Ventral Wall



Ventral Wall





13.1 Omphalocele


Description and Clinical Features

An omphalocele is a ventral wall defect at the umbilicus through which abdominal contents herniate into the base of the umbilical cord. The herniated contents are contained by a peritoneal membrane, and the vessels of the umbilical cord travel through the omphalocele. Omphaloceles are associated with other anomalies in approximately 80% of cases and with aneuploidy in approximately one-half of cases. The risk of aneuploidy is lower if the omphalocele contains liver than when liver is not herniated. Omphalocele is also a component of Beckwith–Wiedemann syndrome, which also includes macroglossia (large tongue) and macrosomia (large size).






Figure 13.1.1 Omphalocele containing bowel. A: Transverse image of fetal abdomen (arrowheads) demonstrating echogenic mass (calipers) protruding from the anterior abdominal wall into the base of the umbilical cord. The mass contains herniated bowel. B: Longitudinal image showing echogenic mass (arrow) surrounded by umbilical cord vessels (arrowhead) (S, stomach). C: 3D ultrasound demonstrating mass of omphalocele (arrow) outside fetal abdomen.


Sonography

An omphalocele appears as a rounded, well-circumscribed mass protruding from the anterior abdomen at the umbilical cord insertion (Figure 13.1.1). The omphalocele sac usually
contains bowel and may also contain liver (Figure 13.1.2). Rarely, other intra-abdominal organs are herniated into the sac. The vessels of the umbilical cord travel through the omphalocele and are best imaged with color Doppler (Figure 13.1.3). Because of the association with other anomalies, a careful fetal survey should be performed after an omphalocele has been identified.






Figure 13.1.2 Omphalocele containing bowel and liver. (A) 26-week fetus and (B) 21-week fetus, both with omphaloceles containing bowel and liver (arrows), shown in transverse view of abdomen. The liver (L) is homogeneous and less echogenic than herniated bowel as seen in Figure 13.1.1. C: 3D image showing smooth outer contour (arrow) typical of omphaloceles.







Figure 13.1.3 Umbilical vessels coursing through omphalocele. A: Transverse image with color Doppler of abdomen in 29-week fetus with small omphalocele (arrow) showing blood flow through umbilical vessels (arrowhead) coursing through and out of the omphalocele on color Doppler. B: Color Doppler image in another fetus showing umbilical vessels (arrowhead) coursing through large omphalocele (arrows).


13.2 Gastroschisis


Description and Clinical Features

Gastroschisis is a paraumbilical defect in the anterior abdominal wall through which intra-abdominal contents, usually bowel, herniate into the amniotic cavity. Unlike an omphalocele, the herniated tissue is free-floating in the amniotic fluid, not contained by a peritoneal membrane. The defect is usually to the right of the umbilicus. Gastroschisis tends to affect young mothers more often than older mothers. Aneuploidy is uncommon. Other anomalies are present in approximately 25% of cases, many of which are related to the gastrointestinal tract, such as malrotation.

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Feb 2, 2020 | Posted by in GYNECOLOGY | Comments Off on Ventral Wall
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