[Myxoma of the heart: aspects of its histogenesis].

15 cases of heart myxomas are presented. Their origin from remains of embryonal mesenchymal tissue is hypothesized. Predominant localization at the foramen ovale area, where remains of embryonal tissue can be found, and peculiarities of histological structure resembling embryonal mesenchyma may be proofs of the hypothesis. Microscopic structure of myxomas is homogeneous: branching cells of histiocytic origin amidst basophilic or eosinophilic stroma presented by myxoid tissue, capillaries and vessels of various gauges at different stages of functional activity (shut-down, compressed, dilated, filled with erythrocytes).