Polyp (medicine)

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This article is about the medical condition. For the biological structure, see Polyp.
Colon polyps
Classification and external resources
Specialty Pathology
ICD-10 K63.5 & various
MedlinePlus 000266
eMedicine med/414
MeSH C23.300.825

A polyp is an abnormal growth of tissue projecting from a mucous membrane. If it is attached to the surface by a narrow elongated stalk, it is said to be pedunculated. If no stalk is present, it is said to be sessile. Polyps are commonly found in the colon, stomach, nose, ear, sinus(es), urinary bladder, and uterus. They may also occur elsewhere in the body where mucous membranes exist like the cervix,[1] vocal folds, and small intestine. Some polyps are tumors (neoplasms) and others are nonneoplastic (for example, hyperplastic or dysplastic). The neoplastic ones are generally benign, although some can be premalignant and/or concurrent with a malignancy.


Digestive polyps[edit]


Polyp Histologic appearance Risk of malignancy Picture Syndromes
Hyperplastic Serrated unbranched crypts if polyps

are more than 100

Hyperplastic polyp1.jpg
Hyperplastic polyposis syndrome
Sessile serrated adenoma3.jpg
Tubular adenoma 2 high mag.jpg
Traditional serrated adenoma intermed mag.jpg
Peutz-Jeghers syndrome polyp.jpg
Peutz–Jeghers syndrome
Gastric juvenile polyp - 2 - very low mag.jpg
Juvenile polyposis syndrome, identical polyps in Cronkhite-Canada syndrome
Inflammatory fibroid polyp - intermed mag.jpg


Colorectal polyp[edit]

Main article: Colorectal polyp

Colon polyps are not commonly associated with symptoms. Occasionally rectal bleeding, and on rare occasions pain, diarrhea or constipation may occur because of colon polyps. Colon polyps are a concern because of the potential for colon cancer being present microscopically and the risk of benign colon polyps transforming over time into malignant ones. Since most polyps are asymptomatic, they are usually discovered at the time of colon cancer screening. Common screening methods are occult blood test, colonoscopy, sigmoidoscopy (usually flexible sigmoidoscopy, using a flexible endoscope, but more rarely the older rigid sigmoidoscopy, using a rigid endoscope), lower gastrointestinal series (barium enema), digital rectal examination (DRE), and virtual colonoscopy.[4] The polyps are routinely removed at the time of colonoscopy either with a polypectomy snare (first description by P. Deyhle, Germany, 1970[5]) or with biopsy forceps. If an adenomatous polyp is found with sigmoidoscopy or if a polyp is found with any other diagnostic modality, the patient must undergo colonoscopy for removal of the polyp(s). Even though colon cancer is usually not found in polyps smaller than 2.5 cm, all polyps found are removed since the removal of polyps reduces the future likelihood of developing colon cancer. When adenomatous polyps are removed, a repeat colonoscopy is usually performed in three to five years.

Most colon polyps can be categorized as sporadic.

Inherited polyposis syndromes[edit]


Non-inherited polyposis syndromes[edit]

Types of colon polyps[edit]

Adenomatous polyps[edit]

Adenomatous polyps, or adenomas, are polyps that grow on the lining of the colon and which carry a high risk of cancer. The adenomatous polyp is considered pre-malignant, i.e., likely to develop into colon cancer.[6] The other types of polyps that can occur in the colon are the hyperplastic and inflammatory polyps. They are unlikely to develop into colorectal cancer.




There are three types of adenomatous polyp:

  • Tubulovillous




It is estimated that an individual whose parents have been diagnosed with an adenomatous polyp has a 50% greater chance to develop colon cancer than individuals with no family history of colonic polyps.[10] At this point, there is no method to establish the risks that patients with a family history of colon polyps have to develop these growths. Overall, nearly 6% of the population, regardless of the family history, is at risk of developing colon cancer.


Screening for colonic polyps as well as preventing them has become an important part of the management of the condition. Medical societies have established guidelines for colorectal screening in order to prevent adenomatous polyps and to minimize the chances of developing colon cancer. It is believed that some changes in the diet might be helpful in preventing polyps from occurring but there is no other way to prevent the polyps from developing into cancerous growths than by detecting and removing them.

According to the guidelines established by the American Cancer Society, individuals who reach the age of 50 should perform an occult blood test yearly. Colon polyps as they grow can sometimes cause bleeding within the intestine, which can be detected with the help of this test. Also, persons in their 50s are recommended to have flexible sigmoidoscopies performed once in 3 to 5 years to detect any abnormal growth which could be an adenomatous polyp. If adenomatous polyps are detected during this procedure, it is most likely that the patient will have to undergo a colonoscopy. Medical societies recommend colonoscopies every ten years starting at age 50 as a necessary screening practice for colon cancer.[4][11] The screening provides an accurate image of the intestine and also allows the removal of the polyp, if found. Once an adenomatous polyp is identified during colonoscopy, there are several methods of removal including using a snare or a heating device.[12] Colonoscopies are preferred over sigmoidoscopies because they allow the examination of the entire colon; a very important aspect, considering that more than half of the colonic polyps occur in the upper colon, which is not reached during sigmoidoscopies.

It has been statistically demonstrated that screening programs are effective in reducing the number of deaths caused by colon cancer due to adenomatous polyps. Yet their use is still controversial because of the complications that sometimes arise[clarification needed]. However, most of the specialists agree that the benefits of colorectal screening overcome the risks. The risk of complications arising from colonoscopies is half the risk of that of developing colon cancer.[13] As there is a small likelihood of recurrence, surveillance after polyp removal is recommended.

Endometrial polyp[edit]

Main article: Endometrial polyp


Cervical polyp[edit]

Main article: Cervical polyp


Nasal polyps[edit]

Main article: Nasal polyp



  1. ^ Weschler, Toni (2002). Taking Charge of Your Fertility (Revised ed.). New York: HarperCollins. pp. 227–8, 330. ISBN 0-06-093764-5. 
  2. ^ Fletcher's Diagnostic Histopathology of Tumors, Third Edition.
  3. ^ Sternberg's Diagnostic Surgical Pathology, Fifth Edition.
  6. ^ "Adenomatous Polyps". Retrieved 2010-04-13. 
  15. ^ a b "Uterine polyps". MayoClinic.com. 2006-04-27. Retrieved 2007-10-20. 

External links[edit]