海綿静脈洞髄膜腫のガンマナイフ治療

Radiosurgery of cavernous sinus meningiomas with gamma-knife

I．はじめに

　海綿静脈洞に発生する腫瘍群の中には，髄膜腫，三叉神経鞘腫，脊索腫，下垂体腺腫，転移性腫瘍などがあげられる．これらの中で髄膜腫はもっともよくみられる良性腫瘍である．髄膜腫の治療は，本来手術的摘出が基本ではあるが，海綿静脈洞では出血のコントロール，洞内脳神経群の剥離，温存の他，髄膜腫ではしばしば内頸動脈に浸潤し，狭窄を生ずることから，その処理が問題となる．このため十分なmonitoringを用いたmicro—surgeryでもその全摘出は容易ではなく，手術合併症も少くない^7,16）．また術後の再発も，頭蓋底部髄膜腫に共通する問題である^4,14）．ガンマナイフあるいはライナックを用いたradiosurgeryはAVMなどの脳血管奇形のみでなく，聴神経腫瘍，髄膜腫などの良性腫瘍に対しても有用とする報告が多い．今回，ガンマナイフによる海綿静脈洞髄膜腫の治病成績を報告し，腫瘍の発育コントロール，治療後の神経症状の推移について検討した．

The treatment results of cavernous sinus meningioma with gamma-radiosurgery are reported. There were 18 cases of cavernous sinus meningioma, including 2 males and 16 females, whose age ranged from 39 to 63 with an average of 51.0 years. As prior treatments, operative tumor resection or biopsy had been carried out in 14 cases, and the pathology was verified. The other 4 cases were diagnosed clinically with radiological stu-dies. The mean tumor diameter was 28.3mm (17.7-35.0) during the radiosurgery. The maximum dose ranged from 22 to 36Gy (mean 28.0Gy), with the mar-ginal tumor dose ranging from 11 to 18Gy (mean 13.9Gy). Irradiation to the near-by optic nerves was less than 10Gy. Follow-up period ranged from 12 to 50 months with a mean of 25.5 months. MRI showed a minor tumor shrinkage in 9 (50.0%) and no obvious change in 8 (44.4%), and tumor progression in 1 (5.6%), which required a 2nd radiosurgery. Neurologi-cally facial pain and facial dysesthesia were well im-proved (7/13). However the ophthalmoparesis was usually unchanged and only 1 out of 11 (9.1%) im-proved after radiosurgery. Deterioration of neurological signs was rare. Symptomatic edema presenting neurolo-gical signs was not seen.

In conclusion, radiosurgery with a gamma-knife is one of the useful alternatives to operative intervention in the treatment of cavernous sinus meningiomas, not only for tumor control, but also for relief from the symptoms.