title: Meningioma of the conus medullaris mimicking neurofibroma--possibly radiation induced.
abstract: BACKGROUND
  Radiation-induced meningiomas (RIMs) of the brain are the most common RIMs. However, there has been no report in the literature of an RIM of the spine. Conus medullaris is a favorite site for ependymomas, whereas it is an extremely rare location for meningiomas. Dumbbell-shaped configuration is typical for nerve sheath tumors; however, it is very rarely seen in meningiomas.
  
  
  OBJECTIVE
  To describe imaging findings of a possibly RIM at the level of the conus medullaris mimicking a neurofibroma.
  
  
  METHODS
  A 60-year-old male with 6-year history of irradiated urinary bladder cancer presented with paraparesis.
  
  
  METHODS
  Radiography, computed tomography, and magnetic resonance imaging of the thoracolumbar spine were undertaken.
  
  
  RESULTS
  Radiography showed widening of intervertebral foramina at T12-L1 level. Computed tomography and magnetic resonance imaging disclosed a lobulated intradural mass at the level of the conus medullaris causing widening and scalloping of adjacent bony structures, with dumbbell-shaped configuration. Surgical biopsy of the mass was consistent with fibroblastic meningioma.
  
  
  CONCLUSIONS
  The reported tumor might have developed secondary to irradiation for urinary bladder cancer because meningiomas are the most common radiation-induced central nervous system tumors. Although location at the level of the conus medullaris is atypical for meningioma, and dumbbell-shaped configuration is rather characteristic for neurogenic tumors, they should not exclude a diagnosis of meningioma.
authors.affiliation: Department of Radiology, University Hospital of Alexandroupolis, Democritus University of Thrace, Dragana, 68100 Alexandroupolis, Greece. aoikonom@med.duth.gr
authors.forename: Anastasia
authors.initials: A
authors.lastname: Oikonomou
authors.forename: Theodosios
authors.initials: T
authors.lastname: Birbilis
authors.forename: George
authors.initials: G
authors.lastname: Daskalogiannakis
authors.forename: Panos
authors.initials: P
authors.lastname: Prassopoulos
mesh_terms: D003937:Diagnosis, Differential; D006801:Humans; D008297:Male; D008579:Meningioma / Q000175:diagnosis* / Q000209:etiology / Q000601:surgery; D008875:Middle Aged; D009381:Neoplasms, Radiation-Induced / Q000175:diagnosis* / Q000209:etiology; D009455:Neurofibroma / Q000175:diagnosis* / Q000209:etiology; D013120:Spinal Cord Neoplasms / Q000175:diagnosis* / Q000209:etiology / Q000601:surgery; D016896:Treatment Outcome