A Case of Isolated Focal Cerebellar Heterotopia in a Patient Affected by HHT: MR and MR Spectroscopy Findings

A practical imaging-based classification of cerebellar malformations distinguishes between focal and diffuse conditions, and between cerebellar hypoplasias and cerebellar dysplasias [1]; among the latter, an important subgroup is represented by cerebellar cortical dysplasias (CCD). CCD has been reported in association with chromosomal abnormalities, congenital muscular dystrophies, other supratentorial brain anomalies, various intrauterine pathologic events (such as infections, toxins or hypoxia); however, its embryogenesis and clinical significance remain poorly understood [2]. Most relevant MR findings of CCD may consist of defective, large, or vertical abnormal fissures; of irregular gray-white matter junction; of lack of normal arborisation of the white matter; of heterotopias in the hemispheric white matter. Cases of major CCD are uncommon in absence of other brain anomalies; on the other hand, focal isolated cerebellar heterotopias are often incidentally diagnosed in asymptomatic patients undergoing MR scan for various indications, and while they may represent a minimal form of CCD, their pathologic significance remains unknown [3].