失神発作で発症した第2頸神経神経鞘腫の1例

A Case of C2 Neurinoma Suffering Syncopal Episodes

I．はじめに

　椎骨動脈を外側から絞扼して椎骨脳底動脈循環不全をきたす疾患には，椎体骨蕀，頭蓋—上位頸椎奇形，リウマチ性関節炎，外傷，fibrous bandなどが知られており^7）．また環椎軸椎関節部の運動の特異性に由来するいわゆるbow hunter's strokeも近年関心を集めている^{5,8，10-14）}．しかしながら椎骨脳底動脈循環不全症状で発症する椎骨動脈近傍腫瘍は著しく少ない^2,3,6,7,9）．

　今回われわれは頭部回旋運動時に椎骨動脈が閉塞し，これにより椎骨脳底動脈循環不全症状で発症した第2頸神経神経鞘腫の症例を経験した．術前の血行動態や術中のドプラー血流測定の有用性など興味深い症例であったので報告する．

Abstract

A 32-year-old male had a 4-year history of episodes of loss of consciousness. These episodes occurred several seconds after he would turn his head 60 degrees to the left, and had increased in frequency at the time previous to the operation he underwent. MRI revealed a round mass on the right side between the atlas and the axis. (Fig. 1) . Cerebral angiography demonstrated that the right vertebral artery (VA) was occluded at the transverse foramen of the axis with the head ro-tated toward the left (Fig. 2, 3). Intensity of the T1-weighted image of the tumor in the sphenoid ridge was homogenously iso intensity, and low intensity in the pituitary fossa.

The diagnosis of adjacent tumors in the sphenoid ridge meningioma and pituitary adenoma had been made preoperatively. Left front-temporal craniotomy and removal of these tumors were performed. These tumors were close to each other, but were separated by the internal carotid artery and anterior cerebral artery. Pathological examination demonstrated meningothe-liomatous meningioma in the sphenoid ridge and sparsely granulated somatotroph adenoma in the pituit-ary fossa.

Fourteen cases showing association of meningioma and pituitary adenoma, which had no history of radia-tion and trauma, have been reported previously. Although Gil producing pituitary adenoma may stimu-late adjacent Jura and arachnoid cells resulting in the formation of meningioma, the possibility of coincidental occurrence of the two tumors cannot be ignored.