What does colon cancer generally look like?

It varies: Colon cancer can be in the form of a polyp or what is referred to as an apple-core lesion, meaning a circumferential narrowing at a specific site in your colon. The above descriptions refer to what is seen either endoscopically during a colonoscopy or radiologically during a barium enema lower GI series.

Mass or ulcer: Most colon cancers manifest as a raised ulcer on the luminal (phenobarbital) surface of the colon. Sometimes it causes a stricture (narrowing) of the involved segment.