Infravesical obstruction caused by a retrovesical malignant schwannoma.

A 77-year-old male presented himself with acute urinary retention, and a history of infravesical obstruction. Cystourethroscopy failed to show the obstruction. A malignant schwannoma (MS) causing impression in the bladder was removed through a laparotomy. Postoperatively there were no urologic symptoms, and the urodynamic investigations had changed to normal.