We report a case of a large angiomyolipoma in a horseshoe kidney associated with a macro-aneurysm bleeding into the retroperitoneum. The patient was successfully treated by embolization of the macro-aneurysm, using thrombogenic cois and Ivalon particles. He remains free of symptoms at 18 months of follow-up. CT scan and renal ultrasound confirm no flow to the previous area of the macro-aneurysm and no change in size of the benign tumor.