Case contributed by Aws Qahtan Hamdi


An antenatal ultrasound examination during the second trimester.

Patient Data

Age: Intrauterine (21 weeks)
Gender: Female

​​A live fetus (21 weeks) showing an absence of calvarium, brain tissue, and scalp, with a frog-like appearance of eyes. Associated with polyhydramnios. No other associated anomalies were seen.

Case Discussion

Anencephaly is the most severe form of cranial neural tube defect (NTD) and is characterized by an absence of cortical tissue (although the brainstem and cerebellum may be variably present) as well as the absence of the cranial vault. Many associated abnormalities are recognized like spina bifida, spinal dysraphism, diaphragmatic hernia, and cleft lip/palate.

If some amount of neural tissue is present, the condition is termed exencephaly.

It is usually associated with polyhydramnios like other neural tube defects.

It differs from amniotic band syndrome in which the band passes through the head.

Folic acid supplementation is important for women of reproductive age to prevent neural tube defects.

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