Neuroradiologic, clinic and genetic characterization of cerebellar heterotopia: a pediatric multicentric study.

Background and purpose:Cerebellar heterotopia (CH) is a neuroradiological abnormality poorly reported and investigated in the literature. It can be observed as an isolated finding, but it has been mainly reported in the context of cerebellar dysgenesis and in syndromic conditions. The aim of this study is to provide a comprehensive neuroradiological, clinical, and genetic characterization of a cohort of pediatric patients with cerebellar heterotopia.Materials and methods:Patients with a diagnosis of CH were systematically selected from the neuroimaging databases of the four Italian Centers participating in this retrospective study. For each patient, information regarding demographic, clinical, genetic and neuroradiological data were collected.Results:Thirty-two pediatric patients were recruited and subdivided into two groups: patients with isolated CH and/or cerebellar malformations (n= 18) and patients with CH associated with cerebral malformations (n=14). Isolated CH consistently showed a peripheral subcortical localization in the inferior portion of cerebellar hemispheres, with either unilateral or bilateral distribution. Ten patients belonging to the second group had a diagnosis of CHARGE syndrome, and their nodules of CH were mainly but not exclusively bilateral, symmetric, located in the peripheral subcortical zone and in the inferior portion of the cerebellar hemispheres; the remaining 4 patients of the second group, showed either bilateral or unilateral CH, located in both peripheral cortex and deep white matter and in the superior and inferior portions of cerebellum. Patients with isolated CH showed high prevalence of language development delay; neurodevelopmental disorders were the most represented clinical diagnoses. Recurring features were behavioral problems and motor difficulties. A conclusive genetic diagnosis was found in 18/32 patients.Conclusions:We found distinctive neuroradiological patterns of CH. Genetic results raise the possibility of a correlation between cerebellar morphological and functional developmental disruption, underscoring the importance of CH detection and reporting to orient the diagnostic path.Abbreviations CH Cerebellar heterotopia; MRI Magnetic resonance imaging; CC Corpus callosum; ASD autism spectrum disorder; IVH inferior vermian hypoplasia.