Purpose or Case Report: Significant advances in the pre- and postnatal neuroimaging techniques in correlation with neurogenetics have led to more accurate diagnosis and classification of posterior fossa abnormalities. The poster aims to highlight important aspects of normal anatomy of the posterior fossa, illustrate cases of the cystic abnormalities in the posterior fossa, and how to differentiate between them based on neuroimaging findings.
Methods & Materials: Many classification schemes have been devised. A classification by Doherty et al in 2013 divides the posterior fossa abnormalities in groups based on its anatomical location: predominantly cerebellar, cerebellar and brainstem, predominantly brainstem and predominantly midbrain. In this poster, we focused on the cystic abnormalities which include Dandy Walker syndrome and its differentials. The pattern of inheritance and long term implications are also reviewed.
Results: Differentials of cystic abnormalities in the posterior fossa include Dandy Walker syndrome, isolated vermian hypoplasia, Blake pouch cyst, arachnoid cyst and mega cisterna magna. Cases illustrating these conditions are presented in this poster. Table 1 provides a summary on congenital cystic malformations in the posterior fossa.
Conclusions: Congenital cystic abnormalities of the posterior fossa have different imaging patterns and long term implications. Therefore, it is imperative for radiologists to differentiate between these abnormalities as they have an impact on therapy.