Embryonic remnants of the umbilical cord: morphologic and clinical aspects.

Embryonic vestiges of the umbilical cord are classic findings in routine morphologic examination of the placenta. In order to evaluate their clinicopathologic significance, we examined samples from the fetal and placental ends of 1,000 umbilical cords and collected the principal clinical findings of the corresponding newborns. Microscopic evidence of embryonic remnants were found in 231 cases (23.1%) divided into remnants of the allantoic duct (63%), the omphalomesenteric duct (6.6%), and the embryonic vessels (30.4%), including one case of hemangioma and an accessory small artery. There were no significant clinical differences between the three vestigial groups, and no particular association with congenital malformations or perinatal complications. In 70.9% of the cases, the embryonic remnants were found at the fetal end of the umbilical cord, where most tumors of the cord develop.