Gastric cancer is a major cause of mortality worldwide. The presentation outlined the epidemiology, risk factors, carcinogenesis, premalignant lesions, pathology, staging, gastric lymphoma, gastrointestinal stromal tumors (GIST), and gastric carcinoids of gastric cancer. Risk factors that increase risk include family history, diet, H. pylori infection, and premalignant conditions like atrophic gastritis and intestinal metaplasia. Gastric cancer is staged using the TNM system evaluating tumor invasion depth, lymph node involvement, and distant metastases. Other tumors of the stomach discussed included gastric lymphoma, GIST, and carcinoid tumors.

1. Pathology of gastric cancer
B Y O L A N S O N R E G A S S A ( G S R 1 )
M O D E R A T O R D R . G E L E T A ( A . P R O F E S S O R O F
S U R G E R Y )
D E C 1 1 , 2 0 1 9
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2. Presentation outline
 Introduction
 Epidemiology
 Risk factors
 Carcinogenesis
 Premalignant lesions
 Pathology
 Staging
 Gastric lymphoma
 GIST
 Gastric carcinoids
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3. Introduction
 Major cause of mortality worldwide
 Poor prognosis with cure rates 5-10%
 Imminent curable disease if it detected earlier and
treated adequately
 Resectional surgery is the only treatment modality
to cure
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4. Epidemiology
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5. Risk factors
Increase risk
 Family history
 Diet (high in nitrates, salt, fat)
 Familial polyposis
 Gastric adenomas
 Hereditary nonpolyposis colorectal cancer
 Helicobacter pylori infection
 Atrophic gastritis, intestinal metaplasia, dysplasia
 Previous gastrectomy or gastrojejunostomy (>10 y ago)
 Tobacco use
 Ménétrier’s disease
Decrease risk
 Aspirin
 Diet (high fresh fruit and vegetable intake)
 Vitamin C
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6. Gastric carcinogenesis
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7. Hereditary risk factors
 Hereditary diffuse
gastric ca
 FAP ,
 Li-fraumeni syn-
 HNPCC (lynch
syndrome)
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8. Other risk factors
• Pernicious anemia
• Polyps
• PPIs
• EBV
• Alcohol ?
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9. Premalignant conditions
polyps
neoplastic nonneoplastic
-adenoma
-FGP
-hyperplastic
inflammatory,
hamartomatous
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10. non atrophic gastritis vs. atrophic
gastritis
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11. Intestinal metaplasia
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12. Benign Gastric Ulcer
 confounded by the inclusion of inadequately
biopsied ulcers s as “benign,” when, in fact, they
were malignant.
 all should be viewed as malignant until proven
otherwise with adequate biopsy and follow-up.
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13. Gastric Remnant Cancer
 Develop 10 years after initial operation
 Near area of anastomosis
 Bile or alkali reflux gastritis is precursor
 Common after Billroth II procedure
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14. Histology of stomach
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15. pathology
• Dysplasia : low grade (adenomatous )
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16. Dysplasia ; high grade
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17. Early gastric cancer
• adenocarcinoma limited to the mucosa (T1a)
and submucosa (T1b)
• 10 %will have lymph node metastases
• 70% are well differentiated, and 30% are
poorly differentiated
• Cure rate is 95%
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18. Subtypes EGC….
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19. Gross Morphology
• Useful today for description of endoscopic findings
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20. Histology
• There are several histologic classifications of
gastric cancer. 1.WHO
• 2.lauren
• 3.japanese
4.Mings classification system
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21. WHO classification
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22. Lauren classification
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23. Intestinal vs. diffuse
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24. Staging
• The most widespread system for staging of
gastric cancer is the tumor-node-metastasis
(TNM) staging system based :-on depth of
tumor invasion (T)
-extent of lymph node metastases(N),
-presence of distant metastases (M)
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27. Concerns of TNM staging
• 1. tumors of GE junction of stomach
•
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28. 2). R status Hermanek in 1994
• describe tumor status after resection
• is important for determining the adequacy of
surgery
• R0 microscopically margin negative resection
• R1 removal of all macroscopic disease, but
microscopic margins are positive for tumor
• R2 gross residual tumor
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29. 3.Nodal location
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30. GASTRIC LYMPHOMA
• Arise in stomach commonly
• (4%) of stomach tumors,
• nonHodgkin’s B-cell type
• The most characteristic histological feature is tumour
cell infiltration of the epithelium of gastric glands
• Submucosal and difficult for biopsy
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32. Pathogenesis : lymphoma
• MALT in the stomach is, in the great majority
of individuals, a reaction to H. pylori infection.
• Lymphoid cells, initially attracted to the
mucosa by H. pylori, slowly accumulate
genetic changes and eventually develop into
an autonomously proliferating, monoclonal, B-
cell lymphoma.
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33. Classification
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34. Staging system
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35. Gastrointestinal Stromal Tumors
• most common sarcomatous tumors of the GI tract
• derived from the interstitial cells of Cajal, an intestinal
pacemaker cell.
• usually found in the stomach (40% to 60%), small intestine
(30%), and colon (15%)
• Could present from small benign tumors to massive lesions
with necrosis, hemorrhage, and wide metastases
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36. GIST ; pathogenesis
• gain-of-function mutations of the gene
encoding the tyrosine kinase KIT, the receptor
for stem cell factor.(75-85%)
• 8% of GISTs have mutations that activate a
related tyrosine kinase, platelet-derived
growth factor receptor A (PDGFRA
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37. GIST; classification
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38. • Pathologically, GISTs
have smooth muscle
and
• neuroendocrine
features, consistent
with their origin from
the interstitial cells of
Cajal
• morphology
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39. Gastric carcinoid tumor
• Rare malignancy (0.48%)
• Arise from NE precursor cells (ECL)
• Most common site is GIT (60%)
• Stomach is 8% of all NETs
• Has 3 types type
Type I Associated with atrophic gastritis & p.
anemia
Type II associated with ZLE & MEN-1
Type III sporadic tumors , common in men
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40. • Pathogenesis :-Hypergasterenimia , low acid
states and NETs
• Classifications :- WHO
-low or intermediate
- high grade w/c resembles SCC lungs-
jejunum
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41. • Morphology :-
intramural or
submucosal masses
that create small
polypoid lesion
• elicit an intense
desmoplastic reaction
that may cause
kinking of the
bowel and
obstruction
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42. References
1. GLOBOCAN 2018
2. Baily & love short practice of surgery 27th edition
3. Muir's Textbook of Pathology, Fifteenth Edition -
Herrington, Simon C.Netter’s
4. Maingot’s abdominal operations 12th edition
5. Robbins Basic Pathology 10e Robbins
6. Sabiston Textbook of Surgery 20th ed The Biological
Basis of Modern Surgical Practice
7. Schwartz's Principles of Surgery,11th edition
8. Uptodate 2018
9. https://gut.bmj.com/content/45/5/784#F1
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