The spectrum of fetal midline disruption syndrome is wide; it includes anomalies and congenital syndromes such as limb-body wall complex, body stalk anomaly (BSA), and pentalogy of Cantrell . Despite accumulated data on these anomalies, there is still no consensus as to one causative etiological factor. Several theories have been suggested . 2D ultrasonography remains the principal tool for diagnosis of first-trimester anomalies; however, 3D ultrasonography has use in confirming diagnosis of a variety of fetal malformations. We have found that use of 2D and 3D ultrasound together yields optimal results in diagnosis and analysis of limb-body wall complex for both care providers (obstetricians, radiologists, sonographers) and affected parents.
Two-dimensional ultrasound (2D)
Three-dimensional ultrasound (3D)
Expands and confirms diagnosis.
Grayscale hard for parents to see;
3D look helps parents comprehend location and severity of fetal malformations.
Medical confirmation of defects;
Visual rendering of defects to develop global view for medical team and affected families.
Limb-body wall complex is a rare polymalformative syndrome with two distinct phenotypes: one form with placentocranial adhesions, and the other form with placento-abdominal adhesions [3, 4, 5, 6]. Coelosomia is found in all cases; it variably coexists with other anomalies, such as brain, vertebral, visceral and limb anomalies .
Most authorities believe that limb-body wall complex results from early rupture of the amnion sometime between the third and fifth week of embryogenesis . The prognosis for limb-body wall complex is uniformly fatal [7, 8].
With advances in ultrasonographic technique and equipment (providing increasing spatial and temporal resolution), earlier and earlier prenatal diagnosis is possible. Adjuvant usage of 2D and 3D sonography is the best means to diagnose and manage this complex. We report a case of limb-body wall complex at 12 weeks GA which was well visualized on 2D and 3D ultrasonography.
A 25-year-old patient, G3P2 without contributive history, was referred to our level-three center at 13 weeks GA because of the suspicion, on sonography at 12 weeks GA, of a significant anomaly in the lower half of the fetal body.
Detailed two-dimensional ultrasonography was performed endovaginally, showing a live fetus with a coelosomia measuring 20 x 15 mm protruding from the anterior abdominal wall (Figures 1A, 1B, 1C). The nuchal translucency was 2.9 mm (Figures 2A, 2B). The bladder was not seen, but amniotic bands were observed (Figures 3A, 3B). Three-dimensional endovaginal surface rendering clearly demonstrated an omphalocele as a solid mass protruding from the ventral wall; malpositioned lower extremities were also seen (Figure 4C).
Russo et al (1993) hypothesized that limb-body wall complex with craniofacial defects is caused by an early vascular disruption, whereas limb-body wall complex without craniofacial defects is related to a faulty lateral and caudal folding process of the embryonic disk. The presence or absence of craniofacial defects has been used as a discriminating factor to establish two groups in limb-body wall complex:
(1) Cases with craniofacial defects frequently show cranioplacental attachment; severe anomalies of the upper extremities; and constrictive amniotic bands.
(2) By contrast, cases without craniofacial defects usually present with abdominoplacental attachment; persistence of extra-embryonic coelom; umbilical cord abnormalities; renal defects; abnormal genitalia; anal atresia; and major anomalies of the lower extremities.
Diagnosis of limb-body wall complex by early ultrasonography is now possible. To investigate it, we have found 3D ultrasound very useful in the investigation of limb-body wall complex, particularly when making a detailed assessment of fetal structural defects and of any amniotic bands. In cases of limb-body wall complex, 3D ultrasound expands our diagnostic foundation, identifying limb-body wall complex more clearly and completely, and making information understandable for parents. Because there is little-to-no risk of recurrence of limb-body wall complex, awareness and education on the part of the medical team will help families plan their reproductive futures with more confidence.