To the Editor:The Dandy-Walker malformation (DWM) is a rare congenital malformation involving the posterior fossa.Diagnosis of the DWM is based on a series of characteristic neuroimaging findings,which include complete or partial agenesis of the cerebellar vermis,cystic dilatation of the fourth ventricle,and enlarged posterior fossa.[1] Several malformation syndromes and cytogenetic abnormalities have been associated with the DWM.However,the co-existence of the DWM and neoplasms is rare.[2] There are rare reports of the co-existence of the DWM and ganglioglioma.