[Cardiac glomus tumor. Light- and electron microscopic investigations (author's transl)].

A cardiac glomus tumor, first described by Masson, was observed in a 28 year old woman who presented symptoms of cardiac dysfunction. Electron microscopic studies disclose a wide range of differentiation of glomus cells from smooth muscle cells to epitheloid cells. The common feature of both cell types include cytoplasmic microfibrils, fusiform condensations and small vesicles. The endothelial cells also show some structural similarities to these glomus cells. The histogenesis of this cardiac tumor is discussed on the basis of its ultrastructure and its uncommon localization. It is concluded that cardiac glomus tumors arise from primitive mesenchymal cells.