HLA-B51陽性を示し網膜毛細血管炎を合併した急性後部多発性斑状色素上皮症の1例

A case of HLA-B51 positive acute posterior multifocal placoid pigment epitheliopathy with retinal capillaritis

要約　目的：HLA-B51陽性を示し網膜毛細血管炎を合併した急性後部多発性斑状色素上皮症（APMPPE）の1例を報告する。

症例：患者は25歳，女性。突然の右視力低下を自覚し受診した。視力は右（0.6），左（2.0），眼圧は両眼とも正常であった。両眼の前房および前部硝子体に軽度の炎症細胞を認め，眼底に多数の黄白色斑状病巣を認めた。フルオレセイン蛍光眼底造影検査で，斑状病巣は造影早期に低蛍光を示し，中期以降は過蛍光を示したことからAPMPPEと診断した。また，両眼の耳側周辺部にシダ状蛍光漏出を認めた。血液検査でHLA-B51が陽性であった。光干渉断層血管撮影（OCTA）の脈絡毛細血管板層で，病巣はdark spotsとして描出された。斑状病巣が右眼中心窩に及んでいたため，ステロイド内服治療を開始した。その後，斑状病巣は消退傾向を示し，治療開始2か月後に右視力は（1.2）まで回復した。その後，OCTAにおけるdark spotsの範囲も縮小した。

結論：網膜毛細血管炎を合併したAPMPPEの報告例はほとんどない。HLA-B51陽性者に発症したAPMPPEでは，網膜毛細血管炎を合併する可能性がある。

Abstract　Purpose：To report a case of HLA-B51 positive acute posterior multifocal placoid pigment epitheliopathy（APMPPE）with retinal capillaritis.

Case：A 25-year-old woman presented with sudden decreased visual acuity in the right eye. At first visit, corrected visual acuity was 0.6 in the right eye and 2.0 in the left eye. Her intraocular pressure was normal in both eyes. She had mild inflammatory cell infiltration in the anterior chamber and anterior vitreous and multiple yellow-white placoid lesions on funduscopy in both eyes. On fluorescein angiography, the lesions demonstrated early hypofluorescence and late hyperfluorecent staining and were diagnosed as APMPPE. Moreover, a fern-like pattern of diffuse vascular leakage was observed in the temporal periphery of both eyes. Human leukocyte antigen（HLA）-B51 was positive. On optical coherence tomography angiography（OCTA）, the lesions were visualized as dark spots in the choriocapillaris slab. Owing to the extension of a placoid lesion into the fovea of the right eye, the patient was started on oral steroid therapy. Thereafter, the placoid lesions showed a tendency to fade, and her right visual acuity recovered to 1.2 after 2 months of treatment. Subsequently, the dark spots on OCTA were also reduced.

Conclusion：There have been few reported cases of APMPPE complicated by retinal capillaritis. APMPPE that develops in HLA-B51 antigen-positive individuals may be complicated by retinal capillaritis.