A new clinical entity mimicking meningioma diagnosed pathologically as rosai-dorfman disease.

Sinus histiocytosis with massive lymphadenopathy (SHML, Rosai-Dorfman disease), is a well-defined histioproliferative disorder. The extranodal type of the disease is not uncommon, but CNS involvement is extraordinary. Moreover, the isolated extranodal intracranial manifestation of the disease is extremely rare. Only a few cases of the latter form have been reported. We present a case of meningioma-like intracranial lesion, which after total resection, pathologically and immunohistochemically proved to be an isolated form of the Rosai-Dorfman disease. No concurrent nodal involvement was found, even after a detailed postoperative diagnostic work-up.Two years follow-up disclosed full recovery from the CNS symptoms, while no other SHML signs were noted. The extranodal form of the Rosai-Dorfman Disease, nowadays has been enlisted in the differential diagnosis of the space occupying intracranial and skull base lesions. However, a number of questions, dealing with the preoperative diagnosis, the surgical strategies, as well as the natural history, the prognosis of the disease, and the possible need for adjunctive therapy, remain obscured. Additional reports are useful to better understand this rare type of disease and may lead to the establishment of a more profitable management.