乾燥症状に先行したSjögren症候群に伴う脊髄炎の2例―MRI所見の特徴について

Two Cases of Myelitis Associated with Sjögren Syndrome without Xerosis : Characteristic MRI Findings

　要旨　症例1は30歳，女性。乾燥症状を自覚したことはなかった。両上肢の異常感覚，右上肢の脱力が出現したため入院した。頸髄MRI（T2強調画像）で第1から第7椎体レベルにかけて高信号病変を認め，精査の結果Sjögren症候群（SjS）に伴う脊髄炎と診断した。ステロイド治療で症状は改善したが，ステロイド剤の中止後，再発した。頸髄MRIでは第1から第3椎体レベルの右側後索に造影効果を認めた。ステロイド治療により，深部感覚障害は改善した。症例2は31歳，女性。乾燥症状を自覚したことはなかった。頸部から両上肢の異常感覚，四肢の筋強直が出現したため入院した。頸髄MRI（T2強調画像）で第1から第6椎体レベルにかけて高信号病変を認め，精査の結果SjSに伴う脊髄炎と診断した。ステロイド治療により症状は改善した。このように乾燥症状がない場合でも脊髄炎の原因としてSjSの検索を行う必要があると考える。また，SjSによる脊髄炎の特徴として，病変は腫脹し，3椎体以上に病変が及び，再発部位は同じ部位であることが多く，多発性硬化症との鑑別のポイントになると考える。

　We report two cases of myelitis associated with Sjögren syndrome without xerosis. Case 1 : A 30-year old woman developed dysesthesia on both upper extremities and weakness of the right arm. A T2-weighted MRI examination showed a high-intensity signal and a swollen lesion between the first and seventh cervical vertebral levels. She was diagnosed as having primary Sjögren syndrome based on the positive finding of a Saxon test, typical salivary gland scintigraphy findings, and an elevated anti-SS-A antibody titer. We suspected that her myelitis was associated with Sjögren syndrome and treated her using steroid therapy. Although her symptoms were alleviated, her myelitis relapsed at the same location after the cessation of steroid therapy. Case 2 : A 31-year-old woman developed dysesthesia on her neck and both upper extremities and exhibited tonic spasm. A T2-weighted MRI examination showed a high-intensity signal and a swollen lesion between the first and sixth cervical vertebral levels. She was diagnosed as having primary Sjögren syndrome based on the positive findings of a Rose Bengal test, a Schirmer's test, and a Saxon test as well as typical salivary gland scintigraphy findings and elevated titers of anti-SS-A and anti-SS-B antibodies. We suspected that her myelitis was associated with Sjögren syndrome and treated her using steroid therapy. Her symptoms improved after steroid therapy. Based on these two cases, we concluded that MRI findings for myelitis associated with Sjögren syndrome are characterized by a swollen lesion of more than three vertebral segments in length, and the relapse tends to occur at the same location.