Hemangiopericytoma of the Urinary Bladder: a case report and review of the literature.

A case of hemangiopericytoma arising in the urinary bladder is presented. Initial symptoms included hematuria and frequency of urination. Hemangiopericytoma is a vascular tumor of pericyte origin which occurs primarily in several organs and can be benign or malignant. Reports in the literature of genitourinary system involvement are reviewed. It is concluded that genitourinary tumors of this type should be considered malignant and treated aggressively.