Relapsed Antineutrophilic Cytoplasmic Antibody–Associated Vasculitis Presenting as Diplopia

A 39-year-old man with a history of antineutrophilic cytoplasmic antibody–associated vasculitis in remission presented to the emergency department with 1 month of diplopia. Imaging revealed an infiltrating extraconal enhancing mass along the floor of the left orbit involving the left inferior rectus muscle. Biopsy demonstrated granulomatous inflammation and vasculitis consistent with recurrence of his antineutrophilic cytoplasmic antibody–associated vasculitis. Symptoms resolved with resumption of immunosuppression.