Rhombencephalosynapsis, The Famous Unknown: Own Experience and Literature Review of Prenatal Diagnosis with Sonography and Magnetic Resonance Imaging

Abstract

Rhombencephalosynapsis (RES) is a rare cerebellar malformation characterized by congenital fusion of the hemispheres and absence of the vermis. This condition is associated with developmental delay, seizures and involuntary head movements. Although the clinical and imaging aspect of this condition have been thoroughly investigated in the adult, prenatal diagnosis remains still a challenge in the modern Fetal-Maternal Medicine. Here we report our experience with 3 cases and review the current literature as well, focusing specifically on the obstetric imaging as well as on the prenatal diagnosis and management of this rare condition. RES should be considered in the differential diagnosis when absence of the vermis in the Posterior Fossa (PF) is suspected at prenatal Ultrasound Sonography (US), especially when ventriculomegaly or other Central Nervous System (CNS) anomalies are detected. A complete anatomical workup is necessary in these cases. Magnetic Resonance Imaging (MRI) remains to be the imaging modality of choice in confirming the diagnosis.