Successful treatment of BK virus‐associated severe hemorrhagic cystitis with bilateral single‐J ureteral stenting

INTRODUCTION: BK virus‐associated hemorrhagic cystitis is a significant complication of hematopoietic stem cell transplantation. Although severe BK virus‐associated hemorrhagic cystitis is associated with treatment‐related mortality, sufficient evidence regarding its management is lacking. CASE PRESENTATION: A 14‐year‐old boy presented with BK virus‐associated hemorrhagic cystitis and bladder clot retention after hematopoietic stem cell transplantation. Various urological interventions failed to improve cystitis. While bladder clot retention frequently recurred, surgical intervention was difficult because of the underlying hematological disorder. Hence, bilateral single‐J ureteral stenting followed by Foley catheter placement was performed as a urinary diversion. The bladder clot completely disappeared 27 days after stenting. No additional procedure was required. BK virus‐associated hemorrhagic cystitis did not recur after the blood clot disappeared. CONCLUSION: Bilateral single‐J ureteral stenting followed by Foley catheter placement is a simple and effective treatment method and should be considered before surgical intervention for severe BK virus‐associated hemorrhagic cystitis.