Anterior (atypical) callosal absence due to cortical dysplasia and schizencephaly.

The corpus callosum develops from anterior to posterior, starting at the commissural plate of the lamina terminalis. We report a patient with cortical dysplasia and schizencephaly, which apparently interfered with the normal callosal development before 20 gestational weeks. The result was an atypical callosal dysgenesis in which the anterior parts (including anterior body, genu and rostrum) were absent while the remaining parts were developed. This finding suggests that the commissural plate may not be the only region where the corpus callosum starts to develop in some congenital brain malformations.