Ameboma presenting as acute urinary retention.

A patient with several weeks of diarrhea developed for the first time severe urinary frequency and urgency and was admitted with acute urinary retention. Imaging techniques showed a large mass compressing the posterior wall of the bladder adjacent to the rectosigmoid colon, leading to a bilateral dilatation of the ureters. Cystoscopy and biopsy of the affected part of the bladder showed no tumor but a nonspecific acute inflammation. After identification of trophozoites of Entamoeba histolytica in the stool and confirmation by colonoscopy, barium enema, and serology of acute amebic colitis, the patient was treated with metronidazole. Urinary symptoms immediately resolved with a complete disappearance of the mass and a later cure of the colitis. This is a first report of severe urinary symptomatology dominating the clinical picture in amebic colitis, due to compression of the urinary bladder by an ameboma.