Spontaneous Bilateral Renal Forniceal Rupture Secondary to Acute Urinary Retention in a Patient with Prior Prostate Radiotherapy: A Case Report

Background and Clinical Significance: Spontaneous renal forniceal rupture is an uncommon complication of obstructive uropathy and is classically associated with ureteric calculi rather than distal urinary retention. Bilateral retention-related rupture appears to be exceptionally rare and may be diagnostically challenging when renal function begins to improve after bladder decompression; Case Presentation: An 82-year-old man with a history of prostate cancer treated five years earlier with external beam radiotherapy and androgen deprivation therapy presented with acute abdominal pain radiating to both flanks and inability to void. Bedside ultrasonography showed urinary retention and bilateral hydronephrosis, and a 16-Fr Foley catheter drained 900 mL of urine. Admission evaluation showed severe acute kidney injury, microscopic hematuria, minimal leukocyturia, and elevated inflammatory markers. Post-obstructive diuresis developed after bladder decompression. CT urography with excretory-phase imaging on hospital day 3 demonstrated severe bilateral hydroureteronephrosis with bilateral renal forniceal rupture and associated urinomas, including a larger left-sided collection extending toward the psoas compartment. Bilateral percutaneous nephrostomies were placed on hospital day 4 for upper-tract diversion. Immediate nephrostography showed no active contrast extravasation. At one-month follow-up, combined CT and nephrostographic assessment confirmed complete resolution of the bilateral urinomas without persistent leak, and the nephrostomy tubes were removed; Conclusions: This case suggests that urinary retention in an older man with prior prostate radiotherapy may reflect radiation-associated outlet pathology and/or impaired detrusor function rather than simple prostate enlargement. Delayed-phase CT urography was essential for diagnosis, and active bilateral diversion was justified by bilateral rupture, acute kidney injury, and the extent of urinary extravasation. The report expands the limited PubMed-indexed literature on retention-related upper urinary tract rupture and supports cautious follow-up aimed at defining the underlying mechanism of retention.