リウマチ因子陽性の肥厚性脊髄硬膜炎の1例

A Case of Rheumatoid Factor-positive Hypertrophic Spinal Pachymeningitis

Ⅰ．緒　言

　Hypertrophic spinal pachymeningitisは，硬膜の慢性炎症性肥厚を認めるが，非特異的所見のため術前診断に苦慮することが多い．今回われわれは，1カ月間で急速に進行し，リウマチ因子が陽性であった1例を経験し，緊急後方除圧およびステロイド，免疫抑制剤の投与により良好な結果が得られたので，症例を提示し若干の文献的考察を加えて報告する．

Ⅱ．症　例

　＜患　者＞　54歳　女性

　主　訴　対麻痺

　既往歴・家族歴　特記事項なし

　現病歴　2002年11月中旬，特に誘因なく左側腹部痛が出現し，近医での検査ではerythrocyte sedimentation rate（ESR）の亢進，CRPと尿潜血陽性だったが，原因は不明であった．約1カ月後には数日間で急速に対麻痺が進行して当院内科へ入院し，magnetic resonance imaging（MRI）で異常を認めたため当科を紹介された．入院時両下肢の筋力は，徒手筋力テストで2/V，左下肢は膝立て不可能で，stocking typeの温痛覚障害，および排尿障害を認めた．血液検査では，CRP：6.08mg/dl，CH50：48U/ml（30～45），C3：168mg/dl（80～140），C4：46mg/dl（11.0～34.0）と炎症反応および補体の活性化を認め，またrheumatoid factor（RF）が22U/ml（＜15）と陽性であった．

　A 54-year-old female was admitted to our hospital with the complaint of progressive gait disturbance,starting with left abdominal pain 1 month previously. She developed acute paraparesis and stocking-anesthesia type sensory disturbance within a few days. MR imagings on admission,revealed an encircled subdural mass at the Th1-9 vertebral level,and her spinal cord was compressed at several places at the Th5-6. The subdural mass showed low intensity on T1 and T2 weighted image,and was homogenously enhanced after Gd-DTPA administration. Laboratory data revealed elevation of rheumatoid factor,CH50,C3,C4,and C-reactive protein. An emergency operation was performed by left hemilaminectomy from Th4 to Th6. The subdural mass was resected as far as possible,followed by dural plasty and initiation of steroid intraoperatively. Histopathologic examination of the resected lesion documented a hypertrophic pathymeningitis. Postoperatively,her neurological findings were improved immediately,followed by adjuvant therapy. Recurrence was not present on radiographic images 3 years after surgery. Laboratory data normalized within 4 months. Hypertrophic pachymeningitis is a rare case,and it is difficult to diagnose preoperatively. If there are subdural mass lesions at the multiple vertebral levels,we should suspect this disease. Treatment by immediate decompressive surgery and continuous adjuvant therapy was effective in our case.