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Neoplasia of Colon

Neoplasia of Colon. Polyps. Benign elevations of mucosa Most common in colon, but also in Oesophagus Stomach Small intestine Initially sessile, may become pedunculated. Classification of Polyps. Neoplastic Villous Tubular Tubulovillous Non-neoplastic Inflammatory Hamartomatous

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Neoplasia of Colon

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  1. Neoplasia of Colon

  2. Polyps • Benign elevations of mucosa • Most common in colon, but also in • Oesophagus • Stomach • Small intestine • Initially sessile, may become pedunculated

  3. Classification of Polyps • Neoplastic • Villous • Tubular • Tubulovillous • Non-neoplastic • Inflammatory • Hamartomatous • Hyperplastic

  4. Non Neoplastic Polyps • Inflammatory • IBD • Solitary rectal ulcer syndrome • Hamartomatous • Juvenile polyps • Peutz-Jeghers Syndrome • Cowden Syndrome • Cronkhite-Canada Syndrome • Hyperplastic

  5. Typo in Robbins!! pg 816 Inflammatory Polyp A, The dilated glands, proliferative epithelium, superficial erosions, and inflammatory infiltrate are typical of an inflamatory polyp. However, the smooth muscle hyperplasia within the lamina propria suggests that mucosal prolapse has also occurred. B, Epithelial hyperplasia. C, Granulation tissue-like capillary proliferation within the lamina propria caused by repeated erosion and re-epithelialization.

  6. Hamartomatous Polyps Juvenile Polyposis Peutz-Jeghers Syndrome

  7. Hamartomatous Polyps Which is not hereditory…?

  8. Hyperplastic Polyps • < 5mm nodular polyps • Often multiple • Must be distinguished from sessile serrated polyps! • No malignant potential • Crowded histology • Pathogenesis not well known… • Shedding < Proliferation

  9. Neoplastic Polyps • Caused by any neoplastic mass in the GIT • Colonic adenoma • Carcinoid tumour • Stromal tumour • Lymphoma • Metastasis • 50% prevalence by age 50 • Clinically silent • Large polyps may cause occult bleeding and anaemia • Some villous polyps may secrete potassium and protein

  10. Adenomatous Polyp • Pedunculated or sessile • 0.3cm – 10cm diameter • Velvet or raspberry texture

  11. Adenomatous Polyp Histology • Hyperchromasia • Elongation • Stratification • large nucleoli • eosinophilic cytoplasm • Reduced number of goblet cells • Peduncle (if present) has slender fibromusclular stalk with prominent blood vessels

  12. Polyp classification • Villous • Large, sessile, slender villi • Tubular • Small, pedunculated, tubular glands • Tubulovillous • Half cast

  13. Sessile Serrated Adenoma • Most common in right colon • Histologically similar to hyperplastic polyps • Malignant potential

  14. Familial Polyp Syndromes • Familial AdenomatousPolyposis (FAP) • Autosomal dominant • >100 polyps for Dx • Numerous polyps onset during teenage years • Size ranges from microscopic to large • Colorectal adenocarcinoma in all patients, usually by age 30 • Prophylactic colectomy recommended • Polyp type depends on mutation • Subtypes: Gardner syndrome, Turcot syndrome

  15. Familial Polyp Syndromes • Hereditory Non-Polyposis Colorectal Cancer (HNPCC) Syndrome / Lynch Syndrome • Often affects right colon • Risk of cancer in colorectum, endometrium, stomach, ovary, ureters, brain, small bowel, hepatobiliary tract, skin • Sessile serrated adenoma; mucinous adenocarcinoma

  16. Adenocarcinoma of Colon

  17. Adenocarcinoma Morphology • Proximal: • Polypoidexophytic masses • Rarely cause obstruction • May bleed and cause anaemia • Distal: • Annular • Constrictions and narrowed lumen

  18. Adenocarcinoma Histology • Generally tall, columnar cells, resembling adenomas • ± glands • ± mucin (poor prognosis) • ± signet rings • ± neuroendocrine differentiation • Prognistic factors: depth and lymph node invasion

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