Hydranencephaly: This condition is characterized by the near-complete absence of the cerebral hemispheres, which are replaced by cerebrospinal fluid (CSF). The diagnosis is often made based on prenatal ultrasound or postnatal imaging studies.

Severe Hydrocephalus: This condition involves an accumulation of CSF in the brain, leading to increased intracranial pressure and potentially causing the cerebral hemispheres to be compressed or damaged, mimicking hydranencephaly.
Porencephaly: A rare condition where there are cysts or cavities within the cerebral hemispheres, which can be confused with hydranencephaly on imaging studies.
Holoprosencephaly: A disorder characterized by the failure of the brain to properly divide during development, which can result in a single-lobed brain and significant cerebral abnormalities.

Vein of Galen Malformation: A rare congenital condition where there is an abnormal connection between arteries and veins in the brain, leading to high-output heart failure and potentially mimicking hydranencephaly due to associated hydrocephalus.
Dandy-Walker Malformation: A condition involving the cerebellum and fourth ventricle, which can cause hydrocephalus and significant neurological abnormalities, potentially leading to a misdiagnosis of hydranencephaly.

Aicardi Syndrome: A rare genetic disorder that affects the development of the brain, eyes, and spine, and can include features that might be confused with hydranencephaly, such as agenesis of the corpus callosum.
Walker-Warburg Syndrome: A rare genetic disorder characterized by muscular dystrophy, brain malformations (including hydrocephalus and lissencephaly), and eye abnormalities, which could potentially be mistaken for hydranencephaly due to the significant brain abnormalities.