Differential diagnosis of term brain cysts

Approach to the differential diagnosis of term infant brain cysts:

  • Arachnoid cyst – cyst is extraaxial in location, of varying size, can be anywhere in the brain, may cause bone erosion
  • Agenesis of the corpus callosum with interhemispheric cyst – large midline cyst actually is a high riding third ventricle
  • Cavum septum pellucidum – cyst lies between the leaflets of septum pellucidum
  • Cavum vellum interpositium – cyst lies between the atria/trigones of the lateral ventricles
  • Cavum vergae – cyst is posterior extension of cavum septum pellucidum and anterior to the splenium of the corpus callosum
  • Encephalocoele – intracranial cyst communicates with extracranial cystic structure