[A case of rectal cancer with malacoplakia].

A 59-year-old man was hospitalized for rectal bleeding. Barium enema and proctoscopy revealed an elevated tumor, completely stenosing the rectum. The microscopic features of the specimens obtained by proctoscopic biopsy of the tumor comprised aggregations of histiocytes with intracytoplasmic inclusions (von Hansemann cells and Michaelis-Gutmann bodies). Rectal malacoplakia was diagnosed. In the course of laparotomy, the tumor was found to be strongly infiltrated to the pelvis. Thus, radical surgery was not performed, and an artificial anus was made. Excisional biopsy from the tumor tissue revealed the features of well-differentiated adenocarcinoma and malacoplakia. Forty-three cases of malacoplakia of the gastrointestinal tract from a review of the literature including ours were collected and discussed.