The Retro-Cerebellar Arachnoidal Cyst: Prognosis and Literature Review

Arachnoid cysts are collections of cerebrospinal fluid developed within the arachnoid. The arachnoid cyst of the posterior fossa is sometimes responsible for neurological, motor, severe and irreversible disorders. We report a case of an arachnoid retro cerebellar cyst’s antenatal diagnosis on a fetus during an ultrasound performed at 33 WG and confirmed by a MRI at day of life. Treatment consisted of ventriculoperitoneal Shunt at six months of life with immediate decrease of the cyst volume. The eleven-month control found a complete resorption of the arachnoid cyst but a minor psychomotor retardation. It results that the prognosis is mainly related to the presence of associated lesions whose research requires the availability of magnetic resonance imaging.