Bibliogr. s. 73-74

Background: Duplicated collecting system of a kidney occurs in 1.7-4.2% of the population. It is a complex, unilateral or bilateral, congenital abnormality of the pyelocalyceal system and the ureter. The 2 ureters fuse to form a single ureteral orifice or empty separately into the bladder (ureter duplex). Duplicated collecting systems with complete ureteric duplication may lead to developing vesicoureteral reflux, hydronephrosis, and urinary infection. Case Report: This article presents a case of a 49-year-old woman with duplicated collecting system and hydronephrosis in the upper pole. The anomaly was diagnosed using urography, ultrasonography and computed tomography examination. Conclusions: The best method for diagnostics of the duplicated pyelocalyceal system complicated by hydronephrosis is computed tomography examination, especially multislice computed tomography. The authors present also the options for therapy.