The document discusses tumors of the small and large intestines. It classifies intestinal tumors and provides details on various benign and malignant tumor types. The most common tumors are epithelial tumors, with colorectal cancer representing 70% of all gastrointestinal malignancies. Adenomas are precursors to most colorectal cancers. Risk factors include inflammatory bowel disease, familial polyposis, and diet. Prognosis and treatment depend on tumor stage and characteristics.

1. TUMORS OF THE SMALL
AND LARGE INTESTINES
SMS 2044

2. Tumors of the small and large intestine
Classification
 Non-neoplastic polyps
 Hyperplastic polyps
 Hamartomatous polyps (Juvenile & Peutz-Jeghers polyps)
 Inflammatory polyps
 Lymphoid polyps
 Neoplastic ( epithelial) polyps
 Benign polyps (adenoma)
 Malignant lesions
Adenocarcinoma
Carcinoid
Anal zone carcinoma
 Mesenchymal lesions
 GI stromal tumors (benign & malignant)
 Others ( lipoma, neuroma, angioma, Kaposi sarcoma)
 Lymphoma
• Diffuse large cell lymphoma. MALT cell lymphoma.

3. Intestinal Neoplasms
Small intestine= neoplasms are rare
Benign tumors
 MC (membranous cells) = Adenoma
 MC site - ampulla of Vater (the union of the pancreatic duct and the
common bile duct)
 Complaints= occult blood loss/ rarely-obstruction or intussusceptions
 Associated with familial polyposis
 Rx =surgical excision difficult
 Clinical Course=premalignant
Malignant tumors
 MC= Adenocarcinoma
 MC site - Duodenum
 clinical -intestinal obstruction
 occult blood loss -only sign
 if involves ampulla of Vater -cause fluctuating obstructive jaundice
Risk factors
Most tumors -no identifiable factor, Crohn’s, celiac disease

4. SMALL INTESTINAL NEOPLASMS
 3-6% of GIT neoplasm, slight preponderance to benign tumors.
 BENIGN
 Discovered incidentally, leiomyoma, adenoma and lipoma
 Large lesions may cause obstruction, bleeding, intussusception,
volvulus.
 ADENOMAS
 Single or multiple polyps, most often in the duodenum and ileum.
 There is a risk of malignancy with larger adenomatous polyps.
 MALIGNANT
 In descending order of frequency: carcinoid, adenocarcinomas,
lymphomas and leiomyosarcomas.
 Leiomyosarcomas have tyrosine kinase receptors, can be treated by
STI-571(gleevec)

5. Adenoma in duodenum

6. INTESTINES - PATHOLOGY TUMORS
L I Tumors
GI Lymphoma
Nonneoplastic Polyps
Adenomas
Colorectal Carcinoma
Familial Polyps
Carcinoid Tumor
Miscellaneous Tumors
Anal Canal Tumors
Benign Malignant

7. Intestinal Neoplasms
Large intestine= neoplasms are common
Benign tumors
MC = Adenoma= Polyp
MC site of GI Polyps= Colon
Types
 Non-neoplastic (Hyperplastic, inflammatory, hamartomatous)
 Neoplastic or adenomatous( Tubular, Villous, Tubulo-villous)
Malignant risk of adenomatous polyps correlates with:
1) polyp size ( > 4cm)
2) degree of dysplasia
3) extent of villous component (More villous= more cancerous)
Feature Non-neoplastic Neoplastic
Frequency &
Age
MC (90%) young people
Mostly Hyperplastic,
Only 10%, elderly people
Mostly Tubular
Dysplasia without dysplasia With dysplasia
Mechanism excess production of epithelial cells
than their loss
Mutations in genes
Complication No risk of malignancy premalignant

8. Tumours of the small and large intestine
The most common:
Epithelial tumours are a major cause of morbidity
and mortality worldwide.
The colorectal is the GIT most commonly affected
by primary tumors
Adenocarcinoma in colorectum represent 70% of all
malignancy of GIT
Benign tumors, primarily epithelial, are present in 25
to 50% of older adults.

9. Hamartomatous polyp

10. N…P.
 All adenomatous lesions arise as the result of epithelial
proliferation and dysplasia, which may range from mild to so
severe as to represent transformation to carcinoma.

11. Tubular adenoma

12. Villous Adenoma

13. Malignant Tumors of Large Intestine
Adenocarcinoma
Constitutes 98% of all cancers in the large
intestine.
Worldwide distribution, highest incidence in west.
Peak incidence: 60 to 70 years of age
< 20% cases before age of 50
adenomas – presumed precursor lesions for most
tumors
males affected ≈ 20% more often than females

14. • Incidence rates for colorectal cancer differ
by sub-sites
Anatomic Distribution

15. Carcinogenesis
• Chromosome instability pathway

16. Malignant Tumors of Large Intestine
Adenocarcinoma
 Predisposing factors: IBD, polyposis syndrome.
 Male:female ratio is 2:1 in rectal cancer, roughly equal in
colon cancer, generally males are affected about 20% more
than females.
 Higher BMI is associated with an increased risk of colon
cancer
 Diet appears to play an important role in the risk for colon cancer:
 Low content of unabsorpable vegetable fibre.
 High content of refined carbohydrates. High fat content.
 Increased intake of nitrites, nitrates (nitrosamines).
 Reduced intake of vit A, C & E.
 The use of aspirin and NSAID (cyclooxygenase-2 inhibitors)
exerts a protective effect against colon cancer
 Alcohol, Tobacco
Causes

17. Colorectal ad.Carcinoma
Morphology
 Sixty to 70% of colorectal carcinomas are in the
rectum, rectosigmoid and sigmoid colon.
 The carcinomas tend to be annular, encircling
lesions with early symptoms of obstruction.
 Neoplasms start superficially, slowly invading the
deeper layers with ulceration and eventually
metastasis.

19. Early carcinomas, i.e., tumors limited to the submucosa, are
mostly
• Polypoid
• Pedunculated
• Semipedunculated
• Sessile
• Flat lesions
• Flat with slight elevation with light central depression
Advanced carcinomas (invading beyond the submucosa)
are four types, similar to the Borrmann categories of gastric
carcinoma:
• Polypoid (protuberant)
• Ulcerated, with sharply demarcated margins
• Ulcerated without definite borders
• Diffusely infiltrating

20. There is a solitary mass attached via a long stalk to the colonic
mucosa. It is discreet and does not involve the wall of the colon.
The surface is dark red (hemorrhagic). The stool guaiac was
positive

22. Histological Description
 Most lesions consist of gland formation lining of tall columnar
cells with palisading large oval or pencil shaped nuclei with
increased coarse chromatin, easily found.
 The epithelium bears a clear resemblance to the dysplastic
epithelium which covers adenomas.
 Tumor has well defined margins
 The center is depressed due to tumor necrosis
 Mucin lakes are found in 10-15% of tumors and these
patients are often those with hereditary non-polyposis
syndromes or ulcerative colitis
 Bleeding from the tumor is often apparent as the tumor tends
to grow blood vessel

24. • Tumor has well defined margins
• The center is depressed due to tumor necrosis
• The thin margin of intact tumor is raised (arrow)
• Adjoing mucosa is normal with delicate mucosal folds

25. MUCINOUS ADENOCARCINOMA
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26. Colorectal Carcinoma
Clinical Features
 May remain asymptomatic for years and the symptoms
develop insidiously
 Abdominal pain and tenderness in the lower abdomen
 Blood in the stool
 Diarrhea, constipation, or other change in bowel habits
 Narrow stools
 Weight loss with no known reason
 Weakness, malaise, weight loss, unexplained anemia
(secondary to early bleeding).

27. Colorectal Carcinoma
Spread: - Direct extension.
- Metastasis through:
- Lymphatic
- Blood vessels
- Favored sites are regional lymph node,
liver, lungs, bones.
Serum level of carcinoembryonic antigen (CEA) is
related to tumor size and extent of spread.
It is helpful in monitoring for recurrence of tumor
after resection.
Overall 5-year survival is 35 to 49% in the United
States.

28. Staging
 Tx: No description of the tumor's.
 Tis: In situ carcinoma; the tumor involves only the muscularis
mucosa
 T1: The cancer has grown through the muscularis mucosa
and extends into the submucosa
 T2: The cancer has grown through the submucosa and
extends into the muscularis propria
 T3: The cancer has grown through the muscularis propria and
into the outermost layers of the colon but not through them; it
has not reached any nearby organs or tissues
 T4a: The cancer has grown through the serosa (visceral
peritoneum)
 T4b: The cancer has grown through the wall of the colon and
is attached to or invades nearby tissues or organs

31. Colorectal Neoplasm
Other Tumors
 Malignant spindle cell (mesenchymal) tumors and
lymphomas.
Grossly and microscopically resemble those arising elsewhere in
the GI tract.
 Carcinoid tumors may arise anywhere in the colon,
especially the rectum.
 Squamous cell carcinomas are largely limited to the anal
canal. Initially present as plaque-like lesions, later becoming
ulcerated or fungating.
 Malignant melanoma at the anal verge.

32. Small Intestinal Neoplasms
Carcinoid Tumors
 Neoplasms arising from endocrine cells Kulchitsky
(enterochromaffin) cells found along the length of GIT mucosa.
Cells have an affinity for silver salts.
 60 to 80% appendix and terminal ileum: 10 to 20% rectum, the
remainder in the stomach, duodenum or esophagus.
 Other Location: Lungs, pancreas, biliary tract, ovaries and liver.
 Peak age: 6th decade, comprise 2% of colorectal carcinoma and 50%
 of small intestinal carcinoma.
 Tumors in the appendix and rectum, although spreading locally,
 seldom metastasize.
 Ileal, gastric, and colonic carcinoids are frequently malignant.

33. Carcinoid Tumors
Pathological Lesion
 Round submucosal elevations that are bright yellow or yellow-gray,
may be deeply infiltrative and penetrate muscle to the serosa.
 Gastric and ileal carcinoids are frequently multiple.
 Tumor cells arranged in trabecular, insular, glandular or
undifferentiated patterns are monotonously similar to each other with
regular round nuclei
 Ultrastructral features: neurosecretory electron dense bodies in the
cytoplasm

34. Small Intestinal Neoplasms
Carcinoid Tumor
Clinical features
 Asymptomatic
 May cause obstruction, intussusception or bleeding.
 May elaborate hormones: Zollinger-Ellison , Cushing’s ,
carcinoid or other syndromes.
 5 years survival rate is 90%,
 small bowel Carcinoid with liver metastasis the 5 years
survival rate is better than 50%

35. Small Intestinal Neoplasms
Lymphoma
Up to 40% of lymphomas arise in sites other than lymph
nodes, gut is the most.
1% to 4% of all gastrointestinal malignancies are
lymphomas.
Primary GIT lymphomas exhibit no evidence of liver,
spleen, or bone marrow involvement at the time of
diagnosis.

36. Small Intestinal Neoplasms
Lymphoma
Sporadic lymphoma arise from the B cells of
mucosa-associated lymphoid tissue (MALT).
This usually affects adults, lacks a sex
predilection, and may arise anywhere in the gut:
stomach - 55% to 60%
small intestine - 25% to 30%
proximal colon - 10% to 15%
distal colon - up to 10%

37. Small Intestinal Neoplasms
Lymphoma
• Gastric MALT lymphomas arise in the
setting of mucosal lymphoid activation, as a
result of Helicobacter associated chronic
gastritis.
• Celiac disease is associated with a higher
than normal risk of T-cell lymphomas.

38. Small Intestinal Neoplasms
Lymphoma
Primary GIT lymphomas have a better
prognosis than do those arising in other
sites.
Treatment: combined surgery,
chemotherapy, and radiation therapy.

39. Therapy
• Chemotherapy
• Radiotherapy
• Photodynamic therapy
• Radical surgery
• Gene therapy

40. Question?????