Malformations of the midbrain and hindbrain: a retrospective study and review of the literature.

We report the results of a retrospective analysis of radiological and clinical findings in 45 cases of midbrain-hindbrain anomalies and review recent advances in embryology and molecular neurogenetics. Among 45 patients with midbrain-hindbrain malformations, 16 cases of molar tooth malformation, 12 of cerebellar hypoplasia, ten of posterior fossa cyst and cerebellar vermian hypoplasia, three of rhombencephalosynapsis, two of Fukuyama congenital muscular dystrophy and two cases of isolated cerebellar dysplasia were identified. Twenty-six patients presented with motor-mental retardation, which was the most common clinical finding. Eleven patients were born to consanguineous parents. The correct diagnosis of cerebellar malformation is important for determining prognosis, the risk of recurrence and the need for genetic counselling. Integrated classification of malformations based on morphology, embryology and molecular neurogenetics may be useful.