Polyps of the colon and rectum

[Renato]

A polyp is a projecting growth of tissue from the wall of a hollow space, such as the intestines.

Some polyps are caused by hereditary conditions.
Bleeding from the rectum is the most common symptom.
Some polyps become cancerous (see Colorectal Cancer).
A colonoscopy is performed to make the diagnosis.
Removal during colonoscopy is the best form of treatment.

Polyps also may grow inside the nose (nasal polyps).
Polyps that grow on the intestinal or rectal wall protrude into the intestine or rectum and may be noncancerous (benign), precancerous (adenomatous), or cancerous (malignant carcinoma). Polyps vary considerably in size, and the bigger the polyp, the greater the risk that it is cancerous or likely to become cancerous (that is, they are precancerous). Polyps may grow with or without a stalk (a thin piece of tissue that joins the polyp to the intestinal wall, similar to how the neck joins the head to the body).
There are many types of polyps but doctors typically divide them into

Adenomatous polyps
Nonadenomatous polyps

Adenomatous polyps, which consist primarily of glandular cells that line the inside of the large intestine, are likely precancerous.
Nonadenomatous polyps can develop from many cell types, including the nonglandular cells that line the intestine, fat cells, and muscle cells. Some nonadenomatous polyps are caused by other disorders, for example the inflammatory polyps that develop in people with chronic ulcerative colitis. Nonadenomatous polyps are less likely to be precancerous.