A solitary hydatid cyst of the retrovesical region.

A 70-year-old man presented with a large suprapubic mass. Ultrasonography revealed that the mass was cystic and displaced the bladder anteriorly and superiorly. Computed tomography suggested that the mass could be an echinococcal cyst. Computed tomography also showed that the patient had bilateral hydroureteronephrosis. Echinoccocal haemagglutination was positive at 1:320 dilution. The patient underwent surgical exploration during which the cyst was found to be located in the retrovesical region. The cyst was completely excised and the pathologic examination confirmed the diagnosis.