Scanning electron microscopy of intracardiac myxoma.

Scanning electron microscopy was utilized to study the surface morphology of intracardiac myxomas and to compare it with that of an atrial thrombus. The thrombus was only partially endothelialized, whereas myxomas were almost always completely covered by endothelial cells. Endothelium-lined crevices and clefts were a striking feature of the myxoma, and they were not seen in the atrial thrombus. In areas where the surface endothelium was denuded, fibrin and platelet aggregates were noted in both the myxoma and the thrombus.