Duplicated collecting system with lower pole ureteropelvic junction obstruction.

Two examples of the rare case of complete duplicated collecting system with lower pole ureteropelvic junction obstruction are described. Ureteropelvic junction obstruction (UPJO) and duplicated collecting systems seldom occur in combination. Complete duplication of the ureter may be asymptomatic or recognized when complications develop as a result of reflux into the lower pole ureter or obstruction of the upper pole with an ectopic ureterocele. It is difficult to choose an optimal therapy due to the high variability in function, degree of obstruction, damage and potential for regeneration in growing kidneys. The diagnosis and management of UPJO of the lower pole in complete duplicated collecting systems are discussed.