RESUMO
Fetal vesicoallantoic cyst is extremely rare anomaly of umbilical cord. This disorder is thought to be a remnant of the extraembryonic portion of the allantois and incomplete obliteration of the vesico-allantoic lumen results in a wide spectrum of urachal anomalies. A 23-years-old primigravida was referred to our hospital at 18 weeks of gestation age because of fetal abdominal cystic mass in basal part of umbilicus. On the ultrasonographic examination, the cystic mass appeared to be in direct communication with the urinary bladder markedly distended. The cytogenetic study by amniocentesis showed normal 46, XY. The fetus was dead at 21 weeks of gestation age. The results of autopsy showed multiple anomalies. We report this rare case with review on similar anomalies of the allantois.