FDG PET/CT in a Case of Primary Multifocal Intraparenchymal Rosai-Dorfman Disease of the Brain

Intracranial Rosai-Dorfman disease presents most commonly with dura-based, extraparenchymal masses mimicking meningioma. Rosai-Dorfman disease of the brain parenchyma is very rare. We describe FDG PET/CT findings in a case of primary multifocal intraparenchymal Rosai-Dorfman disease of the cerebrum and cerebellum. These tumors, located in the cortical, subcortical, or periventricular areas, showed inhomogeneous enhancement with or without surrounding edema on MRI and variable FDG activity (SUV max range, 4.5-18) on FDG PET/CT.