Global cerebral dysplasia due to dysplasia and hyperplasia of periventricular germinal cells.

Complete obliteration of the cerebral ventricular cavities has not been previously described as an entity among central nervous system malformations. Markedly disorganized maldevelopment of the deep cerebral nuclei and moderately disorganized maldevelopment of the cerebral cortex were observed in the brains of two cases, a 3-year-old female and a male newborn infant. One showed complete and the other partial obliteration of the lateral and third ventricles. Both showed severe maldevelopment of the basal ganglia, which were represented by a large central mass consisting of randomly distributed multiple nodules of gray matter without any discernible differentiation into lenticulostriate nuclei, thalamus, or hypothalamus. Minor malformations involved the cerebral cortex, cerebellum, and mesencephalon to varying degrees. Each of the above two cases was thought to be unique and different until the brain of a fetus of 155 days' gestation was studied. This fetal brain showed exuberant and disorganized periventricular proliferation and migration of germinal matrix cells, with obliteration of the lateral and third ventricles. It was concluded that hyperplasia and disorganized migration of the periventricular germinal matrix early in gestation of whatever cause itself can result in severe maldevelopment of the deep cerebral nuclei and obliteration of the ventricular cavities.