Necrosis of the fetal brain stem with cerebellar hypoplasia.

Two neonates are presented with intrauterine necrosis of the brain stem. In one of the necrosis and calcification were multifocal and extended from the thalamus to the medulla oblongata. In the other the process was limited to the medulla, but was associated with severe hypoplasia of the nuclei pontis. In both cases the cerebellum was hypoplastic and immature for the gestational age. The connection between the two lesions remains obscure, and two hypotheses are discussed. One hypothesis ascribes the delay in cerebellar development to subliminal damage caused by the same insult that produced the brain-stem lesions, the other considers the possible effects of partial deafferentation on the maturation of the cerebellum.