[A case of rheumatoid factor-positive hypertrophic spinal pachymeningitis].

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.