[Umbilical cord cyst--should it concern us?]

Advancements in sonographic technology have led to improved prenatal detection of fetal umbilical cord and placental anomalies. The prevalence of umbilical cord cystic masses detected in the first trimester is 0.4% to 3.4%. The second- and third-trimester umbilical cord cysts are a rare sonographic finding and its prevalence is unknown. There is a strong association between umbilical cord cysts and fetal anomalies but not in all cases. The main questions are: what are the implications of these findings and what is the prenatal follow-up that should be offered.

In this study the authors present a case in which an umbilical cord cyst was diagnosed at 29 weeks of gestation following normal integrated test and anatomical sonographic survey. At 32 weeks of gestation, fetal karyotype was found to be normal. The outcome of the pregnancy was normal and so was the developmental follow-up during the first three years.

From the literature survey it appears that transient first-trimester cysts are not associated with chromosomal anomaLies, yet they might be associated with congenital maLformations, especially those of the abdominal wall and the urinary tract, and should lead to further detailed sonographic evaluation. Routine karyotype may not be necessary. Second and third trimester umbilical cord cystic masses accompanied by additional malformations are strongly associated with chromosomal anomalies, especially with trisomy 18. Second- and third-trimester umbilical cord cystic masses without additional abnormal findings were also found to be associated with chromosomal anomalies in some works. Therefore, these findings should be an indication for fetal karyotype. In the case of an isolated umbilical cord cyst with normal karyotype, serial sonographic evaluation is needed. If all these are normal, it may be presumed that the cyst is an isolated umbilical cord anomaly and that the fetal prognosis is good.