What is the difference between a polyp on a stem and other polyps?

Polyps that are on a stem (or stalk) are called "pedunculated" polyps. These polyps are shaped like mushrooms with a cap on the top and a stem (stalk) that attaches them to the inside lining (mucosa) of the colon. Because their stem elevates them above the colon lining, pedunculated polyps are often easier to find and remove however they are less common then the other two shapes.

Sessile polyps are the most common shape of colon polyp described. These polyps look like raised "bumps" on the colon lining. I often tell patients that sessile polyps are shaped like flesh colored skin moles.

The third polyp shape is flat. Flat polyps are the same height as the colon lining which can make them difficult to find and remove, especially if the colon is not completely clean for the procedure. Because of this, following your doctor’s instructions to prepare for your procedure is extremely important to make sure you have the best examination possible.

Regardless of a polyp's shape, the most important factor in determining the risk of a polyp becoming cancer one day is its size and cell type (seen under the microscope). Based on these features, your doctor will give you individual recommendations after your test about when to schedule future screenings.