What are colon polyps and polyposis?
Colon polyps are small, abnormal growths in the lining of the colon or rectum. Most colorectal polyps are benign, but some can become precancerous if they are not found and removed. Polyps are common, especially as people age.
Polyposis refers to several syndromes in which a person develops many polyps throughout the gastrointestinal (GI) tract, including the colon, stomach, or small intestine. These conditions are often inherited and may greatly increase the risk of colon cancer and rectal cancer. While polyposis affects multiple areas of the GI tract, the colon is the most common site for polyps to develop.
Penn Medicine provides expert care for people with colon polyps and polyposis. Our gastroenterologists perform a high volume of advanced endoscopic procedures to detect and remove all types of GI polyps. We work closely with genetic counselors and surgeons as needed to provide you with well-rounded care to stay healthy.
Types of polyposis
Polyposis can occur in several parts of the GI tract, and there are multiple types of polyposis syndromes. These conditions involve developing many polyps over time.
FAP is a hereditary condition caused by mutations in the APC gene, a gene that helps control how cells grow and die. When the APC gene is not working properly, hundreds to thousands of adenomatous polyps (growths made of gland-like tissue) can form in the colon, often beginning in the teenage years. Without close monitoring and polyp removal, people with FAP have a very high risk of colorectal cancer. Polyps may also appear in the stomach and small intestine.
- Classic FAP is characterized by hundreds to thousands of colon polyps starting in adolescence.
- Attenuated FAP (AFAP) involves fewer polyps that tend to develop later in adulthood.
MAP occurs when a person inherits two mutations in the MUTYH gene, a gene that helps repair DNA damage in colon cells. When both copies of this gene are not working correctly, multiple adenomatous polyps can form, often beginning in young adulthood. Without treatment or frequent colonoscopy, the risk of colon cancer is significantly higher.
These rare conditions involve distinctive hamartomatous polyps, tumor-like growths made of a mix of normal tissues arranged in an unusual way, which may appear throughout the GI tract. Although these polyps are benign, the related syndromes carry an increased risk of cancers in the digestive system and sometimes in other organs.
Conditions in this group include:
- Peutz-Jeghers syndrome
- Juvenile polyposis syndrome
- Cowden syndrome (also called PTEN hamartoma tumor syndrome)
SPS is marked by multiple serrated polyps, a group of polyps with a saw-toothed appearance. These can raise the risk of colon cancer. Because SPS patterns can vary, people with this syndrome benefit from specialized surveillance.
This diagnosis is used when someone develops more than 20 adenomatous polyps over a lifetime but no genetic syndrome is identified through testing. Even without a known cause, these individuals still need careful monitoring because their risk of colon cancer is higher.
Symptoms of colon polyps and polyposis
Many people with polyposis have no symptoms. When symptoms do occur, they may include:
- Rectal bleeding or blood in the stool
- Changes in bowel habits (diarrhea, constipation, or narrowing of stool)
- Abdominal discomfort
- Iron-deficiency anemia
Because early signs of colon polyps can be subtle, screening colonoscopy is the most reliable way to detect and remove them before they become cancerous.
What causes colon polyps and polyposis?
Most colon polyps develop from a combination of genetics and environmental factors. Even without a known inherited syndrome, polyps can form simply as part of aging. Common causes and risk factors include:
- Genetic changes that affect how cells grow (especially in polyposis syndromes)
- Family history of colon polyps or colorectal cancer
- Certain bacteria in the colon
- Unhealthy habits such as smoking
- Diet low in fiber
- Obesity
- Some environmental exposures
Diagnosing polyps and polyposis of the digestive tract
Early and accurate diagnosis helps prevent colon cancer, especially when polyps are precancerous or when polyposis syndromes are present. Diagnosis usually starts with a detailed medical and family history, including a review of genetic risks. Genetic testing may be recommended when someone has multiple polyps or features of a known polyposis syndrome. Imaging studies may also be used in certain cases to evaluate other parts of the gastrointestinal tract.
Treatment and management of colon polyps
Treatment aims to remove polyps before they turn into cancer and to monitor people at higher risk over time. Most polyps can be removed during a colonoscopy or upper endoscopy. If you have polyposis syndrome, you may need more frequent monitoring, medicines to reduce polyp growth, and coordinated risk-management plans that include genetic counseling for you and your family. Surgery becomes necessary when polyps are too numerous or too difficult to remove endoscopically.
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