title: Magnetic resonance imaging features of pilocytic astrocytoma of the brain mimicking high-grade gliomas.
abstract: OBJECTIVE
  The typical magnetic resonance/computed tomographic imaging appearance of pilocytic astrocytoma (PA) is that of a cyst with an intensely enhancing mural nodule. The purpose of this study was to illustrate the aggressive imaging features of PA.
  
  
  METHODS
  One hundred patients referred to the cancer center with brain tumors histologically proven to be PA were retrospectively reviewed (95 by magnetic resonance imaging and 5 by computed tomographic imaging) and analyzed.
  
  
  RESULTS
  The patient population includes 76 pediatric patients younger than 18 years and 24 adults ranging from 19 to 45 years old. Tumor locations consisted of the following: optic chiasm (22), lateral ventricle (3), thalamus (12), basal ganglia (1), cerebral hemisphere (10), corpus callosum (2), brain stem (26), fourth ventricle (1), and cerebellum (23). The imaging appearance of PA consisted of typical features in 71 cases and aggressive features in 29 cases.
  
  
  CONCLUSIONS
  It is important to recognize the aggressive imaging appearance of PA (grade 1 astrocytoma) because it can be mistaken for high-grade gliomas and may thus lead to inappropriate therapy. Despite the aggressive imaging appearance of PA, there is no histopathologic evidence of anaplasia.
authors.affiliation: Division of Diagnostic Imaging, University of Texas, MD Anderson Cancer Center, Houston, TX 77030, USA. akumar@mdanderson.org
authors.forename: Ashok J
authors.initials: AJ
authors.lastname: Kumar
authors.forename: Norman E
authors.initials: NE
authors.lastname: Leeds
authors.forename: Vinodh A
authors.initials: VA
authors.lastname: Kumar
authors.forename: Gregory N
authors.initials: GN
authors.lastname: Fuller
authors.forename: Frederick F
authors.initials: FF
authors.lastname: Lang
authors.forename: Zvonimir
authors.initials: Z
authors.lastname: Milas
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Weinberg
authors.forename: Joann L
authors.initials: JL
authors.lastname: Ater
authors.forename: Raymond
authors.initials: R
authors.lastname: Sawaya
mesh_terms: D000328:Adult; D001254:Astrocytoma / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D001921:Brain / Q000000981:diagnostic imaging / Q000473:pathology; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology; D003937:Diagnosis, Differential; D005260:Female; D005910:Glioma / Q000175:diagnosis*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods; D055815:Young Adult