Posterior fossa tumor has a very different differential in an adult as opposed to a child.
- cerebellar metastases (most common)
- hemangioblastoma: most common posterior fossa primary brain tumor in adults
- astrocytomas, medulloblastomas, and ependymomas 6 are encountered in the posterior fossa of younger adults but are rare in older adults, accounting for <1% all tumors
- lymphoma 4
- lipoma 4
- Lhermitte-Duclos disease
An important space-occupying lesion (the most common in fact) to remember is that of a stroke, which when subacute can mimic a tumor.
- posterior fossa astrocytoma
- medulloblastoma: most common (30-40%) 7
- atypical teratoid/rhabdoid tumor (AT/RT)
- hemangioblastoma (uncommon except in patients with vHL)
- teratoma (in infants)
A quick and handy mnemonic for posterior fossa tumors in children is BEAM.
Although it is true that posterior fossa tumors are much more common in children than in adults the distribution does vary with age 2:
- 0 to 3 years of age: supratentorial > infratentorial
- 4 to 10 years of age: infratentorial > supratentorial
- 10 to early adulthood: infratentorial = supratentorial
- adults: supratentorial > infratentorial
Overall 50-55% of all brain tumors in children are found in the posterior fossa 3.
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- 3. Diagnostic Neuroradiology. Valery N. Kornienko, Igor Nikolaevich Pronin. Springer ISBN:3540756523 (find it at amazon.com)
- 4. Wolfgang Dähnert. Radiology Review Manual. (2011) ISBN: 9781609139438
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- 6. Grossman R, Ram Z. Posterior Fossa Intra-Axial Tumors in Adults. (2016) World neurosurgery. 88: 140-5. doi:10.1016/j.wneu.2015.12.066 - Pubmed
- 7. Kerleroux B, Cottier JP, Janot K, Listrat A, Sirinelli D, Morel B. Posterior fossa tumors in children: Radiological tips & tricks in the age of genomic tumor classification and advance MR technology. (2020) Journal of neuroradiology 47 (1): 46-53. doi:10.1016/j.neurad.2019.08.002 - Pubmed