A case of abdominal aortic aneurysm with horseshoe kidney.

A 69-year-old male who had an abdominal aortic aneurysm with horseshoe kidney is reported. Preoperative 3-dimensional computed tomoangiography (3DCTA) images confirmed two accessory renal arteries diverging from the aneurysm to the isthmus. We operated on the abdominal aortic aneurysm using the left retroperitoneal approach, which provided excellent exposure of the aneurysm without dividing the renal isthmus. This exposure showed us the accessory arteries, so we could easily recognize these arteries visualized by 3DCTA, and we could reconstruct the larger one of two accessory arteries. Preoperative 3DCTA was very useful for the operation of the abdominal aortic aneurysm with horseshoe kidney. The postoperative course was uneventful.