Fluid collections

Choroid plexus cysts are normal variants that have a variable appearance but in the vast majority of cases appear as small round sonolucent areas in the atrium of lateral ventricles. They are usually seen after 14 weeks’ gestation and typically disappear in the third trimester.

Intracranial cysts are fluid collections occurring in the cranial cavity that exert a mass effect on the brain. Histologically, they can be subdivided into arachnoid cysts, that occur within the internal layers of the meninges, and glio-ependymal or neuroepithelial cysts, that contain glial, ependymal and choroid plexus cyst.