Epidemiology of pediatric tumors of the nervous system according to the WHO 2000 classification: a report of 1,195 cases from a single institution

Abstract

Object: The purpose of this study is to determine the epidemiology of tumors of the nervous system diagnosed according to the WHO 2000 classification in a single Brazilian institution.

Patients and method: One thousand one hundred ninety-five tumors in children between 0 and 21 years of age diagnosed between 1974 and 2003 were classified according the sex, topography, and age distribution.

Results: In all ages, males were slightly more affected. In the first 2 years, the prevalence for boys was higher (68.3%). In the whole series, 58.7% were supratentorial, 31.4% infratentorial, and 9.9% spinal (44% intra- and 56% extramedullary). Among these latter, ependymomas and schwannomas were the most frequent. In the cerebral compartment, pilocytic astrocytomas were the single most frequent tumors (18%), followed by diffuse astrocytomas (14%), medulloblastomas (11%), and craniopharyngiomas (11%). In the posterior fossa, there was an even distribution among medulloblastomas and pilocytic astrocytomas, but the former was much more frequent in the first 2 years of age. High-grade (III and IV) diffuse astrocytomas were slightly more frequent than low grades (II), and this difference becomes more evident as the child grows older. Due to the new development of the surgery of epilepsy, the frequency of neuronal and mixed neuronal-glial tumors is increasing (8%).

Conclusion: Classified according to the latest WHO classification, by a single neuropathologist in a single institution, this large series of pediatric neurological tumors may reflect fairly well their real incidence. Our results obtained in a developing country do not differ substantially from other similar series reported in the literature from the First World.