An involvement of temporal lobe of CNS parenchyma is unusual presentation of the disease that occurred in our patient. CNS can be involved less than 5% of Rosai-dorfman disease.[6
] In 70% of CNS-Rosai-Dorfman disease, the presentation is limited to the brain or to the spinal cord and is not associated with lymphadenopathy.[10
] Approximately, 75% of CNS afflictions are intracranial, whereas 25% involve the spine.[10
] Over 90% of CNS Rosai-Dorfman disease leptomeninges are only involved.[8
At literature, we founded 8 cases in additional to our case that had been afflicted with intra-axial CNS-Rosai-Dorfman disease. Their clinical data are summarized in . 70% of the patients were male, and the disease occurred in the range of 14 to 68 years old. The main complain of the patients were related to the site of involvement that were mostly frontotemporal region. The common treatment was surgical (maybe due to uncertain diagnosis), and prognosis was good at least for the short term follow-up.
The characteristic of CNS-Rosai-dorfman disease
In the present case, clinical differential diagnosis included several diseases (such as glioma and lymphoma), characterized by the extensive infiltrating mass adjacent to the left ventricle. Obviously, a precise diagnosis could not been reached on clinical grounds alone.
Histologically, Rosai-Dorfman disease is characterized by an attenuated infiltration of lymphoplasma cells and pale histiocytes of varying size, either interspersed or in sheet like pattern. These histiocytes have round or oval vesicular nuclei with well-defined, delicate nuclear membranes and single prominent nucleoli. Over 70% of the case, the histiocytes show emperipolesis that is characteristic of Rosai-Dorfman disease. Occasionally, neutrophils and eosinophils are noted. Fibrosis in the background can be seen in extranodal involvement of disease. On immunohistochemical examination, histiocytes are immunoreactive for S-100 protein, HAM 56, α1 antitrypsin, α1 chymotrypsin, lysozyme, Mac 387 and Ki-1, but are negative for CD 1a and EMA.[5
Although it is difficult to diagnose the CNS-Rosai-Dorfman disease on frozen section examination, it is easy to find emperiopolesis in FNA or in cytologic examination, and thus the role of fine-needle aspiration cytology in its diagnosis is more powerful.[13
The histopathologic differential diagnosis of this particular case included lymphoma, plasma cell granuloma, plasma cell rich meningioma and Langerhans cell histiocytosis. In our case, lymphoma was unlikely, considering the lack of monotonous atypical lymphocytes. It might be difficult to distinguish Rosai-Dorfman disease from plasma cell granuloma in the absence of emperipolesis. Langerhans cell histiocytosis was unlikely, because Langerhans histiocytes with their folded nuclei and eosinophil infiltrates were absent. Plasma cell rich meningioma was unlikely, because there were no staining for EMA. In our case, the plasma cells were immunoreactive for EMA.
The choice of treatment for Rosai-Dorfman disease is not well-established. Common treatments are surgical, steroids, chemotherapeutic agents and radiation. Surgical resection seems to be the most effective treatments.[14
] Recurrence after surgical therapy is rare and limited to uncompleted debulking, multi-organ involvement and large mass.[3
] Spontaneous regression could happen.[17
] Prognosis of the disease is good, and no death was reported to CNS-Rosai-Dorfman disease. Our patient is alive after the follow-up of 14 months.
The precise etiology of Rosai-Dorfman disease remains unknown. The researches reveal some association between RDD and bacteria (Klebsiella
), virus (Epstein barr virus, parvovirus B 19), immune dysfunction (or an aberrant response to an unspecified antigen, HHV-6 or EBV), defective Fas/FasL signaling.[6
] The high frequency of cases in some part of the world may be due to the environmental factors.[3