Malignant fibrous histiocytoma of the heart.

We describe a 54-year-old man with a recurrent malignant fibrous histiocytoma in the left atrium. During the patient's first hospitalization, the tumor clinically presented as a typical atrial myxoma and was removed by routine procedure. Histologically, it was diagnosed as sarcoma, probably rhabdomyosarcoma. Nine months later the patient was readmitted because of recurrence. This time, the tumor, along with interatrial septum and a part of the anterior atrial wall, was excised by means of cardiac explantation and reimplantation. On light microscopic, immunohistochemical, and electron microscopic examination, the tumor was classified as a storiform-pleomorphic type of malignant fibrous histiocytoma. No other therapeutic procedures were performed, and 11 months after the second surgery the patient died of massive hemorrhage from a duodenal ulcer. A recurrent tumor in the left atrium and several distant metastases were found at autopsy.