In October 1996 a 67-year-old man underwent transthoracic and transesophageal echocardiography (TEE) because of dyspnea on exertion and was found to have 2 left atrial cardiac masses. The 2 masses were surgically removed from the atrium and showed histopathologic and ultrastructural features of a leiomyosarcoma. Seven months later a double recurrence of left atrial masses was found with TEE; the patient refused surgery and decided instead to receive chemotherapy. In May 1998 he was in stable condition (New York Heart Association class III), but a further growth of the 2 left atrial masses was observed at TEE. We describe the echocardiographic features of the 2 cardiac masses and the clinical and prognostic implications.