Daily Radiology Case

Explanation

Omphalocele is a congenital anterior abdominal wall defect in which abdominal contents herniate through the umbilical ring into a membrane-covered sac at the base of the umbilical cord. The sac is composed of an inner peritoneal layer and an outer amniotic layer. Contents may include bowel, liver, and spleen. It is distinguished from gastroschisis by the presence of the covering membrane, the central/umbilical location of the defect, and the insertion of the cord at the apex of the sac — whereas gastroschisis is typically to the right of the umbilicus, lacks a covering membrane, and has a normally inserting cord. Omphalocele carries significant associations with chromosomal abnormalities (trisomy 13, 18, 21), congenital heart defects, and Beckwith-Wiedemann syndrome. Prenatal diagnosis is made by ultrasound, with elevated maternal AFP serving as a screening clue. Postnatal management involves surgical repair, with timing and approach depending on sac size and organ involvement.

Source: vHamidi H, Omphalocele. Case study, Radiopaedia.org (Accessed on 24 Mar 2026) https://doi.org/10.53347/rID-72767

Hints

• The perinatologist counsels the family that this finding carries a 30–40% association with chromosomal aneuploidy
• A fetal echocardiogram is ordered given the known association of this defect with congenital cardiac anomalies
• A routine 18-week prenatal ultrasound reveals a midline anterior abdominal wall defect
• The covering membrane is identified as a two-layered structure composed of amnion and peritoneum
• The umbilical cord is seen inserting directly at the apex of the wall defect rather than at the abdominal wall itself
• The defect is found to contain not only small bowel but also a portion of the liver