Hemangiopericytoma in the setting of acromegaly.

Acromegaly is associated with an increased incidence of neoplasia thought to be related in part to tonic increases in circulating levels of insulin-like growth factor-1 (IGF-1). Hemangiopericytomas, particularly those occurring in soft tissues, are known to possess IGF receptors. These tumors often behave aggressively and can be recalcitrant to surgery and radiation therapy.