Clinical and Imaging Features Predictive of Orbital Granulomatosis with Polyangiitis and the Risk of Systemic Involvement

Objective Granulomatosis with polyangiitis (GPA), previously Wegener's granulomatosis, requires prompt diagnosis and systemic review to exclude life-threatening disease. However, early diagnosis of orbital GPA may be difficult because anti–neutrophil cytoplasmic antibody (ANCA) and anti-PR3 antibody screening can be negative at presentation and orbital biopsies taken for diagnosis may not show the classic features of GPA. This study was designed to compare GPA with other causes of orbital inflammation and to identify the presenting clinical and imaging features most likely to predict GPA and its systemic spread. Design Retrospective noninterventional comparative case series. Participants A total of 247 patients who had undergone orbital biopsies for clinical presentations with orbital inflammation were identified from the Institute of Ophthalmology pathology database. Methods Patients were divided into GPA and non-GPA groups on the basis of their final clinical diagnosis. Clinical and imaging features of these 2 groups were compared to determine those predictive of GPA, and patients with GPA also had long-term evaluation for systemic involvement. Main Outcome Measures A diagnosis of orbital GPA and development of systemic GPA were the main outcome measures. Results Features highly suggestive of GPA were sinonasal symptoms, sinonasal changes, or paranasal bone erosion on imaging ( P