Coincidence of seminoma and sarcoidosis: a myth or fact?

A patient with a stage II seminoma of the testis was treated with a routine orchidectomy and irradiation. One and a half years later enlarged mediastinal lymph nodes were noted. Additional staging showed no other abnormalities and a mediastinoscopy was performed. The initial histologic examination confirmed the clinically suspected diagnosis of sarcoidosis. However, additional immunohistochemical analysis unexpectedly demonstrated that there was also a microscopic relapse of the testis tumor. The literature concerning the co-incidence of non-caseating granulomas and testis tumors is reviewed. It is not clear, whether the granulomas indicate the presence of genuine idiopathic sarcoidosis or whether they reflect a sarcoid-like reaction against tumor antigens. The immunopathogenesis of sarcoid formation and its possible biologic significance in obtaining a spontaneous tumor remission is discussed.