Effective Response of Methotrexate for Recurrent Idiopathic Hypertrophic Spinal Pachymeningitis

Idiopathic hypertrophic spinal pachymeningitis (IHSP) is a chronic progressive and diffuse inflammatory fibrosis of the spinal dura mater. Though treatment of IHSP is surgical decompression with steroid therapy, treatment for recurrent IHSP is controversial. Our patient was diagnosed with IHSP based on magnetic resonance imaging (MRI) and underwent laminectomy for decompression following steroid pulse therapy. Despite maintenance of steroid therapy, the patient experienced 3 recurrences. As an alternative immunosuppressant medication, methotrexate was introduced with low-dose steroid. Fortunately, the symptom was resolved, and a decrease of dura thickening was revealed on MRI. We present the case and suggest that methotrexate might be an effective treatment modality for recurrent IHSP.