Orbital Apex Syndrome with Perinuclear Anti-neutrophil Cytoplasmic Antibody-associated Pachymeningitis

Purpose: To report a rare case of perinuclear anti-neutrophil cytoplasmic antibody-associated pachymeningitis presenting as bilateral orbital apex syndrome. Case summary: A 79-year-old female presented with a visual acuity decrease and ophthalmoplegia in both eyes from 1 week prior to her visit. Orbital magnetic resonance imaging showed diffuse hypertrophy and enhancement of the dura mater near the optic canal and superior orbital fissure causing orbital apex syndrome. The serum titer of perinuclear anti-neutrophil cytoplasmic antibody was elevated. Based on these findings, she was diagnosed with pachymeningitis related to perinuclear anti-neutrophil cytoplasmic antibody-associated vasculitis. The antibody titers decreased and ophthalmoplegia recovered after treatment with high dose intravenous steroid injection, cyclophosphamide, and long-term maintenance therapy with oral azathioprine and prednisolone. However, her visual acuity did not improve in either eye. Conclusions: Perinuclear anti-neutrophil cytoplasmic antibody associated vasculitis can present as orbital apex syndrome and should be considered as a differential diagnosis.