Testicular germ cell tumors may have multiple histologic subtypes. Teratoma components are capable of transformation into somatic malignancies. An alternative hypothesis for the development of angiosarcoma in a patient with germ cell tumors is secondary to radiation or chemotherapy. We report a patient with a mixed testicular germ cell tumor who presented with retroperitoneal, mediastinal, and pulmonary metastases after chemotherapy. Forty months after his original diagnosis, a mediastinal angiosarcoma...