Ten-year epidemiological study of ocular and orbital tumors in Chiba University Hospital

Abstract Background The purpose of this study is to determine the epidemiology of tumors of the ocular adnexa and orbit in Japan. Methods We conducted a retrospective study on the histopathological reports in the medical records of the Chiba University Hospital from April 2009 to March 2019. Three hundred and seventy two records were examined. In addition, we examined the annual changes in the major types of tumors including malignant lymphomas and IgG4-related diseases (IgG4-RDs). Results There were 270 conjunctival or eyelid tumors with 166 benign and 104 malignant. There were 102 orbital tumors with 55 benign, 47 malignant tumors, and 21 cases of IgG4-RDs. Ten cases of adenoma (2.7%), another benign tumor, was also diagnosed. The major malignant tumors were malignant lymphoma in 74 cases, sebaceous gland carcinoma (SGC) in 28 cases, basal cell carcinoma in 15 cases, and squamous cell carcinoma in 8 cases. The SGCs were the most common malignant eyelid tumor at 54%. Among the malignant lymphomas, extranodal marginal zone lymphomas of the mucosa-associated lymphoid tissue type, MALT lymphomas, was the most common at 51 cases and the second most common was the diffuse large B-cell lymphoma at 11 cases. The ratio of MALT lymphomas to that of all malignant lymphomas increased significantly with years. The serum IgG4 values were measured more often in the last 5 years (70%) than in the former 5 years (33%). Conclusions We conclude that malignant lymphoma is a major malignant tumor in Japan and pathological biopsies should be done proactively to prevent missing IgG4-positive MALT lymphomas.