title: Incidental parenchymal magnetic resonance imaging findings in the brains of patients with neurofibromatosis type 2.
abstract: OBJECTIVE
  Whereas T2 hyperintensities known as NF-associated bright spots are well described in patients with neurofibromatosis type I (NF-1), there is a paucity of data on incidental findings in patients with neurofibromatosis type II (NF-2). We aim to characterize unexplained imaging findings in the brains of patients with NF-2.
  
  
  METHODS
  This study is retrospective, HIPAA-compliant and approved by the institutional review board. 34 patients with NF-2 underwent brain magnetic resonance imaging (MRI) between January 2000 and December 2012. T2 and T1-weighted imaging characteristics, diffusion weighted imaging (DWI) characteristics, and enhancement patterns were analyzed by visual inspection. Clinical information at time of imaging was available for all patients. Neuropathologic data was available for one patient.
  
  
  RESULTS
  We found unexplained T2 hyperintensities present on initial imaging in 23/34 patients (67%). Of the 23 patients with unexplained MRI findings, 15 (65%) had wedge-shaped T2 hyperintensities in the subcortical white matter extending to the cortex suggestive of a cortical dysplasia. 3 additional cases (17%) had a lesion within the cerebellum suggestive of a neuronal migration anomaly. In one patient where the MRI was suggestive of focal cortical dysplasia, histopathologic analysis revealed dysplastic glial foci without other alterations of cortical architecture or other cytologic abnormalities.
  
  
  CONCLUSIONS
  Unexplained T2 hyperintensities occur frequently in patients with NF-2. While they may not be the NF-2 equivalent of NF-associated bright spots seen in NF-1, some of these T2 hyperintensities in patients with NF-2 may represent underlying disorders of neuronal migration. Further studies are needed to validate our findings.
authors: Division of Pediatric Neurology, Weill Cornell Medical Center/New York Presbyterian Hospital, USA.
authors: Wendy S
authors: WS
authors: Vargas
authors: Division of Neuroradiology, Weill Cornell Medical Center/New York Presbyterian Hospital, USA.
authors: Linda A
authors: LA
authors: Heier
authors: Department of Pathology, Division of Neuropathology, Johns Hopkins University, USA.
authors: Fausto
authors: F
authors: Rodriguez
authors: Department of Neurology, Johns Hopkins University, USA.
authors: Amanda
authors: A
authors: Bergner
authors: Division of Pediatric Neurology, Weill Cornell Medical Center/New York Presbyterian Hospital, USA.
authors: Kaleb
authors: K
authors: Yohay
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001921:Brain / Q000473:pathology*; D001932:Brain Neoplasms / Q000473:pathology*; D002648:Child; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D033162:Incidental Findings; D008297:Male; D008875:Middle Aged; D016518:Neurofibromatosis 2 / Q000473:pathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult
keywords: Cortical dysplasia; MRI; Micro-hamartomas; Migration anomalies; NF-associated bright spots; Neurofibromatosis type 2