篩骨洞腫瘍に対する陽子線治療後に発症した放射線網膜症・放射線視神経症の1例

A case of radiation retinopathy and radiation optic neuropathy after proton therapy for an ethmoid sinus tumor

要約　目的：篩骨洞滑膜肉腫に対する陽子線治療後に放射線網膜症，放射線視神経症を発症した1例の報告。

症例：患者は50歳，女性。複視を主訴に近医眼科を受診，左副鼻腔内腫瘍を疑い耳鼻咽喉科を紹介され受診した。左篩骨洞腫瘍摘出術を施行し，病理診断にて滑膜肉腫と診断された。化学療法および70.4Gyの陽子線照射後2か月が経過した頃から左眼の流涙と充血が出現したため，当科を受診した。左涙道閉塞と診断し左涙囊鼻腔吻合術を施行し，その後定期的に経過観察を行っていた。照射後2年4か月で左視力低下が出現，精査の結果，放射線網膜症，放射線視神経症と診断した。左放射線網膜症に対し汎網膜光凝固術および硝子体手術を施行した。陽子線照射後7年が経過した現在，左眼視力は0.03（矯正不能）で安定しており，眼圧上昇はない。

結論：放射線網膜症や放射線視神経症を早期に診断し治療することで，視機能を温存することができる可能性が示唆された。

Abstract　Purpose：To report a case of radiation retinopathy and radiation optic neuropathy that developed after proton beam therapy for a synovial sarcoma of the ethmoid sinus.

Case：A 50-year-old woman visited her local ophthalmologist with a complaint of diplopia；she was referred to an otolaryngologist because of a suspected tumor in the left paranasal sinus. She underwent left ethmoid sinus tumor removal, and the tumor was diagnosed as a synovial sarcoma on postoperative pathological examination. Two months after chemotherapy and 70.4 Gy proton beam irradiation, epiphora and hyperemia appeared in the left eye, and she came to our department of ophthalmology. We diagnosed her with left lacrimal duct obstruction and performed dacryocystorhinostomy. Two years and four months after the irradiation, she noted a decrease in vision in her left eye. We diagnosed her with radiation retinopathy and radiation optic neuropathy, and we performed pan-retinal photocoagulation and vitrectomy. Currently, her visual acuity is preserved at 0.03（n.c.）in the left eye, and there has been no increase in the intraocular pressure.

Conclusion：Early diagnosis and treatment of radiation retinopathy may help to preserve visual function.