Hemangiopericytoma of bone.

Hemangiopericytoma primary in bone is a rare tumor. A review of 15 cases (five from the Mayo Clinic files and 10 from the consultation files) revealed that all tumors were unifocal and that the most common location was the pelvis (three lesions in the sacrum and two in the ischium). The series involved seven male and eight female patients whose ages ranged from 14 to 74 years. Histologically, all of the tumors were composed of cells with round to oval nuclei arranged around vascular spaces. On the basis of cellularity, nuclear atypia, and mitotic activity, four tumors were benign, two intermediate, and nine malignant. Surgery was the primary treatment for the 15 patients. Of the 14 patients with adequate follow-up, eight died of disease, three were alive with recurrent disease, and three were alive and disease-free.