Meningeal Rosai-Dorfman disease: report of three cases and literature review.

Rosai-Dorfman disease is a well-recognized clinicopathological entity, which in rare cases affects the central nervous system, where it mimics meningioma. We describe three cases and review the literature. Histological and immunohistochemical confirmation is essential for definitive diagnosis. In addition to emperipolesis (lymphophagocytosis), reactivity for S-100 and CD68 and nonreactivity for CD-la immunostaining are characteristic features of this histioproliferative disease. In contrast to meningioma, this tumor usually occurs in young males and infiltrates the brain parenchyma.