Urachal-sigmoid fistula in an adult male without urachal cyst.

Urachal anomalies are uncommon defects arising either by incomplete obliteration of the urachus during the foetal period or by its reopening after postnatal regression. Five anomalies have been described: congenital patent urachus, urachal cyst, umbilical-urachal sinus, vesico-urachal diverticulum, and alternating sinus. Only congenital patent urachus is present at childbirth. The other forms are usually acquired disorders. Nevertheless, they commonly appear in children, being less common in the adult. Colic-urachal fistulas are quite uncommon findings. Only three cases have been reported thus far. The aim of this study is to report the fourth case of sigmoid-urachal fistula, and the first one appearing without an urachal cyst.