Orbital biopsy findings consistent with granulomatosis polyangiitis in a 14-year-old boy with Crohn's disease

Both granulomatous polyangiitis (GPA) and Crohn's disease (CD) can cause orbital inflammation though rarely coincide and can often be differentiated by presenting features and histological findings. Here, we report the clinical and therapeutic course of a 14-year-old White male with binocular diplopia caused by orbital myositis. Imaging and biopsy obtained at presentation revealed necrosis and necrotizing granulomatous vasculitis suspicious for GPA. He subsequently developed gastrointestinal symptoms and terminal ileitis consistent with CD. Orbital symptoms responded well to high-dose steroids and remained quiet on methotrexate maintenance therapy. While clinical history, thorough physical exam, and complete laboratory work-up are essential in the management of pediatric orbital myositis, orbital biopsy can prove critical for diagnosis and suitable treatment strategy.