title: Epidemiology of central nervous system tumors in childhood and adolescence based on the new WHO classification.
abstract: METHODS
  The topography, sex distribution and histology of 340 primary CNS tumors in children up to 17 years of age were investigated and (re-)classified according to the latest WHO classification of nervous system tumors.
  
  
  RESULTS
  Overall the prevalence for boys (60.9%) was higher and supratentorial locations predominated (53.3%); there was an even distribution of low-grade WHO I/II (51.5%) and high-grade WHO III/IV (48.5%) tumors. Boys were more commonly affected in all age groups throughout childhood and adolescence. Infratentorial location was more common between the ages of 3 and 11 years (57.5%). High-grade tumors were more frequently encountered up to the age of 5 years (53.2%). The main histological entities were pilocytic astrocytomas (23.5%), followed by medulloblastomas (16.3%), ependymomas (10.1%), anaplastic astrocytomas and glioblastomas (7.2% each), and craniopharyngiomas (5.6%); astrocytomas overall accounted for 47.3% of pediatric brain tumors. Rarer entities included germ cell tumors, gangliogliomas, and meningiomas (2.5% each), supratentorial PNET and pineal parenchymal tumors (1.9% each), atypical teratoid/rhabdoid tumors (1.3%), choroid plexus tumors (0.9%), and desmoplastic infantile astrocytomas and dysembryoplastic neuroepithelial tumors (0.6% each). A meta-analysis of 10,582 childhood brain tumors accumulated from 16 international surveys revealed a male-female ratio of 1.29 and a supra-/infratentorial ratio of 0.92. The most common histological diagnoses were astrocytomas (37.6%), medulloblastomas (17.7%), ependymomas (9.9%), craniopharyngiomas (7.3%), and germ cell tumors (4.4%).
  
  
  CONCLUSIONS
  Pediatric brain tumors vary considerably in their histological, topographical and gender distribution throughout childhood and adolescence, reflecting different dynamics of individual tumor entities as well as a susceptibility to their occurrence during certain periods of a child's life. Although at times difficult to characterize, pediatric CNS tumors can be satisfactorily classified according to the latest WHO classification of nervous system tumors.
authors.affiliation: Institute of Neuropathology, University Clinics Münster, Germany. rickchr@uni-muenster.de
authors.forename: C H
authors.initials: CH
authors.lastname: Rickert
authors.forename: W
authors.initials: W
authors.lastname: Paulus
mesh_terms: D000293:Adolescent; D000367:Age Factors; D016543:Central Nervous System Neoplasms / Q000145:classification / Q000453:epidemiology*; D002648:Child; D002675:Child, Preschool; D003431:Cross-Cultural Comparison; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D008297:Male; D011379:Prognosis; D012737:Sex Factors; D014944:World Health Organization