Introduction There are 3 types of benign polyps (hamartomas) hyperplastic polyp most common type in adults often rectosigmoid sawtoothed appearance on histology without marked nuclear enlargement or dysplasia does NOT predispose to malignancy juvenile polyps most common type in children often rectosigmoid multiple cystic and dilated crypts, edematous lamina propria with associated lymphocytes and plasma cells on histology Peutz-Jeghers polyposis arborization of smooth muscle within the lamina propria on histology There are 3 types of neoplastic polyps (adenomas) tubular adenoma most common polyp usually pedunculated (stalked) colonic mucosa with dysplastic nuclei in a pseudostratified pattern that rapidly transitions to normal epithelium, ≥75% tubular component on histology tubulovillous adenoma usually pedunculated (stalked) finger-like projections away from the muscularis mucosa with low-grade dysplasia on histology 20-80% of villosity characterizes tubulovillous adenoma villous adenoma greatest malignant potential usually sessile may secrete protein and K+-rich mucus finger-like projections away from the muscularis mucosa with low-grade dysplasia on histology >80% of villosity characterizes villous adenoma may involve Familial Adenomatous Polyposis Presentation Sympoms rectal bleeding polyp prolapse from rectum Evaluation Sigmoidoscopy / colonoscopy Labs villous adenoma may show hypokalemia and hypoalbuminemia Differential Polyposis syndromes Juvenile polyposis AD inheritance multiple juvenile polyps in GI tract ↑ risk of adenocarcinoma Cronkhite-Canada syndrome consists of juvenile polyposis with fingernail dystrophy Prognosis, Prevention, and Complications Malignancy risk ↑ by ↑ size ↑ villous histology villous = villainous ↑ epithelial dysplasia