Hydronephrosis due to ureteropelvic junction obstruction in left pelvic kidney

The article presents a rare case of hydronephrosis due to ureteropelvic junction obstruction (UPJO) in the pelvic kidney. The rarity of this anomaly determines the presence of a limited number of publications on this problem in modern literature. For the following reasons, we find the case presented by us interesting. On the one hand, there was an erroneous tactic of monitoring the patient by outpatient specialists and it was based on data from ultrasound (US) alone, ignoring data from ante- and postnatal ultrasound, which noted the presence of a significant dilatation of the pelvis. On the other hand, the revealed dissonance between the large pelvis and the non-dilated calyces, the inability to visualize the expected wide communications between the calyces and the pelvis, which created the illusion of the presence of a pararenal cyst. The patient underwent Lichtenberg pyeloplasty, which has advantages over dissecting pyeloplasty, when the cause of the UPJO, as in our patient, was a high insertion of the ureter with a structurally normal ureteropelvic junction.