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arachnoid cysts

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  • arachnoid cysts are incidental findings on CT brain or MRI scans of the brain
  • prevalence is ~1.4%
  • rarely they may be symptomatic - usually in childhood
  • they are thought to arise from a congenital splitting of the arachnoid layer and thus form very thinly lined cystic spaces which are filled with CSF
  • most arise in the Middle Cranial Fossa where they may encroach on the Sylvian fissure, but they can arise anywhere in the CSF space

Differential Diagnosis

  • old infarcts
  • subdural hygroma
  • chronic subdural haemorrhage
  • mega cisterna magna
  • epidermoid cyst
  • other cysts
  • cysticercosis
  • low grade glioma

Complications of arachnoid cysts

Mx of asymptomatic cysts

  • usually nil
  • larger cysts may warrant serial imaging or neurosurgical referral for opinion
arachnoid_cysts.txt · Last modified: 2018/08/13 21:55 (external edit)