Elsevier

Neurologic Clinics

Volume 36, Issue 3, August 2018, Pages 533-556
Neurologic Clinics

Pediatric Brain Tumors

https://doi.org/10.1016/j.ncl.2018.04.009Get rights and content

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Key points

  • Pediatric central nervous system tumors are the most common solid tumors in children and the leading cause of cancer-related morbidity and mortality.

  • The World Health Organization brain tumor classification is in flux and now includes some molecular parameters.

  • Recent understandings of tumor biology and genomic aberrations have led to better prediction of outcome and alteration of treatment approaches for children with brain tumors.

Presentation

The clinical presentation primarily depends on location of tumor and age of the patient. Infants tend to exhibit relatively nonspecific symptoms, such as macrocephaly, irritability, failure to thrive, loss of developmental milestones, and vomiting.4 Older children most commonly present with localizing neurologic deficits and symptoms related to increased intracranial pressure secondary to obstruction of the normal flow of cerebral spinal fluid (CSF) leading to hydrocephalus. Nonlocalizing

Classification

Brain tumor classification is difficult given that many pediatric CNS tumors may have multiple cell types. Previous classifications tried to identify morphologic appearance on histology and stages of development within the nervous system. As a result, the 2007 World Health Organization (WHO) classification of CNS tumors was based primarily on histologic appearance. However, with recent advancements in tumor biology, in 2016, this classification was changed to incorporate some molecular

Medulloblastoma

Medulloblastoma is, by definition, an embryonal tumor of the posterior fossa and is thought to be the most common malignant brain tumor in children. It comprises up to 20% of all pediatric brain tumors.1 Primarily a tumor of childhood, medulloblastoma is most commonly diagnosed before 15 years of age and has a male predominance.6 There is a biphasic incidence with peaks at 3 to 4 years of age and again at 8 to 9 years of age.7 Previously, in the 2007 WHO classification, medulloblastoma was

Supratentorial embryonal tumors

Non–posterior fossa embryonal tumors, formally known as CNS-primitive neuroectodermal tumors (PNETs), are a group of rare pediatric brain tumors comprising fewer than 3% of pediatric brain tumors and carry a poor prognosis.40, 41 The 2016 WHO classification system incorporates the presence or absence of amplification of the C19MC region on chromosome 19 in defining several subgroups.5 All CNS embryonal tumors are highly malignant and are considered WHO grade IV tumors. Molecular studies have

Atypical teratoid/rhabdoid tumors

ATRTs are rare malignant intracranial neoplasms most commonly occurring in infants and young children. They account for only 1% to 2% of all pediatric brain tumors but approximately 10% to 20% of CNS tumors in patients younger than 3 years.47, 48 ATRTs were previously misclassified until being described as a discrete clinical entity in the 1980s. The genetic hallmark of ATRTs are mutations in SMARCB1.49 In addition to the somatic mutation detected in tumor tissue, approximately a third of the

High-Grade Gliomas

In children, high-grade gliomas (HGGs) occur at an incidence of 0.8 per 100,000 children per year.30 Approximately 20% of all childhood gliomas are HGGs, and include anaplastic astrocytoma (AA), diffuse intrinsic pontine glioma (DIPG), and glioblastoma multiforme (GBM).57 Children with HGGs have an overall poor prognosis despite intensive therapy. Patients may present with headaches, weakness, behavioral changes, or seizures.58 The extent of surgical resection remains one of the most important

Ependymomas

Ependymomas are the third most common brain tumor in children and account for approximately 8% to 10% of all childhood CNS tumors.94 They are neuroepithelial malignancies that occur in the supratentorial brain, posterior fossa, and spinal cord and can affect both children and adults. In children, most occur intracranially with two-thirds located in the posterior fossa.8, 95 There is an increased risk for intramedullary spinal cord ependymomas in patients with NF-2.96 The clinical presentation

Craniopharyngioma

Craniopharygiomas are slow-growing benign epithelial tumors that arise from embryonic remnants of the Rathke pouch in the suprasellar region adjacent to the optic chiasm. They account for approximately 5% to 10% of pediatric brain tumors.103, 104 Symptoms occur as a result of compression of nearby neural structures and can include visual deficits, endocrinopathies, panhypopituitarism from compression of the pituitary gland or stalk, and symptoms of increased intracranial pressure from

Choroid plexus tumors

Choroid plexus tumors are very rare and account for fewer than 1% of all brain tumors and 3% to 4% of pediatric intracranial tumors.115 Patients often present with symptoms of hydrocephalus due to overproduction of CSF by the tumor and less commonly obstruction.116, 117 They are intraventricular papillary neoplasms derived from the choroid plexus epithelium. Histologically they can range from benign well-differentiated choroid plexus papillomas (CPPs) (WHO grade I), atypical CPPs (WHO grade II)

Germ cell tumors

Intracranial germ cell tumors (GCTs) represent approximately 3% of pediatric brain tumors and most commonly arise in midline locations, such as the pineal or suprasellar region of the brain.126 The incidence can vary according to geography, with CNS GCTs accounting for up to 11% of all pediatric brain tumors in Asian countries such as Japan.126, 127, 128 The WHO classification system divides intracranial GCTs into germinomas and non-germinomatous GCTs (NGGCTs). NGGCTs comprise a heterogeneous

Spinal cord tumors

Primary spinal cord tumors are rare CNS tumors in childhood with an annual incidence of less than 1 per 100,000 children per year141 and account for fewer than 6% of all childhood CNS tumors.142 They are difficult to diagnose due to the vague nature of symptoms that can be difficult to characterize. Spinal cord tumors are unique in that they can cause both local and distal symptoms due to tumors interrupting ascending and descending spinal cord pathways. Symptoms typically have a gradual onset

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