Thick corpus callosum: a clue to the diagnosis of fetal septopreoptic holoprosencephaly?

We describe fetal septopreoptic holoprosencephaly (HPE) associated with a thick corpus callosum (CC) diagnosed with MRI in a fetus at 31 weeks' gestation. Our report supports a recently published study connecting a thick fetal CC to other brain abnormalities. On diffusion tensor imaging (DTI), the body of the CC contained an abnormal longitudinal bundle, presumed to be a congenital heterotopic cingulum. Prenatal and postmortem brain MRI with DTI, CT, and pathological analyses are described and illustrated.