Introduction. This fascinating disorder is also known as Sinus Histiocytosis. It is very rare, probably less than 1000 cases reported in the literature. R.D.D affects lymph nodes, although extranodal involvement has been reported such as: Centaral nervous system (CN.S). All of the cases of R.D.D with CN.S involvement without other sites involvement are 11 cases. Methods. The case is a male patient, 26y/o, with a history of head trauma 2 years ago that has been resulted to unconsciousness. He has been referred to a hospital and brain CT scan and brain M.R.I has been done for him. In M.R.I a brain tumor with left orbit and sphenoidal sinus involvement and compression effect on frontal lobe has been seen. A neurosurgeon operated him and the pathological report was Rosai-Dorfman DISEASE. Then he was referred to radiation therapy department.Results. Treatment approach in CN.S involvement cases consists of surgery, radiotherapy and chemotherapy.
Discussion. Over all, response has been inferior to those expected with malignant hematopoietic neoplasms.