Cardiac myxomas correlative study by light, transmission, and scanning electron microscopy.

A correlative morphologic study of 17 cardiac myxomas surgically excised or observed at autopsy was performed by light (LM), transmission (TEM), and scanning electron microscopy (SEM). Tumor cells occurred singly (frequently in lacunae), in cords, as vascular-like aggregates, and in complex interdigitating clusters. By TEM, myxoma cells were predominantly undifferentiated mesenchymal cells. The surface topography by SEM revealed numerous clefts and crevices and a continuous cellular lining which, by TEM, appeared to be derived from underlying myxoma cells. The myxoid stroma by SEM was interspersed by numerous reticular fibers that appeared as a sponge-like supportive framework. Complex patterns of interdigitating myxoma cells corresponded well with similar patterns by LM and TEM, demonstrating the advantage of SEM in correlative morphologic studies.