Dear Editor, Monkeypox is a rare zoonotic infectious disease caused by the Monkeypox viruses, a type of Orthopoxvirus of the family Poxviridae, which is endemic to Africa. The virus was first discovered in 1958 in laboratory monkeys (1). The first human case was diagnosed in 1970 in a 9-month-old infant in Zaire (the Democratic Republic of the Congo) (2). Since then, Monkeypox has become endemic in the Congo and has spread to other African countries (mainly central and western Africa) (3). Monkeypox has been reported outside Africa due to travel to endemic areas or animal contact (4). . .

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.