Aim: Evaluate the outcome of children with prenatally diagnosed arachnoid cysts.
Material and methods: Retrospective study of seventeen cases of children who were diagnosed with an arachnoid cyst during prenatal MRI between July 1994 and January 2007 and followed up for a mean 6 years and 6 months. Follow-up was based on evaluation of clinical files and contacts with the physicians who were following the children. The children were divided into three groups: group 1 normal development, group 2: minor clinical signs, normal schooling, group 3: major clinical symptoms, schooling disturbed.
Results: Eight of the 17 patients included in this study underwent derivation surgery for the cyst. Eight of the 17 children were in group 1, and 3 in group 2. Four of the 6 children in group 3 had associated symptoms. Two of the children in group 3 present with a supratentorial cyst, and 4 with a cyst of the posterior fossa.
Conclusion: The prenatal diagnosis of a arachnoid cyst should be accompanied by a search for associated lesions. The risk of hydroencephalitis should be explained to the parents.