IDENTIFICATION OF DYSPLASIA IN HUMAN COLONIC ABERRANT CRYPT FOCI

Aberrant crypt foci (ACF) are grossly invisible putative premalignant lesions in the colon. As dysplasia is considered an important precurso r of colon carcinoma, we wanted to determine the presence and severity of dysplasia in human ACF. Fifty ACF from 28 patients were embedded i n paraffin, cut serially, and stained with hematoxylin and eosin. Mult iple slides from each ACF were evaluated for dysplasia according to a defined set of criteria. Of 50 ACF, 3 (6%) contained focal areas with severe dysplasia, ie. carcinoma in situ, 4 (8%) contained focal areas with moderate dysplasia, and 20 (40%) contained focal areas with mild dysplasia. Twenty-three ACF (46%) contained no detectable dysplasia. I n 15 of 27 ACF with dysplasia, less than 50% (eg, 4 of 28, 10 of 54, a nd 10 of 30 sections) of the sections cut and evaluated from each ACF demonstrated dysplasia. The presence of dysplasia in a large proportio n of ACF supports the hypothesis that they may be precarcinomatous.