title: Non-polypoid adenoma of the large intestine.
abstract: In order to find non-polypoid (flat) adenomas in the large intestine, one hundred and twenty-six consecutively resected large bowels were stained with methylene blue or haematoxylin and examined using a stereoscopic microscope with special attention to pit pattern abnormalities. The primary diseases were classified into familial adenomatous polyposis (FAP) in 9 cases, multiple adenomas in 2 cases, colorectal cancers in 90 cases, Crohn's disease in 5 cases, ulcerative colitis in 2 cases, constipation in 9 cases, diverticular disease in 3 cases and others in 6 cases, respectively. Thirty-five flat adenomas were detected in 14 colons (14/126 = 11%). Twenty-one flat adenomas were found in 9 non-FAP cases (7 colons removed for cancer and 2 for multiple adenomas) and the remaining 14 flat adenomas were found in 5 FAP colons. No flat adenomas were found in any of the 25 colons removed for non-neoplastic disease. Nine flat adenomas (26%) had a depressed shape. The mean age of the non-FAP cases was 57 years and that of the FAP cases was 29 years (P < 0.005). The mean size of non-FAP flat adenomas was 6.1 mm and that of FAP flat adenomas was 3.1 mm (P < 0.005). Non-FAP flat adenomas were more frequently right-sided than those in FAP. Epithelial dysplasia was graded as mild in 31 (89%) and moderate in 4 (11%), respectively. Moderate dysplasia was found in non-FAP cases exclusively. These results suggest that flat adenomas may be heterogeneous. The significance of these lesions is discussed.
authors.affiliation: Department of Endoscopy, St. Mark's Hospital, London, UK.
authors.forename: T
authors.initials: T
authors.lastname: Masaki
authors.forename: J P
authors.initials: JP
authors.lastname: Sheffield
authors.forename: I C
authors.initials: IC
authors.lastname: Talbot
authors.forename: C B
authors.initials: CB
authors.lastname: Williams
mesh_terms: D000236:Adenoma / Q000453:epidemiology / Q000473:pathology*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000453:epidemiology / Q000473:pathology*; D004171:Diploidy; D005060:Europe; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged