ABERRANT CRYPT FOCI IN HUMAN COLONS - DISTRIBUTION AND HISTOMORPHOLOGIC CHARACTERISTICS

Abberant crypt foci (ACF) are one of the earliest putative preneoplast ic, and in some cases, neoplastic lesions in human colons. These micro scopic lesions, identified on methylene blue-stained mucosa with a low -power-magnification microscope, are thought to be closely related to the earliest steps in multistage colonic tumorigenesis. We investigate d the distribution pattern and histomorphological features of ACF in 7 4 patients with sporadic colorectal cancer. The distribution pattern s hows a slightly higher prevalence with older age. The prevalence of th e ACF in sigmoid colon was significantly higher in patients with color ectal cancer as compared with patients with benign colonic diseases. A lso, significantly more ACF were detected in distal parts of the large bowel (descending, sigmoid colon, and rectum) than in proximal parts. Of 42 microdissected lesions, 12 were dysplastic and 30 were hyperpla stic foci. The average size of dysplastic lesions was significantly la rger than hyperplastic foci. More apoptotic bodies were found in dyspl astic lesions. These lesions also showed an upward expansion of prolif erative compartment and higher proliferation indices expressed as prol iferating cell nuclear antigen-labeling index. Lymphoid follicles were frequently observed in the base of both hyperplastic and dysplastic f oci (40% and 66.6%, respectively). The coincidence of lymphoid follicl es was 2.5 to 8 times big-her than expected. These features may be rel ated to further progression of selected ACF during colorectal tumorige nesis. Copyright (C) 1998 by W.B. Saunders Company.