Image-Guided Thermal Ablation in De Novo Renal Tumor Arising in Kidney Allograft: 3-Year Follow-Up. A Case Report

De novo tumors in renal allograft recipients are a severe complication during long-term followup after transplantation and may require transplantectomy. Herein we present a case of de novo renal tumor arising in the renal allograft, treated with the less invasive image-guided radiofrequency ablation (RFA) with long-term follow-up. A tumor was detected during the routine annual follow-up in a patient with good renal function who underwent renal transplantation in 1989. Computed tomography (CT) showed a mass in the allograft whose shape, vascularization, and density suggested the presence of a solid, malignant mass, located in the upper renal pole, that measured 17 mm. CT-guided RFA was performed successfully, and the outcome was verified by an immediate control CT after the intervention. No residual pathologic tissue, major bleeding, or damage to the adjacent parenchyma was evidenced. The patient was discharged with stable renal function. CT scan and ultrasound were performed 3, 6, 12, 18, 24, and 36 months after RFA. No signs of change in renal function, recurrence, neovascularization, or damage to the adjacent microcirculation were observed during the 3-year follow-up. In conclusion, percutaneous RFA of small renal tumors occurring in renal allografts can be considered a function-sparing, safe, and effective therapeutic option when difficult surgical removal may be anticipated. Our experience also supports the need for yearly renal allograft ultrasound follow-up for early identification of small neoplasm than can be treated less invasively.