[A Case of Transverse Colon Cancer with Intestinal Malrotation].

The patient was a 73-year-old female with left lower abdominal pain. Colonoscopy revealed a tumor in the transverse colon, which was biopsied and diagnosed as a well-differentiated adenocarcinoma. Computed tomography revealed incomplete formation of the ligament of Treitz, with the small bowel located in the right abdomen and the ascending colon along the midline. The superior mesenteric vein(SMV)was positioned on the left side of the superior mesenteric artery(SMA). The tumor was located in the central part of the transverse colon. The patient was diagnosed with transverse colon cancer with intestinal malrotation before surgery. Laparoscopic partial colectomy(of the transverse colon)was performed. The lymph nodes were dissected from the right margin of the SMV. The middle and right colic arteries were severed, and D3 lymph node dissection was performed. The colon was found to have shifted to the left side, with extensive adhesions between the omentum and mesocolon. The postoperative pathological diagnosis was tub1, pT3, pN0, pM0, and pStage Ⅱ a. Intestinal malrotation was diagnosed preoperatively, and unusual vascular positioning was identified. Consequently, we were able to perform safe and adequate lymph node dissection during laparoscopic surgery.