Imaging description

Gastroschisis is a para-umbilical, anterior abdominal wall defect, resulting in the herniation of bowel, and occasionally other organs, such as stomach and liver, into the amniotic cavity. The defect is usually to the right of midline and the umbilicus insertion (Figs. 78.1a–f and see 78.3a, b). There is no membrane covering the herniated structures and, as a result the extracorporeal loops of bowel are directly exposed to amniotic fluid. This causes an inflammatory, fibrous coating on the bowel, called peel; additionally, there is thickening of the muscularis propria and atrophy of the mucosa (Fig. 78.1b).

During fetal gastrointestinal development, the midgut elongates rapidly, such that at the sixth week of gestation, developing loops of bowel project into the extra-embryonic coelom, causing physiologic herniation of bowel into the umbilicus (Fig. 78.2a and b). The intestines return into the fetal abdominal cavity after 11 weeks of gestation. As a result, the diagnosis of an anterior abdominal wall defect should not be made until after this event is expected to have occurred.