Small colonic adenomas with adenocarcinoma. A retrospective analysis.

The purpose of this study is to alert colonoscopists to a relatively high incidence of small colonic adenomas with invasive adenocarcinoma among a group of colonic adenomas with invasive adenocarcinoma removed colonoscopically. Retrospective analysis (1973 to 1983) documented nine such lesions that were 1 cm or smaller, representing 15 percent of all colonic adenomas with invasive adenocarcinoma removed during that period. These lesions had no distinctive gross features and could be easily confused with hyperplastic polyps. It is recommended that all colonic polyps be removed at colonoscopy regardless of their size, because even lesions 1 cm and smaller, with "benign" gross appearance, may harbor invasive adenocarcinoma.