Embryonal tumours of the central nervous system

Abstract

Embryonal tumours are the most frequent brain cancers in children. Most occur before 15 years of age, with a peak between ages 5 and 10 years, but their incidence in infants is proportionally higher, accounting for 20– 30% of all brain tumours in this age group. Other terms used to describe these tumours include small round blue tumours and primitive neuro-ectodermal tumours (PNETs). Five principal histological diagnoses are recognised: medulloblastoma, ependymoblastoma, supratentorial primitive neuro-ectodermal tumour (PNET), medulloepithelioma and atypical teratoid/ rhabdoid tumour (ATRT) (Table 1), but medulloblastoma accounts for 70–80% of the total. Survival for patients with embryonal central nervous system (CNS) tumours has improved over the past 40–50 years. Advances in diagnostic imaging, neuro-anaesthesia, surgical techniques, improved delivery of radiation therapy and chemotherapy have each contributed and chemotherapy is now regarded as a standard treatment in most cases.