An 81-year-old man underwent virtual colonoscopy for symptoms of change in bowel habits. The reconstruction based on air insufflation shows an apple core lesion of the sigmoid colon (bracket). Note the narrow lumen with central ulceration and overhanging "shoulders" characteristic of an exophytic colon carcinoma.
Colonoscopy performed in the operating room prior to surgery showed a typical carcinoma at 27cm. The lumen was too narrow to pass the scope to examine the rest of the colon for smaller early lesions that might have been missed by the virtual study.
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