環椎骨巨細胞腫の1手術例

A Case of Giant Cell Tumor in Atlas

Ⅰ．はじめに

　原発性骨腫瘍のうち骨巨細胞腫の発生頻度は全体の約5％程度を占め，その大部分は長管骨骨端部，特に大腿骨遠位部に多く，脊椎に発生する頻度は低い（7～13％）^3,5,7)．そのうち，環椎原発骨巨細胞腫はわれわれが渉猟し得た限りでは4例の報告があるのみで，極めて稀である^2,8,10)．

　今回，われわれは環椎原発骨巨細胞腫の1手術例を経験したので，臨床所見および治療に関して報告する．

We report a rare case of giant cell tumor in the atlas. A 50-year-old female presented with severe pain in her right neck and shoulder. The preoperative magnetic resonance images showed a tumor mixed with solid and cystic components in the right side of the atlas. CT scan showed that the anterior and posterior arches of the atlas were destroyed. Preoperative biopsy led to the pathological diagnosis of giant cell tumor with multinuclear giant cells and mononuclear stromal cells. A preoperative vertebral angiogram demonstrated tumor stain supplied from the muscular branches. To reduce intraoperative bleeding,the embolization of the right vertebral artery by GDC was performed before surgical removal. The tumor was subtotally removed following ligation of the right external carotid artery to reduce bleeding of tumor. We used the Olerud cervical system to prevent cervical instability after resection of the tumor. Although the symptoms disappeared completely after surgery,regrowth of tumor was observed in follow-up MRI 4 months after the operation. For this reason,local radiation therapy was performed (50Gy). Then,the size of the tumor has not changed in the 1.5 years since the operation.