Hypertrophic Pachymeningitis in Eosinophilic Granulomatosis with Polyangiitis.

Eosinophilic granulomatosis with polyangiitis (EGPA) is one of the anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV), which is characterized by systemic small vessels vasculitis with associated eosinophilia. Hypertrophic pachymeningitis (HP) is an inflammatory disease in which the cerebral or spinal dura mater is thickened. AAV other than EGPA may sometimes develop HP; however, patients with EGPA rarely develop HP. This is the case of myeloperoxidase-ANCA-positive EGPA that presented with headache and blurred vision and was diagnosed with HP. It was successfully treated with pulsed steroid therapy and intravenous cyclophosphamide without any relapse for more than four years.