Situs ambiguous with gastric cancer: report of a case.

Situs ambiguous is an unpredictable anomaly characterized by disorder of the organ arrangement in the chest and abdomen. We report a case of situs ambiguous found incidentally in a 73-year-old man with gastric cancer. Preoperative imaging showed polysplenia, a bridging liver, a midline gall bladder, and pancreatic divisum. The vessels around the stomach were clearly shown by computed tomography with multiplanar reconstruction (MPR). Computed tomography with MPR proved a good diagnostic tool for identifying both the abdominal vessels and the location of the organs. Based on a precise evaluation of this unusual anatomy, we performed distal gastrectomy with dissection of the regional lymph nodes.