Brain Tumor



A primary neoplasm arising in the central nervous system (CNS)


  • Most common solid neoplasm of childhood (second to leukemia in overall incidence)
  • Most common cause of cancer death in children 0 to 14 years
  • Slight male predominance
  • Majority arise infratentorially (within cerebellum or brainstem) in children 1 to 14 years of age.
  • Majority arise supratentorially in children <1 year of age.


  • Incidence >3,000 new cases/year
  • 5.4 cases/100,000 children/year (age-adjusted incidence rate, ages 0 to 19 years, between 2007 and 2011)
  • Peak incidence in children ≤7 years of age
  • Approximately 1 in 2,000 children born 2009 to 2011 will be diagnosed with a primary malignant CNS tumor by age 14 years.

Risk Factors


  • Brain tumors are not inherited.
  • About 5% of primary brain tumors may be linked to hereditary genetic syndromes:
    • Neurofibromatosis with optic pathway gliomas (NF1) and meningiomas, vestibular schwannomas (NF2)
    • Tuberous sclerosis with gliomas and rarely ependymomas
    • Li-Fraumeni syndrome with astrocytomas
    • von Hippel-Lindau with cerebellar hemangioblastoma
    • Turcot syndrome with medulloblastoma


Tumors are now classified based on histology and molecular genetic features. The most common are the following:

  • Diffuse gliomas/other astrocytic tumors
    • Arises from glial cells (e.g., astrocytes most common in children)
    • ~50% of childhood CNS tumors
    • Ranges from low-grade (grade I to II; often in the cerebellum or optic pathway) to high-grade (grade III to IV; in the cerebrum or brainstem)
    • Locally recurrent and invasive when high grade
    • Molecular alterations distinguish pediatric from adult gliomas.
  • Embryonal tumors
    • Heterogenous group of tumors that arise from malignant embryonic cells
    • Comprises ~15% of childhood CNS tumors
    • Most common malignant brain tumor in children
    • Most common embryonal tumor (60%) is medulloblastoma (cerebellum).
    • Predisposition for leptomeningeal dissemination
  • Ependymoma
    • Arises from ependymal cells that line the ventricular system
    • 5–8% of childhood CNS tumors
    • Most commonly occurs in the 4th ventricle; may arise in the spinal cord
    • Locally recurrent and invasive; spinal metastases rare at initial diagnosis
  • Germ cell tumors
    • Derived from totipotent germ cells
    • 3–5% of childhood CNS tumors
    • Majority are located in the pineal or suprasellar region.
  • Atypical teratoid/rhabdoid tumor
    • Now classified under embryonal tumors
    • <3% of childhood CNS tumors
    • Majority arise in children <5 years of age.
    • Propensity to arise in the posterior fossa with frequent leptomeningeal dissemination; reported in association with malignant rhabdoid tumors of the kidney
  • Neuronal and mixed neuronal-glial tumors: 6% of childhood CNS tumors
  • Craniopharyngioma: 3–5% of childhood CNS tumors
  • Choroid plexus tumors (papilloma and carcinoma)
  • Meningioma and hemangioblastoma, rare in children


  • No specific causative agents are known, but there is an association with exposure to ionizing radiation, other malignancies, familial/heritable diseases, immunosuppression/immunodeficiency (CNS lymphoma).
  • Molecular markers and variants of individual tumor types are being identified.

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