脳脊髄病変を反復し髄液細胞の遺伝子解析によりBing-Neel症候群と診断した1例

A Case of Bing-Neel Syndrome With Repeated Long Spinal Cord Lesions

45歳，男性。2019年からステロイドで改善する排尿障害と長大な脊髄病変を反復した。2020年6月の再発時に血清IgMの著増があり造血器疾患を疑った。髄液細胞にMYD88 L265P変異を認め，ビング・ニール症候群（Bing-Neel syndrome：BNS）と診断した。ブルトン型チロシンキナーゼ阻害薬で加療し，排尿障害や画像所見の増悪なく経過した。本例は難治性自己免疫性疾患との鑑別を要したが，高IgM血症が診断の一助になった。高IgM血症を伴う中枢神経病変ではBNSを鑑別に挙げる必要がある。

Abstract

The patient was a 45-year-old man. Since 2019, he had exhibited repeated steroid-improved dysuria and long spinal cord lesions. At the time of recurrence in June 2020, he exhibited a marked increase in serum IgM levels, suggesting hematopoietic disease. We found an MYD88 L265P mutation in cerebrospinal fluid cells, which subsequently led to the diagnosis of Bing-Neel syndrome (BNS). The patient was treated with Burton's tyrosine kinase inhibitors and his condition progressed without dysuria or worsening of the imaging findings. This case was challenging to differentiate from intractable inflammatory diseases; however, the identification of hyper-IgM helped in the diagnosis. BNS should be differentiated from central nervous system lesions through the identification of hyper-IgM.