Hematogenous extraneural metastasis of the germinomatous component of a pineal mixed germ cell tumor

A 23-year-old man presented with a mass in the pineal region and obstructive hydrocephalus. A neuroendoscopic biopsy for the lesion, ventriculoperitoneal (VP) shunting, and focal irradiation were conducted as initial treatment. Histological diagnosis of the biopsy specimen was germinoma. He underwent further irradiation and two tumor resections. Histological diagnosis was mature teratoma without a germinomatous component. After serial treatments, the intracranial lesion was controlled. However, 14 months after presentation, extraneural lesions were confirmed in the posterior mediastinum and retroperitoneal space. The biopsy specimen of the retroperitoneal space lesion was histologically diagnosed as germinoma. Although chemotherapy with cisplatin and etoposide was undertaken, extraneural lesions ware uncontrollable and he died. At autopsy, extraneural lesions were confirmed in the posterior mediastinum, retroperitoneal space, and right lung. Histological diagnosis of extraneural lesions was germinoma. This case was considered to be a pineal mixed germ cell tumor mainly consisting of germinoma and mature teratoma, which caused hematogenous metastasis of the germinoma component. Systemic chemotherapy and irradiation for primary lesions as an initial treatment is important to cure the primary lesion and prevent extraneural metastasis.