Dural-based Rosai-Dorfman disease: differential diagnostic considerations.

Extranodal sinus histiocytosis with massive lymphadenopathy (Rosai-Dorfman disease) is a non-neoplastic condition that has rarely been reported to involve the central nervous system. This report documents a 28-year-old man with Rosai-Dorfman disease who presented with a seizure and a dural-based mass that was thought to represent a meningioma. Resection showed a lesion marked by large, S-100 protein immunoreactive histiocytic cells with intermixed benign lymphocytes and plasma cells. Emperipolesis with intracytoplasmic lymphocytes and plasma cells was present. Differential diagnostic considerations will be discussed.