Allantoic cyst

Allantoic cyst

A swelling formed at the base of umbilicus associated with a patent urachus which results from an allantoic remnant. The urachus is a fibrous remnant of the allantois which communicates from the apex of the urinary bladder to the umbilicus. Failed obliteration of the urachus can lead to various abnormalities: urachal cyst, urachal diverticulum, sinus or patent urachus - the most common type. Allantoic cysts in infants with patent urachus can be formed due to the drainage of urine into the umbili