蝶形骨洞部腺様囊胞癌に対する重粒子線治療により放射線網膜症を発症した1例

A case of radiation retinopathy after carbon ion radiotherapy for adenoid cystic carcinoma in the sphenoid sinus

要約　目的：蝶形骨洞部腺様囊胞癌に対する重粒子線治療後に放射線網膜症を発症した症例の報告。

症例：26歳女性。右蝶形骨洞から海綿静脈洞に及ぶ腺様囊胞癌に対して総量57.6GyE（16回）の重粒子線照射を受けた。19か月後，右眼視力低下を訴え当科を受診。矯正視力は右0.8，左1.2，右眼底に点状出血と軟性白斑があった。蛍光眼底造影で右眼に無灌流域，後極に血管外漏出があり，放射線網膜症と診断した。32か月後より右眼白内障が進行し，白内障手術を行った。42か月後，蛍光眼底造影で右眼網膜新生血管が出現し，網膜光凝固を行った。以後5年間の経過は良好で腫瘍の再発はない。

結論：蝶形骨洞部腺様囊胞癌への重粒子線治療により放射線網膜症が発症することがある。

Abstract　Purpose: To report a case of radiation retinopathy after carbon ion radiotherapy for adenoid cystic carcinoma in the sphenoid sinus.

Case: A 26-year-old female was referred to us for impaired visual acuity in the right eye. She had received carbon ion radiotherapy for adenoid cystic carcinoma in the right sphenoid sinus extending to the right cavernous sinus 19 months before. The dosis of radiation totaled 57.6 GyE.

Findings: Corrected visual acuity was 0.8 right and 1.2 left. The right fundus showed a few retinal hemorrhages and cotton-wool spots. Fluorescein angiography showed dry leakage from retinal vessels. Retinal nonperfusion was also present, leading the diagnosis of radiation retinopathy. The right eye developed cataract 32 months later followed by cataract surgery. Retinal neovasucularization developed another 10 months later and was treated by photocoagulation. There has been no recurrence of carcinoma in the sphenoid sinus for 97 months with right visual acuity maintained at 1.0.

Conclusion: The present case illustrates that radiation retinopathy may develop years after carbon ion radiotherapy for adenoid cystic carcinoma in the sphenoid sinus.