Glioependymal cyst regression in watchful waiting follow-up.

Background: Intracranial glioependymal cysts are rare developmental benign lesions usually derived from the third and lateral ventricles. They can show no symptoms throughout life and be an incidental finding or can cause mild-to-severe symptoms which need surgical treatment. Case Description: We present the case of a giant glioependymal cyst of the left lateral ventricle in a newborn baby diagnosed at birth. Hydrocephalus was suspected in the prenatal ultrasound check-up at 37 weeks, leading to careful imaging exploration with brain computed tomography and magnetic resonance imaging (MRI), which suggested the diagnosis of a neuroepithelial cyst. Apgar score at birth was normal and there was no sign of hydrocephalus. Watchful waiting follow-ups every month in the 1st year and every 6 months for the upcoming years with fundoscopic examinations and brain MRI showed a significant cyst shrinking. The last clinical evaluation showed normal activity at the age of eight. Conclusion: In symptomatic neuroepithelial cysts with progressive growth, surgery is recommended. The natural history of untreated glioependymal cysts remains unknown. A conservative approach with periodical follow-ups can be considered in asymptomatic cases, because, rarely, spontaneous shrinking of the cyst can happen.