前立腺癌の転移による眼窩先端部症候群の1例

A case of orbital apex syndrome due to metastasis of prostate carcinoma

要約　目的：前立腺癌の転移で眼窩先端部症候群が生じた症例の報告。症例：48歳男性が6週前からの左眼視力低下で受診した。矯正視力は右1.2，左0.01であり，眼底に異常はなかった。左眼上方を除き視野が欠損していた。経過：球後視神経炎の疑いで副腎皮質ステロイド薬の全身投与を行った。6日後に左眼視力は零になり，左眼の内転不全麻痺と左前額部の知覚低下が生じた。磁気共鳴画像検査（MRI）で左眼窩先端部に径2cmの腫瘤が発見された。全身検査で骨転移を伴う前立腺癌が発見された。保存的治療を行い，10か月後に眼窩腫瘤は消失したが視力は回復しなかった。結論：球後視神経炎が疑われても，悪性腫瘍などの全身疾患が関与していることがある。

Abstract.　Purpose：To report a case of orbital apex syndrome due to metastasis of prostate carcinoma. Case：A 48-year-old male presented with impaired vision in the left eye since 6 weeks before. His corrected visual acuity was 1.2 right and 0.01 left. Funduscopic findings were inconspicuous. The visual field in the left eye was defective except the superior periphery. Clinical Course：He was tentatively diagnosed with retrobulbar neuritis. Six days after systemic corticosteroid, his left visual acuity lost light perception associated with paralysis of adduction and hypesthesia in the left forehead. Magnetic resonance imaging（MRI）showed a tumor of 2cm in diameter in the left orbital apex. Systemic studies led to detection of postate cancer with systemic bone metastasis. The orbital tumor disappeared after 10 months of hormonal and chemotherapy. The left eye failed to recover from visual loss. Conclusion：Extraocular malignancy may induce findings simulating retrobulbar optic neuritis.