This page was reviewed under our medical and editorial policy by
Toufic Kachaamy, MD, Chief of Medicine, City of Hope Phoenix.
This page was updated on January 17, 2022.
Polyps are fleshy growths found on mucous membranes throughout the body. They may be flat against the tissue (sessile) or grow mushroom-like on a stalk (pedunculated). They’re typically smaller than a dime, but may vary in size from the head of a pin to the size of a ping-pong ball. There may be just one present, or there may be many.
Polyps are common in the colon, rectum, all along the intestines, the stomach, nose and sinuses, ear canal and uterus. They may develop on any mucous membrane, including in the cervix, vocal folds and—rarely—in the urinary system and bladder.
Most polyps don’t have a known cause. They may be due to inflammation or irritation from a foreign object. Patients may be at increased risk if they have a family history of polyps or an inherited genetic syndrome or mutation.
Polyps don’t always cause symptoms, which is why regular screenings are important. Doctors may discover polyps through imaging tests such as X-rays, an ultrasound or a computed tomography (CT) scan. If polyps are thought to be along the digestive tract, the doctor may use a thin, flexible tube called an endoscope to see the lining of the intestines, stomach or throat.
Polyps found during a colonoscopy or endoscopy may be removed as part of the procedure. In other areas of the body, doctors may want to biopsy the polyp to learn more.
Though rectal and colon polyps don’t typically cause symptoms, they may occasionally cause bleeding, pain or digestive changes. Most colorectal polyps are noncancerous. Screening methods that detect polyps and colorectal cancer include a colonoscopy, virtual colonoscopy or blood tests.
If doctors find and remove certain types of polyps, they may suggest another colonoscopy in three years, or sooner, as recommended by the American Cancer Society. Colorectal polyps recur 20 percent to 50 percent of the time, according to a 2020 review in Gut and Liver.
Sometimes colorectal polyps develop because of an inherited syndrome, but typically there’s no known cause. Age plays a role, too. The risk for getting colorectal polyps increases as you get older.
Most gastric and stomach polyps aren’t cancerous. Symptoms are rare and may include bleeding or pain from an obstruction in the digestive tract.
They’re often diagnosed with an endoscope, which is a lighted tube inserted through the mouth to see the inside of the digestive tract. Doctors may take a tissue sample to biopsy to determine the kind of growth. The polyp may be removed during the endoscopy.
Risk factors for stomach polyps include:
Endometrial polyps—those occurring in the lining of the uterus—are common, developing in 16 percent to 34 percent of people who have a uterus, according to a 2011 review in the Journal of Research in Medical Sciences.
Endometrial, or uterine, polyps may cause difficulty getting or staying pregnant, which is one way they’re discovered. They may also cause irregular, long or heavy bleeding during or between menstrual periods—or even after menopause.
Imaging tests to see inside the uterus are used to diagnose endometrial polyps. If found, the polyps may be biopsied and removed.
Researchers don’t know exactly what causes uterine polyps, but excess estrogen may play a role in their development. Uterine polyps are more likely to occur in women as they get older. Other factors may play a role as well, such as obesity, treatment for breast cancer with a drug called tamoxifen, hormone replacement therapies, or genetic conditions.
Polyps may also develop on the cervix, the opening between the uterus and the vagina. They don’t usually cause symptoms but may cause inflammation; heavy periods; bleeding after intercourse, after menopause or between periods; or a white or yellow mucus discharge.
For uterine and cervical polyps, medication may be recommended to shrink them. Cervical polyps may also be removed or cauterized. Samples of the polyp may be tested to determine whether the growth is cancerous.
Nasal polyps, which occur in the mucous membranes of the nose and sinuses, are typically benign growths. They may block the airway or cause stuffiness, a loss of smell or taste, snoring, a sinus infection or headache.
Risk factors for nasal polyps include:
Steroids may help treat nasal polyps, but they usually come back after treatment. Large polyps that cause symptoms may be removed with an endoscopic surgery.
These polyps develop inside the throat and on the larynx. Risk factors may include stressing the vocal cords, having acid reflux and smoking. Throat and laryngeal polyps may cause hoarseness. Rarely, they may make it difficult to breathe. Depending on their size and symptoms, they may be removed or just monitored.