What should be included for the differential diagnosis in this case?
Hydranencephaly, Severe Obstructive Hydrocephalus, Alobar Holoprosencephaly
What important features helps differentiate hydranencephaly from alobar holoprosencephaly and severe obstructive hydrocephalus?
Presence of falx cerebri and unfused midline structres helps differentiate from aloabar holoprosencephaly. Thin cortical mantle compressed against inner table deifferentiates severe hydrocephalus from hydranencephaly.
Cerebral hemispheres replaced by large membranous CSF filled sac (“water bag” brain), with remnants of cortical mantle present, predominantly the occipital and temporal lobes. Thalami are at most only partially fused (third ventricle is visible), cerebellum and brain stem are intact. Choroid plexus present, tentorium cerebelli is intact, but the falx cerebri is absent.