Rosai-Dorfman disease of the central nervous system.

Rosai-Dorfman disease (RDD) is an idiopathic, non-neoplastic, lymphoproliferative disorder characterized by sinus histiocytosis and massive lymphadenopathy. When RDD involves the central nervous system the lesion simulates a meningioma. Histological and immunohistochemical confirmation is essential for a definitive diagnosis. In this paper, ten cases of RDD confined to the central nervous system are reported. Another case with orbital RDD was excluded. Nine cases involved the cranial cavity alone; in one, the cervical extradural region was also involved. Treatment consisted of surgical excision or biopsy. Histology and immunohistochemistry revealed a mixed cell population of predominantly mature histiocytes with evidence of emperipolesis and strong positivity for S100 protein in all cases. No recurrence was observed during follow up ranging from three months to eight years.