 Redemonstrated is complete absence of the corpus callosum with bilateral resultant colpocephaly and parallel orientation of the lateral ventricles. The lateral and third ventricles again dilated, with the atrium of the right lateral ventricle being the most dilated although slightly decreased from the last exam. The fourth ventricle remains normal in size. Myelination pattern appears appropriate for age on T2 images. There is no midline shift or mass effect or acute infarct. There is unchanged mild prominence of the intra-axial space along the inferior aspect of the posterior fossa probably representing a magna cisterna magna versus small cerebellar tonsils. There is an unchanged 8-mm subcutaneous soft tissue nodule probably representing a superficial lymph node in the right occipital region.
Complete absence of the corpus callosum redemonstrated with third and lateral ventriculomegaly, most prominent in the right atrium. Compared to prior exam, there is slight decreased dilatation of right atrium with the remaining ventricles overall unchanged.