Rapidly progressing left atrial hemangiopericytoma.

Cardiac hemangiopericytoma is a rare soft tissue tumor. We describe a case of hemangiopericytoma in the left atrium, which was diagnosed as myxoma preoperatively. A 70-year-old woman was admitted with heart failure. An echocardiogram showed a large myxoma-like mass in the left atrium, herniating into the left ventricle; therefore, an emergency operation was performed. Histological examination revealed a malignant hemangiopericytoma. The patient's postoperative course was uneventful, but she died due to a local recurrence 4 months after the operation.