Clinico-epidemiological analysis of 1000 cases of orbital tumors

Purpose To clarify the incidence, demography and clinical features of orbital tumors diagnosed in a single institute in Japan. Study design Retrospective, observational case series. Methods Patients with primary orbital tumors including tumor-like lesions diagnosed clinically or histopathologically at Tokyo Medical University Hospital between 1995 and 2019 were analyzed. Incidence of all orbital tumors, demographic profile and clinical features of major benign and malignant tumors were reviewed retrospectively. Results Totally 1000 cases of primary orbital tumor were diagnosed clinically or histopathologically during the study period. Benign tumors accounted for 72% and malignant tumors 28%. 55% of benign tumors and 99% of malignant tumors were proven histopathologically. The most common benign orbital tumor was idiopathic orbital inflammation (27%), followed by IgG4-related ophthalmic disease (17%), cavernous venous malformation (13%) and pleomorphic adenoma (9%). The most common malignant tumor was lymphoma (70%), followed by adenoid cystic carcinoma (7%) and solitary fibrous tumor (5%). Conclusions Epidemiology of orbital tumors has changed by the improvement of imaging techniques, establishment of novel clinical and histopathological criteria, and changes in population age structure associated with the aging society. Currently, lymphoproliferative diseases including lymphoma and IgG4-related ophthalmic diseases form the major orbital tumors in Japan.