TESE CFM MIXOMA.pdfCardiac Myxoma; histopathology; literature review, clinical aspects

Cardiac Myxoma StudyThe aims of this study are to obtain new data for the characterization of the cell types in the cardiac myxoma (CM), as well as to obtain more insight into its histogenesis, cellular differentiation and ways of growth.<br><br>The authors have studied 13 CMs found among 12 patients, during 10 years; 9 were surgical specimens while<br>four were obtained at necropsy room. The material was submitted to a multiple approach: conventional microscopy<br>(including histochemistry), transmission electron microscopy, high resolution optic microscopy, and immunohistochemistry with correlation of results.<br><br>Frequency: 0,12%, among surgical specimens, 0,0574%, among the necropsies and 65,0%, among the primary cardiac benign neoplasms. Nine were female and three male; average 45,2 years old; median of 46 years. Clinical presentation was: obstruction in 66,7%, systemic involvement in 8, 3%, embolic form (8,3%) manifested as myocardial infarct. In 16,7% there were no symptoms.<br><br>The case distribution according with age, s8€x, race were similar to previous publications. All of them were<br>intra-cavitary tumors; two gross types of CMs were found:Nodular (7 CMs), Papillary (5 CMs) and one Mixed type. The Ns forms were larger than Ps, with M in intermediary position. There were no gross evidences favoring thrombotic origin. Two basic cells were found: stellate and polygonal cells, which due to both indifferentiated look and large number seemed to represent the precursor cells of CM. We were able to observe morphological and immunohistochemical differentiation towards the following cell types: 1) cells still indifferentiated but with certain features of fibroblasts, 2) endothelial cells, 3) smooth muscle cells and 4) epithelial cells; the latter in two cases (15,4%). The differentiation was irregular inside each MC and from MC to MC. The cells were disposed alone or more frequently in groups, usually forming bizarre blood vessels and less commonly gland-like structures or true glands.<br><br>One case recurred 12 months after the operation, there were no symptoms; diagnosis was by routine ecocardiogram. Only one case showed malignant behaviour, with infiltrative metastases found in many organs. The<br>malignant potential was graded as low, since tumor cells were found just around the arteries without destruction of<br>the organs. The CM grows through 4 ways probably acting concomitantly: 1) celular proliferation, taking place at<br>superficial germinative foci, followed by both migration ("centripetal migration") towards inner regions of the CM,<br>and differentiation towards the cells inside the OM, 2) endogenous matrix production composed of — acid<br>mucopolysaccharide, by the neoplastic cells, 3) bleeding from the neoplastic vessels, and 4) thrombosis on the CM surface.<br><br>We conclude that CM is a true neoplasm originated from indifferentiated multipotential mesenchymal cells of<br>the subendocardium; there were no microscopical evidences favoring thrombotic origin.. The glands possibly have the same origin, as transitions with other cells groups were observed; besides this we observed positivity for<br>citokeratins in single cells of one glandular CM, and we found in many cases, groups of cells forming structures<br>similar to glands, but not conclusive for them. We suggest that the amall CMs are papillary and, as they get larger,<br>they become nodular due to inter-papillary thrombosis and contact with atrial walls.<br>