Agyria (lissencephaly) with anomalous pyramidal crossing. Case report and review of literature.

A case of agyria (lissencephaly) with a highly unusual course of the corticospinal tract at the crossing and in the spinal cord is described. Published cases of agyria (lissencephaly) are reviewed with special attention to the cortical fiber system and organization of the necortex, and their implications for possible pathogenetic mechanisms. The problem of nomenclature is discussed.