Prenatal Diagnosis of Arachnoid Cysts Without Extra-Central Nervous System Anomalies in the Korean Population: A Multi-Center Retrospective Study on Postnatal Diagnosis and Clinical Outcomes.

Background: The aim of our study was to investigate the clinical characteristics, discrepancies in postnatal diagnosis, and outcomes of prenatally diagnosed arachnoid cysts without extra-CNS anomalies.

Methods: This study was a multi-center retrospective cohort study from 16 participating university hospitals in South Korea, with patient data pooled from January 2010 to December 2019. This study focused on cases with prenatally diagnosed arachnoid cysts and analyzed postnatal diagnoses related to CNS anomalies, the need for surgery, and clinical outcomes.

Results: Thirty-seven fetuses with fetal arachnoid cysts were ultimately included in our analysis. These included 27 supratentorial cysts and 10 posterior fossa cysts, with 11 cases (29.7%) presenting associated CNS anomalies. The most common associated anomalies were ventriculomegaly (18.9%) and callosal abnormalities (10.8%). No chromosomal abnormalities were detected during antenatal care. Postnatal regression was observed in 14.8% of supratentorial cysts and 10.0% of posterior fossa cysts. Neurologic complications, present in 21.6% of all cases, were more prevalent in cases with associated CNS anomalies compared to isolated arachnoid cysts.

Conclusion: In cases diagnosed with prenatal arachnoid cysts, ventriculomegaly and callosal anomalies are the most commonly associated CNS anomalies. The presence of additional CNS anomalies is the most critical factor affecting neurologic outcomes.