Atypical juvenile polyposis.
Two cases of atypical juvenile polyposis are described in males of 9 months and 25 years-of-age. The first was associated with congenital megacolon and presented as juvenile polyps with features suggesting mild dysplasia. In the second case six histological lesions are found: I hyperplastic polyps; 2 juvenile polyps; 3 hyperplastic polyps with adenomatous areas; 4 juvenile polyps with areas of dysplastic epithelium; 5 adenomas; and 6 adenocarcinomas. On the basis of the morphological features we propose a pathogenetic sequence of focal mucosal hyperplasia to adenoma and carcinoma through stages of non-neoplastic and non premalignant polyps. Finally, the possibility that hyperplastic epithelium can in some circumstances have a greater dysplastic potential that normal colorectal mucosa is raised.
D000236:Adenoma / Q000473:pathology; D000328:Adult; D003106:Colon / Q000473:pathology; D003110:Colonic Neoplasms / Q000150:complications / Q000473:pathology*; D006801:Humans; D006965:Hyperplasia; D007223:Infant; D007413:Intestinal Mucosa / Q000473:pathology; D007417:Intestinal Polyps / Q000150:complications / Q000473:pathology*; D008297:Male; D008531:Megacolon / Q000150:complications; D012004:Rectal Neoplasms / Q000473:pathology*; D012007:Rectum / Q000473:pathology