The horseshoe kidney is one of the more common congenital developmental malformations of the kidney, but the combination of an abdominal aortic aneurysm is less common. Abdominal aortic aneurysms with horseshoe kidneys are difficult to treat surgically because of the surgical exposure and the complex anatomy of the anomalous renal artery branches. With the advancement of interventional procedures and related materials such as aortic overlay stents, endoluminal isolation surgery is gradually becoming the treatment of choice for abdominal aortic aneurysms combined with horseshoe kidney disease. A case of abdominal aortic aneurysm combined with horseshoe kidney in our department is reported as follows: Case The patient was a 77-year-old male, who was admitted to the hospital for 1 day because of abdominal pack fast found on physical examination. Ultrasound examination of the abdomen on routine physical examination revealed a U-shaped protrusion of the lower abdominal aortic wall convex to the posterior, and abdominal aortic aneurysm was considered. There was no abdominal or back pain. On admission, the blood pressure was 140/80 mmHg; no obvious package was found in the abdomen; the pulsation of both lower limbs was normal. Emergency 64-row enhancement CT showed a cystic aneurysm-like dilatation of the abdominal aorta in the L3 plane, with a size of 31.0 mm × 55.9 mm × 62.5 mm and a neck width of about 27.5 mm; significant enhancement in the lumen after enhancement; horseshoe kidney with multiple small cysts; multiple renal arteries supplying the horseshoe kidney. Laboratory tests included routine blood, liver and kidney function, and normal coagulation time. The diagnosis was “abdominal aortic pseudoaneurysm combined with horseshoe kidney”, and the decision was made to perform intracavitary aneurysm isolation surgery. After general intravenous anesthesia and tracheal intubation, the right inguinal longitudinal incision was performed at 100 px. The right femoral artery was freed, and the 6F arterial sheath was inserted by Seldinger’s method of puncture; a 5F scale pigtail duct was inserted for imaging, which showed 8 renal artery branches supplying the horseshoe kidney, including 2 on the right upper pole (4.0 mm, 2.0 mm), 1 on the left upper pole (2 mm), and 3 on the right lower pole (3.7 mm, 2.1 mm, 1.0 mm). mm, 2.1 mm, 1.5 mm), and 2 left lower poles (2.1 mm, 2.3 mm). The lowest superior renal artery was 22 mm from the superior margin of the aneurysm, except for a 2.3-mm collateral renal artery supplying the left lower pole, which originated from the aortic aneurysm; the lowest superior renal artery was 22 mm from the superior margin of the aneurysm breach. 60-mm overlapping stent (Shanghai Minimally Invasive Company) was delivered via a 22 Fr sheath, and the tip of the bare stent was precisely positioned at the inferior margin of the opening of the lowest superior renal artery. Repeat imaging showed good isolation of the lumen without endoleaks; all renal artery branches remained patent except for a blockage of the collateral renal artery originating from the lumen. The postoperative renal function creatinine level was normal on the postoperative follow-up; the patient was discharged on the 5th postoperative day. Eisendrath et al. divided the horseshoe kidney into 5 categories according to the origin and distribution of the blood supplying arteries of the horseshoe kidney; however, the blood supplying arteries of the horseshoe kidney with abdominal aortic aneurysm should be focused on 3 parts However, in the case of combined abdominal aortic aneurysm, there are three branches of the renal blood supply: the renal artery proximal to the aortic aneurysm neck, the distal branch of the aortic aneurysm originating from the iliac artery, and the renal artery branch originating from the aortic aneurysm lumen. There are currently two main clinical approaches to management: surgical and endovascular isolation procedures. However, the indications for the application of the two methods and the specific treatment methods are not fully unified in the opinions of various medical centers. The main difficulties in surgical management of horseshoe kidney combined with abdominal aortic aneurysm include: ① the isthmus of the horseshoe kidney is usually located directly in front of the abdominal aortic aneurysm; and the ureter of the horseshoe kidney is closer to the midline than normal and is located in front of the isthmus; this makes surgical exposure very difficult; ② 80% of horseshoe kidneys have collateral renal arteries, and the average number of renal artery branches in patients with horseshoe kidney combined with abdominal aortic aneurysm is 3.2 (2-16); the major renal artery branches as well as the collateral renal arteries are closely related to the abdominal aortic aneurysm and need to be avoided during surgery; they may even need to be reconstructed to protect renal function. (iii) Some patients may have hydronephrosis, kidney stones or even chronic urinary tract infection because of abdominal aortic aneurysm; this may lead to infection of the artificial vessels. Therefore, the current surgical management mainly adopts the retroperitoneal route, which can reveal the abdominal aortic aneurysm more clearly, reduce the damage to the horseshoe kidney and its ureter and possibly achieve the reimplantation of the related branches of the renal artery. The use of endoluminal isolation surgery, in which a femoral route is used to isolate the aneurysm cavity with the placement of an overlapping vascular stent, for abdominal aortic aneurysms in combination with a horseshoe kidney requires careful management of the problems associated with the variant renal artery. First, the specific anatomy of the renal artery branches and collateral renal arteries should be fully evaluated, including their origin, relationship to the location of the aortic aneurysm, diameter size, and main blood supply area. Blocking 1-2 anomalous renal artery branches less than 3 mm in diameter resulted in less than 20% renal parenchymal infarction in some patients; however, it did not affect normal renal function. Secondly, there are case reports in the literature of type II endoleaks caused by collateral renal arteries and ruptured aortic aneurysms; therefore, some suggest that the paranephric arteries in the overlying area with significant collateral circulation regurgitation be blocked first by using spring coils on imaging. However, it has been suggested that these collateral renal arteries are mainly the terminal vessels providing collateral circulation to a very small portion of the renal parenchyma, and most cases do not have type II endoleaks; no special treatment of these collateral renal arteries is needed [1]. In the present case, one of the collateral renal arteries originating from the tumor cavity was only 2.3 mm and was not specially treated, but no endoleaks were seen after the intraluminal isolation surgery. In conclusion, in patients with abdominal aortic aneurysm combined with horseshoe kidney, adequate evaluation of renal artery branch diameter, location, and relationship to the aneurysmal lumen and rational use of intraluminal isolation surgery avoids surgical trauma, complex exposure problems during surgery; thus significantly reducing the patient’s surgical risk and hospital stay.