Presentation
Acute abdominal pain.
Dilation of the large bowel to the level of the mid-descending colon where there is an apple-core like enhancing mass causing obstruction. The cecum is particularly patulous. Free air and mild peritonitis (notice distal ileum thickening).
Distal descending colon adenocarcinoma is circled.
Case Discussion
The biggest risk of this case is to focus all of your attention on the fact there is a perforation of the colon, and potentially be distracted by the cecum alone and neglect to notice the rest of the colon is also dilated (although to a lesser degree). While you might think this is related to ileus in the setting of perforation, there is an apple-core like mass of the mid distal descending colon responsible for colonic obstruction, and the cecum has become particularly patulous to accommodate the presumably slow progression of colonic obstruction as the mass enlarged. Although the precise site of cecal perforation is not well seen, it is safe to assume this is the location of perforation as when it becomes this dilated it is at risk for ischemia.
- run the colon from the anus through the cecum on every case, even if you find a presumed cause of pain
- rely on both axial and coronal images when you are evaluating large bowel pathology; notice how hard the mass is to see on axial images (very easy to skip over), but becomes more apparently on coronal/sagittal images
Surgery confirmed cecal perforation, and pathology confirmed descending colon adenocarcinoma.