[Case report of Rosai-Dorfman disease mimicking pachymeningitis].

Rosai-Dorfman disease (RDD) is a rare idiopathic histioproliferative disease affecting the lymph nodes. Extranodal sites may be involved and occasionally represent the initial or sole manifestation of the disease. Central nervous system manifestations especially are exceedingly rare. We reported a case of isolated, intracranial, dural-based RDD. A 69-year-old male, admitted with a second generalized convulsion, was examined by high-resolution MR images that revealed a thickened, stratified dura in the left frontal region with associated cortical edema. The patient underwent craniotomy with subtotal resection of the lesion. Microscopically, with the cytoplasmic staining against S-100 protein the lesion was shown to consist of proliferative histiocytes exhibiting emperipolesis. The histopathological diagnosis was compatible with RDD. The diagnosis of RDD mimicking pachymeningitis is presented, and the previous reported cases of intracranial RDD are reviewed.