Crossed fused renal ectopia with segmental fusion of bilateral ureters and abdominal aortic anomalies in a patient with caudal regression syndrome.

Caudal regression syndrome consists of multiple congenital anomalies, mainly caudal segment defects. We describe a preterm baby born to a healthy mother with typical caudal regression picture, including imperforated anus with rectovesical fistula, sacral agenesis, multiple rib and vertebral anomalies, and club feet. Crossed fused renal ectopia with fused ureters resulting in urinary obstruction was managed with transureteroureterostomy and cutaneous vesicostomy. We also found a single large umbilical artery with high abdominal aortic insertion which usually presents in sirenomelia. Because of the anatomical diversity of the urinary and cardiovascular systems associated with multiple congenital anomalies, careful evaluation is mandatory.