視神経乳頭腫脹を契機として発見された肺腺癌の1例

Optic disc swelling as the initial manifestation in a case of lung adenocarcinoma

要約　目的：片眼の視野障害を初発症状とした肺腺癌の視神経乳頭への転移例の報告。症例：54歳男性が3か月前からの左眼視野異常を主訴として受診した。所見：矯正視力は右1.2，左1.0で，左眼に乳頭腫脹と上方の水平半盲様の視野欠損があった。造影MRI検査で頭蓋内に異常はなかった。ステロイドパルス療法で乳頭腫脹と視野に変化がなかった。悪性腫瘍の転移を疑い，全身検索を行ったところ，上皮成長因子受容体遺伝子変異を伴った肺腺癌が判明した。分子標的薬のゲフィチニブ（イレッサ^®）の全身投与で原発巣と乳頭腫脹は速やかに縮小した。結論：本症例は，片眼の視野障害を初発症状とした肺腺癌の視神経乳頭への転移例であった。分子標的薬は視神経乳頭転移にも奏効した。

Abstract.　Purpose：To report a case of lung adenocarcinoma metastatic to the optic disc with unilateral visual field defect as the initial manifestation. Case：A 54-year-old male presented with visual field defect in the left eye since, 3 months before. Findings：Best corrected visual acuity was 1.2 right and 1.0 left. The left eye showed swelling of the optic disc and upper horizontal hemianopia. No intracranial lesion was detected by contrast-enhanced magnetic resonance imaging. Corticosteroid pulse therapy showed no change in the fundus or visual field. Systemic examinations led to the detection of bilateral lung tumor and to the diagnosis of lung adenocarcinoma with gene mutation in the epidermal growth factor receptor. Systemic treatment with gefitinib（Iressa^®）was followed by prompt reduction of lung tumor and swelling of optic disc. Conclusion：The present case showed unilateral visual field defect due to metastasis of lung carcinoma to the optic disc. Treatment with molecular target-based drug was effective to the metastatized lesion.