A case of rapidly progressive Rosai-Dorfman disease restricted to the central nervous system

Sinus histiocytosis with massive lymphadenopathy, also known as Rosai-Dorfman disease (RDD), is an idiopathic condition typically associated with cervical lymphadenopathy, fever and hypergammaglobulinaemia. Extranodal involvement has been reported in diverse sites such as the skin, upper respiratory tract, orbit and the central nervous system. We document a case of intracranial RDD in a 40-year-old woman with rapid evolution over a period of three months. Clinically, the patient suffered from headache. The MRT showed a left parietal tumour with dural attachment. Histologically, the lesion consisted of pale-staining histiocytes with emperipolesis, neutrophilic granulocytes and scattered lymphocytes. Focally, the granulocytes dominated the histological picture. By immunohistochemical analysis, the characteristic histiocytes were positive for S100 protein, CD68 and FXIIIa, but negative for CD1a. No Birbeck-granula were detectable in electron microscopic analysis. Granulocytes showed a positive Anti-HHV6b immunoreaction. The tumour was diagnosed asA'an intracranial manifestation of RDD primary to the CNS with an unusual preponderance of neutrophilic granulocytes and with only scattered lymphocytes. The postoperative clinical staging showed no other manifestations of the disease. On postoperative MRI the lesion had been completely resected. No further therapy has been applied and the patient has had an unremarkable clinical course for the last ten months.