Cryptic infection by whipworm mimicking a sessile polyp of the colon.

A case of trichocephaliasis in a 70-year-old male is described. The original diagnosis, based on radiological and endoscopic findings, was of a sessile polyp of the colon. Only when a fragment of the supposed polyp was removed at biopsy and examined histologically was it revealed as a single male specimen of whipworm.