Cytologic diagnosis of rhabdomyosarcoma in a patient with germ cell tumor. A case report.

The development of sarcomas in patients with germ cell tumors is rare but has been reported previously. Theories about its pathogenesis include derivation of the tumor cells from pluripotential germ cells and malignant transformation from teratomatous elements. This report describes the occurrence of rhabdomyosarcoma in a patient with a history of mixed germ cell tumor of the testis who developed a malignant pleural effusion. Cytologic evaluation of the fluid revealed single malignant cells with high nuclear/cytoplasmic ratios and prominent nucleoli. While these features initially suggested a diagnosis of metastatic seminoma, careful cytologic and immunohistochemical examination revealed features consistent with metastatic rhabdomyosarcoma. The exfoliative cytologic findings of other germ cell tumors are also discussed.