title: The development of ring-shaped contrast enhancement in a case of cerebellar dysembryoplastic neuroepithelial tumor: case report.
abstract: OBJECTIVE
  Dysembryoplastic neuroepithelial tumor (DNT) occurs rarely in the cerebellum. We describe a rare case of cerebellar DNT that developed contrast enhancement after long-term observation and discuss the underlying mechanism and clinical relevance of this unusual phenomenon.
  
  
  METHODS
  A 34-year-old woman with known cystic cerebellar lesions presented with increased frequency of vertigo and new onset of truncal ataxia. Magnetic resonance imaging revealed new contrast enhancement in the dominant cystic lesion of the cerebellar vermis without any change in size and shape or evidence of edema.
  
  
  METHODS
  The lesions were resected under magnetic resonance imaging guidance. Histological assessment revealed populations of small, round cells in a microcystic background containing "floating" neurons, diagnostic of DNT. Microvascular proliferation and pigmented neurons were also present.
  
  
  CONCLUSIONS
  This is the first report of the development of contrast enhancement in a previously nonenhancing case of cerebellar DNT. The acquisition of ring-shaped contrast enhancement may be associated with microvascular proliferation, but otherwise no evidence of malignant progression. In addition, this case presents the novel pathological finding of pigmented neurons in DNT.
authors.affiliation: Department of Neurosurgery, Brigham and Women's Hospital, Boston, Massachusetts 02115, USA.
authors.forename: Jignesh K
authors.initials: JK
authors.lastname: Tailor
authors.forename: Albert H
authors.initials: AH
authors.lastname: Kim
authors.forename: Rebecca D
authors.initials: RD
authors.lastname: Folkerth
authors.forename: Peter M
authors.initials: PM
authors.lastname: Black
mesh_terms: D000328:Adult; D002528:Cerebellar Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D003287:Contrast Media; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods / Q000639:trends; D018302:Neoplasms, Neuroepithelial / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D011859:Radiography; D013724:Teratoma / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery
chemical_list: D003287:Contrast Media