Double ureter and congenital diverticulum of the ureter.

The ureteral duplication is a relatively common malformation and usually has no pathologic consequences. On the contrary, congenital diverticula of the ureter are rare and often give rise to urinary complications. A double malformation combining left ureteral duplication and a congenital diverticulum of the right ureter is reported and discussed. This rare case illustrates one and the same malformational process arrested at different stages of development.