Dandy-Walker syndrome without hydrocephalus in an adult

It is commonly believed that Dandy-Walker malformation is due to increased intracranial pressure resulting from atresia of the foramina of the fourth ventricle, but this is not true in all cases. An adult with asymptomatic Dandy-Walker malformation without hydrocephalus was studied. Increased intracranial pressure could not have caused the malformation in the posterior fossa in this case since no hydrocephalus was present. The findings in this case support the view that Dandy-Walker malformation is due to congenital abnormalities that are not necessarily related to obstruction of CSF flow from the fourth ventricular foramina.