Malignant transformation of testicular teratoma to primitive neuroectodermal tumor.

Teratoma is a common germ cell tumor that affects young adult males. A small number of testicular teratomas have the potential for malignant transformation along endodermal, ectodermal, or mesodermal lines. The metastatic mixed germ cell tumor we reported consists of the primitive neuroectodermal tumor (PNET) with mature teratoma. PNET is a highly aggressive tumor with a poor prognosis given its poor response to standard platinum-based chemotherapy. The primary treatment for PNET is surgical resection. Malignant transformation of teratoma to PNET is a rare phenomenon. Only a few cases of malignant transformation of teratomas to PNET are reported in the literature. Here, we present a rare case of PNET arising in a malignant mixed germ cell tumor in a 23-year-old male who underwent adjuvant adriamycin, cyclophosphamide (VAC) alternating with ifosfamide and etoposide (IE) chemotherapy and retroperitoneal lymph node dissection.