Malignant hemangiopericytoma of the bone.

Hemangiopericytoma is a rare vascular tumor of pericyte origin with variable malignant potential. Very rarely, this tumor occurs as a primary bone lesion. We present a case of a highly malignant hemangiopericytoma of the proximal tibia. Current therapy consists of radical resection of the tumor with postoperative radiation therapy being recommended. Chemotherapy seems to be useful in disseminated disease. The prognosis correlates to the histological grading of the tumor. Early or late recurrence and distant metastases with fatal outcome, as shown in our case study, are not uncommon.