Prenatal diagnosis of omphalocele associated with umbilical cord cyst.

BACKGROUND: To study the cytogenetics, ultrasound findings, biochemical screening, perinatal outcome, and associated abnormalities in cases of omphaloceles associated with umbilical cord cysts.

METHODS: From 1988 to 1994, three cases of omphaloceles with umbilical cord cysts were identified at Mackay Memorial Hospital. We compared the clinical data of our three cases with six other cases in the published literature.

RESULTS: Two cases of omphaloceles with umbilical cord cysts were affected with trisomy 18. One had bilateral choroid plexus cyst, intrauterine growth retardation, low levels of maternal serum alpha-fetoprotein and free beta-human chorionic gonadotropin, and the other had cleft lip and palate, single umbilical artery and intrauterine growth retardation. An elevated level of maternal serum alpha-fetoprotein was found in the case with normal karyotype. Elevated levels of amniotic fluid alpha-fetoprotein were found in two cases. Rupture of the umbilical cord cyst and disruption of the umbilical cord occurred in one case at delivery. Based on the gross and microscopic examinations, the cord cysts we observed are likely to be pseudocysts.

CONCLUSION: The umbilical cord cysts most commonly associated with omphaloceles are pseudocysts and allantoic cysts. Among our three cases and the six other cases published in the literature, four out of these nine cases were trisomy 18. Prenatal diagnosis of omphaloceles or umbilical cord cysts by ultrasound warrants cytogenetic analysis and detailed sonogram to rule out the possible combination of both abnormalities and trisomy 18. If an omphalocele is associated with a large umbilical cord cyst and a normal karyotype, cesarean section is recommended to prevent the dilemma of intrauterine vascular compromise of umbilical blood flow during labor.