Essentially, there was a polyp that they mistook for a fatty, but harmless deposit called a lipoma, and so they didn't remove it. The doc did a biopsy, however, and showed it was a polyp, so now I have to go back in for a second colonoscopy to take it out. It's benign at the moment, so there's no great health risk, but it's still kind of annoying to have to repeat the whole dang thing.