Lessons for the clinical nephrologist: a rare case of unfused renal ectopia

Right crossed inferior unfused renal ectopia is a rare developmental anomaly in which both kidneys are located on the left side of the body. It's the result of a halt in migration of kidneys to their normal location during the embryonic period and in ureteral bud faulty that migrates to the opposite side and induces the metanephric blastema on the wrong side. In this article, we aim to review embryology and complete description of renal ectopia anatomy and describe a rare case of right crossed unfused inferior renal ectopia with a left lower kidney artery originated directly from an abdominal aortic aneurism (AAA). The treatment consisted in AAA's exclusion with a custom-made endograft device shaped on purpose with a dedicated branch allowing perfusion of the ectopic lower left kidney.