Abstract
BACKGROUND: Intestinal malrotation is a congenital defect of embryonic development caused by various teratogenic factors. In this condition, the intestinal tube, along with the superior mesenteric artery serving as the axis for the counterclockwise movement, is incomplete or abnormally rotated due to incomplete attachment of the mesentery and abnormal intestinal tube position. Such a case is usually asymptomatic and thus difficult to detect. Therefore, similar variant malformations are only found during an operation required for other abdominal diseases. CASE SUMMARY: An elderly male patient was admitted to the hospital due to gastric cancer. An abdominal computed tomography (CT) scan with contrast revealed that the ascending and descending colon were parallel on the right side of the abdominal cavity, while the sigmoid colon extended into the right iliac fossa, allowing the diagnosis of congenital midgut malrotation. Following thorough preoperative preparation, the patient underwent laparoscopic radical gastrectomy to treat his gastric cancer. Intraoperatively, an exploration of the abdominal cavity uncovered the absence of the transverse colon. The distal colon at the hepatic flexure, along with the ascending colon, extended into the right iliac fossa, where it continued as the sigmoid colon. As planned, the laparoscopic radical gastrectomy was performed, and the patient was discharged from the hospital 7 d after the surgery. CONCLUSION: Asymptomatic intestinal malrotation is best detected by CT, requiring no treatment but possibly interfering with the treatment of other diseases.