Background:Inflammatory lesions of orbital disease encompass a wide spectrum of clinical entities including rheumatic disorders.Objectives:To describe our experiences in adult patients who applied to a tertiary rheumatology center due to orbital disease.Methods:This is a retrospective descriptive study and data were extracted from patient’ charts. We described the clinical, laboratory, radiologic, histopathological presentations and final diagnoses of patients with inflammatory orbital disease who applied to our rheumatology clinic between January 2014 and December 2019.Results:Thirty-eight patients (Female: 63.2%) were identified; median age at onset of orbital symptoms was 44.5 (min.-max 5-72) years. Swelling (57.9%) and orbital pain (47.4%) were the most common symptoms, followed by erythema (13.2%), vision loss (13.2%), proptosis (7.9%) and diplopia (%7.9). Table summarizes the demographic and clinical characteristics of the patients. Imaging (MRG) was performed in all patients and 63.2% had an orbital biopsy. Orbital imaging revealed extraocular muscles (71.1%), lacrimal glands (50.0%) and optic nerve (42.1%) involvement. Of patients 34.2% had bilateral and 18.4% had retroorbital involvement. The final diagnoses of patients were: IgG4-related disease (34.2%, n =13), idiopathic orbital inflammatory pseudotumor (36.8%, n = 14), granulomatosis with polyangiitis (18.4%, n =7), Sjogren’s syndrome (n=1), relapsing polychondritis (n=1), thyroid-associated orbitopathy (n=1) and fungal granulomatous angiitis (n=1).Conclusion:Inflammatory lesions of the orbit are rare and the diagnosis may be challenging. Differential diagnosis is based on clinical, laboratory, radiologic and histopathologic findings. Although IgG4-related disease is a relatively new diagnostic cause for orbital inflammation, it should be considered more in differential diagnosis.Figure:Disclosure of Interests:Melek Seren Aksun: None declared, Taha Koray Sahin: None declared, Ertugrul Cagri Bolek: None declared, Levent Kiliç: None declared, Elif Günay Bulut: None declared, Kader Karli Oğuz: None declared, Umut Kalyoncu Consultant of: Abbvie, Amgen, Janssen, Lilly, Novartis, UCB, Omer Karadag: None declared