[Study on the histopathological abnormalities of the umbilical cord].

There have been very few reports of studies on histological abnormalities of the umbilical cord. In the present study, we have investigated various abnormalities of the cord with special emphasis on the cord vasculature and the vestigial remnants based on developmental abberations. The incidence of single umbilical artery was 1/509 (0.2%), by which no special relation was signified between the single artery and the occurrence of congenital malformations of the neonate. Supernumerary umbilical vessels were found in 5/509 (1.0%) of the cases examined. Three out of five revealed the umbilical cord with two arteries and two veins, while two of them showed the umbilical cord with the normal 3 vessels associated with an accessory fourth vessel. It is of a great interest to note that fetal distress with or without fetal acidosis was demonstrated in all cases with the accessory fourth vessel, whereas the presence of supernumrary umbilical vessels was least related to the occurrence of congenital malformations of the neonates. The incidence of vestigial remnants was 30/509 (5.9%). The vestigial remnants were classified into two groups according to their epithelial pattern, i.e. flat epithelium and cuboidal or columnar epithelium. The vestigial remnants with flat epithelium type, considered to originate in the allantoic duct, were found in 2/3 (66.7%) of all cases with vestigial remnants. The vestigial remnants with cuboidal or columnar epithelium, considered to originate in the omphalomesenteric duct, were found in 1/3 (33.3%) of all cases with vestigial remnants, one of which case was associated with congenital malformation of omphalocele of the neonate.