[Prenatal diagnosis of isolated posterior fossa anomalies: attempt at a simplified approach]. / Diagnostic anténatal des anomalies isolées de la fosse postérieure: tentative d'approche simplifiée.

ABSTRACT

The authors suggest, after some embryological, anatomical and nosological reviews, a simplified approach mainly based on the appearance of the pons, cerebellar hemispheres and vermis, independently from an associated cystic dilatation of the posterior fossa. Pontocerebellar hypoplasias and partial or total vermian agenesis are detailed because they can be diagnosed with a prenatal MRI. This classification based on our experience and on the literature data should be of value to evaluate the neurological prognosis.