Neoplastic colonic polyp with extensive squamous metaplasia. Case report.

Extensive squamous metaplasia in neoplastic colonic polyps is rare. This paper describes extensive squamous metaplasia in an adenomatous polyp evolving into adenocarcinoma. The origin of squamous cell carcinoma and adenocanthoma of the colon is not well understood. This case is the only case reported in the literature that demonstrates the development of squamous metaplasia in dysplastic colonic glands, in situ adenocarcinoma, and finally invasive adenocarcinoma of the colon. The pertinent literature is reviewed.