Posterior fossa tumours in children and adolescents. A clinicopathological study of 216 cases.

Posterior fossa tumours are characteristics of paediatric population. This report is a study of 216 consecutive cases of neuropathologically verified brain tumours in children under the 18th year of age, who underwent surgery at the Polish Mother Memorial Hospital in Lódź, Poland, between 1990 and 2003. Children with posterior fossa tumours constituted 47% of all paediatric patients with brain tumours. Male-to-female ratio was 1.35:1, and the major peak in the incidence of tumours was observed between 4 and 6 years of age. The most common locations were the cerebellum along with the fourth ventricle (61.5%), cerebellar hemispheres (27.5%), and brain stem (7.5%). Astrocytic tumours (predominantly pilocytic astrocytomas) were the most common group of neoplasms (41.5%) followed by embryonal tumours (all but one medulloblastomas--34.5%), ependymal tumours (13%), and mixed neuronal-glial tumours (5.5%). Altogether, nineteen histological types of brain tumours were diagnosed in the analysed population. The location of tumours, age and sex were compared with those of previously published series of paediatric posterior fossa tumours.