Malacoplakia-like reaction in association with colorectal adenocarcinoma

17 cases of malacoplakia in association with an adenocarcinoma of the colon or rectum are known. In this report we describe a new case of this rare combination. An 83-year-old comatose female patient was admitted in an emergency situation because of an incipient ileus. A carcinoma had been known for months, but the patient had previously rejected any diagnostic or therapeutic measures. A tumor (6 cm in diameter) in the upper rectum was removed. This tumor had caused an obstruction of the lumen and reached the serosa. Histologically, an adenocarcinoma with suppurations in the stroma was staged pT3, G2, pN0 (clinically pT4 because of the perforated colonic wall). PAS- and von-Kossa-positive Michaelis-Gutmann-bodies were found in macrophages. Ultrastructurally, they turned out to be circular shifted early stage calcifications. Any malacoplakia-like lesion in suspicious areas of the colonic wall should be followed up by further diagnostic measures, since it may indicate the presence of an adenocarcinoma.