頸静脈孔神経鞘腫の1例：95例の文献的考察

A case of jugular foramen neurinoma originating from glossopharyngeal nerve

I．はじめに

　頸静脈孔部に発生する頸静脈孔神経鞘腫（jugular foramen neurinoma；以下JFN）は比較的稀であり，Tanら^14）によると頭蓋内神経鞘腫のうち2.9％に過ぎないとされている．この腫瘍は難聴を主訴とすることが多いという点で，聴神経腫瘍との鑑別上重要であるが，最近はCT，MRIにより比較的容易に診断が可能となった．今回われわれは，三次元CT画像，MRIを含む神経放射線学的検査により術前に頸静脈孔部腫瘍と診断し，術中所見により舌咽神経由来と考えられたJFN症例を経験したので，過去の報告例と自験例を含めた95例につき文献的考察を加え，報告する．

A 39-year-old man was admitted with right hearing loss, tinnitus and vertigo. Neurological examination on admission revealed right facial palsy, right acoustic nerve disturbance and cerebellar ataxia. CT scan de-monstrated a mass with intra-and extracranial extension in the pyramid bone concomitant with enlarged jugular foramen. MRI showed a ring-like enhanced, extra-axial mass in the right. CP angle. Cerebral angiography showed no tumor stain. Venous phase of VAG revealed lateral displacement of the right sigmoidal sinus and obstruction of the internal jugular vein. Three dimen-sional CT was very useful to reveal enlarged jugular foramen.

The tumor was resected totally and was approached through a right suboccipital craniectomy and mas-toidectomy on July, 1994. Surgery confirmed that the tumor was a neurinoma originating from the glos-sopharyngeal nerve. After the operation, right facial palsy developed and transient fugitive CSF leakage was observed, but the patient is doing well. There was no amelioration of right hearing loss.

JFN originating from the glossopharyngeal nerve is rare. Twenty-five cases of glossopharyngeal neurinoma are reviewed.