Umbilical cyst due to patent urachus in a fetus with complete urorectal septum malformation sequence.

Urorectal septum malformation sequence is a sporadic malformation due to failure of septation of primitive cloaca with no anal opening. Umbilical cyst can be associated with chromosomal aneuploidy such as trisomy 18 or trisomy 13. We report on a fetus with complete urorectal septum malformation sequence with an umbilical cyst resulting from a patent urachus and with meconium as its content. This report adds to the variety of the causes of umbilical cyst and the spectrum of consequences of urorectal septal defect.