Colonic polyp
| Colon polyps | |
|---|---|
 |
|
| Polyp of sigmoid colon as revealed by colonoscopy. Approximately 1 cm in diameter. The polyp was removed by snare cautery | |
| Classification and external resources | |
| Specialty | gastroenterology |
| ICD-10 | K63.5 & various |
| MedlinePlus | 000266 |
| eMedicine | med/414 |
| MeSH | C23.300.825 |
A colorectal polyp is a polyp (fleshy growth) occurring on the lining of the colon or rectum. Untreated colorectal polyps can develop into colorectal cancer.
Colorectal polyps are often classified by their behaviour (i.e. benign vs. malignant) and/or etiology (e.g. as a consequence of inflammatory bowel disease). They may be benign (e.g. hyperplastic polyp), pre-malignant (e.g. tubular adenoma) or malignant (e.g. colorectal adenocarcinoma).
The most common general classification is:
Most hyperplastic polyps are found in the distal colon and rectum. They have no malignant potential, which means that they are no more likely than normal tissue to eventually become a cancer.
Hyperplastic polyps are serrated polyps. Hyperplastic polyps have three histologic patterns of growth: microvesicular, goblet cell and mucin poor.
Hyperplastic polyposis syndrome is a rare condition that has been defined by the World Health Organization as either:
Although thought to exhibit no malignant potential it has been shown that hyperplastic polyps on the right side of the colon do exhibit a malignant potential. This occurs through multiple mutations which affect the DNA-mismatch-repair pathways. As such DNA mutations during replication are not repaired. This leads to microsatellite instability which can eventually lead to malignant transformation in polyps on the right side of the colon.
A neoplasm is a tissue whose cells have lost its normal differentiation. They can be either benign growths or malignant growths. The malignant growths can either have primary or secondary causes.
Neoplastic polyps of the bowel are often benign hence called adenomas. An adenoma is a tumor of glandular tissue, that has not (yet) gained the properties of a cancer.
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