What aetiologies are recognised?
Infarction is by far the most common. Other rare causes include: leukomalacia; diffuse hypoxic-ischemic brain necrosis; infection; thromboplastic material from a deceased co-twin (see related article for further information)
What size is the skull in these patients?
It is variable; small, normal or large
What is the differential?
Severe hydrocephalus, alobar holoprosencephaly, large open lip schizencephaly.
Non contrast CT demonstrates marked enlargement of the skull with no anterior circulation cerebral cortex identified. Parts of the occipital lobes, the thalami and the posterior fossa appear preserved. The falx is present.