If they are large enough, it's possible for polyps to protrude from the anus. If that is the case, they are likely to be cancerous.
A 2022 study investigated post-surgical outcomes following rectal polyp removal and noted that most of the polyps had grown within 6–11 cm of the anus.
A 2018 case study features a rare case of a person passing an adenomatous polyp during a bowel movement. In this case, a 60-year-old man had experienced several weeks of persistent constipation and worsening abdominal pain prior to passing the polyp. The study authors noted that this is the first published case of spontaneous expulsion of an AP during defecation.