眼球摘出に至った中型の脈絡膜悪性黒色腫の1例

A case of medium-sized choroidal malignant melanoma treated by enucleation

要約　目的：眼球摘出に至った脈絡膜悪性黒色腫の症例の報告。症例と経過：59歳女性が2か月前からの左眼視力低下で受診した。矯正視力は右1.2，左指数弁であった。左眼の乳頭上方から耳側に灰白色で一部が黒色の隆起性病変があり，黄斑部には薄い網膜剝離があった。磁気共鳴画像検査（MRI）ではT1強調画像で高信号，T2で低信号の長径10mm，高さ6mmの腫瘤があった。超音波検査と蛍光眼底造影所見からも中型の悪性黒色腫が疑われた。腫瘍マーカーを含む全身検査では他臓器からの転移性腫瘍，または脈絡膜黒色腫から他臓器への遠隔転移を示す所見はなかった。小線源療法を検討したが，腫瘍が乳頭に近接しているので放射線視神経症の可能性があり，眼球摘出を行った。組織学的にmixed cell typeの悪性黒色腫と診断され，腫瘍細胞の周囲組織への浸潤はなかった。結論：中型の脈絡膜黒色腫は治療法の選択が困難であるが，本症例では上記の理由から眼球摘出を選んだ。

Abstract.　Purpose：To report a case of choroidal malignant melanoma treated by enucleation. Case and Findings：A 59-year-old woman presented with impaired vision in her left eye since 2 months before. Her corected visual acuity was 1.2 right and hand motion left. The left fundus showed a gray and partially black elevated lesion superior and nasal to the optic disc. Flat retinal detachment was present in the macular area. Magnetic resonance imaging（MRI）showed a tumor of 6mm in height and 10mm across. It showed high intensity by T1-weighted image and low intensity by T2-weighted image. Findings by echographe and fluorescein angiography were also suggestive of malignant melanoma. Systemic examinations ruled out metastasis of malignant tumor to or from the choroid. The left eye was enucleated as radiotherapy was contraindicated because of vicinity of the tumor to the optic disc. The tumor was diagnosed with mixed cell type malignant melanoma. There was no infiltration of tumor cells to adjacent tissues. Conclusion：Choice for treatment is still controversial for middle-sized choroidal malignant melanoma. We opted for enucleation because of above reasons.