This paper presents four posterior, interhemispheric cerebral cysts found at perinatal autopsy. All cysts appeared to attenuate the overlying posterior corpus callosum. All had a base over the roof of the third ventricle and midbrain with a lining that resembled tela choroidea with the choroid plexus tufts projecting into the lumen of the cyst. Three cases had enlargement of the lateral ventricles. One case had complete communication between the cyst and the posterior lateral ventricles reminiscent of a holoprosencephaly confined to the posterior telencephalon. One case demonstrated a complete VATER association and two others had some features of the VATER association. We hypothesize that this latter relationship suggests an origin for the cysts during blastogenesis.