen in a minority  {1939}
Oncogene products
c-erbB-2 13/17 IPMN positive, including all with {1675}
moderate or severe dysplasia {1939}
p27 p27 staining exceeds cyclin E {556}
Tumour suppressor gene products
TP53 Often positive in borderline tumours and  {1939}
carcinomas
Proliferation markers
PCNA and Ki67 Labeling index increases with progression {1917}
from adenoma to carcinoma
Antibody or epitope Comments on staining in IPMN Reference
Table 10.05
Summary of mucin histochemistry and immunostaining of IPMN.
241Acinar cell carcinoma
Acinar cell carcinoma D.S. Klimstra
D. Longnecker
Definition
A carcinoma occurring mainly in adults,
composed of relatively uniform neoplas-tic cells that are arranged in solid and
acinar patterns and produce pancreatic
enzymes.
ICD-O codes
Acinar cell carcinoma 8550/3
Acinar cell cystadenocarcinoma   8551/3
Mixed acinar-endocrine carcinoma  8154/3
Epidemiology
Acinar cell carcinomas represent 1-2% of
all exocrine pancreatic neoplasms in
adults {739, 936}. Most occur in late
adulthood, with a mean age of 62 years
{825, 979, 2073}. The tumour is rare in
adults under the age of 40. Pediatric
cases do occur, usually manifesting in
patients 8 to 15 years of age {979, 1282}.
Males are affected more frequently than
females, with an M:F ratio of 2:1 {739,
936}.
Aetiology
The aetiology is unknown.
Localization
Acinar cell carcinomas may arise in any
portion of the pancreas but are some-what more common in the head.
Clinical features
Symptoms and signs
Most acinar cell carcinomas present clin-ically with relatively non-specific symp-toms including abdominal pain, weight
loss, nausea, or diarrhoea {739, 936,
979, 2073}. Because they generally push
rather than infiltrate into adjacent struc-tures, biliary obstruction and jaundice
are infrequent presenting complaints.
A well-described syndrome occurring in
10-15% of patients is the lipase hyper-secretion syndrome {1781, 213, 936,
975}. It is most commonly encountered in
patients with hepatic metastases, and is
characterized by excessive secretion of
lipase into the serum, with clinical symp-toms including subcutaneous fat necro-sis and polyarthralgia. Peripheral blood
eosinophilia may also be noted. In some
patients, the lipase hypersecretion syn-drome is the first presenting sign of the
tumour, while in others it develops follow-ing tumour recurrence. Successful surgi-cal removal of the neoplasm may result in
the normalization of the serum lipase
levels and resolution of the symptoms.
Laboratory analyses
Other than an elevation of serum lipase
levels associated with the lipase hyper-secretion syndrome, there are no specif-ic laboratory abnormalities in patients
with acinar cell carcinoma. A few cases
show increased serum alpha-fetoprotein
{819, 1426, 1369, 1747}.
Imaging
Acinar cell carcinomas are generally
bulky with a mean size of 11 cm {979}.
On abdominal CT scans, they are cir-cumscribed and have a similar density to
the surrounding pancreas. Because of
their larger size and relatively sharp cir-cumscription, acinar cell carcinomas can
generally be distinguished from ductal
adenocarcinomas radiographically.
Fine needle aspiration cytology
There is usually a high cellular yield from
fine needle aspiration {1446, 1978, 2015}.
The cytological appearances of acinar
cell carcinomas closely mimic of pancre-atic endocrine neoplasms, although the
latter are more likely to exhibit a plasma-cytoid appearance to the cells and a
speckled chromatin pattern. Immuno-histochemistry may be used on cytologi-cal specimens to confirm the diagnosis of
acinar cell carcinoma {1446, 1978}.
Macroscopy
Acinar cell carcinomas are generally cir-cumscribed and may be multinodular
{739, 936}. Individual nodules are soft
and vary from yellow to brown. Areas of
necrosis and cystic degeneration may
be present. Occasionally, the neoplasm
is found attached to the pancreatic sur-face. Extension into adjacent structures,
such as duodenum, spleen, or major
vessels may occur. Multicystic examples
of acinar cell carcinoma have been
reported as acinar cell cystadenocarci-noma {229, 739, 1815}.
Tumour spread and staging
Metastases most commonly affect
regional lymph nodes and the liver,
although distant spread to other organs
occurs occasionally. Acinar cell carcino-mas are staged using the same protocol
as ductal adenocarcinomas.
Histopathology
Large nodules of cells are separated by
hypocellular fibrous bands. The desmo-plastic stroma characteristic of ductal
adenocarcinomas is generally absent.
Tumour necrosis may occur and is gen-erally infarct-like in appearance. Within
the tumour cell islands, there is an abun-dant fine microvasculature.
Several architectural patterns have been
described. The most characteristic is the
acinar pattern, with neoplastic cells
arranged in small glandular units; there
are numerous small lumina within each
island of cells giving a cribriform appear-ance. In some instances, the lumina are
more dilated, resulting in a glandular pat-tern, although separate glandular struc-tures surrounded by stroma are usually
not encountered. A number of the micro-Fig. 10.27  Acinar cell carcinoma. The hypodense
lobulated tumour occupies the tail of the pancreas.
242 Tumours of the exocrine pancreas
glandular tumours previously reported as
‘microadenocarcinoma’ were more
recently shown to have been acinar cell
carcinomas (see chapter on miscella-neous carcinomas). The second most
common pattern in acinar cell carcino-mas is the solid pattern: solid nests of
cells lacking luminal formations are
separated by small vessels. Within these
nests, cellular polarization is generally not
evident, but there may be an accentua-tion of polarization at the interface with
the vessels, resulting in basal nuclear
localization in these regions and a pal-isading of nuclei along the microvascula-ture. In rare instances, a trabecular
arrangement of tumour cells may be
present, with exceptional cases also
showing a gyriform appearance {936}.
The neoplastic cells contain minimal to
moderate amounts of cytoplasm that
may be more abundant in cells lining
lumina. The cytoplasm varies from
amphophilic to eosinophilic and is char-acteristically granular, reflecting the pres-ence of zymogen granules. In many
instances, however, only minimal cyto-plasmic granularity may be detectable.
The nuclei are generally round to oval
and relatively uniform, with marked
nuclear pleomorphism being exception-al. A single, prominent, central nucleolus
is a characteristic finding but not invari-ably present. The mitotic rate is variable
(mean 14 per 10 high power fields, range
0 to > 50 per 10 high power fields).
Zymogen granules are weakly positive
with PAS staining, and resistant to dia-stase. Mucin production is generally not
detectable with mucicarmine or Alcian
blue stains and, if present, is limited to
the luminal membrane in acinar or glan-dular formations. The histochemical stain
for butyrate esterase can be used to
identify active lipase within the tumour
cells {936, 938}. Due to the scarcity of
zymogen granules in many examples of
acinar cell carcinoma, histochemical
stains are relatively insensitive for docu-menting acinar differentiation, and very
focal staining may be difficult to interpret
with confidence.
Immunohistochemistry
Immunohistochemical identification of
pancreatic enzyme production is helpful
in confirming the diagnosis of acinar cell
carcinoma. Antibodies against trypsin,
chymotrypsin, lipase, and elastase have
all been used {739, 810, 936, 1282}. Both
trypsin and chymotrypsin are detectable
in over 95% of cases; lipase is less com-monly identified (approximately 70% of
cases) {936}. Pancreatic stone protein is
also commonly expressed {739}. In solid
areas, immunohistochemical staining for
enzymes may show diffuse cytoplasmic
positivity, whereas the reaction product is
restricted to the apical cytoplasm in aci-nar areas.
Immunohistochemical markers of endo-crine and ductal differentiation may also
be detected in acinar cell carcinomas,
generally in a minor cell population {739,
936}. Scattered individual cells stain for
chromogranin or synaptophysin are
found in over one third of lesions. Over
half exhibit focal CEA and B72.3 expres-sion {739, 936}. Uncommonly, there is
immunohistochemical positivity for alpha-fetoprotein, generally in cases associat-ed with elevations in serum alpha-feto-protein {819}.
Ultrastructure
Electron microscopy provides further evi-dence of enzyme production {675, 408,
936, 1978}. Exocrine secretory features
are consistently found, with abundant
rough endoplasmic reticulum arranged in
parallel arrays and relatively abundant
mitochondria. Cellular polarization is gen-erally evident, with basal basement mem-branes and apical lumina. Adjacent cells
are joined by tight junctions. Although the
distribution varies from cell to cell, most
acinar cell carcinomas exhibit electron
dense zymogen granules. In polarized
cells, they are located in the apical cyto-plasm, and the secretory contents may
be seen within the luminal spaces where
granules have fused with the apical
membrane. The size range of zymogen
granules in acinar cell carcinomas (125-1000 nm) is somewhat greater than that
found in non-neoplastic acinar cells (250-1000 nm). In addition to typical zymogen
granules, a second granule type, the
irregular fibrillary granule, is detected
ultrastructurally in many cases {302, 936,
938, 1477}. It has been suggested that
irregular fibrillary granules may represent
a recapitulation of the fetal zymogen
granules, although attempts to document
the presence of pancreatic enzymes
within them by immunohistochemistry
have been unconvincing {936, 938,
1032}.
Acinar cell carcinoma variants
Acinar cell cystadenocarcinoma
Acinar cell cystadenocarcinomas are
rare, grossly cystic neoplasms with
cytoarchitectural features of acinar cell
carcinomas {229, 825, 739, 1815}.
Mixed acinar-endocrine carcinoma
Rare neoplasms have shown a substan-tial (greater than 25%) proportion of more
than one cell type. These neoplasms
have been designated ‘mixed carcino-mas’, and, depending upon the cell
types identified, as ‘mixed acinar-endocrine carcinoma’, ‘mixed acinar-ductal carcinoma’, or ‘mixed acinar-endocrine-ductal carcinoma’ {997, 1369,
2015}. Of these, the best characterized is
the mixed acinar-endocrine carcinoma
{997}. In many mixed acinar-endocrine
carcinomas, the evidence for divergent
differentiation is only provided by
immunohistochemical staining. Although
different regions of the tumours may sug-gest acinar or endocrine differentiation
morphologically, many areas have inter-mediate features, and immunohisto-chemistry generally shows a mixture of
cells expressing acinar or endocrine
markers (or both). In exceptional cases,
however, there is also morphological evi-dence of multiple lines of differentiation,
Fig. 10.28  An acinar cell carcinoma (AC) lies near
the spleen (SP). The tumour’s cut surface is lobulat-ed.
Fig. 10.29  Acinar cell carcinoma showing well dif-ferentiated acinar structures.
SP
AC
243Acinar cell carcinoma
with some regions exhibiting obvious aci-nar features and other areas endocrine
features. Most reported acinar-endocrine
carcinomas have been composed pre-dominantly of acinar elements based on
the proportion of cells staining immuno-histochemically {997}. There are insuffi-cient cases recorded to suggest that the
biological behaviour of mixed acinar-endocrine carcinomas differs from that of
pure acinar cell carcinomas.
Precursor lesions
No documented precursor lesions for
acinar cell carcinomas have been
defined. Initial suggestions that so-called
atypical acinar cell nodules may repre-sent preneoplastic lesions of acinar cells
have not been substantiated by later
studies {1094}. Atypical acinar cell nod-ules occur either because of dilatation of
the rough endoplasmic reticulum (result-ing in reduced basophilia of the basal
cytoplasm) or depletion of zymogen
granules (resulting in reduced eosino-philia of the apical cytoplasm and an
increase in nuclear:cytoplasmic ratio);
these lesions are relatively common inci-dental findings in resected pancreases.
Genetics
In contrast to ductal adenocarcinomas,
acinar cell carcinomas very rarely show
KRAS mutations and TP53 immunoreac-tivity {739, 1485, 1920, 1921}.
Prognosis and predictive factors
These neoplasms are aggressive, with a
median survival of 18 months and a
5-year survival rate of less than 10%
{739, 936}. Approximately 50% of
patients have metastases at the time of
diagnosis, and an additional 25% devel-op metastatic disease following surgical
resection of the primary tumour {936}.
The most important prognostic factor is
tumour stage, with patients lacking
lymph node or distant metastases surviv-ing longer {936}. Patients with the lipase
hypersecretion syndrome were shown to
have a particularly short survival, be-cause most of these patients had wide-spread metastatic disease. Despite poor
overall survival rates, there are anecdot-al reports of survival for several years in
the presence of metastatic disease, and
responses to chemotherapy have been
noted {936}. Thus, the prognosis of aci-nar cell carcinoma may be somewhat
less poor than that of ductal adenocarci-noma.
No specific grading system for acinar
cell carcinomas has been proposed. No
association between the extent of acinus
formation and prognosis has been
observed.
There is an insufficient number of pedi-atric acinar cell carcinomas to allow an
accurate assessment of the biological
behaviour in children. Available data
suggest that acinar cell carcinomas
occurring under the age of 20 may be
less aggressive than their adult counter-parts 936, 1446}.
Fig. 10.30 Acinar cell carcinoma. Solid pattern with uniform round nuclei.
Fig. 10.31 Acinar cell carcinoma showing
immunoreactivity for chromogranin.
244 Tumours of the exocrine pancreas
Pancreatoblastoma D.S. Klimstra
D. Longnecker
Definition
A malignant epithelial tumour, generally
affecting young children, composed of
well-defined solid nests of cells with aci-nar formations and squamoid corpus-cles, separated by stromal bands. Acinar
differentiation prevails, often associated
with lesser degrees of endocrine or duc-tal differentiation.
ICD-O code 8971/3
Epidemiology
Incidence
Pancreatoblastoma is an exceedingly
rare tumour, less than 75 cases having
been reported {782, 939, 2117}.
However, it is among the most frequent
pancreatic tumours in childhood, proba-bly accounting for 30-50% of pancreatic
neoplasms occurring in young children
{631}.
Age and sex distribution
The majority of pancreatoblastomas
occur in children, most being under the
age of 10. The median age of pediatric
patients is approximately 4 years {742,
939}, and only a few cases have been
described in the second decade of life
{782}. A number of congenital examples
have also been documented {939}.
Rarely, tumours histologically indistin-guishable from pancreatoblastomas
occur in adult patients ranging between
19 and 56 years of age {939, 1053,
1452}. There is a slight male predomi-nance, with an M:F ratio of 1.3:1 {939}.
Aetiology
The aetiology is unknown.
Localization
The head of the gland is affected in
about 50% of cases, the remainder
being equally divided between the body
and the tail.
Clinical features
The presenting features of pancreato-blastoma are generally non-specific.
Especially in the pediatric age group,
many patients present with an incidental-ly detected abdominal mass {782, 939}.
Related symptoms include pain, weight
loss, and diarrhoea. The paraneoplastic
syndromes associated with acinar cell
carcinoma (lipase hypersecretion syn-drome) and pancreatic endocrine neo-plasms have not been described, but
one patient developed Cushing syn-drome {1478}.
Radiologically, pancreatoblastomas are
large, well-defined, lobulated tumours
which may show calcifications on CT
scan {1833, 2027, 2117}.
There is no consistent elevation of serum
tumour markers, but some cases have
exhibited increased alpha-fetoprotein
levels {802, 939}.
Macroscopy
The size of pancreatoblastomas varies
from 1.5-20 cm. Most tumours are soli-tary, solid neoplasms composed of well-defined lobules of soft, fleshy tissue sep-arated by fibrous bands. Areas of necro-sis may be prominent. Uncommonly the
tumours are grossly cystic, a phenome-non reported in all cases associated with
the Beckwith-Wiedeman syndrome {432}.
Histopathology
The epithelial elements of pancreato-blastomas are highly cellular and
arranged in well-defined islands separat-ed by stromal bands, producing a ‘geo-graphic’ low power appearance. Solid,
hypercellular areas composed of nests
of polygonal cells alternate with regions
showing more obvious acinar differentia-tion, with polarized cells surrounding
small luminal spaces. In rare tumours,
larger glandular spaces lined by mucin-containing cells may be seen {939}.
Nuclear atypia is generally minimal.
Squamoid corpuscles.  One of the most
characteristic features of pancreatoblas-toma is the ‘squamoid corpuscle’. These
enigmatic structures vary from large
islands of plump, epithelioid cells to
whorled nests of spindled cells to frankly
keratinizing squamous islands. The
nuclei of the squamoid corpuscles are
larger and more oval than those of the
surrounding cells; nuclear clearing due
to the accumulation of biotin may be
seen {1895}. The frequency and compo-sition of the squamoid corpuscles varies
in different regions of the tumour and
between different cases.
Stroma.  Especially in pediatric cases, the
stroma of pancreatoblastomas is often
hypercellular, in some instances achiev-ing a neoplastic appearance. Rarely, the
presence of heterologous stromal ele-ments, including neoplastic bone and
cartilage, has been reported {127, 939}.
Histochemistry and immunohistochemistry
Over 90% of pancreatoblastomas exhibit
evidence of acinar differentiation in the
form of PAS-positive, diastase resistant
cytoplasmic granules as well as immuno-histochemical staining for pancreatic
enzymes, including trypsin, chymo-trypsin, and lipase {939, 1282, 1400}. The
staining may be focal, often limited to the
apical cytoplasm in areas of the tumour
with acinar formations. At least focal
Fig. 10.32  Pancreatoblastoma. A CT image showing
a large tumour (PB) in the head of the pancreas,
with hypodense areas.  B The cut surface of the
neoplasm demonstrates a lobulated structure.
PB
PB
A
B
245Pancreatoblastoma
immunoreactivity for markers of endocrine
differentiation (chromogranin or synapto-physin) is found in over two-thirds of
cases, and expression of markers of duc-tal differentiation such as CEA, DUPAN-2,
or B72.3 is found in more than half of
cases {939}. In most instances, the pro-portion of cells expressing acinar markers
outnumbers the proportion expressing
endocrine or ductal markers. In cases
associated with elevations in the serum
levels of alpha-fetoprotein, immunohisto-chemical positivity for AFP has been
detectable {802, 939}.
Immunohistochemical evaluation of the
squamoid corpuscles has failed to define
a reproducible line of differentiation for
this component {939}.
Relationship to acinar cell carcinoma
Both pancreatoblastomas and acinar cell
carcinomas consistently exhibit acinar
differentiation and may exhibit lesser
degrees of endocrine and ductal differ-entiation. {936, 939}. Histologically, aci-nar formations are characteristic of pan-creatoblastoma, and the solid areas
resemble the solid pattern of acinar cell
carcinoma. Biologically, the two tumours
are also similar, with a relatively favorable
prognosis in childhood, but a very poor
prognosis in adulthood. For these rea-sons, some observers have suggested
that pancreatoblastoma represents the
paediatric counterpart of acinar cell car-cinoma. Although this proposal is attrac-tive in many ways, pancreatoblastoma
remains a separately definable neoplasm
with characteristic histologic, immunohis-tochemical, and clinical features.
Ultrastructure
By electron microscopy, pancreatoblas-tomas generally exhibit evidence of aci-nar differentiation {939, 1758}, with rela-tively abundant rough endoplasmic retic-ulum and mitochondria, and apically
located dense zymogen granules. The
zymogen granules may be round and
uniform, resembling those of non-neo-plastic cells. In addition, irregular fibril-lary granules similar to those described
in acinar cell carcinomas may be found
{936, 939}. In rare cases, dense-core
neurosecretory-type granules and muci-gen granules have also been observed
{939}. Examination of the squamoid cor-puscles has revealed tonofilaments but
no evidence of a specific line of differen-tiation.
Genetic susceptibility
In several reported cases (all congenital
examples), pancreatoblastomas have
been a component of the Beckwith-Wiedeman syndrome {432}.
Prognosis
Pancreatoblastomas are malignant
tumours. Nodal or hepatic metastases
are present in 35% of patients {782, 939}.
More widespread dissemination may also
occur. In pediatric patients lacking evi-dence of metastatic disease at first pres-entation, the prognosis is very good,
most patients being cured by a combina-tion of surgery and chemotherapy {894,
1299}. In the presence of metastatic dis-ease or in adult patients with pancreato-blastomas, the outcome is usually fatal
{312, 939}, the mean survival being 1.5
years {939}. However, a favourable
response to chemotherapy has been
noted in some children {235, 2027}.
Fig. 10.33  Pancreatoblastoma with squamoid corpuscule (arrowhead), surrounded by solid (left) and tubular
(right) structures.
246 Tumours of the exocrine pancreas
Definition
A usually benign neoplasm with predomi-nant manifestation in young women, com-posed of monomorphic cells forming solid
and pseudopapillary structures, frequent-ly showing haemorrhagic-cystic changes
and variably expressing epithelial, mes-enchymal and endocrine markers.
ICD-O codes
Solid pseudopapillary neoplasm   8452/1
Solid pseudopapillary carcinoma  8452/3
Synonyms
Solid-cystic tumour {946}, papillary-cys-tic tumour {170}, solid and papillary
epithelial neoplasm.
Epidemiology
Solid-pseudopapillary neoplasm is
uncommon but has been recognized
with increasing frequency in recent years
{946, 1192, 1358}. It accounts for
approximately 1-2% of all exocrine pan-creatic tumours {359, 941, 1280}.
It occurs predominantly in adolescent
girls and young women (mean 35 years;
range 8-67 years) {1781, 1072}. It is rare
in men (mean, 35 years; range 25-72
years) {945, 1193, 1975}. There is no
apparent ethnic preference {978, 1395}.
Aetiology
The aetiology is unknown. The striking
sex and age distribution point to genetic
and hormonal factors, but there are no
reports indicating an association with
endocrine disturbances including over-production of oestrogen or progesterone.
Moreover, only very few women devel-oped a solid pseudopapillary neoplasm
after long-term use of hormonal contra-ceptives {359, 436, 1655}.
Localization
There is no preferential localization within
the pancreas {1282, 1358}.
Clinical features
Usually, the neoplasms are found inci-dentally on routine physical examination
or they cause abdominal discomfort and
pain {1358}, occasionally after abdomi-nal trauma {945}. Jaundice is rare {1427},
even in tumours that originate from the
head of the pancreas, and there is no
associated functional endocrine syn-drome. All known tumour markers are
normal.
Ultrasonography (US) and computed
tomography (CT) reveal a sharply demar-cated, variably solid and cystic mass
without any internal septation {300}. The
tumour margin may contain calcifications.
Administration of contrast medium results
in enhancement of the solid tumour parts.
On angiography, the neoplasms are usu-ally hypovascular or mildly hypervascular
lesions with displacement of surrounding
vessels {2153}. Fine needle aspiration
cytology performed under radiological
control shows monomorphic cells with
round nuclei and eosinophilic or foamy
cytoplasm {234, 2119, 2140}.
Macroscopy
The neoplasms present as large, round,
solitary masses (average size 8-10 cm;
range, 3-18 cm), and are often fluctuant.
They are usually encapsulated and well
demarcated from the surrounding pan-creas. Multiple tumours are exceptional
{1427}. The cut surfaces reveal lobulat-ed, light brown solid areas, zones of
haemorrhage and necrosis, and cystic
spaces filled with necrotic debris.
Occasionally, the haemorrhagic-cystic
changes involve almost the entire lesion
so that the neoplasm may be mistaken
for a pseudocyst. The tumour wall may
contain calcifications {1358}. A few
tumours have been found to be attached
to the pancreas or even in extrapancre-atic locations {812, 914, 945}. Invasion of
adjacent organs or the portal vein is rare
{1655, 1684, 1701}.
Tumour spread
Only few metastasizing solid-pseudo-papillary neoplasms have been reported
{359, 1358}. Common metastatic sites
include regional lymph nodes, the liver,
peritoneum, and greater omentum {300,
2209, 1358}.
Histopathology
In large neoplasms, extensive necrosis is
typical and the preserved tissue is usual-ly found in the tumour periphery under
the fibrous capsule. This tissue exhibits a
solid monomorphic pattern with variable
sclerosis. More centrally there is a
pseudopapillary pattern, and these com-ponents often gradually merge into each
G. Klöppel R. Hruban
J. Lüttges S. Kern
D. Klimstra G. Adler
Solid-pseudopapillary neoplasm
Fig. 10.35  Solid-pseudopapillary neoplasm. The
pseudopapillary structures are lined by small
monomorphic cells.
Fig. 10.34 Solid-pseudopapillary neoplasm.  A The
round hypodense tumour (T) replaces the tail of the
pancreas. B The pseudocystic neoplasm is
attached to the spleen, and shows haemorrhagic
necrosis.
T
A
B
247Solid-pseudopapillary neoplasm
other. In both patterns, the uniform poly-hedral cells are arranged around deli-cate, often hyalinized fibrovascular stalks
with small vessels {1395}. Neoplastic
cells that are arranged radially around the
minute fibrovascular stalks may resemble
‘ependymal’ rosettes. Luminal spaces are
consistently absent. In the solid parts,
disseminated aggregates of neoplastic
cells with foamy cytoplasm or cholesterol
crystals surrounded by foreign body cells
may be found. The spaces between the
pseudopapillary structures are filled with
red blood cells. The hyalinized connec-tive tissue strands may contain foci of cal-cification and even ossification {1193}.
The neoplastic cells have either eosino-philic or clear vacuolar cytoplasm.
Occasionally they contain eosinophilic,
diastase-resistant PAS-positive globules
of varying size, which may also occur
outside the cells. Glycogen or mucin
cannot be detected. Grimelius positive
cells may occur. The round to oval nuclei
have finely dispersed chromatin and are
often grooved or indented. Mitoses are
usually rare, but in a few instances
prominent mitotic activity is observed
{1358}. In rare cases, there is also vessel
invasion {2140}. The neoplastic tissue is
usually well demarcated from the normal
pancreas, although a fibrous capsule
may be absent and invasion of tumour
cell nests into the surrounding pancreat-ic tissue may occur {1193, 1358}.
Criteria of malignancy
Although criteria of malignancy have not
yet been clearly established, it appears
that unequivocal perineural invasion,
angioinvasion, or deep invasion into the
surrounding tissue indicate malignant
behaviour, and such lesions should be
classified as solid-pseudopapillary carci-noma. Nishihara et al. {1358} compared
the histological features of three metasta-sizing and 19 nonmetastasizing solid-pseudopapillary neoplasms, and found
that venous invasion, degree of nuclear
atypia, mitotic count and prominence of
necrobiotic cell nests (cells with pyknotic
nuclei and eosinophilic cytoplasm) were
associated with malignancy. However,
neoplasms in which the above-mentioned
histological criteria of malignancy are not
detected may also give rise to metas-tases. Consequently, benign appearing
solid-pseudopapillary neoplasms must be
classified as lesions of uncertain malig-nant potential.
Histochemistry and immunohistochemistry
The most consistently positive markers
for solid-pseudopapillary neoplasms are
alpha-1-antitrypsin, alpha-1-antichymo-trypsin, neuron specific enolase (NSE),
vimentin and progesterone receptors
{306, 945, 963, 1226}. The cellular reac-tion for alpha-1-antitrypsin and alpha-1-antichymotrypsin is always intense, but
only involves small cell clusters or single
cells, a finding that is characteristic of
this neoplasm. Alpha-1-antitrypsin also
stains the PAS-positive globules. Staining
for NSE and vimentin, in contrast, is usu-ally diffuse.
Inconsistent results have been reported
for epithelial markers, synaptophysin,
pancreatic enzymes, islet cell hormones
and other antigens such as CEA or CA
19.9. Most authors report negative results
for chromogranin A, CEA, CA 19.9 and
AFP. A few neoplasms have been found
to express S-100 {945, 1226, 1358}.
Cytokeratin is detected in 30% {946} to
70% {963, 2195}, depending on the
method of antigen retrieval applied.
Fig. 10.37 Solid pseudopapillary tumour. In this solid area, the uniform tumour cells are separated by vas-cular hyalinized stroma.
Fig. 10.36 Solid pseudopapillary tumour. Solid area containing cholesterol crystals and foreign body giant
cells.
248 Tumours of the exocrine pancreas
Usually, the staining for keratin is focal
and faint. The keratin profile (CK 7, 8, 18
and 19) is that of the ductal cell {740,
1844}. Positive immunoreactivity for
trypsin, chymotrypsin, amylase and/or
phospholipase A2 has been reported
{166, 1072, 1192, 1226, 1844}, but has
not been confirmed by most other
authors {812, 945, 1282}. Similarly, focal
positivity for glucagon, somatostatin
and/or insulin has been described in
some tumours {1226, 2021, 2147}, but
was not detected in most other cases
{1072, 1282, 1844}.
Ultrastructure
The neoplastic cells have round or
markedly indented nuclei containing a
small single nucleolus and a narrow rim of
marginated heterochromatin. The cells
show abundant cytoplasm, which is rich
in mitochondria. Zymogen-like granules
of variable sizes (500-3000 nm) are
conspicuous, probably representing
deposits of alpha-1-antitrypsin. The
contents of these granules commonly dis-integrate, forming multilamellated vesi-cles and lipid droplets {946, 1031, 1226,
2154}. Neurosecretory-like granules have
been described in a few tumours {867,
880, 1684, 2119, 2147}. Intermediate cell
junctions are rarely observed and micro-villi are lacking, but small intercellular
spaces are frequent.
Genetics
In contrast to infiltrating ductal carcino-mas, solid-pseudopapillary neoplasms
appear to have wild-type  KRAS genes
and do not immunoexpress p53 {512,
1007, 1039}. An unbalanced transloca-tion between chromosomes 13 and 17
resulting in a loss of 13q14→qter and
17p11→pter has been described in one
solid-pseudopapillary neoplasm {616}.
Prognosis and predictive factors
In general, the prognosis is good. After
complete removal more than 95% of the
patients are cured. Local spread or dis-semination to the peritoneal cavity has
been reported in the context of abdomi-nal trauma and rupture of the tumour
{1060}. Even in patients who had local
spread, recurrences {359, 999}, or
metastases {234, 1192, 1642}, long dis-ease-free periods have been recorded
after initial diagnosis and resection. Only
a few patients have died of a metastasiz-ing solid-pseudopapillary neoplasm
{1192, 1395}.
Histological criteria. Perineural invasion,
angioinvasion, or deep invasion into the
surrounding tissue indicate malignant
behaviour, and such lesions are classi-fied as solid-pseudopapillary carcinoma.
Venous invasion, a high degree of
nuclear atypia, mitotic activity and promi-nence of necrobiotic cell nests (cells with
pyknotic nuclei and eosinophilic cyto-plasm) were reported to be associated
with malignancy {1358}.
DNA content.  There is evidence that an
aneuploid DNA content assessed by flow
cytometry is associated with malignant
behaviour, although the number of cases
studied is small {867, 1358, 234}.
249
Primary mesenchymal tumours of the
pancreas are exceedingly rare. Leio-myosarcomas and malignant gastroin-testinal stromal tumours appear to be the
least uncommon.
Recently, solitary fibrous tumours, similar
to those more commonly seen on the
serosal surfaces of the pleura and peri-toneum, have been described (1118).
Histologically they show bland spindle
cells in a collagenous background. The
lesional cells are positive for CD34 but
negative for KIT and desmin; focal actin
positivity may occur.
M. Miettinen
J.Y. Blay
L.H. Sobin
Mesenchymal tumours of the pancreas
Miscellaneous carcinomas and lymphoma
Miscellaneous carcinomas
of the pancreas
G. Zamboni
G. Klöppel
Oncocytic carcinoma
These lesions are characterized by large
cells with granular eosinophilic cytoplasm
and large nuclei with well-defined nucle-oli. Ultrastructurally, the cells show abun-dant mitochondria and lack zymogen and
neuroendocrine granules. Local invasive-ness, lymph node and pulmonary metas-tasis can occur {1781}. Differential diag-nosis includes endocrine tumour {1454}
and solid pseudopapillary tumour.
Nonmucinous, glycogen-poor cyst-adenocarcinoma
A large, encapsulated mass with cystic
spaces lined by serous adenoma like
component and malignant-appearing
columnar epithelium. The tumour cells are
negative for mucins and show oncocytic
features by electron microscopy {533}.
Choriocarcinoma
An aggressive tumour, associated with
elevated levels of serum human chorion-ic gonadotrophin (hCG), composed of
cytotrophoblastic cells intermingled with
syncytiotrophoblastic cells immunoreac-tive for hCG. Choriocarcinoma can be
‘pure’ or associated with mucinous cys-tadenocarcinoma {1781, 2194}.
Clear cell carcinoma
A carcinoma composed of clear cells,
rich in glycogen and poor in mucin,
morphologically resembling renal cell
carcinoma {941}. Adenocarcinomatous,
anaplastic, or intraductal papillary com-ponents can be found {1781}. A ductal
phenotype has been suggested by the
pattern of immunoreactivity for cytoker-atins, the lack of vimentin expression, and
the presence of KRAS mutation {1121}.
Ciliated cell carcinoma
This lesion shows the pattern of ductal
adenocarcinoma, but contains many cili-ated cells, as demonstrated at the ultra-structural level {1781}.
Microglandular carcinoma
Also known as microadenocarcinoma,
this lesion is characterized by cribriform
or microglandular pattern of growth
{941}. The same cases were reclassified
with immunohistochemistry as adenocar-cinoma, acinar cell carcinomas and
endocrine carcinoma {1090}. Microglan-dular carcinoma is best regarded as a
pattern of growth rather than a distinctive
entity.
Medullary carcinoma
This recently described carcinoma shows
a syncytial growth pattern and lymphoep-ithelioma-like features (see chapter on
ductal adenocarcinoma,  other rare carci-nomas) {590}.
250 Tumours of the endocrine pancreas
Definition
Primary lymphoma of the pancreas is
defined as an extranodal lymphoma aris-ing in the pancreas with the bulk of the
disease localized to this site. Contiguous
lymph node involvement and distant
spread may be seen but the primary clin-ical presentation is in the pancreas with
therapy directed to this site.
Epidemiology
Primary lymphoma of the pancreas is
very rare accounting for less than 0.5%
of pancreatic tumours. As with primary
lymphomas occurring elsewhere in the
digestive tract, patients are more fre-quently elderly {796}.
Aetiology
Immunodeficiency predisposes to pan-creatic lymphoma, both in the setting of
HIV infection {866} and as post-trans-plant lymphoproliferative disorders fol-lowing solid organ transplantation {240}.
Familial pancreatic lymphoma has been
reported in a sibling pair (brother and
sister) who each presented with a high-grade B-cell lymphoma in their seventh
decade {830}. Pancreatic lymphoma has
also been described in a patient with
short bowel syndrome {903}.
Clinical features
The presentation of primary pancreatic
lymphoma may mimic that of carcinoma
or pancreatitis {240}. Pain free jaundice
can occur {1330}. Ultrasonography may
show an echo-poor lesion {1330}.
Histopathology
Primary pancreatic lymphomas are usu-ally of B phenotype. Lymphomas of vari-ous types have been described, includ-ing low-grade lymphomas of diffuse
small cell type {903, 1480}, follicle centre
cell lymphoma {1330, 1238}, low-grade
MALT lymphoma {1925}, and large B-cell
lymphoma {1529, 830}. Only extremely
rare cases of pancreatic T-cell lymphoma
have been reported, including a single
case of anaplastic large cell lymphoma
(CD30 positive) of T-cell type {1179} and
a case of pancreatic involvement by
adult T-cell leukaemia/lymphoma {1408}.
The histology of these cases varies little
from that seen where these lymphoma
types are encountered more frequently.
Prognosis
The distinction between lymphoma and
carcinoma is important, as pancreatic
lymphomas are associated with better
prognosis and may be curable even in
advanced stages. Occasional cases of
relapse following prolonged remission
have been reported in cases treated by
chemotherapy {1529}.
H.K. Müller-Hermelink
A. Chott
R.D. Gascoyne
A. Wotherspoon
Lymphoma of the pancreas
Secondary tumours of the pancreas E. Paál
A. Kádár
Epidemiology
Secondary tumours of the pancreas are
in most cases part of an advanced
metastatic disease. They account for
3-16% of all pancreatic malignancies,
affecting males and females equally
{1190, 1012, 1597, 1781}. In our experi-ence based on combined autopsy and
histology material, out of 610 neoplasms
involving the pancreas 26 (4.25%) were
secondary. Any age may be affected,
but the highest incidence is in the 6th
decade.
Localization
Any anatomic region of the pancreas
may be involved and there is no site
predilection {934}. Lesions can be soli-tary, multiple, or diffuse {502}.
Clinical features
There are no specific symptoms for sec-ondary tumours of the pancreas.
Abdominal pain, jaundice, and diabetes
might be the first sign, or in some cases
an attack of acute pancreatitis {1290,
1608, 1772}.
The lesions are most commonly detected
by imaging studies {934}. Fine needle
aspiration can provide a rapid diagnosis
{905, 645, 1250}.
Origin
Both epithelial and non-epithelial sec-ondary tumours occur in  the pancreas.
The pancreas may be involved by direct
spread (e.g. from stomach, liver, adrenal
gland, retroperitoneum) or by lymphatic
or haematogenous spread from distant
sites {905}. Renal cell carcinoma is
251
unique as a primary site since it might
give rise to late solitary metastases
{1644, 218}.
Histopathology
The main differential diagnostic problem
is to distinguish metastases from primary
pancreatic neoplasms. The most prob-lematic tumours are metastases from the
gastrointestinal tract, renal cell carcino-mas, small cell carcinoma, and lym-phomas {240, 645, 1781}. Apart from the
clinical and radiological signs {934}, mul-tiple tumour foci with an abrupt transition
from normal pancreas to the neoplastic
tissue without signs of chronic pancreati-tis in the surrounding parenchyma sup-port metastatic origin {2089}. Immunohis-tochemistry specific for certain primary
tumours may also be helpful {1190, 1707}.
Prognosis
Since in most cases pancreatic metas-tases indicate an advanced neoplastic
disease, the prognosis is generally poor.
In cases of solitary metastases, com-bined adjuvant therapy and surgical
resection might be beneficial {360, 674,
218, 1597}.
Secondary tumours
Fig. 10.38 Secondary tumours in the pancreas. A Metastatic small cell lung carcinoma. B Metastatic melanoma. C Metastatic renal cell carcinoma.
D Metastatic gastric signet ring cell carcinoma.
AB
CD
253Contributors
Dr Lauri A. AALTONEN *
Department of Medical Genetics
Haartman Institute, University of Helsinki
PO Box 21 (Haartmaninkatu 3)
SF-00014 Helsinki
FINLAND
Tel. +358 9 1912 6278
Fax +358 9 1912 6677
lauri.aaltonen@helsinki.fi
Dr Guido ADLER
Department of Medicine I
University of Ulm
Robert Koch Strasse 8
D-89070 Ulm
GERMANY
Tel. +49 731 50 24300/24301
Fax +49 731 50 24302
guido.adler@medizin.uni-ulm.de
Dr Jorge ALBORES-SAAVEDRA *
Dept. of Pathology, Univ. of Texas
Southwestern Medical Center
5323 Harry Hines Blvd
Dallas, TX 75235-9072
USA
Tel. +1 214 590 6585
Fax +1 214 590 1411
rmuril@mednet.swmed.edu
Dr Peter P. ANTHONY *
Histopathology Department
Royal Devon and Exeter Hospital
Church Lane
Exeter EX2 5AD
UNITED KINGDOM
Tel. +44 1392 402942
Fax +44 1392 402964
peter.anthony@ukgateway.net
Dr Mark J. ARENDS
Dept of Histopathology, Box 235
Addenbrooke’s Hospital
Hills Road
CB2 2QQ  Cambridge
UNITED KINGDOM
Tel. +44 1223 217176
Fax +44 1223 216980
mja40@cam.ac.uk
Dr Rudolf ARNOLD
Zentrum für Innere Medizin
Klinikum der Philipps Universitat Marburg
Baldingerstrasse, P.O.B. 2360
D-35033 Marburg
GERMANY
Tel. +49 6421 286 6460
Fax +49 6421 286 8922
arnoldr@mailer.uni-marburg.de
Dr Marc Billaud
Faculté de Médecine
Lab. de Génétique et Cancer, UMR 5641
8 avenue Rockefeller
69373 Lyon
FRANCE
Tel. +33 4 78 77 72 14
Fax +33 4 78 77 72 20
billaud@univ-lyon1.fr
Dr Jean-Yves BLAY
Centre Leon Berard
Université Lyon I
28 rue Laennec
69008 Lyon
FRANCE
Tel. +33 4 78 78 27 57
Fax +33 4 78 78 28 16
blay@lyon.fnclcc.fr
Dr Hubert E. BLUM
Department of Medicine II
University Hospital
Hugstetter Strasse, 55
D-79106 Freiburg
GERMANY
Tel. +49 7612 703403
Fax +49 7612 703610
heblum@ukl.uni.freiburg.de
Dr Randall W. BURT
Div. of Gastroenterology, Rm 4R118
University of Utah Health Science Ctr.
50 North Medical Drive
Salt Lake City, UT 84132
USA
Tel. +1 801 581 7802
Fax +1 801 581 7476
randall.burt@hsc.utah.edu
Dr Carlo CAPELLA *
Department of Pathology
University of Pavia at Varese
Ospedale di Circolo
I-21100 Varese
ITALY
Tel. +39 0332 278231 or 272
Fax +39 0332 278599
carlo.capella@ospedale.varese.it
Dr Fatima CARNEIRO
IPATIMUP
Medical Faculty, University of Porto
Rua Roberto Frias s/n
4200 Porto
PORTUGAL
Tel. +351 2509 0591
Fax +351 2550 3940
fcarneiro@ipatimup.pt
Dr Norman J. CARR *
Department of Cellular Pathology
Southampton General Hospital
Tremona Road
Southampton S016 6YD
UNITED KINGDOM
Tel. +44 2380 796051
Fax +44 2380 796869
Dr Andreas CHOTT
Department of Clinical Pathology
University of Vienna
Waehringer  Guertel 18-20
A 1090  Vienna
AUSTRIA
Tel. +43 1 405 3402
Fax +43 1 405 3402
andreas.chott@akh-wien.ac.at
Contributors
* The asterisk indicates participation in
the Working Group Meeting on the WHO
Classification of Tumours of the Digestive
System that was held in Lyon, France,
Nov 6-9, 1999.
254 Contributors
Dr W.H. CHOW
National Cancer Institute
EPS   8100
6120 Executive Blvd.
Bethesda, MD 20892-7182
USA
Tel. +1 301 435 4708
Fax +1 301 402 1819
choww@exchange.nih.gov
Dr Pelayo CORREA
Department of Pathology,
Louisiana State Univ. Medical Center
1901 Perdido Street
New Orleans, LA 70112
USA
Tel. +1 504 568 6035
Fax +1 504 599 1278
correa@isuhsc.edu
Dr G.T. DEANS
Consulting Surgeon
Stepping Hill Hospital
Poplar Gr.
Stockport SK2 7JE
UNITED KINGDOM
Tel. +44 161 440 8820
Fax +44 161 483 8576
gtdeans@uk.gateway.net
Dr Pierre DEMATOS
Department of Surgery, Box 37049
Duke University Medical Center
Erwin Road
Durham, NC 27710
USA
Tel. +1 919 681 2559
Fax +1 919 681 2779
demat001@mc.duke.edu
Dr Yves DEUGNIER
Centre Hospitalier Régional Ponchaillou
Université de Rennes
2 rue Henri Le Guilloux
35033 Rennes
FRANCE
Tel. +33 2 99 28 42 97
Fax +33 2 99 28 41 12
yves.deugnier@univ-rennes1.fr
Dr Michael F. DIXON
Academic Unit of Pathology
University of Leeds
Algernon Firth Builiding
LS2 9JT  Leeds
UNITED KINGDOM
Tel. +44 113 243 1751
Fax +44 113 292 2834
miked@pathology.leeds.ac.uk
Dr Charis ENG
Human Cancer Genetics Program
Ohio State University Cancer Ctr.
420 W 12th Avenue, 690 MRF
Columbus, OH 43210
USA
Tel. +1 614 688 4508
Fax +1 614 688 3205
eng-1@medctr.osu.edu
Dr Claus FENGER *
Dept. of Pathology
Odense University Hospital
Winsloewparken 15
DK-5000 Odense C
DENMARK
Tel. +45 6541 4807
Fax +45 6591 2943
claus.fenger@ouh.dk
Dr Cecilia FENOGLIO-PREISER *
Department of Pathology
University of Cincinnati, School of Medicine
231 Bethesda Ave, POB 670529
Cincinnati, OH 45267-0529
USA
Tel. +1 513 558 4500
Fax +1 513 558 2289
cecilia.fenogliopreiser@uc.edu
Dr J.K. FIELD
Molecular Genetics and Oncology Group
Clinical and Dental Sciences
University of Liverpool
Liverpool L69 3BX
UNITED KINGDOM
Tel. +44 151 794 8900
Fax +44 151 794 8989
j.k.field@liv.ac.uk
Dr Hans-Peter FISCHER
Institute of Pathology
University Hospital
Sigmund Freud Str. 25
D-53127 Bonn
GERMANY
Tel. +49 228 287 6340
Fax +49 228 287 5030
fischer@mailer.meb.uni-bonn.de
Dr Jean-François FLEJOU
Serv. d’Anatomie et de Cytologie
Pathologiques, Hôpital Saint Antoine
184 rue du Faubourg St Antoine
75012 Paris
FRANCE
Tel. +33 1 40 87 54 59
Fax +33 1 40 87 00 77
jean-francois.flejou@bjn.ap-hop-paris.fr
Dr Franz FOGT
Department of Pathology, Presbyterian
Med. Center, Univ of Pennsylvania
39th & Market Streets
Philadelphia, PA 19104-2699
USA
Tel. +1 215 662 8077
Fax +1 215 662 1694
fogt@mail.med.upenn.edu
Dr M. FRISCH
Viral Epidemiology Branch
National Cancer Institute
6120 Executive Blvd, EPS / 8015
Bethesda, MD 20852
USA
Tel. +1 301 594 7825
Fax +1 301 402 0817
frischm@mail.nih.gov
Dr Helmut GABBERT *
Institute of Pathology
Heinrich Heine University
Moorenstr. 5
40225 Düsseldorf
GERMANY
Tel. +49 211 811 8339
Fax +49 211 811 8353
gabbert@med.uni-duesseldorf.de
Dr Randy D. GASCOYNE
Department of Pathology
British Columbia Cancer Agency
600 West 10th Avenue
Vancouver, BC V5Z 4E6
CANADA
Tel. +1 604 877 6000, ext. 2097
Fax +1 604 877 6178
rgascoyn@bcccancer.bc.ca
Dr Robert M. GENTA
Department of Pathology – 113
Veterans Affairs Medical Center
2002 Holcombe Blvd
Houston, TX 77030
USA
Tel. +1 713 794 7113
Fax +1 713 794 7810
rmgenta@bcm.tmc.edu
Dr David GOLDGAR
International Agency for
Research on Cancer (IARC)
150 Cours Albert Thomas
69372 Lyon
FRANCE
Tel. +33 4 72 73 85 33
Fax +33 4 72 73 83 42
goldgar@iarc.fr
255
Dr Stephen B. GRUBER
Division of Molecular Medicine and Genetics
University of Michigan
4301 MSRB III
Ann Arbor, MI 48109-0652
USA
Tel. +1 734 763 2532
Fax +1 734 763 7672
sgruber@umich.edu
Dr Parry GUILFORD
Cancer Genetics, Lab. of Biochemistry
University of Otago
PO Box 56
Dunedin, Aorearoa
NEW ZEELAND
Tel. +64 3 479 7868
Fax +64 3 479 7738
parry.guilford@otago.ac.nz
Dr Pierre HAINAUT
International Agency for
Research on Cancer (IARC)
150 Cours Albert Thomas
69372 Lyon
FRANCE
Tel. +33 4 72 73 85 32
Fax +33 4 72 73 83 22
hainaut@iarc.fr
Dr Stanley R. HAMILTON *
Department of Pathology
M.D. Anderson Cancer Center
1515 Holcombe Boulevard
Houston, TX 77030, USA
Tel. +1 713 792 6313
Fax +1 713 794 1824
shamilto@notes.mdacc.tmc.ed
shamilto@md.anderson.org
Dr Setsuo HIROHASHI *
National Cancer Center
Research Institute
1-1, Tsukiji 5-chome, Chuo-ku
104-0045  Tokyo
JAPAN
Tel. +81 3 3542 2511 (ext 4101)
Fax +81 3 3248 0326
shirohas@gan2.ncc.go.jp
Dr Heinz HÖFLER
Institute of Pathology
Technische Universität München
Ismaninger Str. 22
D-81675 München
GERMANY
Tel. +49 89 4140 4160
Fax +49 89 4140 4865
hoefler@lrz.tu-muenchen.de
Dr James R. HOWE
Department of Surgery
University of Iowa, College of Medicine
200 Hawkins Drive
Iowa City, IA 52242-USA
Tel. +1 319 356 7945
Fax +1 319 356 8378
james-howe@uiowa.edu
Dr Ralph H. HRUBAN
GI Liver Pathology, Meyer 7-181
Johns Hopkins Univ. School of Medicine
600 N. Wolfe Street
Baltimore, MD  21287
USA
Tel. +1 410 955 9132
Fax +1 410 955 0115
rhruban@jhmi.edu
Dr Gyorgy ILLYES
Department of Pathology
Semmelweiss University of Medicine
Ulloi ut 93
1061 Budapest
HUNGARY
Tel. +36 1 215 6921
Fax +36 1 215 6921
igy@korb2.sote.hu
Dr Haruhiro INOUE *
Department of Surgery
Tokyo Medical & Dental University
1-5-45 Yushima, Bunkyo-ku
113-8519 Tokyo
JAPAN
Tel. +81 3 5803 5225
Fax +81 3 3817 4126
hiro.inoue.srg1@med.tmd.ac.jp
Dr Kamal G. ISHAK *
Dept. of Hepatic and GI Pathology
Armed Forces Institute of Pathology
Alaska Avenue at 14th St
Washington, DC 20306
USA
Tel. +1 202 782 1707
Fax +1 202 782 9020
ishak@afip.osd.mil
Dr Heikki J. JÄRVINEN
Department of Surgery
Helsinki University Central Hospital
Haartmaninkatu 4, PO Box 260
00029 HUCH Helsinki
Finland
Tel. +358 9 4717 3852
Fax +358 9 4717 4675
Dr Jeremy R. JASS *
Pathology Department, Grad Med School
University of Queensland
Herston Rd.
4006 Brisbane, Queensland
Australia
Tel. +61 7 3365 5340
Fax +61 7 3365 5511
j.jass@mailbox.uq.edu.au
Dr Anna KADAR
Department of Pathology
Semmelweiss University of Medicine
Ulloi ut 93
1061 Budapest
HUNGARY
Tel. +36 1 215 6921
Fax +36 1 215 6921
kadann@korb2.sote.hu
Dr G. KELLER
Institute of Pathology
Technische Universität München
Ismaninger Str 22
D-81675 München
GERMANY
Tel. +49 89 4140 4592
Fax +49 89 4140 4915
gisela.keller@irz.tum.de
Dr S.E. KERN
Department of Pathology
Johns Hopkins Univ School of Medicine
1650 Orleans Street – CRB 451
Baltimore, MD 21205-2196
USA
Tel. +1 410 614 33 14
Fax +1 410 614 97 05
sk@jhmi.edu
Dr Lars G. KINDBLOM
Department of Pathology
University of Gothenburg
Sahlgren University  Hospital
41345 Gothenburg
SWEDEN
Tel. +46 31 342 1928
Fax +46 31 827194
lars-gunnar.kindblom@llcr.med.gu.se
Dr Paul KLEIHUES *
International Agency for
Research on Cancer (IARC)
150 Cours Albert Thomas
69372 Lyon
FRANCE
Tel. +33 4 72 73 85 77
Fax +33 4 72 73 85 64
kleihues@iarc.fr
Contributors
256 Contributors
Dr David S. KLIMSTRA
Department of Pathology
Memorial Sloan Kettering Cancer Center
1275 York Avenue
New York, NY 10021
USA
Tel. +1 212 639 2410
Fax +1 212 717 3203
klimstrd@mskcc.org
Dr Günter KLÖPPEL *
Institute of Pathology
University of Kiel
Michaelistrasse 11
D-24105 Kiel
GERMANY
Tel. +49 431 597 3400
Fax +49 431 597 3462
gkloeppel@path.uni-kiel.de
Dr Masamichi KOJIRO
Department of Pathology
School of Medicine, Kurume Univ.
67 Asahi-machi
8030-0001 Kurume
JAPAN
Tel. +81 942 317546
Fax +81 942 320905
kojiro@med.kurume-u.ac.jp
Dr Shin-ei KUDO *
Department of Gastroenterology
Akita Red Cross Hospital
222-1 Naeshirosawa-aza Saruta, Kamikitade
010-1495 Akita-City
JAPAN
Tel. +81 18 829 5000, ext 3325
Fax +81 18 829 5115
kudo-s@synap.ne.jp
Dr René LAMBERT *
International Agency for
Research on Cancer (IARC)
150 Cours Albert Thomas
69372 Lyon
FRANCE
Tel. +33 4 72 73 85 14
Fax +33 4 72 73 86 50
lambert@iarc.fr
Dr Pierre LAURENT PUIG
U490 Laboratoire de Toxicol. Moleculaire
Faculté de Médecine, Université Paris V
45 rue des Saints Pères
75006 Paris,  FRANCE
Tel. +33 1 42 86 20 81
Fax +33 1 42 86 20 72
pierre.laurent-puig@biomedicale.univ-paris5.fr
Dr Anthony S.Y. LEONG
Discipline of Anatomical Pathology
University of Newcastle, Locked Bag 1
Hunter Regional Mail Centre
Newcastle 2310
AUSTRALIA
Tel. +61 2 4921 4000
Fax +61 2 4921 4440
aleong@mail.newcastle.edu.au
Dr Daniel S. LONGNECKER *
Department of Pathology
Dartmouth-Hitchcock
Medical Center
Lebanon, NH 03756
USA
Tel. +1 603 650 7899
Fax +1 603 650 6120
daniel.s.longnecker@dartmouth.edu
Dr Jutta LÜTTGES
Institute of Pathology
University of Kiel
Michaelistrasse 11
D-24105 Kiel
GERMANY
Tel. +49 431 597 3422
Fax +49 431 597 3428
jluettges@path.uni-kiel.de
Dr Marc-Claude MARTI
Policlinique de Chirurgie
Hôpital Cantonal Universitaire
Rue Michel Servet
CH-1211 Geneva 4
SWITZERLAND
Tel. +41 22 372 790?
Fax +41 22 372 7909
marc-claude.marti@hcuge.ch
Dr Francis MEGRAUD
Laboratoire de Bactériologie
Hôpital Pellegrin
Place Amélie Raba Léon
33076 Bordeaux
FRANCE
Tel. +33 5 56 79 59 10
Fax +33 5 56 79 60 18
francis.megraud@chu-aquitaine.fr
Dr Herman R. MENCK
Commission on Cancer
American College of Surgeons
633 N Saint Clair Street
Chicago, IL 60611
USA
Tel. +1 312 664 4050
Fax +1 312 202 5009
mencky@aol.com
Dr Markku MIETTIENEN *
Dept. of Soft Tissue Pathology
Armed Forces Institute of Pathology
Alaska Avenue at 14th St
Washington, DC 20306
USA
Tel. +1 202 782 2793
Fax +1 202 782 9182
miettenen@afip.osd.mil
Dr Ruggero MONTESANO
International Agency for
Research on Cancer (IARC)
150 Cours Albert Thomas
69372 Lyon
FRANCE
Tel. +33 4 72 73 84 63
Fax +33 4 72 7