PRIMITIVE NEUROECTODERMAL TUMOR OF THE MYOCARDIUM - A CASE-REPORT, REVIEW OF THE LITERATURE, IMMUNOHISTOCHEMICAL, AND ULTRASTRUCTURAL-STUDY

We report the case of a primitive neuroectodermal tumor (PNET) arising in the heart of a 63-year-old man. The neuroectodermal nature of this tumor was confirmed by the immunohistochemical positivity for O13 (CD 99) (the P30/32(MIC2) gene product) neuron specific enolase (monoclona l and polyclonal), synaptophysin and vimentin. Other markers, such as actin, desmin, myoglobin, chromogranin, keratin, and leukocyte common antigen were negative. The diagnosis was made on an endomyocardial bio psy and was confirmed in sections from the myocardial tumor found with in the heart excised during cardiac transplant. Primitive neuroectoder mal tumors have been reported in a variety of sites, most commonly in the extremities. No case has ever been reported within the myocardium, although one has been reported in the pericardium. In addition to mor phological similarities, PNET and extraskeletal Ewing's sarcoma have b een shown to possess the same chromosomal translocation, t11;22, and t he same cell surface antigen, P 30/32. Separation of this case from ex traskeletal Ewing's sarcoma was possible because of the absence of PAS positivity, as well as the immunohistochemical positivity for at leas t two neural markers, as extraskeletal Ewing's sarcoma is only positiv e for neuron specific enolase. Copyright (C) 1996 by W.B. Saunders Com pany