bronchogenic carcinoma, extracardiac mass, mediastinal mass, left atrial massSpread of bronchogenic carcinoma to the hilar nodes and posterior mediastinum is common. Echocardiographic visualization of such Figure 1. Transthoracic echocardiogram in parasternal long-axis view (top left) and apical long-axis view (top right). The three lower panels show the apical 4-chamber view, in slightly different planes. In all there is an apparent mass in the left atrium (arrows). LV, left ventricle; LA, left atrium; RV, right ventricle; RA, right atrium.a retrocardiac neoplastic mass has been described. 1−4 We describe a patient in whom the transthoracic echocardiogram (TTE) showed an apparent intraatrial mass but transesophageal echocardiography and computed tomography demonstrated that the mass was actually posterior to the left atrium and encroaching on it, producing the illusion on the TTE that it was intraatrial.