Ultrasonographic evaluation of fetal posterior fossa anomalies: Six years experience of a tertiary center

Purpose: The aim of this study is to reveal ultrasonographic features, associated anomalies and genetic errors in posterior fossa anomalies. As secondary aim postnatal outcomes of the cases were reviewed. Methods: We conducted a retrospective case series from 2018 to 2024 involving fetuses with posterior fossa anomalies (PFA). Terminated cases confirmed by radio- logic and postmortem pathologic findings and cases confirmed by postnatal clinical findings were included in the study. Results: A total of 138 cases were included. In 81 (59%) cases there were multipl anomalies including cranial anomalies other than posterior fossa in 31 (22%) and non-central nerve system anomalies in 69 (50%) cases. Of the 94 cases born, 28 (20%) died within a median of 2 months, within 1.5 years at the latest. Of the 66 (48%) cases still living, 30 (22%) have neurodevelopmental delay in Denver II Turkish standardized test. Conclusions: It is crucial to have accurate and standardized prenatal classification and a multidisciplinary approach in fetuses with PFA. Specific ultrasonographic findings may be diagnostic especially where fetal MRI is not always available. We offer "arrow sign" to be tested whether it is accurate to diagnose Joubert syndrome by ultrasonography.