Renal Granuloma Distinct From the Renal Pelvis Following Bacillus Calmette–Guérin Treatment for Bladder Cancer: A Case Report

Introduction: The incidence of renal complication following BCG treatment is rare. Few previous studies have reported a solitary renal granuloma distinct from the renal pelvis following BCG treatment. Case Presentation: An 85-year-old male underwent transurethral resection of the bladder tumor. A 6-week induction of intravesical BCG instillation therapy was planned; however, the sixth instillation was canceled owing to fever. Regular follow-up revealed no recurrence. However, 4 years later, CT revealed a right renal mass. With a clinical diagnosis of renal cell carcinoma, robot-assisted partial nephrectomy was performed. The pathological diagnosis was epithelioid cell granuloma with caseating necrosis. Stress cystography revealed no vesicoureteral reflux. Conclusion: A renal granuloma caused by BCG is one of the differential diagnoses for solitary renal mass following BCG treatment, even if the mass is not adjacent to the renal pelvis.