Renal Collecting System Calcified Hematoma Following Parenchymal Perforation by Ureteral Stent in Kidney Transplantation: A Case Report

Introduction: Renal parenchymal perforation by ureteral stent placement is a rare but serious complication. There is also a paucity of data regarding collecting system hematomas and potential calcification in renal allografts. Case presentation: We report a unique case of a 51-year-old male who underwent unrelated living-donor kidney transplantation with stent incorporation during ureteroneocystostomy. Post-operatively he was found to have renal parenchymal perforation by the ureteral stent resulting in a pelvicalyceal hematoma with subsequent calcification and obstruction. At the time of guidewire introduction for percutaneous nephrolithotomy one year later, a nephrostogram and passage of a hydrophilic guidewire resulted in improved contrast drainage into the bladder, so the invasive surgery was no longer needed. Discussion: There are few reported cases of renal parenchymal perforation by a ureteral stent, none of which resulted in a collecting system hematoma. The calcification of urinary tract hematomas is also rare and attributed to metabolic abnormalities, prolonged stagnation of blood, and infection. Conclusions: We suspect the nephrostogram and guidewire introduction created enough antegrade pressure and mechanical disruption to force the calcified hematoma into the bladder.