Large bowel obstruction in colon cancer

Case contributed by Roberto Schubert


No gas or bowel movements for 5 days. Left lower quadrant abdominal pain.

Patient Data

Age: 70 years
Gender: Male

There is distension of the large bowel proximal to the sigmoid, with prominent fluid levels. An obstructing mass in the upper sigmoid / distal descending colon with contrast enhancement is noted, the large bowel beyond it being collapsed. In addition the ileocecal valve is competent and despite significant distention of the large bowel, the small bowel is collapsed. 

Annotated image

Enhancing mass at the junction between descending colon and sigmoid colon (dotted blue line) results in proximal large bowel obstruction, with the cecum (yellow * ) most prominently distended. 

The ileocecal valve (orange arrow) is competent and there is no associated small bowel obstruction; the small bowel loop (green arrows) are collapsed. 

Widespread gas is seen adherent to the bowel wall. It can be shown not to be intramural, as A) the gas is on the luminal side of the mucosa (red dotted line) and B) it is only visible where there is liquid fecal matter next to it: it is never seen anti-dependently. Also the fact that the bowel wall enhances normally (red arrows) is against the presence of ischemic colitis, the most common cause of pneumatosis coli in this setting. 

Case Discussion

This case illustrates an early / evolving large bowel obstruction due to a colorectal carcinoma, in a patient with a continent / competent ileocecal valve. 

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