Introduction: We report two cases requiring nephrectomy in long-term follow-up of sporadic left renal angiomylipoma (AML) after transarterial ethanol ablation (TEA). Ethanol is an excellent sclerosing agent that causes complete occlusion of normal or abnormal renal arteries.

Case Series: Case 1 was a 33-year-old woman with a large AML, 12 cm in diameter and concomitant hydronephrosis. A 60% volume reduction of the tumor was achieved by TEA on 1-year follow up. However, a laparoscopic left nephrectomy was performed due to a progressive hydronephrosis by a possible complication of the ablation of the ureteral artery as the volume of the AML was decreased. Pathological examination showed epithelioid AML in a part of the residual tumor and regional lymphnode involvement. Case 2 was a 42-year-old woman with two AMLs in the right kidney, a four cm-sized lesion in the upper pole and a two-cm lesion near the hilus. TEA was performed in the treatment of the AML in the upper pole. However, the one in the hilus was not treated because of potential risk for ablation of the ureteric artery. Nephrectomy was performed with a suspicious of left renal vein involvement of the enlargement of the untreated hilar AML on MDCT although a marked reduction of the volume of the AML in the upper pole on a 4-year follow-up was deserved. Pathological examination showed benign AML extending the renal sinus without the involvement of the renal vein.

Conclusion: TEA can achieve a sufficient reduction of sporadic AML, but has a potential risk for residual tumor of malignant epithelioid AML. Additionally, the therapeutic technique has a fear of unintended ablation of the ureteral artery causing hydronephrosis.

Keywords: Angiomyolipoma, Epitheliod angiomyolipoma, Ethanol ablation, Kidney