CT shows a transition point in the descending colon. Although no definite mass is seen, this is concerning for an obstructing colon cancer. Ischemic or diverticular strictures are also on the differential.
Gas adjacent to the wall of the ascending colon is pseudopneumatosis (gas trapped between stool and colon wall). This is distinguished from true pneumatosis (gas within the colon wall) because the gas is only seen adjacent to stool or fluid, and is not seen above the fluid level.
The patient had a left hemicolectomy, and pathology showed a 3.5 cm moderately differentiated invasive adenocarcinoma.
Large bowel obstruction is a surgical emergency due to the risk of perforation. In contrast, most small bowel obstructions are initially managed non-operatively, with NG tube suction. (However, closed loop small bowel obstructions are also surgical emergencies.)
A colonic transition point without a definite mass is still suspicious for an obstructing cancer. Look for surrounding lymph nodes.
Normal patients often have a decompressed descending colon, creating an apparent transition point at the splenic flexure. Thus, you should not call a transition point at the splenic flexure unless there is additional evidence.