Dandy-Walker malformation at 27 postmenstrual weeks

(A-D) Panels A through D are serial coronal sections going from anterior to posterior showing the dilated lateral ventricles, the large cisterna magna, and the small cerebellum with the missing vermis.
(E) Axial section showing the large posterior fossa cyst and the cerebellar hemispheres widely splayed out.
(F) Oblique section showing hydrocephaly.