Which abdominal wall defect larger than 4 cm is covered by a translucent, avascular sac through which the umbilical cord inserts?

• A. Omphalocele
• B. Gastroschisis
• C. Umbilical hernia
• D. Enterocele

Answer: (A)

This description describes an omphalocele. It is a midline abdominal wall defect in which abdominal contents herniate into the base of the umbilical cord and are covered by a translucent, avascular sac. The umbilical cord inserts into this sac, rather than directly into the abdominal wall. The size is often several centimeters, and being larger than 4 cm fits the typical presentation of a true omphalocele.

Gastroschisis lacks a surrounding protective sac; the intestines protrude through a defect beside the umbilicus and are exposed to amniotic fluid. An umbilical hernia at the umbilicus is typically covered by skin and does not involve a sac into which the cord inserts. An enterocele is not the described neonatal presentation.