Oncocytoma in a 10-year post-transplant allograft kidney: A rare case report

Kidney transplant recipients, receiving long-term immunosuppressive treatment, are at a 2-4-fold increased risk for developing malignancies as compared to the general population, with a 5-10-fold increased risk of renal cell carcinoma (RCC). Usually, these tumors occur in the native kidney, and very rarely in the allograft. To the best of our knowledge in the searched literature, three cases of oncocytoma in native kidney and only a single case in allograft kidney have been reported. Here, we report the second case of oncocytoma developing de novo in an allograft kidney, 10 years post-renal transplant, successfully treated using cryoablation. In view of the benign nature of oncocytoma, these patients can be effectively treated with nephron-sparing surgery (NSS), radiofrequency, microwave ablation, or cryoablation, and sometimes with only active surveillance. Thus, accurate early diagnosis helps preserve renal function and avoid unnecessary surgery.