Colonic polyps

Last updated: March 24, 2021

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Colonic polyps are abnormal colonic mucosal overgrowths. They are a common finding in people over the age of 50. In rare cases, they may be seen in younger individuals as part of hereditary polyposis syndromes (e.g., familial adenomatous polyposis, Peutz‑Jeghers syndrome). On macroscopic examination, colonic polyps are either pedunculated (with a stalk) or sessile (without a stalk). Histologically, colonic polyps are most commonly adenomas (∼ 70%), followed by hyperplastic polyps, and, rarely, serrated polyps and hamartomatous polyps. Colonic polyps may be benign or have malignant potential. Adenomas have the highest malignant potential (∼ 5%) and most colonic carcinomas arise from them (adenoma-carcinoma sequence). Most patients are asymptomatic, but they may present with altered bowel habits, blood/mucus in stool, and iron deficiency anemia. Colonoscopy is the diagnostic modality of choice since it allows for direct visualization of the polyps, biopsy, and therapeutic snare polypectomy (of pedunculated polyps) or endoscopic submucosal resection (of sessile polyps). Large polyps (> 2 cm) or malignant polyps require surgical resection.


Epidemiological data refers to the US, unless otherwise specified.

The exact etiology is unknown. Risk factors include the following. [2]

Macroscopic classification of colonic polyps

Histologic classification of colonic polyps

Histologic classification of colonic polyps [3]
Histological type Subtypes Characteristics Malignant potential
Inflammatory polyps (pseudopolyps)
  • Low malignant potential
Mucosal polyps
  • Benign (no clinical significance)
  • Typically small < 5 mm
  • Mostly appear like normal mucosa
Submucosal polyps

Hyperplastic polyps

  • Most common type of nonneoplastic polyp among those with low malignant potential
  • Small (< 5 mm)
  • Common in the distal colon (rectosigmoid)
  • Might transform to serrated polyps
  • Histology: hyperplasia of normal cellular components with a sawtooth/serrated pattern of crypt epithelium
Hamartomatous polyps [4]
  • Low for solitary polyps
  • Increased risk of colonic and extra-colonic malignancies when associated with syndromes
Serrated polyps

Sessile serrated polyps

  • Moderate malignant potential (∼ 5%) [5]

Traditional serrated adenoma

Adenomatous polyps

Tubular adenoma

  • Frequency: 65–80% [6]
  • Location: anywhere in the colon
  • Histology: proliferating cells forming tubules

Tubulovillous adenoma

  • Frequency: 10–25% [6]
  • Histology: a mixture of tubular and villous histological picture

Villous adenoma

The majority of colon carcinomas develop from adenomas (adenoma‑carcinoma sequence). However, only ∼ 5% of adenomas develop into colon cancers.

Villous adenomas are villains because they have the highest malignant potential.

Hereditary polyposis syndrome

Adenomatous polyposis syndromes

Familial adenomatous polyposis (FAP)

Variants of FAP

The Turban covers the head: Turcot syndrome is associated with malignant brain tumors.

MYH-associated polyposis [12]

Hamartomatous polyposis syndromes

Peutz-Jeghers syndrome [13]

Juvenile polyposis syndrome (JPS) [14]

Cowden syndrome [16]

Cronkhite-Canada syndrome [17]

Treatment depends on the etiology and nature of the polyp or polyps.

These recommendations are consistent with the US Multi-Society Task Force on Colorectal Cancer 2020 guidelines. [20][21]

Surveillance after polypectomy
Risk category Recommended interval to control colonoscopy

Very low risk: ≤ 20 hyperplastic polyps < 10 mm

  • 10 years


  • 7–10 years
Intermediate risk
  • 3–5 years


  • 3 years

Very high risk: > 10 adenomas

  • 1 year [22]
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  15. Juvenile Polyposis Syndrome . Updated: March 9, 2017. Accessed: August 28, 2017.
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