Solitary intracranial Rosai-Dorfman disease: case report and literature review.

Rosai-Dorfman disease is a well-established autoimmune histioproliferative disorder, and solitary central nervous system involvement is rare. A 35-year-old man presented with headache and transient blurred vision of 4 months' duration and weakness of the left extremities for 1 month. He had left temporal hemianopsia, a right nasal visual field defect of the upper medial quadrant and decreased muscle strength of the left extremities. Magnetic resonance imaging (MRI) showed a contrastenhancing tentorium-based lesion in the right trigone, intruding into the right lateral ventricle. The lesion was totally resected. Rosai-Dorfman disease was confirmed pathologically by an inflammatory infiltrate in the absence of an infectious agent, emperipolesis and positive S100 staining. From a review of the literature on Rosai-Dorfman disease in the central nervous system it is concluded that follow-up MRI should be performed in order to detect possible recurrence and that this rare entity should be considered in the differential diagnosis of intracranial lesions.