[Colonorectal adenoma: relationships among histological structure, dimensions of the polyps, and age distribution].

Among 1258 polyps from the lower gastro-intestinal tract removed by rectoscopy or coloscopy and examined histologically there were 744 adenomas, 72% tubular, 27% papillary and 1% villous. 96.5% of all adenomas were extracted from patients aged over 40 years. Four fifths of the tumours were found in the rectum and sigmoid colon. Only 6% of the tubular adenomas were more than 15 mm in diameter, compared with 32% of papillary and 57% of villous adenomas. The special significance of the adenomas lies in their potential malignancy (adenoma-to-cancer sequence).