Laparoscopic resection for low rectal cancer in a patient with horseshoe kidney - Technical considerations to prevent iatrogenic injuries.

Horseshoe kidney (HSK) is a rare congenital malformation of the kidneys and is commonly associated with other anomalies of the renovascular and ureteropelvic systems. These anomalies present a surgical challenge, especially for surgeries involving the retroperitoneum. We present the case of a 56-year-old male patient with biopsy-proven rectal cancer who had completed neoadjuvant chemoradiation and was planned for curative resection. Contrast-enhanced computed tomography (CECT) of the abdomen and pelvis revealed the presence of an HSK. Reconstructed three-dimensional (3D) images of the renal vasculature revealed the presence of an accessory renal artery originating directly from the aorta and supplying the isthmus of the HSK without any other venous or ureteral anomalies. Laparoscopic abdominoperineal resection with total mesorectal excision was done without any untoward complications. The presence of HSK per se is not a contraindication for laparoscopic operations involving the retroperitoneum. Pre-operative 3D CECT helps to identify the presence of anatomical variations and guides surgical resection.