A Case of Laparoscopic Surgery for Sigmoid Colon Cancer with an Anatomic Abnormality of the Inferior Mesenteric Artery

Abstract

A 69-year-old man who presented with acute heart failure during follow-up for melena elsewhere was diagnosed with sigmoid colon cancer via a colonoscopy after hospitalization to our hospital. He was referred to our department for surgery. A preoperative contrast enhanced abdominal computed tomography revealed that the inferior mesenteric artery (IMA) had arisen from the superior mesenteric artery (SMA). We diagnosed the case as multiple sigmoid colon cancers ; two lesions (cT2N0M0, cStage I) were recognized preoperatively, however, the third lesion was revealed in a resected specimen. Then, we performed laparoscopic sigmoidectomy. During the surgery, we confirmed that the root of the IMA was missing in the abdominal aorta as imaging studies showed. At the site, we identified only the colic branch of the lumbar splanchnic nerve. We preserved the left colic artery and resected the IMA and the inferior mesenteric vein under the level of the bifurcation of the left colic artery. The patient was discharged on postoperative day 17 without any complications. The anatomic variation in the IMA arising from the SMA is very rare. Herein, we report this extremely rare case along with a literature review.