Malacoplakia is a rare infectious disease that has been almost exclusi vely reported in urology and pathology journals. We studied two cases of malacoplakia that were primarily referred to the department of internal medicine because of fever and abdominal masses. In one patient, malacoplakia was diagnosed in the unusual ovarian location, while in the other patient a large renal mass was found and ciprofloxacin therapy failed because of bacterial resistance. The clinical and radiologic appearance of malacoplakia often mimics that of a malignant tumor. The principal disorder is probably a monocytic-macrophagic bactericidal defect. A definitive diagnosis depends on microscopic detection of Michaelis-Gutmann bodies by means of von Kossa stain. We outlined treatment strategies on the basis of a review of the literature since 1981, which included 140 cases. If possible, immunosuppressive drugs should be stopped. Quinolone antibiotic treatment and surgical excision or incision and drainage lead to the highest cure rates (90% and 81%, respectively). Specific intracellular penetration of quinolone antibiotics is a possible reason for the higher cure rate achieved with these antibiotics. Bethanechol has been suggested to correct the supposed fundamental disturbance by increasing the intrecellular cyclic guanosine monophosphate concentration, but there is still no convincing evidence of its clinical efficacy.