Hydranencephaly: This condition is characterized by the near-complete absence of the cerebral hemispheres, which are replaced by cerebrospinal fluid (CSF). It is often due to a severe insult to the brain early in development, such as intrauterine infection or ischemia.

Porencephaly: A rare condition where there are cysts or cavities within the cerebral hemisphere, often resulting from perinatal ischemia or infection. It can mimic hydranencephaly but typically involves less extensive brain tissue loss.
Schizencephaly: A disorder characterized by abnormal slits or clefts in the cerebral hemispheres, which can be bilateral or unilateral. It may present with significant brain tissue loss and can be confused with hydranencephaly.
Hydrocephalus: An accumulation of CSF within the brain, leading to increased intracranial pressure. While it can cause significant ventricular enlargement, it typically does not result in the near-total loss of cerebral hemispheres seen in hydranencephaly.

Vein of Galen Malformation: A type of vascular malformation that can cause hydrocephalus and significant neurological symptoms. Early diagnosis is crucial for potential intervention to prevent further brain damage.
Dandy-Walker Malformation: A congenital disorder involving the cerebellum and fourth ventricle, which can lead to hydrocephalus. It requires prompt recognition for appropriate management.

Walker-Warburg Syndrome: A rare genetic disorder characterized by muscular dystrophy, brain malformations (including hydrocephalus and lissencephaly), and eye abnormalities. It is a differential diagnosis in cases of hydranencephaly due to its severe brain malformations.
Fukuyama Congenital Muscular Dystrophy: A rare condition that involves muscular dystrophy and brain malformations, including lissencephaly and hydrocephalus. It is another rare differential to consider in the diagnosis of hydranencephaly syndromes.