Left atrial myxoma with atypical localization

A 37-year-old man presented with complaints of palpitation and fatigue. Physical examination and laboratory findings were normal except for moderately elevated erythrocyte sedimentation rate (52 mm/hr). Transthoracic echocardiography revealed an extremely mobile mass in the left atrium, 6.5 x 1.5 cm in size, with a fragmented distal portion. It arose from the superior part of the interatrial septum and, in each cardiac cycle, was moving into the left ventricle through the mitral valve. Transesophageal echocardiography showed that the mass was attached with a thin pedicle to the posterosuperior part of the interatrial septum, close to the right upper pulmonary vein. The mass was surgically excised and histopathologic diagnosis was myxoma.