Abstract
This case study describes primary acalvaria, which is a rare congenital postneurulation anomaly. The flat bones of the cranium, dura mater, and associated scalp muscles are absent. The skull base and facial features are fully formed and usually appear normal. The brain matter is complete but is abnormally developed. The cerebral hemispheres with their gyri and sulci can be well visualized due to the lack of bone attenuation. This diagnosis can be distinguished from other neural tube defects, such as exencephaly, by the presence of a skin layer overlying the brain matter. There are no current surgical treatments for this pathology, and there are no preventive measures known at this time. Early diagnosis is critical to allow for better pregnancy management.