Colon polyps pathophysiology

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Sadaf Sharfaei M.D.[2]

Overview

The exact pathogenesis of [disease name] is not fully understood.

OR

It is thought that [disease name] is the result of / is mediated by / is produced by / is caused by either [hypothesis 1], [hypothesis 2], or [hypothesis 3].

OR

[Pathogen name] is usually transmitted via the [transmission route] route to the human host.

OR

Following transmission/ingestion, the [pathogen] uses the [entry site] to invade the [cell name] cell.

OR


[Disease or malignancy name] arises from [cell name]s, which are [cell type] cells that are normally involved in [function of cells].

OR

The progression to [disease name] usually involves the [molecular pathway].

OR

The pathophysiology of [disease/malignancy] depends on the histological subtype.

Pathophysiology

Pathogenesis

  • Any form of unregulated growth in the colon may cause polyps. The exact etiology is unclear. However, risk factors may contribute to the formation of polyps.
  • There are four different types of polyps including inflammatory, hamartomatous, serrated, and adenomatous polyps, which have different pathogenesis.
  • The pathophysiology of colon polyps depends on the histological type.
  • It is thought that colon polyps is mediated by either [hypothesis 2], or [hypothesis 3].

Inflammatory polyps

Hamartomatous polyps

Serrated polyps

  • Serrated polyps are different polyps which have variable malignant potential. They include hyperplastic, sessile serrated and traditional serrated polyps. They have various histopathologies and manifestations.
  • Hyperplastic polyps are the most common polyps. They are small outpouching, less than 5 mm, which are located mostly in rectosigmoid area. Hyperplastic polyp is infolding of the crypt epithelium that forms serration or saw-toothed appearance. The molecular basis of this transformation is still unclear. However, it has been attributed to failure of apoptosis.
  • Serration
  • BRAF mutation
  • KRAS mutation
  • Sessile serrated polyps 
  • Traditional serrated adenomas

Adenomatous polyps

Genetics

  • The development of colon polyps is the result of multiple genetic mutations.
  • Genetic mutations might cause hereditary polyps disorders.

Hereditary nonpolyposis colorectal cancer (Lynch syndrome)

Familial adenomatous polyposis (FAP)

Gardner's syndrome

MYH-associated polyposis (MAP)

  • It is caused by mutations in the MYH gene.
  • They develop multiple adenomatous polyps and colon cancer at a young age. 

Peutz-Jeghers syndrome

Serrated polyposis syndrome

  • They develop multiple serrated adenomatous polyps in the upper part of the colon.
  • There has been some association with familial juvenile polyposis and the gene SMAD4 on chromosome 18 and PTEN on chromosome 10

Gross Pathology

  • On gross pathology, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].
Longitudinally opened freshly resected colon segment showing a cancer and four polyps. Plus a schematic diagram indicating a likely field defect (a region of tissue that precedes and predisposes to the development of cancer) in this colon segment. The diagram indicates sub-clones and sub-sub-clones that were precursors to the tumors. Source: Wikimedia.org By Bernstein0275 - Own work, CC BY-SA 3.0[4]

Microscopic Pathology

  • On microscopic histopathological analysis, [feature1], [feature2], and [feature3] are characteristic findings of [disease name].

References

  1. Shussman, N.; Wexner, S. D. (2014). "Colorectal polyps and polyposis syndromes". Gastroenterology Report. 2 (1): 1–15. doi:10.1093/gastro/got041. ISSN 2052-0034.
  2. Li SC, Burgart L (2007). "Histopathology of serrated adenoma, its variants, and differentiation from conventional adenomatous and hyperplastic polyps". Arch. Pathol. Lab. Med. 131 (3): 440–5. doi:10.1043/1543-2165(2007)131[440:HOSAIV]2.0.CO;2. PMID 17516746.
  3. Zbuk KM, Eng C (2007). "Hamartomatous polyposis syndromes". Nat Clin Pract Gastroenterol Hepatol. 4 (9): 492–502. doi:10.1038/ncpgasthep0902. PMID 17768394.
  4. "File:Image of resected colon segment with cancer & 4 nearby polyps plus schematic of field defects with sub-clones.jpg - Wikimedia Commons".

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