[Diffuse brain involvement in paediatrics: magnetic resonance findings].

Posterior fossa involvement, which may be focal or diffuse, is an uncommon finding in paediatric patients. Acute cerebellitis is the first condition to be suspected among the diffuse forms, and ataxia is the most characteristic symptom. This condition is occasionally difficult to diagnose clinically, thus imaging tests play an important role in this. However, there are other rare conditions which may be clinically and radiologically similar to acute cerebellitis and which should be taken into account when making a differential diagnosis. The aim of this article is to present five diseases with diffuse brain involvement in paediatric patients and describe how they show up in MR imaging.