Variation of the ileocolic artery and superior mesenteric artery in a patient with right-sided colon cancer with Lynch syndrome: a case report.

Background: Complete mesangectomy and central vascular detachment are the core elements of laparoscopic right hemicolectomy. Failure to identify vascular variations in patients undergoing laparoscopic right hemicolectomy can result in unwanted bleeding, a prolonged surgical time, transfer to open surgery, and an elevated risk of postoperative complications. In this case report, we describe a new vascular variation that has not yet been reported in the literature. Parallelly vascular variation and the management of vessels in key areas are essential for successful surgery. Case Description: The patient was a 32-year-old female who was referred to the department of gastrointestinal surgery of our hospital due to intermittent abdominal pain accompanied by changes in stool habits for 3 months. She had not experienced other symptoms. Physical examination revealed mild tenderness in the right lower abdomen. Subsequently, she underwent laparoscopic radical right hemicolectomy for ascending colon cancer under general anesthesia in our hospital. Preoperative abdominal contrast-enhanced computed tomography (CT) and intraoperative photos confirmed that there were two ileocolic arteries derived from the superior mesenteric artery (SMA). On the other side, the SMA and superior mesenteric vein (SMV) were found to be accompanied like "X"-shaped variant. The final surgical pathological diagnosis was pT3N1aM0 adenocarcinoma of the ascending colon. Given the patient's family history of colon and uterine cancer combined with the results of immunohistochemical staining and next-generation sequencing, we concluded that she had Lynch syndrome (LS). Conclusions: This report describes the first case of simultaneous variation of the ileocolic artery (ICA) and SMA in a female patient with colon cancer. This type of vascular variation should be fully recognized by surgeons in order to avoid unnecessary intraoperative bleeding.