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. A 49-yr-old man presented with an erosive, midline scalp mass and cutis gyrata. Further diagnostic imaging and endocrinologic analysis confirmed two diagnoses: a hemangiopericytoma and acromegaly associated with an intrasellar pituitary tumor. Both the hemangiopericytoma and the pituitary adenoma were surgically resected; Western blot analysis confirmed the presence of IGF-1 receptors in the hemangiopericytoma. Two years later, the patient underwent resection of a right frontal hemangiopericytoma with an identical histologic phenotype and receptor positivity for IGF-1. The occurrence of a central nervous system hemangiopericytoma in patient with acromegaly is rare. Growth and recurrence of hemangiopericytoma may have been fostered by the presence of IGF-1 receptors. Paracrine mechanisms related to IGF-1 may have contributed to its pathogenesis and growth. The presence of IGF-1 receptors in hemangiopericytomas may have treatment implications for additional adjuvant therapies.