Bifocal Intracanial Rosai-Dorfman Disease Mimicking Lymphoplasmacyte-Rich Meningioma: Diagnostic Pitfalls About a Case Report.

Rosai-Dorfman disease (RDD) is a clonal histiocytic proliferation characterized by large S100 positive histiocytes with variable emperipolesis. Extranodal locations were confirmed with the central nervous system or the meninges involvement in less than 5% of cases, which is marked as a significant differential diagnosis of meningiomas in radiological and intra-operative pathological examination. Histopathology and immunohistochemistry are the keys to definitive diagnosis. We present a case of bifocal Rosai-Dorfman disease in a 26-year-old man, mimicking Lymphoplasmacyte-rich Meningioma. This case allows us to demonstrate the diagnosis pitfalls encountered in this localization.