Orbital Rosai-Dorfman disease with subperiosteal bone involvement mimicking eosinophilic granuloma

The presentation of RDD as an anterior subperiosteal orbital mass with bone involvement has, to the authors' knowledge, not been previously reported. We describe a case of Rosai-Dorfman disease (RDD) presenting as an anterior superolateral subperiosteal orbital mass with erosion of overlying bone mimicking eosinophilic granuloma. It was debulked using endoscopic-guided curettage and the patient was given both local and systemic corticosteroids. Careful histological analysis revealed the diagnosis of RDD and the patient remains asymptomatic and recurrence free at 16 months follow-up. Involvement of the pituitary gland, a recognized yet unusual finding in this condition was also noted. RDD should be considered in the differential diagnosis of a soft tissue mass of the superolateral orbit.