前立腺癌に関連した傍新生物網膜症（paraneo-plastic retinopathy）と考えられた1症例

Presumed paraneoplastic retinopathy in a case of prostate carcinoma

　76歳男性が右眼の視力低下と夜盲で受診した。矯正視力は右0.6，左1.0であり，右眼視野に感度低下，左眼に中心暗点があった。眼底は正常であり，蛍光造影で網膜血管の透過性亢進が両眼にあった。網膜電図では，a波は維持され，b波が欠如していた。9か月後に視力は右0.02，左0.2に低下し，両眼に中心暗点と輪状暗点が検出された。初診から11か月後に前立腺癌が発見された。局所浸潤のみで転移はなく，内分泌療法と放射線照射で軽快した。以後，矯正視力は左右とも0.1を保っている。血清からはウシ網膜に反応する抗体は検出されなかったが，臨床症状から前立腺癌に関連する抗双極細胞抗体による傍新生物網膜症（paraneoplastic retinopathy）と推定した。

A 76-year-old man presented with visual loss and night blindness in his right eye. His corrected visual acuity was 0.6 right and 1.0 left. Perimetry showed decreased sensitivity in the right eye and central scotoma in the left. Funduscopy showed normal findings. Fluorescein angiography showed hyperpermeability of retinal vessels in both eyes. Electroretinography showed normal a-wave and absent b-wave. The visual acuity decreased to 0.02 right and 0.2 left 9 months later. Both eyes showed central and ring scotomas. Prostate carcinoma was detected 11 months after his first visit. There was no metastasis. It was brought under control by hormone therapy and radiation. The visual acuity has stabilized at 0.1 in either eye. While no antibody against bovine retina was detected in the serum, we diagnosed the case with presumed paraneoplasic retinopathy secondary to prostate carcinoma mediated by a circulating antibody reactive to bipolar cells.