A 59-year-old woman was admitted in our hospital due to persistent cough and dyspnea. Transthoracic 2-dimensional echocardiography demonstrated a cardiac mass (29 x 34 mm) that extended from the right upper pulmonary vein into the left atrium causing the partial obstruction of the right lower vein as indicated by the increased Doppler velocities. Contrast echocardiography confirmed the presence of microcirculation within the mass. During transesophageal (TEE) echocardiographic study, color Doppler imaging and power Doppler imaging (Angio((R)) Vivid 7, GE Medical System, Horten, Norway) demonstrated the presence of vascular flow within the mass. A chest magnetic resonance tomography showed a pulmonary mass of 30 x 25 x 28 mm infiltrating the pulmonary veins. After surgery, biopsy confirmed a high grade mucoepidermoid lung cancer with few large arterioles. The new echocardiographic techniques can reliably differentiate a cardiac tumor from a cardiac thrombus.