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KEY POINTS
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Key Points

  • Body-stalk anomaly is a sporadic disorder leading to severe deformations of the abdominal wall and spine.

  • Prenatal diagnosis is generally straightforward with massive abdominoschisis, severe kyphoscoliosis, and relatively short umbilical cord being clearly visible.

  • There is no indication to perform amniocentesis as almost all cases are karyotypically normal.

  • The condition is considered uniformally fatal, although there has been at least one case report of a survivor following neonatal surgical closure of omphalocele.

  • While there has been one report of recurrence in a subsequent pregnancy, the condition is generally considered to be sporadic.

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CONDITION
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Body-stalk anomaly is a severe abdominal wall defect that results from abnormalities in the development of the cephalic, caudal, and lateral embryonic body folds. This maldevelopment results in the absence or shortening of the umbilical cord with the abdominal organs lying outside the abdominal cavity and directly attached to the placenta (Shalev et al., 1995; Smrcek et al., 2003). Body-stalk anomaly was first described by Kermauner in 1906 in a newborn with an abdominal wall defect consisting of an amniotic sac that contained viscera; the anterior wall of the sac was directly attached to the placenta and there was no umbilical cord. Other than the references given in textbooks of pathology, body-stalk anomaly was not appreciated in the general obstetric literature until the report of Lockwood et al. in 1986.

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After gastrulation, the embryo consists of a three-layered, flat, oval germinal disk. The rapid growth of the embryo, especially along the sagittal axis causes the germinal disk to curve. Through circumferential folding, the embryo becomes cylindrical. As a result of this process, the body of the embryo closes, the body stalk forms, and an intraembryonic coelom (peritoneal cavity) separates from an extraembryonic coelom (chorionic cavity) (Giacoia, 1992). The amniotic cavity, which is initially located dorsal to the germinal disk, grows rapidly and eventually encircles the fetus, obliterates the chorionic cavity, and envelops the umbilical cord. The abnormality in the folding process prevents this obliteration of the chorionic cavity and formation of the umbilical cord. Without an umbilical cord, the fetus becomes directly attached to the placental chorionic plate. This body-stalk anomaly consists of a sac of amnion–mesoderm that contains the displaced abdominal organs (Giacoia, 1992).

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Causes proposed for body-stalk defect include early amnion rupture with direct mechanical pressure and amniotic bands (see Chapter 99), vascular disruption of the early embryo, or an abnormality in the germinal disk that leads to the formation of an anomalous amniotic cavity (Van Allen et al., 1987). In the early amnion-rupture theory, the abdominal wall and spinal defects could be secondary to the passage of the lower half of the fetal body into the coelomic cavity through the defect in the amniotic sac. The fetus has no room to move and remains practically attached to the placenta. Limb ...

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