Hemangiopericytoma of the parotid gland: CT and MR features.

Hemangiopericytomas are uncommon vascular neoplasms with rare occurrence in the head and neck region. They originate from the pericytes, which are small, oval cells encircling capillaries. Hemangiopericytomas traditionally appear in the retroperitoneum and in the capillaries of the extremities. A case of hemangiopericytoma of the parotid gland is presented. The clinical, surgical, histologic, and radiologic features are described and discussed.