Idiopathic granulomatous orbital inflammation: case series and literature review

Objective: Idiopathic granulomatous orbital inflammation is an uncommon histological finding that remains poorly defined due to its overlap with specific causes of granulomatous orbital inflammation, such as orbital sarcoidosis. We aim to identify clinico-radiological features that may differentiate it from other aetiologies of granulomatous inflammation. Methods: Retrospective case series involving 12 patients and review of the literature. Results: Eight patients (66.7%) were female. The mean age at presentation was 57.8 ± 9.1 years of age. Eleven cases were unilateral (91.7%). The most common presenting symptoms and signs were palpable mass (n = 10; 83.3%), lid swelling (n = 9; 75%) decreased extraocular movements (n = 4; 33.3%), and proptosis (n = 4; 33.3%). One patient (8.3%) had signs consistent with optic neuropathy on presentation. The lacrimal glands were involved in 6 (50%) cases. For initial management, 2 patients (16.7%) underwent observation only, 8 patients (66.7%) were managed with immunosuppressive drugs, and 2 patients (16.7%) were managed with surgical excision or debulking. Four patients (33.3%) required additional management with either methotrexate or intralesional triamcinolone. Patients were followed up for a mean of 68.4 months. At last follow-up, 7 patients (63.6%) had complete resolution, and 5 (41.7%) had stable disease without further progression. Conclusion: We present a case series of idiopathic granulomatous orbital inflammation. We found that those with idiopathic disease often had unilateral presentations and appeared to present at a later age than those with orbital sarcoidosis in the literature. Although the differentiation between orbital sarcoidosis and idiopathic disease remains difficult, the features described in this series contribute to a greater understanding of the latter condition.