Polyp overview

Deputy Editor-in-Chief: Raul S. Gonzalez, M.D.
Anna Sarah Erem, M.D.
Christopher Hartley, M.D.

Last author update: 30 June 2020
Last staff update: 31 July 2020

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PubMed Search: colon polyps[title] “loattrfree full text”[sb]

Anna Sarah Erem, M.D.
Christopher Hartley, M.D.
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Cite this page: Erem A, Van Treeck B, Hartley C. Polyp overview. website. Accessed September 28th, 2023.
Definition / general
  • A polyp is an exophytic or sessile lesion distinct from the mucosal surface and may be neoplastic or nonneoplastic
Essential features
  • > 95% of colorectal adenocarcinoma arises from polyps
  • Usually asymptomatic
ICD coding
  • Benign adenomatous:
    • D12.0 - benign neoplasm of cecum
    • D12.2 - benign neoplasm of ascending colon
    • D12.3 - benign neoplasm of transverse colon
    • D12.4 - benign neoplasm of descending colon
    • D12.5 - benign neoplasm of sigmoid colon
    • D12.6 - benign neoplasm of colon, unspecified; or polyposis of colon
    • D12.7 - benign neoplasm of rectosigmoid junction
    • D12.8 - benign neoplasm of rectum
  • Inflammatory:
    • K51.40 - inflammatory polyps of colon without complications
    • K51.411 - inflammatory polyps of colon with rectal bleeding
    • K51.412 - inflammatory polyps of colon with intestinal obstruction
    • K51.413 - inflammatory polyps of colon with fistula
    • K51.414 - inflammatory polyps of colon with abscess
    • K51.418 - inflammatory polyps of colon with other complication
  • Other:
    • K63.5 - polyp of colon (polyp not documented as adenomatous, benign or inflammatory; or hyperplastic polyp)
    • K62.1 - rectal polyp
  • Varies by type of polyp
  • For more information on epidemiology of colon polyps, please refer to the individual chapters pertaining to each type of polyp in Pathology Outlines
  • Etiology of colonic polyps varies from neoplastic to nonneoplastic and can either arise sporadically or in syndromic context
Clinical features
Radiology description
Prognostic factors
Gross description
  • Paris classification based on explicit recognition (Endoscopy 2005;37:570)
    • Polypoid type:
      • Protrudes at least 2.5 mm above mucosal layer
      • Sessile: no stalk (o-Is)
      • Pedunculated: with stalk, may be due to traction on the mass (o-Ip)
      • Semipedunculated (o-Isp)
    • Nonpolypoid type:
      • Less than 2.5 mm above mucosal layer
      • Slightly elevated (o-IIa)
      • Flat (o-IIb)
      • Slightly depressed lesions (o-IIc)
    • Excavated / ulcerated: o-III (Ann Gastroenterol 2017;30:592)
Microscopic (histologic) description
  • Generally depends on type of polyp (see specific topics for details)
  • Histology of submucosal lifting agents used during polypectomy
    • Some examples include ORISE and Eleview
    • Histologic appearance of lifting agents is temporally dependent, ranging from basophilic bubbly amorphous material (early) to eosinophilic hyalinized globules or ribbons (late)
    • Can mimic amyloid but differentiated based on presence of foreign body giant cell reaction to lifting agent that is not polarizable and Congo red negativity (Am J Surg Pathol 2020;44:793, Am J Clin Pathol 2020;153:630)
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