Idiopathic hypertrophic pachymeningitis with anticardiolipin antibody

Rationale: Idiopathic hypertrophic pachymeningitis (IHP) is a rare neurological disorder without a definite etiology. Diagnosis is mainly based on exclusion of other etiologies. Patient concerns: A 41-year-old male patient presented with insidious onset headache of 3-month duration. Diagnoses: Contrast-enhanced brain magnetic resonance imaging (MRI) revealed diffuse pachymeningeal enhancement over bilateral cerebral hemispheres and the tentorium cerebelli. Lumbar puncture showed increased pressure, lymphocytic pleocytosis, and elevated protein level with normal glucose concentration. Blood tests detected elevated erythrocyte sedimentation rate (ESR) and C-reactive protein. Pathological examination of the dura mater from the right frontal convexity disclosed coarse collagenous deposition with focal lymphoid aggregation. After malignancy and infectious etiologies were excluded, a diagnosis of IHP was made. Interventions: Oral prednisolone and azathioprine followed by methotrexate were administered. Outcomes: During the 7-year follow-up period, although the patient was not totally headache-free, medical therapy significantly reduced the severity of headache. Follow-up MRI studies showed a reduction in meningeal enhancement and serial ESR measurements revealed a trend of improvement. Lessons: Methotrexate therapy may be considered in cases of steroid-resistant IHP. In addition to clinical evaluation, serial ESR testing may be considered to guide the treatment strategy and assess the response to therapy.