Co-existing left atrial thrombus and myxoma in mitral stenosis--a diagnostic challenge.

We report an unusual case of an adult who underwent a mitral valve replacement with concomitant excision of the left atrial myxoma and thrombus. Echocardiography showed the presence of a large "thrombus" within the left atrial appendage, body and atrial septum. There was difficulty in trying to distinguish between the atrial thrombus and myxoma due to their morphological similarities. At time of surgery, frozen section confirmed the atrial septal component of the thrombus to be an atrial myxoma and the atrial septum was excised to obtain a clear margin.