Spontaneous Large Urinoma Secondary to Obstructing Ureteral Calculus: A Kidney Pop-Off Mechanism.

Introduction and Background: Spontaneous rupture of the urinary collecting system with extravasation of urine is a rare complication of obstructive stone disease. Most of the cases are caused by obstructive ureteral stones. We herein present a case of a spontaneous caliceal rupture with a large perirenal urinoma formation that was silent on presentation and managed with endoscopic stenting and percutaneous catheter drainage. Case Presentation: A 56-year-old man presented with complaints of vague right flank discomfort. A noncontrast CT scan revealed a 9.4 mm right mid ureteral obstructive calculus with a 14 cm collection in the perirenal space communicating with the lower calix of the right kidney. Retrograde insertion of 6F Double-J stent was done endoscopically and a pigtail catheter was placed in the right perinephric collection. Initially the catheter drained 100 mL clear urine and decreased progressively. A repeat ultrasonography revealed no collection and the catheter was removed after 10 days. The patient underwent clearance of stones after 8 weeks. On table, retrograde pyelogram showed no leak. The patient is doing well 2 weeks postoperatively. Conclusions: Obstructive ureteral stone presenting with spontaneous forniceal rupture and large perinephric collection in a silent manner. Although endoscopic management alone offers excellent results in small ruptures, diversion of the collecting system with drainage of the collection remains the mainstay of treatment in large urinomas to prevent complications. Definitive management of the cause of obstruction is paramount and should be done after complete healing of the rupture.