Uterine hemangiopericytoma.

In a clinicopathologic analysis of previously unreported uterine hemangiopericytomas, malignant behavior was observed in four of 21 followed patients. Recurrent disease occurred in the pelvis, abdomen, and lungs. The role of chemotherapy in the treatment of recurrences was not substantiated. No specific histologic features could be identified that correlated with malignant potential.