title: Magnetic resonance imaging features of meningiomas in children and young adults: a retrospective analysis.
abstract: OBJECTIVE
  Meningiomas are rare in children and, unlike in adults, they have male predominance, unusual locations, cystic components and poorer clinical outcomes. The aims of our study were to: a) evaluate the MRI features of pediatric meningiomas; b) correlate ADC values of meningiomas with clinical and histopathological types; and c) correlate peritumoral edema with size and histopathological type of tumor.
  
  
  METHODS
  Radiological data from 24 patients (mean age: 14.3 years) with an imaging or histopathological diagnosis of meningioma, and presurgical MRI between 1995 and 2009 from two medical institutions, were reviewed. Meningiomas were clinically classified as spontaneously arising meningiomas (SAM), NF2-associated meningiomas (NF2-M) and radiation-induced meningiomas (RIM) and, histopathologically, according to the WHO classification system. The main MRI signal characteristics and enhancement were evaluated. ADC values were compared with histopathological type and clinical group. Tumor size and peritumoral edema were also assessed.
  
  
  RESULTS
  Thirty-four meningiomas (eight SAM, 13 NF2-M, 13 RIM) in 24 patients (12 male, 12 female) were evaluated. Unusual locations were frequently seen in SAM, including cases of intraventricular and intraparenchymal meningiomas. SAM were also always larger than either RIM or NF2-M. Cystic components were only found in SAM, and were not associated with high-grade tumors (WHO II and III). Mean ADC values were significantly different between SAM and NF2-M, but were not associated with histopathological type. Peritumoral edema correlated with tumor size, but did not differ significantly according to clinical group.
  
  
  CONCLUSIONS
  Pediatric SAM have unusual locations, larger size and cystic components, and are diagnosed at a younger age than NF2-M and RIM. NF2-M can have unusual locations such as, in particular, the craniocervical junction. Tumor ADC values did not help to predict tumor grade or clinical type. Peritumoral edema correlated with tumor size, but not with clinical group or histopathological grade.
authors.affiliation: Division of Pediatric Radiology, Department of Radiology and Radiological Science, Johns Hopkins Hospital, Baltimore, 600 North Wolfe Street Nelson Basement, 172, Baltimore, MD 21287-0842, USA.
authors.forename: Pedro S
authors.initials: PS
authors.lastname: Pinto
authors.forename: Thierry A G M
authors.initials: TA
authors.lastname: Huisman
authors.forename: Edward
authors.initials: E
authors.lastname: Ahn
authors.forename: Lori C
authors.initials: LC
authors.lastname: Jordan
authors.forename: Peter
authors.initials: P
authors.lastname: Burger
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Cohen
authors.forename: Zoltan
authors.initials: Z
authors.lastname: Patay
authors.forename: Aylin
authors.initials: A
authors.lastname: Tekes
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008577:Meningeal Neoplasms / Q000175:diagnosis* / Q000473:pathology; D008579:Meningioma / Q000175:diagnosis* / Q000473:pathology; D009381:Neoplasms, Radiation-Induced / Q000175:diagnosis / Q000473:pathology; D012189:Retrospective Studies; D055815:Young Adult