Diagnosis
At this point, differential diagnosis included intracardiac tumor, pericardial cyst or mediastinal mass. Contrast echocardiography revealed free communication between the lateral echolucent structure and LA (Figure 3C) suggesting that this was an intra-cardiac structure. Computerized tomography (CT) chest with intravenous contrast was then ordered for definitive diagnosis. CT chest revealed a large LAAA measuring 6.2 cm transverse x 6.4 cm anteroposterior x 11.0 cm cephalocaudal (Figure 4). The neck of LAA measured 3.3 cm. CT scan showed thickening of the LAA wall and some opacities within the LAAA cavity suggesting presence of thrombus. Aside from the LAAA, there were no pertinent cardiac abnormalities.