The development of a somatic-type malignancy (SM) in a testicular germ cell tumor (TGCT) is an exceptional abnormality, challenging the diagnosis and management of testicular malignancy. The majority of these somatic-type malignancies originate from a teratoma and the remaining from the yolk sac tumor and are seen more commonly in the metastases than in the primary testicular tumors. Sarcoma, carcinoma, embryonic-type neuroectodermal tumor, nephroblastoma-like tumor and hematologic malignancy are the different histologic types of somatic-type malignancies derived from TGCTs. Sarcoma (especially rhabdomyosarcoma) is the commonest somatic-type malignancy in the primary testicular tumors, whereas carcinoma (especially adenocarcinoma), is the commonest in the metastases. Somatic-type malignancies usually develop in the metastasis after a long time interval from the initial diagnosis and this time interval is significantly longer in the carcinomatous SM than that for the sarcomatous SM. Somatic-type malignancies in metastases are associated with a worse outcome, though in primary testicular tumors, they may not affect the prognosis. Carcinomatous somatic-type malignancy is likely associated with a worse prognosis than somatic-type sarcoma. For most patients, prompt complete surgical resection of the SM is an effective treatment option as it generally does not respond well to cisplatin-based chemotherapy for conventional germ cell tumors ¹.