Presentation
Irritable child with excessive crying. Unable to stand or walk without support.
Patient Data
A large posterior fossa cyst elevating the tentorium and straight sinus. The hypoplastic vermis is everted over the posterior fossa cyst. The cerebellar hemispheres with a winged appearance and brainstem are hypoplastic. Thinned occipital bone with occipital bossing is seen. Hypoplastic cerebellar hemispheres.
Findings are suggestive of Dandy Walker Malformation.
Sagittal image shows a large posterior fossa cyst elevating the tentorium and sinus rectus (red arrow). The hypoplastic vermis is everted over the posterior fossa cyst (yellow arrow). The cerebellar hemispheres and brainstem are hypoplastic (green arrow). Thinned occipital squama is seen (blue arrow).
Axial image shows hydrocephalus, a large cerebrospinal fluid cyst in the posterior fossa and hypoplastic cerebellar hemispheres with a winged appearance (white arrowheads).
Case Discussion
Dandy Walker malformation is a rare congenital malformation of posterior fossa structures which can be diagnosed on antenatal ultrasonography. Usually presents in early childhood with delayed motor milestones or with symptomatic intracranial hypertension.
Close imaging differential include: