title: Imaging characteristics of Rosai-Dorfman disease in the central nervous system.
abstract: OBJECTIVE
  Rosai-Dorfman disease (RDD) is a rare, lymphoproliferative disorder of uncertain etiology. The Central Nervous System (CNS) is a very rare site for RDD and only a few imaging appearances have been described. The purpose of this study is to present the largest series of cases in the CNS imaging literature to increase familiarity with this entity and further identify features that may distinguish RDD from meningioma.
  
  
  METHODS
  Findings from imaging examinations in 10 patients with pathologically confirmed RDD were retrospectively reviewed. Two radiologists evaluated the lesion location, shape, size, number, edge, cerebral edema, homogeneous or heterogeneous appearance, attenuation and signal intensity, degree of enhancement, and the relation between lesions and meninges.
  
  
  RESULTS
  RDD in CNS showed similar features in imaging: an extra-axial, well-circumscribed, dura-based mass, isodense or hyperdense on CT, isointensity on T1-weighted imaging and isointensity with hypointensity on T2-weighted imaging. The mass enhanced markedly and homogeneously after the administration of contrast agent and demonstrated dural tail sign in all cases. Significant perifocal edema was associated with the masses. Remarkably, seven patients (77.8%) showed strong hypointensity within isointensity on T2-weighted or FLAIR images and no calcification was observed in CT images or pathologic specimens.
  
  
  CONCLUSIONS
  Although RDD in the CNS is a rare process, it should be considered in the differential diagnoses for meningioma. We believe that a typical representation of hypointensity irrelevant to calcification on T2-weighted or FLAIR images can suggest the diagnosis of RDD.
authors: Department of Radiology, Fudan University Shanghai Cancer Center, PR China.
authors: Hui
authors: H
authors: Zhu
authors: Long-Hua
authors: LH
authors: Qiu
authors: Ya-Fang
authors: YF
authors: Dou
authors: Jin-Song
authors: JS
authors: Wu
authors: Ping
authors: P
authors: Zhong
authors: Cheng-Chuan
authors: CC
authors: Jiang
authors: Rong
authors: R
authors: Xu
authors: Xiao-Qiang
authors: XQ
authors: Wang
mesh_terms: D000328:Adult; D000368:Aged; D002493:Central Nervous System Diseases / Q000473:pathology*; D003287:Contrast Media; D005260:Female; D015618:Histiocytosis, Sinus / Q000473:pathology*; D006801:Humans; D007472:Iohexol; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D007472:Iohexol