Allantoid cyst in the umbilical cord diagnosed with B-flow ultrasound.

Allantiod cysts are true cysts in the umbilical cord. They arise from persistent structures of allantois, and the cysts are filled with urine because of a connection to the urinary bladder. Allantoid cysts are located centrally in the umbilical cord and separate the umbilical cord vessels. B-flow ultrasound is a new technique illustrating blood flow. This method is independent of the insonation angle and therefore superior to Doppler ultrasound visualising long segments of vessels with a winding course. The authors present a case with allantoid cysts diagnosed with B-flow ultrasound.