Leiomyoma of the bladder: case report and review of the literature.

Primary mesothelial tumors of the bladder are rare. Although less than 5% of all bladder tumors are malignant in origin, the most common bladder tumor is the benign leiomyoma. Genitourinary leiomyomata may arise in any anatomic structure containing smooth muscle. They have been reported to involve single or multiple organs. Since they may also mimic malignant lesions, they should always be considered in the differential diagnosis of any pelvic mass. Sometimes, depending upon location, such lesions can only be diagnosed after surgical removal.