Intracranial cysts are rare and make up only 1 % of intracranial lesions in childhood. There are very rare cases reported in a fetus.
Classification and terminology is disunited.
Final diagnosis can be achieved only by use of histology and immunohistology.
The prognosis of intracranial cysts identified prenatally during the 1st or 2nd trimestr is not good. The cyst may present with obstructive hydrocephalus in utero. They are often associated with additional CNS malformations, corpus callosum dysgenesis and grey matter heterotopia in particular. The affected individuals often suffer from epilepsy and psychomotoric impairment.
Cysts identified accidentally during the 3rd trimestr or during childhood tend to be asymptomatic and the prognosis is generally good. Some cysts expand, increase intracranial pressure and thus became symptomatic.