Right parieto-occipital VP shunt in situ. The right lateral ventricle is slit-like with mild prominence of the temporal horn. The left lateral ventricle is dilated, particularly the trigone. No subdural collection. Diffuse abnormal sulcation throughout the occipital and parietal lobes with polygyria but no focal cortical thickening or signal abnormality and no loss of normal grey-white matter interface. The mantle of tissue lying anterior to the temporal horns is reduced in thickness bilaterally.
Callosal dysgenesis with shortened AP diameter and focal thinning of the anterior body. The inferior colliculi of the tectal plates are prominent and the posterior cranial fossa is small with extensive tonsilar herniation again noted and resulting in crowding of the foramen Magnum. The pineal recess of the third ventricle is prominent, presumably related to callosal dysgenesis, however pineal cyst is difficult to entirely exclude on the images provided.