Location, location, location: a left atrial mass.

A 58-year-old man admitted to the hospital with an acute stroke was found to have a left atrial mass attached to the interatrial septum via a stalk. Although initially thought to be a myxoma, the mass was pathologically proved to be a thrombus. Clues pointing to thrombus as the etiology were a history of atrial fibrillation, the absence of anticoagulation, an enlarged left atrium, and the presence of spontaneous echo contrast.