Long pedunculated tumor from the ureteral stump protruding into the bladder after nephrectomy: a case report.

The ureteral stump carcinoma after radical nephrectomy is exceedingly rare. We report a 75-year-old woman who underwent right laparoscopic nephrectomy in April 2024 for a renal mass detected during hypertension evaluation. Pathology confirmed clear cell RCC, ISUP grade 2, with negative ureteral margins. In December 2025, during cystoscopy for contralateral renal calculus management, A long pedunculated tumor, arising from the ureteral stump and protruding into the bladder, was incidentally discovered at the right ureteral orifice. Biopsy revealed low-grade non‑invasive TCC. Subsequent laparoscopic partial cystectomy and ureterectomy confirmed ureteral non‑invasive low‑grade TCC originating from the stump. This case highlights that even with initial negative margins, metachronous primary tumors may arise in the urinary tract, necessitating reconsideration of ureteral stump management after nephrectomy.