Histoplasmosis of the colon in patients with AIDS: imaging findings in four cases.

OBJECTIVE

The purpose of this study was to describe and illustrate the radiographic findings of colonic histoplasmosis in patients with AIDS.

SUBJECTS AND METHODS

Four HIV-positive patients were admitted because of fever, abdominal pain, tenderness, weight loss, and diarrhea. One patient had known disseminated histoplasmosis, one had esophageal moniliasis, and two had no other known opportunistic infections or tumors. All four patients had barium enemas, and two had abdominal CT examinations. The diagnosis was established via colonoscopic biopsy in three patients and with surgery in one patient.

RESULTS

Barium enema in two patients showed separate, short, apple-core lesions in the transverse and descending colon. In one patient, a single lesion in the ascending colon mimicked colonic carcinoma. One patient had segmental involvement of the ascending colon, compatible with inflammatory bowel disease. CT examination revealed circumferential thickening of the wall of the colon with adjacent lymphadenopathy of mixed attenuation. Three patients responded to medical therapy, and one patient remained symptomatic and was found on a follow-up CT examination to have significant recurrence of retroperitoneal lymphadenopathy.

CONCLUSION

Colonic histoplasmosis in patients with AIDS has protean radiographic features and can mimic colonic carcinoma. In these patients, histoplasmosis should be part of the differential diagnosis, particularly when several colonic lesions are detected, associated regional and retroperitoneal lymphadenopathy is present, and the patient is living or has lived in an endemic area.