BackgroundTo evaluate the efficacy and safety of transcatheter arterial embolization for renal angiomyolipoma using a 1.8-French tip microballoon catheter and a mixture of ethanol and Lipiodol.MethodsSeven consecutive patients with total of eight angiomyolipomas underwent this procedure between June 2014 and June 2017. A 1.8-French tip microballoon catheter was advanced to the feeding artery of the angiomyolipoma, and transcatheter arterial embolization was performed with a mixture of ethanol and Lipiodol under microballoon inflation. We retrospectively evaluated the characteristics of angiomyolipomas, technical success rate, clinical success rate, renal function, and adverse events. Technical success and clinical success were defined as complete embolization of all feeding arteries and reduction of tumor size, respectively.ResultsThe median size of the angiomyolipomas was 46 mm (range, 40–64 mm). Transcatheter arterial embolization was successful in all eight angiomyolipomas. The median volume of the mixture of ethanol and Lipiodol was 6.0 ml (range, 2.0–14 ml). The median ratio of ethanol to Lipiodol was 71% (range, 71–75%). All eight angiomyolipomas shrank with a median shrinkage rate of 34% in diameter (range, 9–63%) and 77% in volume (range, 48–94%). The median follow-up period was 13 months (range, 9–54 months). Clinical success was achieved in all cases. Serum creatinine concentrations and the pre- and post-procedural estimated glomerular filtration rates did not change notably, and there were no major complications.ConclusionTranscatheter arterial embolization for renal angiomyolipoma using a 1.8-French tip microballoon catheter with a mixture of ethanol and Lipiodol is effective and safe.