Metachronous Germ Cell Tumors of the Mediastinum.

We report a rare case of mediastinal nonseminomatous germ cell tumor arising after 2 complete resections of mediastinal mature teratomas 18 and 10 years prior. After three cycles of chemotherapy for the mediastinal nonseminomatous germ cell tumor, the serum α-fetoprotein and β-human chorionic gonadotropin levels were normalized. However, chest radiography revealed that the mediastinal tumor had remarkably increased in size, and thus growing teratoma syndrome was diagnosed. The patient underwent urgent resection of the tumor, and a pathologic examination showed an encapsulated mature teratoma without any malignant viable cells. The patient was well without disease 54 months after the third operation.