[Synovial sarcoma of the pericardium].

A precordial tumor of the pericardium was radiologically diagnosed as the cause of an untypical clinical picture of heart disease in a 41-year-old soldier. As the patient had an increased asbestos exposure due to his profession, he was admitted to operation under the tentative diagnosis of a pericardial mesothelioma and the question of an occupational disease (BK 4105). Microscopic and immunohistochemical findings are compatible with the diagnosis of a synovial sarcoma of the pericardium. The present immunohistochemical marker spectrum allowed a reliable differentiation between synovial sarcoma and pericardial mesothelioma, which is more frequent than synovial sarcoma. The epithelioid component was determined using the following antibodies: MNF 116, CK 19, CK 7, EMA and Ber EP-4 were positive while Factor VIII, Calretinin, S100, Vimentin, CEA, CD 31, bcl-2 and HBA-71 were negative. The sarcomatous component was determined with antibodies to Vimentin, bcl-2 and HBA-71 which were positive, and to MNF 116, CK 19, CK 7, Factor VIII, Calretinin, S100, EMA, CEA, Ber EP-4 and CD 31 which were negative. Synovial sarcomas of the pericardium in the lower anterior mediastinum or the myocardium are exceedingly rare. A causal relationship between tumor formation and an increased asbestos exposure--similar to the epidemiologically based experiences with pericardial mesothelioma--is not likely. Primary extrapericardial synovial sarcoma could be excluded.