Posterior fossa tumours
Posterior fossa tumour has a very different differential in an adult as opposed to a child.
- cerebellar metastases (most common)
- haemangioblastoma: most common primary brain tumour
- astrocytomas and medulloblastomas are encountered in the posterior fossa of younger adults but are rare in older adults, accounting for <1% all tumours
An important space occupying lesion (the most common in fact) to remember is that of a stroke, which when subacute can mimic a tumour.
- posterior fossa astrocytoma
- atypical teratoid/rhabdoid tumour (AT/RT)
- haemangioblastoma (uncommon except in patients with vHL)
- teratoma (in infants)
A quick and handy mnemonic for posterior fossa tumours in children is BEAM.
Although it is true that posterior fossa tumours 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 tumours in children are found in the posterior fossa 3.
- 1. Brain imaging. Laurie A. Loevner. St. Louis : Mosby, c1999. ISBN:032300430X (find it at amazon.com)
- 2. Pediatric neuroimaging. A. James Barkovich. Philadelphia, PA : Lippincott Williams & Wilkins, c2005. ISBN:0781757665 (find it at amazon.com)
- 3. Diagnostic Neuroradiology. Valery N. Kornienko, Igor Nikolaevich Pronin. Springer ISBN:3540756523 (find it at amazon.com)