Bladder high-grade urothelial carcinoma in adolescent patient with failed renal transplant: a case report and literature review.

Introduction and importance: Bladder cancer is exceedingly rare in pediatrics and adolescents, particularly after kidney transplantation. Long-term immunosuppression increases oncogenic risk. We report a rare case of high-grade non-invasive urothelial carcinoma in a 17-year-old boy with a failed renal transplant, highlighting risk factors and the need for early evaluation of hematuria. Case presentation: A 17-year-old boy with prior renal transplantation and subsequent graft failure presented with painless gross hematuria. He had a 1-year history of cigarette smoking and was maintained on immunosuppressive therapy. Laboratory tests showed anemia and elevated creatinine; urinalysis confirmed hematuria without infection. Cystoscopy revealed a papillary bladder lesion. A transurethral resection of bladder tumor confirmed high-grade non-invasive urothelial carcinoma. Recurrence was noted on follow-up cystoscopy. BK virus and cytomegalovirus tests were negative. Management included smoking cessation, close cystoscopic surveillance, consideration of immunosuppression withdrawal, and possible intravesical Bacillus Calmette-Guérin therapy. Clinical discussion: Immunosuppression and smoking are major risk factors for bladder carcinoma in transplant recipients. Even mild hematuria warrants urgent evaluation. Early detection and surveillance are critical to prevent recurrence and reduce morbidity. Conclusion: Adolescents with post-transplant hematuria require prompt evaluation. Reducing modifiable risk factors and individualized management of immunosuppression are key to improving outcomes.