A case of orbital Rosai-Dorfman disease responding to radiotherapy.

Rosai-Dorfman disease (RDD) is a rare histiocytic disorder most often characterized by painless cervical lymphadenopathy, but it may also present with orbital disease. The clinical course of RDD is variable; it can be either relapsing-remitting or progressive, and the outcome relates to clinical location and treatment response. Orbital RDD can have an insidious onset and similar presentation to other ophthalmic conditions; this can result in a delayed diagnosis. Nearly all cases of orbital RDD cause visual disturbances and require treatment. Because orbital RDD is an uncommon presentation, a variety of interventions have been employed, including surgery, immunotherapy, chemotherapy, and radiotherapy. We present a case of salvage radiotherapy for progressive orbital RDD refractory to surgery and chemotherapy in a pediatric patient.