Report of a rare case of colon cancer complicated by anomalies of intestinal rotation and fixation: a case report.

Introduction: The Situs viscerum inversus associated with anomalies of intestinal rotation and fixation is an extremely rare condition. To the authors' knowledge, this is the first report of colon cancer associated with intestinal malrotation and mesenterium ileocolicum commune.

Case Presentation: A 34-year-old man with a 2-month history of diarrhea associated with abdominal pain and weight loss underwent abdominal ultrasonography, colonscopy with biopsies and abdominal computed tomography scan with intravenous contrast. A right colonic neoplasm was diagnosed, observed only at surgery, as neither computed tomography or ultrasonography showed the intestinal malrotation. Particularly, the third and the fourth part of the duodenum descended vertically, without Treitz's ligament in support to the duodeno-jejunal flexure. The small bowel and the colon were located in the right and left side of the abdominal cavity, respectively.

Conclusion: The anomaly of situs viscerum inversus influenced the surgical strategy in this case because of the vascular and lymphatic anomalies. Lymphatic vessels were therefore marked with subserosal injection of patent blue in the proximity of the tumor. Subsequently, right colectomy was performed. Colectomy extended from the distal ileum to the descending colon, by ligature of the right colic artery and vein at the origin from the superior mesenteric vessels. Patent blue guided lymphadenectomy was also performed with curative intent. Finally, a mechanical ileo-colic anastomosis was carried out. After right colectomy and ileo-descending anastomosis, the Ladd's procedure for intestinal malrotation was unnecessary. The authors believe that this strategy, despite the anatomical difficulties, represents an effective procedure for the radical surgical treatment of the right colon cancer associated with anomalies of intestinal rotation and fixation.