Ultrasound Features and Management of Body Stalk Anomaly

Abstract

Objectives: This study describes the prenatal diagnosis of body stalk anomaly (BSA) in a large series of affected pregnancies and proposes an algorithm for the differential diagnosis of abdominal wall defects in the first trimester. Methods: This was a retrospective study of all the cases of BSA diagnosed in our tertiary unit between 2009 and 2015. In all cases, we performed a detailed ultrasound examination with particular emphasis on the appearance of the amniotic membrane and content of the amniotic sac and the coelomic cavity. Results: The study included 17 cases of BSA (15 singleton pregnancies, one dichorionic-diamniotic twin pregnancy discordant for BSA and one case of conjoined twins) at a median gestational age of 12⁺³ (range 11⁺⁰ to 16⁺⁶) weeks. In all cases, the liver and bowel were herniated into the coelomic cavity and the amniotic sac was intact containing the rest of the fetus with a normal amount of amniotic fluid; additionally, there was severe kyphoscoliosis and positional abnormalities of the lower limbs. The umbilical cord was absent, but umbilical vessels were seen with color Doppler running from the placenta to the fetus marginally to the eviscerated abdominal content. Conclusion: BSA can be easily diagnosed from 11 weeks' gestation. Examination of the amniotic membrane continuity, content of both the amniotic sac and coelomic cavity and a short umbilical cord help in differentiating this condition from other abdominal wall defects.

Complex malformations involving the fetal body wall – definition and classification issues

“…We categorized different phenotypes according to definitions proposed by Van Allen et al ., Russo et al ., Sahinoglu et al . and Panaitescu et al . (Table ) and compared the incidence of abnormal karyotype and associated anomalies in different types of the syndrome.…”

“…The aim of the study was to analyse the sonographic findings, karyotypes and pregnancy outcomes in complex malformations of the fetal body wall in a large cohort of fetuses with regard to different definitions proposed in the literature (Van Allen et al ., Russo et al ., Sahinoglou et al . and Panaitescu et al ).…”

“…two out of three defects present: thoracoschisis or abdominoschisis, acrania/encephalocoele with facial clefts and limb anomalies) . However, other authors identified different phenotypes of body wall anomalies (like body stalk anomaly [BSA]) using definitions that were later not strictly followed . According to Goldstein et al ., BSA should be considered when there is a body wall defect, skeletal abnormalities and the umbilical cord is absent or rudimentary .…”

Fetal Abdominal Wall Defects

“…Two phenotypes have been described, respectively, as placento-cranial and placento-abdominal [75]. The diagnosis of BSS can be established by the end of the first trimester US scan [76] or at 11 weeks' gestation [77]. The US features of BSS show: the fetus is located (in its entirety or partially) outside the amniotic cavity, with an abnormal fetus, that cannot be separated from the placenta, and has lost his anatomic landmarks (Figure 4a, b).…”

“…There can be also thoracoabdominal defects, spinal cord abnormalities, positional limb deformities and abnormalities of umbilical cord and membranes. As the US appearance can be confusing, the examination of the amniotic continuity, content of both the amniotic sac and coelomic cavity and a short umbilical cord helps in differentiating this condition from other AWD [77]. The differential diagnosis includes other polymalformative conditions, such as pentalogy of Cantrell, omphalocele-exostrophy-imperforate anus-spinal defects and isolated gastroschisis [78].…”