視神経周囲に腫瘍と骨欠損を認めた神経線維腫症1型の2例

Two cases of neurofibromatosis type 1 with bone defect and tumor around the optic nerve

要約　目的：視神経に及ぶ頭蓋内腫瘍が発見された神経線維腫症1型の2症例の報告。症例と経過：1例は65歳男性，他の1例は43歳女性で，2症例とも神経線維腫症1型に特徴的な皮膚所見と虹彩のLisch結節があった。1例は白内障手術の2か月後に左眼視力が1.0から0.7に低下し，右眼視野に輪状欠損が生じた。磁気共鳴画像検査（MRI）で左蝶形骨に径4cmの腫瘍が発見された。他の1例には学童期に脳手術の既往があり，左眼視力が0.7に低下していた。MRIで左蝶形骨に沿って視神経を上部から圧排する軟部陰影が発見された。それぞれ診断から11か月と6か月間，視力と視野は悪化せず，腫瘍の増大もない。結論：神経線維腫症1型では，頭蓋内病変が眼症状として成人に発症することがある。皮膚または虹彩の所見から本症が疑われるときには，眼科医が果たす役割が大きい。

Abstract.　Purpose：To report 2 cases of neurofibromatosis type 1 who manifested intracranial tumor involving the optic nerve. Cases and Findings：One was a 65-year-old male and the other a 43-year-old female. Both showed typical skin manifestations of neurofibromatosis type 1. Lisch nodules were present in both cases. Visual acuity in the left eye decreased from 1.0 to 0.7 two months after cataract surgery in one case. Ring scotoma was present in the right visual field. Magnetic resonance imaging（MRI）showed a tumor of 4 cm in size in the left sphenoidal bone. The other case had received neurosurgery during childhood. Visual acuity had decreased to 0.7 recently. MRI showed a mass of soft tissue along the left sphenoidal bone compressing the optic nerve from above. Both cases are doing for 11 and 6 months after diagnosis with no exacerbation in visual acuity,visual field,or MRI findings. Conclusion：These cases illustrate that ocular symptoms may be the first manifestation of intracranial involvement by neurofibromatosis type 1 in adults.