Rhabdomyosarcomas developing in association with mediastinal germ cell tumours.

Two mediastinal rhabdomyosarcomas that arose in association with germ cell tumours are reported. One presented as a small component of a mixed germ cell tumour with yolk sac and immature teratomatous elements. The other appeared as a large mass 4 months after diagnosis of a yolk sac carcinoma that had been treated with chemotherapy. The first patient was alive and free of disease 7 years later, whereas the second died of tumour 3 months post-operatively. The proportion of rhabdomyosarcoma within the germ cell tumours appears to have influenced the prognosis of these patients. This observation emphasizes the necessity of performing a thorough search for sarcomatous elements and quantifying their relative proportion in germ cell tumours of the mediastinum.