組織型の変化を生じ，V-P Shuntを介して腹腔内転移を来たしたGerminomaの1例

Extraneural Metastasis of Pineal Germinoma through a Ventriculoperitoneal Shunt, Following Histological Change

I．はじめに

　松果体腫瘍は水頭症を合併することが多く，通常最初にV-P shunt術などの短絡術が行われるのが一般的であった．そのためシャントチューブを経由した松果体腫瘍の神経管外転移が増加する傾向が見られている．

　今回われわれは松果体部germinomaが，シャントチューブを介して腹腔内転移を来たし，その際組織学的変化を生じたと思われる希な症例を経験したので若干の文献的考察を加え報告する．

Primary germinoma of the central nervous system carries a good prognosis because of their radiosensitiv-ity. Recurrence is rare and extraneural metastases are even more unusual.

We report a unique case of a primary intracranial germinoma exhibiting complete response to radiother-apy, but recurring as an intra-abdominal yolk sac tumor. The presence of a VP shunt is thought to havefacilitated metastatic spread of the intracranial neoplasm. An 18-year-old male was admitted with headacheand consciousness disturbance. Computed tomography (CT) revealed an enhanced tumor of the pineal re-gion and hydrocephalus. A ventriculo-peritoneal shunt was emplaced immediately. No serum tumor mar-kers such as alpha-fetoprotein or human chorionic gonadotropin were detectable. A test dose of radiotherapy (whole brain 20Gy) was given. The tumor size was remarkably decreased.Clinical diagnosis was germinoma. Additional whole brain radiation (total 45Gy) and whole spine radiation(20Gy) were given. The tumor and the hydrocephalus regressed completely and the patient returned toschool. Three years later, he experienced a feeling of abdominal fullness. CT and echotomography of theabdomen showed a large peritoneal and intra-hepatic tumor. But MRI revealed no recurrent tumor of thepineal lesion or of the other areas in the central nervous system. Radiological and clinical findings showedno tumors in the testis, the retroperitoneal cavity, or the thymus. Laboratory investigation demonstratedelevated serum AFP (26550ng/ml). AFP level regressed after combined chemotherapy. However, the pa-tient (lied due to pneumonia and multiple organ failure. Only needle necropsy was performed. The micro-scopic appearance of the peritoneal tumor was confirmed to be an endodermal sinus tumor. It was sus-pected to be a metastasis of the pineal tumor through the V-P shunt system.