PSEUDO-OMPHALOCELE

1. Deformation of the fetal abdomen by transducer pressure coupled with an oblique scan orientation.
• In the presence of oligohydramnios, the uterus may exert pressure on the anterior abdominal wall of the fetus. The abdomen is pliable and elongates in an AP direction and narrows in a transverse direction.
  This may produce a false impression of herniated viscera. The umbilical cord and vessels appear to extend into the midline of the pseudo-herniation (1).
2. When the fetal abdomen becomes wedged in the uterus and is in contact with the myometrium or placenta on two sides. This position can cause compression of the fetal abdominal wall in the absence of oligohydramnios. By changing the mothers and therefore the fetal position the normal abdomen may be seen (1).
3. Normal physiological midgut herniation between the 8th and 12th weeks of gestation.

Acute angles, formed between an omphalocele and the anterior abdominal wall, help differentiate it from the obtuse angles that are seen with pseudo-omphalocele.

REFERENCES

1. Salzman L, Kuligowska E, Semine A. Pseudoomphalocele: Pitfall in fetal sonography. AJR 1986;146:1283-1285.