1. Tumors of Intestines

2. Introduction
Overall, colorectal cancer ranks second only to bronchogenic carcinoma among the cancer killers.
Adenocarcinomas constitute the vast majority of colorectal cancers and represent 70% of all malignancies arising in the gastrointestinal tract.

3. Terminology
•A polyp is a tumorous mass that protrudes into the lumen of the gut; traction on the mass may create a stalked or pedunculated polyp.
Alternatively the polyp may be sessile, without a definable stalk.
•Non-neoplastic Polyps
abnormal mucosal maturation,
inflammation
do not have malignant potential (excl.Peutz-Jeghers)
•Neoplastic Polyps:
adenomatous polyps, or adenomas,
precursors of carcinoma.

4. Non-neoplastic (benign) Polyps Hyperplastic polyps
Hamartomatous polyps
Juvenile polyps
Peutz-Jeghers polyps
Inflammatory polyps
Lymphoid polyps

5. Neoplastic epithelial lesions
Benign lesions:
Neoplastic polyp
Adenoma
Malignant lesions:
Adenocarcinoma
Carcinoid tumor
Anal zone (anorectal) carcinoma
Mesenchymal lesions (benign/malignant)
Lymphoma

6. Non-neoplastic (benign) Polyps
Common
Hyperplastic polyps
Adults
Rectosigmoid
Multiple
Nipple-like,
Small protrusions (5 mm)
Abundant crypts.
Juvenile polyps
Children
Rectum
Single
Round mass
1-3 cm
Dilated cystic glands.

7. Hyperplastic polyp
Polyps
Juvenile polyp

8. Sessile
Pedunculated

9. Adenomas Small-pedunculated; large-sessile Colon Malignancy:
Familial predisposition
Risk of carcinoma
Subtypes:
Tubular
Villous
Tubulovillous
Malignancy:
Rare: tubular adenoma less than 1 cm
High: sessile villous adenomas more than 4 cm
Dysplasia: villous adenomas.

10. Tubulovillous adenomas:
Tubular adenomas:
Colon (rectosigmoid)
Small-sessile; large-pedunculated
Stalk is covered by normal mucosa
Tumor is composed of neoplastic epithelium
Intramucosal Ca or invasive Ca.
Villous adenomas:
Rectum/rectosigmoid
Larger than tubular
Sessile
Cauliflower-like
Dysplasia  Ca.
Tubulovillous adenomas:
Peduculated or sessile
Mix of tubular and villous patterns
Dysplasia
Malignancy.

11. Adenoma

12. Familial polyposis syndromes
Peutz-Jeghers Syndrome
Multiple polyps (polyposis coli)
large, firm polyps with a tree-like structure
distinctive freckles on the lips, palms, and genitals
risk for colon cancer.
Turcot's syndrome
Multiple polyps
brain tumors.
Gardner's syndrome
Multiple polyps
minor birth defects
risk for other tumors (notably mesenchymal).
Cowden's syndrome
Risk of tumors of:
Thyroid
Breast
Uterus
Skin.

14. Part One Tumors of Small Intestine

15. Small Intestine tumors:
Small intestine -75% but tumors – 3-6%
Benign tumors (common)
Adenoma(25%), lipoma & leiomyoma.
Malignant tumors (rare; <1%)
Adenocarcinoma of Duodenum or Jejunum, Carcinoid, Lymphoma, Sarcoma
Present at late stage, 70% 5 year survival.

16. Classification Non neoplastic polyps Neoplastic – epithelial
Hyperplastic, lymphoid & hamartomatous
Inflammatory
Neoplastic – epithelial
Benign – Adenoma (ampulla of Vater)
Malignant – Adenocarcinoma, carcinoid
Neoplastic – Mesenchymal
Benign - Lipoma, leiomyoma, neuroma, angioma
Malignant – Leiomyosarcoma, liposarcoma.
Lymphoma

17. Benign tumors: Lipoma
Most common
Mature adipose tissue

18. Adenocarcinoma Napkin-ring or polypoid Duodenum (ampulla of Vater’s)
Spreading:
Regional lymph nodes
Liver
Obstructive jaundice.

19. Tumors of Colon & Rectum

20. Colorectal carcinoma Adenocarcinomas (98%)
often arises in one of the benign neoplastic colonic polyp
risk factors
(1) mild hereditary defects in anti-oncogenes lost in colon cancer,
(2) years of eating the typical western diet.
Low content of vegetables
High content of refined carbohydrates
High content of fat (animal)
Low content of micronutrients (vitamins A, C, E).

21. Morphology Proximal colon tumors: polypoid
Cecum and ascending colon: exophytic
Distal colon: napkin-ring
Progression: slow (years)
Types:
Gut: Adenocarcinoma
Mucin production
Anal zone: Squamous cell carcinoma
Spreading:
Regional lymph nodes
Liver

23. Carcinoid Tumors
2% of colorectal malignancies.
Origin: Neuroendocrine cells (paracrine, Kulchitsky, enterochromaffin, neurosecretory, chromaffin)
Location:
gut (common in appendix)
pancreas or peripancreatic tissue,
lungs,
biliary tree
liver.
Rectal and appendiceal carcinoids almost never metastasize
The classic carcinoid syndrome (serotonin)
(1) wheezing (asthmatic);
(2) flushing (vasomotor);
(3) fibrosis (cardiac, pulmonic, pleural, pelvic);
(4) intestinal hypermotility.

24. Midgut carcinoids: Foregut carcinoids: small intestinal, appendiceal,
most colonic carcinoids.
These are usually argyrophil (hormonally active).
Foregut carcinoids:
lung,
duodenal,
biliary carcinoids.
These are almost never argyrophil (hormonally inactive).

26. Gastrointestinal lymphoma
Less common than carcinomas
Western lymphomas are usually familiar B-cell lymphomas
Mediterranean lymphomas usually feature plasmacytoid differentiation (a subset is alpha-heavy chain disease).
Sprue-associated lymphoma exhibits T-cell markers

27. Lymphoma

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