[Anatomopathological and immunohistochemical findings in 6 cardiac myxomas].

Heart myxoma is the most common cardiac neoplasm in adult, even if its biologic profile remains uncertain. The clinicopathologic features of 6 cardiac myxomas in patients ranging in age from 42 to 58 years are described: 5 cases were located in atria, 1 occurred in the right ventricular wall, attached by a thin pedicle to the wall next to the pulmonary artery. Grossly myxomas are generally pedunculated and average 2 to 8 cm in diameter. They appear gelatinous and polypoid, sometimes with areas of hemorrhage. Microscopic examination of specimens of myxomas removed at operation reveals the myxomatous nature of the stroma composed of abundant mucopolysaccharidic matrix, containing stellate or polyhedral cells, singly or in small clusters, and occasional blood vessels. In other cases, the matrix stains more deeply and reticulin fibers and occasional strands of collagen are evident. Immunohistochemical study reveals tumoral positivity for smooth muscle actin cells and for vimentin. In addition, endothelial cells in intramyxomatous vascular channels are positive for factor VIII and CD-34 endothelial markers. Myxomas were diagnosed in patients in whom the symptoms and signs of cardiac tumor may have been attributed to other causes. The clinical pictures produced by cardiac myxomas include non specific manifestations and mechanical interference with cardiac function. The symptoms may simulate a wide variety of other cardiac conditions (mitral valve disease, embolic phemomena, tricuspid valve disease, sudden unexpected death). A wide local excision is needed to assure that the myxoma does not recur.