Hemangiopericytoma is a rare tumor of capillary pericytes which usuall
y develops in the hands, feet, head, neck, or retroperitoneal space. B
ecause there are often no symptoms, the tumor is frequently large at t
he time of diagnosis. The case of a patient with a large retroperitone
al hemangiopericytoma is reported. Clinical features and management of
this malignancy are discussed.