title: Contribution of NMR spectroscopy to the differential diagnosis of a recurrent cranial mass 7 years after irradiation for a pediatric ependymoma.
abstract: METHODS
  We describe the case of a 5-year-old-boy who underwent surgery and focal radiotherapy for an anaplastic ependymoma of the fourth ventricle. One year later, a spinal metastasis was treated the same way. Six years later, a 16-mm lesion was found on a control MRI in the posterior fossa. To help the differential diagnosis between a relapse, a radio-induced modification, and a new tumor, magnetic resonance spectroscopy was performed. The main findings were a peak at the expected resonance frequency of reduced glutathione, a prominent peak of glutamate/glutamine compounds, a low N-acetylaspartate, and the absence of elevated choline. These findings were suggestive of a meningioma, although the latency between irradiation and development of the lesion was quite short. The diagnosis was confirmed by the pathological examination.
  
  
  CONCLUSIONS
  This case exemplifies the fact that magnetic resonance spectroscopy provides useful biochemical information in such a clinical setting.
authors.affiliation: Department of Radiotherapy, Centre Hospitalier Universitaire de Liège, 4000, Sart Tilman/Liège, Belgium. irutten@chu.ulg.ac.be
authors.forename: Isabelle
authors.initials: I
authors.lastname: Rutten
authors.forename: Daniel
authors.initials: D
authors.lastname: Raket
authors.forename: Nadine
authors.initials: N
authors.lastname: Francotte
authors.forename: Pierre
authors.initials: P
authors.lastname: Philippet
authors.forename: Shih-Li
authors.initials: SL
authors.lastname: Chao
authors.forename: Marc
authors.initials: M
authors.lastname: Lemort
mesh_terms: D001932:Brain Neoplasms / Q000175:diagnosis* / Q000601:surgery; D002648:Child; D003937:Diagnosis, Differential; D004806:Ependymoma / Q000175:diagnosis* / Q000601:surgery; D020546:Fourth Ventricle / Q000473:pathology* / Q000601:surgery; D006801:Humans; D008137:Longitudinal Studies; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D011878:Radiotherapy; D012189:Retrospective Studies