Early Embryonal Maldevelopment of the Umbilical Cord with Defect of the Abdominal Wall and Severe Body Malformations (Dysplasia umbilico-fetalis)

Abstract

A case of dysplasia umbilico-fetalis is demonstrated. The malformation comprises a rare and strange reduction anomaly of the feto-umbilical unit, which is caused during early embryonic life (around the 7 mm stage, corresponding to the end of the third week of gestation). The cause of the damage is not known. The folding off of the embryo from the yolk sac and the development of the abdominal stalk are impaired. No abdominal wall is formed, and the umbilicus and umbilical cord are not developed. The abdominal organs are enclosed in a short amnion-mesoderm tube, which is bordered by the retroperitoneum at the fetal side and by the chorionic plate at the placenta side. The umbilical vessels are only a few centimeters long and traverse in the mesodermal layer of the amnion-mesoderm tube. The thin wall of the tube usually ruptures before birth, thus causing an abacterial fibrinoid peritonitis by the chemical irritation of the peritoneum through the constituents of the amniotic fluid. The lower extremities of the fetus reveal varying degrees of reduction deformities. One leg and large parts of the pelvis may be entirely missing, if the side of origin of the extremity is included in the amnion-mesoderm tube. Severe kyphoscoliosis is probably a secondary phenomenon.

In addition, malformations of the inner organs occur such as caudal displacement and hernia of the diaphragma, hypoplasia of the lungs, dysplasia of the genito-urinary tract and non-rotation of the gut.

The pathophysiology of the rare developmental defect and its secondary implications are discussed with special reference to related malformations such as omphalocele and infraumbilical defect of the abdominal wall.