乳癌治療薬タモキシフェン内服後に発症し自然閉鎖した黄斑円孔の1例

A case of spontaneous closure of MH in a patient treated with tamoxifen

要約　目的：タモキシフェン内服後に発症し自然閉鎖した黄斑円孔の1症例の報告。

症例：50歳，女性。45歳時に左乳癌に罹患し，手術と化学療法の後に4年半タモキシフェン20mg/日，総量約32.5gを内服した。50歳時に治療関連急性混合性白血病を発症した。造血幹細胞移植前の眼科検診では異常所見はなかった。初回受診の8か月後に左視力低下と歪視を自覚し，再度眼科を受診した。矯正視力は右1.5，左0.1で，光干渉断層計にて左眼に内境界膜の架橋を伴う黄斑円孔を認めた。タモキシフェン内服は終了していたが同薬剤による内因性の黄斑円孔の可能性を考え，手術はせず経過観察とした。1か月後から徐々に黄斑円孔の閉鎖と視力の回復を認め，24か月後には囊胞とellipsoid zoneの途絶は残存したが黄斑円孔は閉鎖し，矯正視力も左0.8まで回復した。

結論：タモキシフェンによると考えられる黄斑円孔は，本症例のように内境界膜の架橋構造が残る場合，硝子体手術をせずにタモキシフェンの休薬で長期間かけて自然閉鎖する可能性がある。

Abstract　Purpose：To report a case of spontaneous closure of macular hole（MH）in a patient treated with tamoxifen.

Case：A 50-year-old female with past medical history of ductal carcinoma of left breast, status post mastectomy and chemotherapy, had been treated with peroral tamoxifen at daily doses of 20 mg for 4.5 years（estimated cumulative dose, 32.5 g）. She was diagnosed with therapy-related acute myeloid leukemia at the age of 50 years. In the screening test before hematopoietic stem cell transplantation, her visual acuity was normal. After 8 months, she presented with a complaint of visual loss in her left eye. Her corrected visual acuity was 1.5 right and 0.1 left. Optical coherence tomography（OCT）showed MH with bridging with inner limiting membrane（ILM）in her left eye. Although tamoxifen had already discontinued, we suspected tamoxifen retinopathy and followed up without any surgery. After 1 month, OCT gradually revealed spontaneous closure of MH. After 24 months, MH had closed even though cysts and a disruption of ellipsoid zone remained. Her visual acuity improved to 0.8 in the left eye.

Conclusion：We can expect spontaneous closure of tamoxifen induced MH with bridge formation of ILM without any surgery. Therefore, consideration should be taken to stop tamoxifen and follow up for long term.