We report a case of orbital Rosai–Dorfman disease in a 45-year-old man who presented with exophthalmos as the first symptom for 6 months. He did not have any itching, photophobia, tears, headache, dizziness, nausea, vomiting, or other symptoms of discomfort. A soft tissue mass was found in the left orbital by a magnetic resonance imaging scan, and we were able to diagnose lymphoma before the operation. Rosai–Dorfman disease was finally diagnosed by surgical biopsy. The patient received radiotherapy. At a 1-year follow-up, there was no sign of a residual tumor. Rosai–Dorfman disease is easily misdiagnosed and accurate diagnosis of this condition is important for choosing the best treatment plan.
Keywords: Orbital; Rosai–Dorfman; exophthalmos; lymphoid hyperplasia; radiotherapy; tumor.