ultrasound diagnosis of fatal anomalies

ABDOMEN
the small-bowel loops into the abdominal cavity
is incomplete. Some of the abdominal organs
thus lie outside of the abdominal cavity. The
hernia sac is covered with amnion and peritoneum.
Loops of small bowel, liver, spleen, and
pancreas may constitute the content of the
hernia. Developmentally, omphalocele is detected
up to 11 weeks of pregnancy. This “physiological
omphalocele” is not considered to be a
malformation, and should disappear at 13 weeks
latest. The presence of liver outside of the abdomen
excludes a physiological omphalocele.
Associated malformations: These are present in
over 50%, especially if liver is found in the hernia
sac. Cardiac anomalies (15–20%), bladder exstrophy,
anal atresia, neural tube defects, facial
clefts, diaphragmatic hernia and sirenomelia
may also be found.
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Fig. 6.19 Omphalocele. Fetus with trisomy 18 after
termination of the pregnancy; cystic lesion of the
umbilical cord, small omphalocele.
Teratogens: Not known.
Fig. 6.20 Omphalocele. Severe lesion found at
15+2weeksinafetuswithtrisomy 18.
Embryology: Intestinal development takes place
in three stages: 1, herniation of the bowel into
the celom and rotation of the bowel; 2, repositioning
of the intestines within the abdominal
cavity; 3, fixation of the bowel to parietal peritoneum
(from 12 weeks onwards). Each of these
phases may be disturbed, causing specific dysfunctions.
Omphalocele results when at the end
of the first phase of rotation, the repositioning of
Associated syndromes: Twenty-five percent of
cases are associated with chromosomal anomalies,
especially if the content of the omphalocele
is only intestines and umbilical cord cysts are
present: triploidy, trisomy 13 and 18, Pallister–
Killian syndrome. Other associated syndromes
are Beckwith–Wiedemann syndrome, Shprintzen
syndrome, Carpenter syndrome, and
CHARGE association.
Ultrasound findings: Transverse and longitudinal
scans of the abdomen show a circular lesion
at the navel, which is connected to the abdomen
with a wide base. It is covered with a membranous
layer and appears encapsulated. The
umbilical vessels can be followed up to the tip of
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