RHOMBENCEPHALOSYNAPSIS - CEREBELLAR EMBRYOGENESIS

We describe two infants in whom rhombencephalosynapsis was diagnosed w ith MR imaging in vivo. In contrast to Dandy-Walker malformation, the vermian maldevelopment in this anomaly is characterized by an absence of the anterior vermis and a deficiency of the posterior vermis. The c erebellar hemispheres are fused. In an attempt to identify the pathoge nesis of these anatomic manifestations, we question the traditional co ncept of the embryologic development of the cerebellar primordium.