Aberrant crypt foci in the human colon - Frequency and histologic patternsin patients with colorectal cancer or diverticular disease

Aberrant crypt foci are considered potential markers of colorectal cancer r isk. The aim of this study was to analyze a large series of human aberrant crypt foci according to frequency, distribution, and histology. Aberrant cr ypt foci were identified in methylene blue-stained colonic mucosa from 103 patients undergoing surgery for colorectal cancer or diverticular disease. Foci were histologically classified into surface hyperplastic type, surface and glandular hyperplastic type, mixed hyperplastic and adenomatous type, and adenomatous type. The mean frequency of aberrant crypt foci (n = 720) w as higher in the colorectal cancer group (0.20/cm(2)) than in the diverticu lar disease group (0.07/cm(2)), and in distal colonic segments than in prox imal segments. Most of the histologically examined foci (n = 366) were hype rplastic (88.8%). Surface hyperplasia accounted for 30.6% and prevailed in small lesions. Surface and glandular hyperplasia accounted for 58.2% and pr evailed in medium-sized to large foci. Partially or totally dysplastic foci accounted for 10.1% of examined lesions (10.8% and 2.8% in the colorectal cancer and diverticular disease groups, respectively). Most of them (94.6%) were composed of mixed hyperplastic and adenomatous crypts and prevailed i n large lesions. The higher frequency of aberrant crypt foci in patients wi th colorectal cancer sustains their putative role as preneoplastic markers. The high rate of mixed hyperplastic and adenomatous lesions supports the p ossible adenomatous transformation of hyperplastic lesions.