CNS tumor
CNS tumors

Topic Completed: 1 February 2012

Revised: 2 January 2019, last major update February 2012

Copyright: (c) 2002-2017,, Inc.

PubMed Search: CNS tumors [title]

Eman Abdelzaher, M.D., Ph.D.
Page views in 2019: 1,257
Page views in 2020 to date: 701
Cite this page: Abdelzaher E. General. website. Accessed May 24th, 2020.
Definition / general
  • 13K deaths in US annually (2% of cancer deaths)
  • Peaks in childhood, then declines to age 25 years, then increases with age
  • Childhood tumors: 33% in anterior fossa (supratentorial), 67% in posterior fossa (astrocytoma - 26%, medulloblastoma / PNET - 24%, ependymoma - 14%)
  • Adults: metastases are more common than primary brain tumors but are usually not biopsied; of biopsied tumors, 67% arise in anterior fossa (glioma - 33%, meningioma - 13%, metastases - 12%, pituitary adenoma - 5%), 33% in posterior fossa (schwannoma - 8%, misc. - 33%)
  • Most common spinal cord tumors are schwannoma, meningioma and ependymoma
  • Metastasis of primary CNS tumors outside CNS is rare, usually occurs along brain and spinal cord via subarachnoid space or due to surgery related implantation of tumor cells into vessels
  • Benign appearing tumors may still be infiltrative and difficult to resect
  • Tumors may arise from neural stem cells, precursors of neurons and glial cells, recently discovered in mature brain
  • Symptoms: focal deficits, seizures, increased intracranial pressure (due to mass effect, hydrocephalus, cerebral edema), herniation
  • Labeling index / proliferation index: percentage of MIB1+ or PCNA+ nuclei (compared to all nuclei), usually in regions of highest proliferation; useful prognostic indicator (high values associated with poorer prognosis)
  • Intra-axial: within brain and spinal cord
  • Intramedullary: within spinal cord
  • Extra-axial: not within brain and spinal cord (such as meningioma)
  • Extramedullary: not within spinal cord
  • Supratentorial: above tentorial membrane - cerebrum
  • Infratentorial: below tentorial membrane - cerebellum, brainstem or spinal cord
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