[Rhabdomyosarcoma of the heart]

An observation of a clinically unidentified multicentric pleomorphic heart rhabdomyosarcoma in a 66 -- year-old man is described. The case has been verified on the basis of histological and electron-microscopic examination. By means of Heidenhein's and Mallory's histological methods there was found a cross striation in the cytoplasm of some sarcomatous cells. The electron-microscopic examination made it possible to relate the tumour to a poorly differentiated type. The peculiar feature of the observation is the lack of extracardial metastases as well as rapid development of cardiac decompensation.