A Case of Sigmoid Colon Cancer in a Patient with Persistent Descending Mesocolon and Horseshoe Kidney

Abstract

A 66-year-old man presented with a chief complaint of lower abdominal pain. Lower gastrointestinal endoscopy showed a circumferential Type 2 lesion in the sigmoid colon, and contrast-enhanced abdominal and pelvic computed tomography (CT) showed a long-S type persistent descending mesocolon (PDM) and horseshoe kidney. Sigmoid colon cancer cT3N1aM0 Stage III b was diagnosed, and laparoscopic-assisted sigmoid colectomy was scheduled. In addition to the anatomical abnormalities, small bowel invasion was also suspected, and the operation was converted to open surgery. The descending colon was deviated medially, and extensive adhesions due to the long-S type PDM had to be detached. Due to the horseshoe kidney, the root of the inferior mesenteric artery was covered by the renal isthmus, and because the dissection toward the proximal side of the inferior mesenteric artery was considered dangerous, D2 lymph node dissection was conducted. The operating time was 264 minutes.

The characteristics of PDM include extensive adhesions of the left mesocolon and angiectopia due to the shortening of the left mesocolon. In surgery for patients with concomitant horseshoe kidney, attention must also be paid to the courses of accessory renal arteries and veins, the ureters, and autonomous nerves. When embarking on surgery, a full understanding of these anatomical abnormalities is key. This is the first reported Japanese case of colon cancer in a patient with PDM and horseshoe kidney, and it is presented along with a discussion of the literature.