Left atrial rhabdomyosarcoma.

A 27-year-old man complained of frequent chest pain and recurrent syncope for 3 months. He was in mild respiratory distress with a respiratory rate of 20/min and a heart rate of 94 bpm, regular in rhythm. His blood pressure was 120/70 mm Hg. Cardiac auscultation revealed a distinct early diastolic click followed by a grade 2/5 diastolic decrescendo murmur at the apex that was variable in character with postural changes. A grade 2/6 systolic ejection murmur was heard at the left lower sternal border. Transthoracic echocardiography revealed a large peduncu-lated mass within the left atrial chamber, protruding into the left ventricular cavity and obstructing mitral inflow (Figure 1). Computed tomography of the chest showed a large mass in the dilated left atrium. In view of severe mitral valve obstruction by the atrial mass, surgical removal of the tumor was recommended. During operation, an irregular tumor mass measuring 5×6×6 cm was found attached to the roof of the left atrium, with adhesions to the left atrial posterior and lateral walls. Pericardial effu-sion was also noted. The tumor occupied almost the entire left atrium and extended across the mitral valve orifice (Figure 1 and Movies I and II in the online-only Data Supplement). The mass (Figure 2A) was removed en bloc by clean dis-section along the atrial wall; the mitral valve appeared normal without gross evidence of tumor invasion. On surgical inspection, the surface of the posterior atrial wall to which the tumor was attached appeared to be slightly roughened, but no tumor permeation of the atrium wall was evident. There was also no evidence of intramyocardial or pericardial spread of the tumor mass. Histological examination of the excised tumor mass revealed features typical of a rhabdomyosarcoma (Figure 2B). Predischarge echocardiography showed normal ventricular function and no significant dysfunction of the cardiac valves, and the left atrium appeared to be clean without residual tumor. The patient was symptom free and was discharged 10 days after the operation. The patient did well after discharge and returned for a follow-up 38 days after the operation. At this time, echocardiography revealed a recurrent small echodense mass attached to the atrial septum and another larger mass in the left atrial appendage (Figure 3A and 3B). These 2 masses had progressively enlarged on the echocardiography performed 54 days after the operation (Figure 3C and 3D), as demonstrated also by computed tomog-raphy (Figure 4 and Movies III and …