Body stalk anomaly in a 12-week pregnancy

Headnote

Keywords: Abdominal defects, body stalk anomaly, limb body wall complex, first trimester diagnosis

[PP-125]

Introduction: Body stalk anomaly (BSA) massively disfiguring and generally lethal malformation of the thorax and/or abdomen, often associated with limb defects. BSA is rare; reported prevalence ranges from 0.4 to 3.2 per 100,000 live births and stillbirths. However, this range likely under-represents the true prevalence because it does not account for fetal losses due to miscarriage and termination of pregnancy.nWe present a rare case with classic features of this anomaly.

Case: A 26-year-old healthy primigravida was brought to the hospital at 12 weeks of gestation for routine antenatal evaluation. Transvaginal ultrasound revealed single live fetus at 12 weeks of gestation with grossly abnormal morphology (Figure 1a). The fetus had skeletal deformity and a large ventral abdominal wall defect. Biometry revealed a femur length of 11 mm corresponding to a gestational age of 12 weeks. Fetal head could not be visualized. Umbilical cord was very short causing burying of the fetus into the placenta (Figure 1b). A large midline defect of anterior abdominal wall was noted and a membranecovered abdominal mass containing liver and bowel loops was seen herniating through the abdominal wall defect (Figure 1c). Skeletal deformity was severely kyphoscoliotic spine (Figure 1d). Estimated severe prognoses were discussed with the patient and her husband; they opted for termination of pregnancy. Examination of the fetus revealed a large abdominal wall defect with herniation of the small intestine and liver (Figure 2a). Herniated organs were covered by amniotic membrane. Craniofacial features included anencephaly, low-set ears, and cleft lip and palate (Figure 2a). The lower limbs were "with craniofacial defects" phenotype (encephalocele or exencephaly always associated with facial clefts), in which cranial anomalies and cranio-placental attachment predominate, and the "without craniofacial defects" pheonotype (present with urogenital anomalies, anal atresia, lumbosacral meningoceles, and placental anomalies), in which the lower half of the fetal body is found within the persistence of extraembryonic coelom, and intact amnion. Each of these phenotypes may have a different underlying etiology. Our patient is consistent "with craniofacial defects" phenotype.

For practical purposes, both body stalk anomaly is associated with a normal karyotype. They appear in fact to be pathogenetically related. Our patient had normal karyotypes at postabortion genetic analysis (46, XX).

Conclusion: BSA is an accepted fatal anomaly. Therefore efforts should focus onmaking an early diagnosis in order to avoid complications for the mother during the pregnancy and/or childbirth. Although most of the reported cases in the literature suggest that an early diagnosis can be made between 10 and 14 weeks of gestation, in our case the diagnosis was suspected earlier, at 12 weeks of pregnancy. This turns out to be beneficial for both the expecting parents and the physician, as it enables a prompt knowledge of the fetus condition that permits giving an appropriate counseling and a timely management.