Exencephaly

Clinical history: A 25-year-old woman was referred for routine antenatal scan at 14 weeks, 2 days of pregnancy.

Findings: Transabdominal sagittal view of the uterus shows a fetus with a reduced crown-rump length of 6.2 cm, corresponding to12 weeks and 5 days of gestation. There is absent calvaria and the brain is exposed to aminotic fluid.

Image shows reversal a wave in ductus venosus flow.

Transabdominal sag view of the uterus shows the same findings of absent calvaria and exposed brain. There were no other anomalies.

Transvaginal scan shows the reduced CRL, absent calvaria and exposed brain.

Diagnosis: Exencephaly

Discussion: Exencephaly is a rare, lethal anomaly with absent cranial vault and protrusion of brain in amniotic fluid. It is considered as a precursor of anencephaly due to failure of closure of neural pore during embryonic life. Maternal serum alpha protein will be highly elevated. This is one of the indications for termination of pregnancy and the patient was advised the same.

R. Pankajam MD, Consultant Radiologist, Medall Health Care Private Limited, Vadapalani, Chennai, India