Pneumocystis colitis in a patient with the acquired immunodeficiency syndrome.

We report a case of colonic pneumocystosis in a human immunodeficiency virus (HIV)-positive homosexual male who presented with fever and diarrhea. Stool cultures for bacterial pathogens and examinations for ova and parasites were negative. The diagnosis was made by colonoscopic biopsy which revealed Pneumocystis carinii organisms in the lamina propria of the cecum, descending colon, and sigmoid colon. The patient subsequently developed pulmonary and ocular abnormalities consistent with P. carinii involvement of these organs. The diarrhea and other manifestations resolved with antipneumocystis therapy. Many sites of extrapulmonary pneumocystosis have been reported, but we believe this is the first report of colonic P. carinii found in the evaluation of persistent diarrhea in a patient with the acquired immunodeficiency syndrome.