Abstract:AIM: To assess the concordance between diagnosing orbital lesions by clinical examination, orbital imaging, and histological evaluation, in order to help guide future research and clinical practice. METHODS: A retrospective analysis was undertaken at a large regional tertiary referral centre of all surgical orbital biopsies performed over a 5-year period, from 1st January 2015 until 31st December 2019. Accuracy and concordance between clinical, radiological and histological diagnoses are reported as percentage sensitivity and positive predictive value. RESULTS: A total of 128 operations involving 111 patients were identified. Overall, sensitivities of 47.7% for clinical and 37.3% for radiological diagnoses were found when compared to the histological gold standard. Vascular lesions that have characteristic clinical and radiological features had the highest sensitivity at 71.4% and 57.1%, respectively. Inflammatory conditions showed the lowest sensitivity in both clinical (30.3%) and radiological (18.2%) diagnoses. The PPV for inflammatory conditions were 47.6% for clinical and 30.0% for radiological diagnoses. CONCLUSION: Accurate diagnoses are difficult to reach by relying on clinical examination and imaging alone. Surgical orbital biopsy with histological diagnosis should remain the gold standard approach for definitively identifying orbital lesions. Although larger scale prospective studies would help further refine concordance and guide future research avenues.