Rectal aberrant crypt foci identified using high-magnification-chromoscopic colonoscopy: biomarkers for flat and depressed neoplasia.

Background: Aberrant crypt foci may represent preneoplastic lesions in the human colon. The prevalence of aberrant crypt foci detected using magnification chromoscopic colonoscopy is known to follow a stepwise progression from normal subjects to those with exophytic adenomas and colon cancer. No studies have addressed the prevalence of rectal aberrant crypt foci in patients with flat and depressed colonic lesions that cluster within the right hemi-colon and may undergo de novo neoplastic transformation.