Papillary Renal Cell Carcinoma in a Functioning Kidney Allograft: A Graft-Preserving Strategy with Cryoablation and mTORi Conversion.

Background: Renal cell carcinoma (RCC) arising in a kidney allograft is a rare but challenging condition, requiring a careful balance between oncologic control and preservation of graft function. Minimally invasive nephron-sparing approaches may represent a valuable treatment option in selected recipients. Case Presentation: We report the case of a 59-year-old kidney transplant recipient diagnosed with papillary RCC in the renal allograft during routine imaging follow-up. The patient underwent CT-guided percutaneous cryoablation, combined with conversion of immunosuppressive therapy to an mTOR inhibitor-based regimen. The procedure was completed successfully without complications, and graft function was preserved. At 3-year follow-up, no evidence of local recurrence or distant metastasis was detected, with stable renal function maintained throughout the observation period. Conclusions: This case highlights the feasibility and effectiveness of percutaneous cryoablation as a nephron-sparing treatment for RCC arising in a renal allograft. In carefully selected high-risk transplant recipients, this approach may provide durable oncologic control while preserving graft function.