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Neoplasm of colon

Learn about neoplastic and non-neoplastic lesions of the colon, adenomatous polyps, carcinomas, and associated syndromes. Understand the adenoma-carcinoma sequence, colon cancer staging, and grading.

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Neoplasm of colon

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  1. Neoplasm of colon Dr. Amitabha Basu MD

  2. Topic • Terms • Classification of neoplasm • Classification of non-neoplastic polyps • Discussion on polyps • Polyps and syndrome • Discussion on carcinomas

  3. Terms • Polyp: Mass protruded in lumen • Pedunculated • Sessile Adenomatous polyps: a polyp formed by an adenoma.

  4. Classification of neoplasm of colon • Non neoplastic polyp • Neoplastic lesions • Adenomatous polyp • Carcinoma • Mesenchymal neoplasms • Lymphoma

  5. Important Non-neoplastic polyp

  6. Hyperplastic polyp • small star shaped (usually <5 mm in diameter) epithelial polyps like due drop. • Location: recto sigmoid colon • No malignant potential

  7. Hamartomatous Polyps • Juvenile polyps : Focal hamartomatous malformations of mucosa. • Also called as retention polyps=1 to 3 cm in diameter. • Tumor composed of Cystically dilated glands. • Location: colon and rectum • Clinical: spontaneous removal with stool and blood.

  8. Peutz-Jeghers polyps • Hamartomatous polyps that involve the mucosal epithelium, lamina propria, and muscularis mucosa. • Location: mainly small intestine • Associated with Peutz-Jeghers syndrome.

  9. Neoplastic lesions Adenomatous polyp Carcinoma Carcinoid

  10. Adenomas (adenomatous polyps) • Tubular adenoma • Villous adenoma

  11. Adenoma

  12. Tubular adenoma (a Pedunculated adenoma showing a fibro vascular stalk) Adenomatous epithelium in an otherwise normal (mucin-secreting, clear) colonic mucosa

  13. diagnosis?

  14. Villous adenoma: sessile adenoma with villous architecture Dysplasia present: locate it

  15. Malignant risk with an adenomatous polyp • Cancer is rare in tubular adenomas < 1 cm in diameter. • The risk of cancer is high (approaching 40%) in sessile villous adenomas > 4 cm in diameter. • Severe dysplasia, when present, is often found in villous areas.

  16. Treatment • Single pedunculated polyp: polypectomy • Polyposis: complete resection • Sessile adenoma: recestion

  17. Polyps and syndrome • Various syndromes are associate with the polyps of the intestine

  18. Familial Polyposis syndrome • Autosomal dominant. • Number: > 100. • Two syndromes: • Classic FAP syndrome, patients typically develop 500 to 2500 colonic adenomas. • Variant of FAP=Gardner syndrome exhibit intestinal polyps identical to those in classic FAP ( + osteoma , epidermal cysts, fibromatosis, CA breast )

  19. Familial Polyposis syndrome Study other similar picture

  20. Syndromes

  21. Syndromes

  22. Malignant Epithelial Lesions Adenocarcinoma* Carcinoid tumor

  23. Colorectal carcinoma: topic • Features • Colorectal Carcinogenesis; • Multistep carcinogenesis • Morphology

  24. Features • Age: Ages 60 and 79 • Dietary factors: • (1) Excess dietary caloric intake. • (2) A low content of unabsorbable vegetable fiber, • (3) High content of refined carbohydrates, • (4) Intake of red meat, and • (5) Decreased intake of protective micronutrients (vitamins A, C, and E )

  25. Adenoma carcinoma sequence: Multistep carcinogenesis

  26. Adenoma carcinoma sequence • Loss of Adenomatous Polyposis Coli (APC) Gene(5q21 ) : first hit & second hit: 2 hit theory • Mutation of K-RAS + Loss of SMADs + Loss of p53 = adenoma formation. • Activation of Telomerase: invasive tumor.

  27. Gross of colon cancer

  28. Carcinoma of the cecum. The fungating carcinoma projects into the lumen but has not caused obstruction

  29. Carcinoma of the descending colon. Circumferential tumor has heaped-up edges and an ulcerated central portion. The arrows identify separate mucosal polyps

  30. Microscopic morphology • Features of right- and left-sided colonic adenocarcinoma are similar. • Shows desmoplastic reaction. • Many tumors produce mucin- PAS positive • Some cancers the cells take on a signet-ring appearance

  31. Invasive adenocarcinoma of colon, showing malignant glands infiltrating the muscle wall.

  32. Marker and clinical • CEA ( carcino embryonic antigen) • Useful for following the course of the disease. • Stool : occult blood positive ( non specific) • Alternate Constipation and diarrhea.

  33. Staging of colon carcinoma • Depends on: size, node involvement and metastasis. • The Astler-Coller Staging System • TNM

  34. T • Tis=Carcinoma in situ (high-grade dysplasia) or intramucosal carcinoma (lamina propria invasion) • T1=Tumor invades sub mucosa • T2=Extending into the muscularis propria but not penetrating through it • T3=Penetrating through the muscularis propria into subserosa • T4=Tumor directly invades other organs or structures

  35. NM • Nx= Regional lymph nodes cannot be assessed • N0=No regional lymph node metastasis • N1=Metastasis in 1 to 3 lymph nodes • N2=Metastasis in 4 or more lymph nodes • Mx=Distant metastasis cannot be assessed • M0=No distant metastasis • M1=Distant metastasis

  36. Grading • Grade depends on: # of mitosis and differentiation. • Well differentiated tumor (WD) : good prognosis. • Small tumor (usually < 2 cm) : usually good prognosis • Low mitosis (WD): good prognosis • More/ atypical mitosis: bad prognosis

  37. Prognosis depends on Grading and staging – 2 of 2 • Tumor with high mitosis: poor prognosis. • Lymph node involvement : bad prognosis • (more the number worse is the prognosis) • Distant metastasis: bad prognosis always. • Poorly differentiated < undifferentiated tumor < anaplasia : poor prognosis.

  38. Carcinomas arising in the anorectal canal • Dominated by squamous cell carcinoma. • Below the ano-rectal junction • Due to chronic HPV infection

  39. Carcinoid tumors • Origin: Neuroendocrine cells • Age: sixth decade • Appendiceal (commonest) and rectal carcinoids. • Other sites: Ileal , gastric, and colonic carcinoids.

  40. Morphology The appendix is the most common site. • Appendicular tumor: Appear as bulbous swellings of the tip, which frequently obliterate the lumen. • Other place: Bronchus= Intramural masses that create small, polypoid or plateau-like elevations(<3cm) Remember the size

  41. Colour • Characteristic feature is a solid, yellow-tan appearance on transection. • Micro: • form discrete islands, trabeculae, stands, glands. • a scant, pink granular cytoplasm and a round to oval stippled nucleus

  42. Multiple protruding tumors are present at the ileocecal junction

  43. Tumor cells exhibit a monotonous morphology (salt and pepper)

  44. Electron micrograph showing dense core bodies in the cytoplasm Study other similar picture

  45. Clinical Features: many are asymptomatic

  46. Diagnosis and prognosis • Elevated levels of 5-HT and its metabolite, 5-hydroxyindoleacetic acid (5-HIAA), are present in the blood and urine . • Overall five-year survival rate for carcinoids (excluding appendiceal) is approximately 90%

  47. GASTROINTESTINAL LYMPHOMA • Definition ::- Primary gastrointestinal lymphomas exhibit noevidence of liver, spleen, mediastinal lymph node, or bone marrow involvementat the time of diagnosis. • They are nonHodgkins lymphoma(NHL)

  48. Etiology/Risk factors (1) Chronic gastritis caused by H. pylori (2) Chronic sprue like syndromes (3) Natives of the Mediterranean region (4) Infection with human immunodeficiency virus.

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