Hydronephrosis caused by ureteropelvic junction obstruction (UPJO) may be caused by intrinsic stenosis or valves, ureteral insertional anomaly, fibrous bands/adhesions, crossing vessels, or even renal mobility. We report a case of hydronephrosis that developed after open partial nephrectomy for renal cell carcinoma.

A 67-year-old female underwent open partial nephrectomy for an exophytic 4.8cm renal mass located in the inferior pole. 9 months postoperatively, the patient presented with right flank pain and UTI. CT urogram revealed hydronephrosis and luminal narrowing of the right proximal ureter. DJ stent insertion done and replaced every 3 months for 1 year. In the interim, the patient also had recurrent dysuria and flank pain. RGP was done and drain films showed that the right pelvicalyceal system still had inadequate drainage hence reconstructive procedure was done. There was a dilated extrarenal pelvis and fibrous adhesive bands at the area of the UPJ causing kinking of the proximal ureter.

Adhesiolysis and spiral flap pyeloplasty was done. DJ stent was inserted and nephropexy was done. The DJ stent was removed 1 month postoperatively. Symptoms resolved.

UPJO is an under-reported complication of partial nephrectomy. Diagnosed at 7 to 10 weeks postoperatively, injuries caused during dissection of inferior pole mass and removal of perinephric fat may contribute to stricture formation. Include monitoring for UPJO on follow up after partial nephrectomy.