A Case of Isolated Central Nervous System Rosai-Dorfman Disease.

Rosai-Dorfman disease (RDD) is a benign histiocytosis with unknown etiology. It generally occurs in cervical lymph nodes. Isolated central nervous system (CNS) RDD is very rare in the literature. We reported a case of no systemic involvement Rosai-Dorfmann which is rarely seen and shows CNS involvement by mimicking meningioma. A 32-year-old man presented with diplopia and a headache he has been experiencing for the past two years. His neurological examination showed left facial paresthesia, consistent with trigeminal nerve trace. Tendon reflexes were increased at the right side and the right plantar reflex was extensor. Brain magnetic resonance imaging demonstrated irregularly shaped, tumor-like lesions in the bilateral cerebellopontin area that were compressing pons. Rosai-Dorfman disease can be differentiated from IgG4 related disease (IgG4-RD) by its characteristic features such as plasma cell density and emperipolesis seen in its histopathology. Rosai-Dorfman disease can be confused with other diseases radiologically and histopathologically, especially the IgG4-RD, so be careful about differential diagnosis.