Rosai-Dorfman disease with massive intracranial involvement: asymmetric response to conservative therapy.

Rosai-Dorfman Disease (RDD) is a rare, idiopathic lymphoproliferative disorder. Central nervous system (CNS) involvement in this disorder is an uncommon manifestation. The clinical and radiographic appearance of CNS RDD is variable, and may mimic more common diseases. Treatment is controversial, and spontaneous remission is common. Positive outcomes have been reported with radiation therapy, or corticosteroid administration, or surgical excision. Our case is unusual in that the extracranial sites of involvement responded to corticosteroid therapy while the intracranial masses progressed.