Unilateral agenesis of the right cerebellar hemisphere in a child: When one hemisphere is missing, the brain adapts.

Unilateral agenesis of the cerebellar hemisphere is a rare congenital anomaly, typically revealed by psychomotor delay or motor difficulties in children. We report the case of a 5-year-old boy who presented with psychomotor delay, in whom magnetic resonance imaging revealed agenesis of the right cerebellar hemisphere associated with vermian hypoplasia. This case illustrates the clinical variability of cerebellar malformations and underscores the importance of neuroimaging for accurate diagnosis, prognostic evaluation, and the planning of a multidisciplinary management approach.