Anal polyps are small growths on the lining of the anal canal or lower rectum that typically look like fleshy bumps, ranging from smooth rounded mounds to ball-shaped nodules dangling on a thin stalk. Most are under 1 cm across, and many are so small you wouldn’t notice them without a medical scope. Because they grow inside the anal canal, they’re rarely visible from the outside unless they’re large enough to protrude.
Shape and Structure
Polyps come in a few distinct shapes, and doctors classify them largely by how they attach to the lining of the canal. Pedunculated polyps grow on a stalk, looking something like a tiny mushroom or broccoli floret with a rounded head and a narrow stem connecting it to the tissue. Sessile polyps have no stalk at all. They sit directly on the surface as a smooth, slightly raised bump or a gradual mound. Flat polyps are the hardest to spot because they barely rise above the surrounding tissue. In rare cases, a polyp can actually create a small depression or dip in the lining rather than a bump.
Fibroepithelial polyps, one of the more common types found in the anal canal specifically, tend to be elongated or finger-like. They originate near the dentate line, the natural junction between skin and the inner lining of the anus, and can develop a long stalk over time. These are benign growths made of fibrous tissue covered by a layer of skin-like cells. One surgical case documented a fibroepithelial polyp measuring over 4 cm with a 2 cm stalk, though most are considerably smaller.
Color and Texture
The color of a polyp depends on its type and location. Polyps higher in the rectum are often pink to reddish, matching the moist mucosal lining they grow from. Polyps closer to the anal opening, particularly fibroepithelial polyps and hypertrophied anal papillae (which are closely related), tend to appear whitish or pale compared to the surrounding tissue. This whitish color is actually one way doctors distinguish them from other types of growths during an exam. The surface can be smooth and glistening on mucosal polyps, or slightly rougher and more skin-like on those arising from the lower anal canal.
Size and When It Matters
Doctors categorize polyps by diameter. Those 5 mm or smaller (roughly the size of a pencil eraser) are called diminutive. Polyps between 6 and 9 mm are classified as small, and anything 1 cm or larger is considered a large polyp. The vast majority of anal and rectal polyps fall into the diminutive category and are found incidentally during routine screening or exams for other issues.
Size matters because larger polyps carry higher risk. Polyps over 1 cm in diameter are more likely to contain precancerous changes, especially if they have a villous (finger-like) internal structure rather than a smooth tubular one. The number of polyps also plays a role: having more than three raises the concern level. Fibroepithelial polyps and hypertrophied papillae, however, are benign regardless of size and do not progress to cancer.
How Polyps Differ From Hemorrhoids
This is a common source of confusion because both can cause bleeding and discomfort in the same area. Hemorrhoids are swollen blood vessels, not tissue growths. They tend to look like soft, purplish or bluish cushions of tissue around the anus, and external hemorrhoids are often visible without any instruments. They’re squishy to the touch because they’re engorged veins filled with blood.
Polyps, by contrast, are firmer tissue growths attached to the lining of the canal. They don’t have the characteristic dark, vein-filled appearance of a hemorrhoid. Polyps also tend to be located higher up inside the canal, while hemorrhoids commonly appear at or just outside the anal opening. A doctor can usually tell the difference during a physical exam, but sometimes a scope is needed to get a clear look.
How Doctors Spot Them
Because most anal polyps sit inside the canal where you can’t see them yourself, they’re typically found during a proctoscopy. This involves a short, hollow tube with a light and lens at the end that a gastroenterologist or colorectal surgeon gently inserts through the anus. The scope lets the doctor examine the lining in detail, looking for any bumps, discoloration, or irregular texture. If something looks suspicious, they can take a small tissue sample through the same instrument to check under a microscope.
Proctoscopy is also how doctors distinguish true polyps from lookalikes. Hypertrophied anal papillae, for instance, are small projections at the dentate line that can swell and thicken over time until they resemble polyps. They develop a rounded, expanded tip and can be mistaken for a pedunculated polyp. The key difference visible on the scope is their white color and their origin from the lower, skin-covered portion of the anal canal. Despite looking similar, they’re harmless and only need removal if they cause symptoms.
What You Might Notice at Home
Most anal polyps cause no symptoms at all, which is why screening matters. When a polyp is large enough to cause problems, the most common sign is rectal bleeding, usually bright red blood on toilet paper or in the bowl. Occasionally, a polyp on a long stalk can prolapse, meaning it slides down and peeks out of the anus. If this happens, you might feel or see a small, smooth, fleshy lump that doesn’t look like the typical wrinkled skin of a hemorrhoid. It may retract back inside on its own or need to be gently pushed back in.
You cannot reliably identify a polyp by looking at it yourself, even if something protrudes. The visual overlap between polyps, hemorrhoids, skin tags, and prolapsed tissue is significant enough that a proper exam with a scope is the only way to know what you’re dealing with.