初発症状として両側網膜中心静脈閉塞症の所見を呈した多発性骨髄腫の1例

A case of multiple myeloma with findings of bilateral central retinal vein occlusion as the initial presentation

要約　目的：初発症状として両側網膜中心静脈閉塞症（CRVO）の所見を示した多発性骨髄腫の1例を経験したので報告する。

症例：55歳，男性。2023年2月初旬頃からの左眼視力低下を主訴に，2月中旬に近医を受診した。両眼にCRVOを認めたため，近医受診から4日後に滋賀医科大学医学部附属病院（以下，当院）を紹介受診となった。初診時の矯正視力は右1.2，左0.6であった。眼底所見では両眼の全周に刷毛状，およびしみ状の網膜出血，血管の蛇行・拡張を認め，光干渉断層計では両眼に黄斑浮腫，左眼黄斑部に漿液性網膜剝離を認めた。原因精査のために血液検査を施行したところ，貧血，凝固能低下，高蛋白血症，低アルブミン血症，腎機能低下，IgA高値を認め，当院血液内科にて症候性多発性骨髄腫IgAλ型と診断された。血液内科による治療が施行されると，眼底の出血所見は徐々に改善し，漿液性網膜剝離は丈の減少を認めた。治療開始5か月後，矯正視力は右1.5，左1.2まで改善した。

結論：本症例では，多発性骨髄腫による過粘稠度症候群によって両眼にCRVOの所見を認めた。両眼同時発症のCRVOを認めた場合は，血液疾患を疑って全身検査を行う必要がある。

Abstract　Purpose：We report a case of multiple myeloma with bilateral central retinal vein occlusion（CRVO）as the initial presentation.

Case：A 55-year-old male experienced visual impairment in his left eye starting in early February 2023 and visited a nearby ophthalmologist in the middle of February. The patient was referred to our hospital four days after a visit to his primary ophthalmologist because of CRVO in both eyes. His best-corrected visual acuity at initial examination was 1.2 in the right eye and 0.6 in the left eye. Fundus examination revealed flame-shaped and blot retinal hemorrhages as well as tortuosity and dilatation of retinal veins in all four quadrants of the fundus bilaterally. Optical coherence tomography（OCT）showed macular edema in both eyes and serous retinal detachment in the macula of the left eye. Blood tests were performed to investigate the cause of the disease and, revealed anemia, increased coagulability, hyperproteinemia, hypoalbuminemia, decreased renal function, and high IgA levels. The patient was subsequently diagnosed with symptomatic multiple myeloma（IgA-λ type）by our hematology department. After hematological treatment, the hemorrhagic findings in the fundus gradually improved and the serous retinal detachment decreased. The patient's best-corrected visual acuity improved to 1.5 in the right eye and 1.2 in the left eye after five months of treatment.

Conclusion：In this case, the findings of bilateral CRVO were due to hyperviscosity caused by underlying multiple myeloma. When CRVO occurs in both eyes simultaneously, a systemic examination should be performed to rule out hematologic disease.