Localized pseudomembranous colitis simulating carcinoma of the cecum.

A 76-yr-old woman complained of right lower quadrant abdominal pain, nausea, and fever. There was no history of antibiotic therapy or preceding diarrhea. At laparotomy, a cecal lesion simulating a tumor was found with an otherwise normal colon. Right hemicolectomy was performed. Pathological examination showed pseudomembranous colitis confined to the cecum. It is suggested that pseudomembranous colitis unrelated to prior exposure to antimicrobial agents can occur without diarrhea, and may be a localized process mimicking colonic carcinoma.