Gastrointestinal adenomatous polyps.

Adenomatous polyps of the gastrointestinal tract are dysplastic precursor lesions of adenocarcinoma. The features of an adenoma that are associated with a greater tendency to progress to carcinoma include larger polyp size, high grade dysplasia, and increased villous glandular architecture. Alterations in particular oncogenes and tumor-suppressor genes have been correlated with various stages of colonic adenoma formation, thereby facilitating our knowledge of adenoma pathogenesis. Heredity and environment contribute to the risk of developing adenomatous polyps of the colon. The incidence of colorectal cancer can be decreased by the endoscopic removal of adenomas, thereby providing good rationale for screening and surveillance programs.