Polyps are abnormal projecting growths of tissue or tumors that form on the mucous membranes lining the body’s organs. They can develop in the digestive tract, the bladder, the uterus, the genitals, or even in the nose or inside the mouth. Generally, polyps are considered benign. However, some are cancerous, and others can become malignant.
Colon polyps form in the colon, the largest portion of the large intestine. Many things can cause colon polyps, but they tend to occur in people over 50 and those with a family history of developing the growths. Polyps in the colon develop in two different shapes, namely sessile (flat) and pedunculated (with a stalk). They are also classified by type.
Read on for 13 types of colon polyps everyone should know about…
Adenomatous polyps are typically small, measuring about half an inch (1.3 centimeters) in diameter. However, they can grow, placing pressure on nearby organs, and develop into cancerous growths.
Adenomas are the most common type of colon polyp, accounting for approximately 70 percent of polyps that affect the colon. They are usually described as tubular, villous, or tubulovillous.
Tubular Adenomatous Polyps
The most common of the adenomatous colonic polyps is the tubular adenoma. These adenomatous polyps have a tube-like shape (hence the name) and can form in any location within the colon.
Tubular adenomatous polyps are the least likely adenomas to develop into malignant colon cancer. In general, though, adenomatous polyps carry a significant risk of cancer.
Villous Adenomatous Polyps
Villous adenomas tend to be non-pedunculated (stalkless) and have an appearance that resembles cauliflower. They are normally larger in size than tubular adenomatous colon polyps.
Commonly affecting the rectal area of the colon, villous adenomatous polyps are associated with high rates of physical illness and mortality. At least, in comparison with tubular adenomas.
Tubulovillous Adenomatous Polyps
Tubulovillous adenomas are both tubular and villous. That is, their shape and structure are a combination of the two growth patterns, although the polyps are typically flatter in appearance.
Like villous adenomatous polyps in the colon, adenomas that fall into the tubulovillous category are more prone to turning malignant and developing into cancer than tubular adenomas.
As one might expect, serrated colon polyps have a serrated appearance, resembling a sawtooth. Depending on their size and location inside the colon, these growths can be or become cancerous.
Small serrated polyps in the lower part of the colon are not usually malignant. Larger serrated polyps in the upper colon are normally precancerous. These types of polyps can be difficult to detect.
Colon polyps of the hyperplastic variety are generally benign. However, the polyps may lead to cancer in a small number of individuals with a family history of multiple hyperplastic growths.
The main treatment options for hyperplastic polyps are a polypectomy or a laparotomy. Rarely, total resections are required, where the colon and rectum are completely removed.
In a minute percentage of people, genetics, lifestyle, and other risk factors can cause colon polyp growths called carcinomatous polyps. These dangerous protuberances, though rare, are cancerous.
Polypectomies are the first-line treatment for carcinomatous colon polyps, but the surgeries aren’t always entirely effective. Sometimes, cancer cells can be left behind and spread within the body.
Lymphoid polyps (also known as lymphoid hyperplasia) of the colon are uncommon, benign growths. They occur mostly in children and are typically found among clusters of lymphoid follicles.
Colonic lymphoid polyp presentations can vary widely. Patients can be completely asymptomatic with no problems or present with symptoms and complications that require surgical intervention.
Inflammatory polyps are benign “false” polyps that are unlikely to become cancerous. They form in people with inflammatory bowel diseases like Crohn’s disease or ulcerative colitis.
Polyps arising from these conditions look like finger-like projections and can accompany pain and other symptoms. Large inflammatory colon polyps can cause obstructions or intestinal folding.
Hamartomatous polyps are pedunculated growths that can develop sporadically or as components of certain genetic or acquired syndromes. They can become cancerous but usually don’t.
Growths or tumors that are hamartomatous often develop in the large intestine. Varying in size, they can sometimes cause bleeding in the colon and problems such as intestinal blockages.
Peutz-Jeghers polyps are a type of hamartomatous polyp that grows in people with the Peutz–Jeghers syndrome. This is a rare hereditary condition in which polyps grow singularly or in multiples.
The polyps seen in Peutz–Jeghers syndrome carry little malignant potential. Nevertheless, they can become cancerous and cause symptoms and complications, so they should be removed.
Juvenile polyps in the colon are hamartomatous polyps that affect children (especially those under 10 years of age) and, to a lesser degree, teenagers and young adults. They are most prevalent in males.
Often found in the rectum and causing rectal bleeding, juvenile polyps normally grow singularly and are relatively large. When they grow in multiples, the condition is called juvenile polyposis syndrome.
Polyps are described as complex when the tumors present in the colon have a diameter of more than two centimeters. These types of polyps are sometimes referred to as “defiant” in the medical literature.
Flat polyps are considered too difficult to remove endoscopically because of where they are located internally and can also be called complex. Surgical polyp removal is required in such cases.