Elena Knochenhauer, Daniel Behrendt, Uwe Zimmermann, Alexandra Busemann, Stephan Kersting

• Introduction and importance This case report describes the rare encounter of a large infrarenal abdominal aortic aneurysm (AAA) and a horseshoe kidney (HEN), which was managed through comprehensive preoperative planning and effective multidisciplinary collaboration, with the patient being fully informed and consenting to the publication of data and images. Case presentation The patient was referred to the Department of Vascular Surgery with increasing abdominal pain. Computed tomography angiography showed that the aneurysm was significantly advanced. For surgical correction of the aortic aneurysm, the horseshoe kidney was autotransplanted intraoperatively to ensure renal vascular reconstruction for further renal perfusion after treatment of the aneurysm. Discussion Abdominal aortic aneurysm carries a significant risk of rupture, with more than half of ruptures being fatal before reaching the hospital. When the AAA occurs concomitantly with a HEN, detailed imaging is critical for planning the procedure, as the unusual arterial supply to the HEN complicates the procedure and requires careful strategies to protect renal function while treating the aneurysm. Conclusion The treatment of complex cases with severe disease manifestations and difficult anatomy requires careful planning to ensure effective treatment and optimise patient survival and quality of life.