Hippocampal malrotation with normal corpus callosum in a child with Opitz syndrome.

We present cranial magnetic resonance imaging (MRI) findings in a 6-year-old boy with Opitz syndrome. The electroencephalogram revealed epileptiform abnormalities in both frontal regions. MRI showed normal callosal development, but a rounded shape of the left hippocampus due to malrotation. The temporal horn was slightly dilated on the left side. These features were consistent with isolated hippocampal malrotation.