Laparoscopic resection aided by preoperative 3-D CT angiography for rectosigmoid colon cancer associated with a horseshoe kidney: A case report.

We herein report a case of laparoscopic high anterior resection with D3 lymph node dissection for rectosigmoid colon cancer with a horseshoe kidney. A 65-year-old Japanese man referred to our hospital for rectosigmoid colon cancer was found to have a horseshoe kidney on a CT scan. On 3-D CT angiography, an aberrant renal artery was visualized feeding the renal isthmus that arises from the aorta just below the root of the inferior mesenteric artery (IMA). Laparoscopic anterior rectal resection with D3 lymph node dissection was performed. During the operation, the IMA, left ureter, left gonadal vessels and hypogastric nerve plexus could be seen passing over the horseshoe kidney isthmus. With the aid of preoperative 3-D CT angiography, the root of the IMA was identified on the temporal side of the isthmus and divided safely just above the hypogastric nerve. As a horseshoe kidney is often accompanied by aberrant renal arteries and/or abnormal running of the ureter, 3-D CT angiography is useful for determining the location of these structures and avoiding intraoperative injury.