副神経鞘腫の1例

Accessory Nerve Schwannoma of the Intracisternal Type: A Case Report

Ⅰ．は じ め に

　頭蓋内神経鞘腫は原発性脳腫瘍の約8％を占める^21）．その多くは感覚神経である前庭神経に生じ，運動神経に発生することは少ない．さらに運動神経を発生起源とする神経鞘腫の中でも副神経鞘腫は稀である．今回われわれは，cerebellomedullary cisternに病変を有する副神経鞘腫の1例を経験したため，過去の文献を渉猟しその臨床的な特徴について報告する．

　Accessory nerve schwannomas are extremely rare and they are classified into three types according to their locations; intrajugular, intracisternal and spinal canal type. We report a case of intracisternal schwannoma that arose from the spinal accessory nerve roots and we describe it's clinical characteristics.

　A-48-year-old female was admitted to our hospital with a complaint of left occipital pain. Magnetic resonance imaging (MRI) showed a well-defined mass 2.5×1.5 cm in the left cerbellomedullary cistern. It was enhanced heterogeneously with gadolinium. Cerebral angiography showed a mildly hypervascular lesion. Total removal of the tumor was performed by the left lateral suboccipital approach and the histological diagnosis was schwannoma.