Chondrosarcoma simulating malignant atrial myxoma.

A 69-year-old patient underwent removal of a left atrial tumor which was diagnosed clinically and pathologically as atrial myxoma. Fourteen, 18 and 22 months later, distant metastases were discovered. Two of the metastases were removed entirely and one partially. The metastatic tumors were also thought to be of myxomatous origin by light and electron microscopy. Only at autopsy was it demonstrated that the patient had a primary chondrosarcoma of the pelvis giving rise to widespread myxoid metastases to the heart and other sites.