A case of recurrent and metastatic hemangiopericytoma of the left thigh is presented. T h e following conclusions as to clinical and pathologic features, with special reference to the malignant potential and recurrence rate of this tumor, and the results of various forms of treatment have been drawn from a comprehensive review of 224 cases collected from the literature: 1. Hemangi-opericytoma is highly malignant over a lifetime in about 50% of all cases treated; 2. T h e recurrence rate varies with the particular organ-system involved , with a recurrence rate of 80% for tumors within the central nervous system, compared to a rate of 50.5% for the musculoskeletal system. Primary hemangiopericytoma of the lung and mediastinum distinguishes itself by early recurrence-S6.3% recurring within one year; 3. Wide surgical excision is the treatment of choice; 4. T h e tumor is relatively radioresistant; 5. If conservative treatment is under consideration in a n attempt to avoid amputation, adjunctive measures, such as regional perfusion with tumoricidal drugs, are in dire need of future clinical investigation.