Prenatal diagnosis of omphalocele with extracorporeal liver.

Omphalocele is a congenital anomaly characterized by a structural defect in the abdominal wall that leads to the protrusion of the intestines or other abdominal organs covered by a protective membrane. Approximately 20%-50% of omphalocele cases are associated with trisomy 13, 18, and 21 and result in fetal death. Prenatal diagnosis of omphalocele can be made by late first trimester ultrasound with a sensitivity of 75% and specificity of 95%, or by elevated maternal serum alpha-fetoprotein concentration.