Disorganised unilateral cerebellar folia: a mild form of cerebellar cortical dysplasia?

We describe MRI findings in two patients with disorganised foliation of one cerebellar hemisphere, with folia running vertically rather than horizontally. The thickness of individual folia and corticomedullary interdigitations were normal. These patients have no cerebellar neurological deficit. This rare abnormality is probably a maldevelopment of the hemispheric part of the posterior lobe of the developing cerebellum, and no clinical significance can be elicited.