Colon tumor
Polyps
Hyperplastic polyp of colon

Author: Elliot Weisenberg, M.D. (see Authors page)

Revised: 6 March 2018, last major update February 2018

Copyright: (c) 2003-2018, PathologyOutlines.com, Inc.

PubMed Search: Hyperplastic polyp [title] colon

Cite this page: Weisenberg, E. Hyperplastic polyp of colon. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/colontumorhyperplastic.html. Accessed September 22nd, 2018.
Definition / general
  • A localized non dysplastic epithelial proliferation characterized by a superficial serrated architecture and variably elongated crypts with proliferation confined to the lower portion of the crypt
Essential features
  • Hyperplastic polyps (HPs) are asymptomatic and have no malignant potential
  • They are the most common colonic polyp (75 - 90% of colon polyps), typically 1 - 5 mm in greatest dimension, rarely 1 cm or greater
  • Most common in left colon, especially the rectum; often multiple
  • Usually found during endoscopy in patients age 50+, but may be found in much younger patients; the incidence increases with age
  • They must be distinguished from sessile serrated adenoma / polyp (SSA / P) that may demonstrate very similar histopathologic features and are considered to have malignant potential
  • Some authorities consider large right sided hyperplastic polyps to have malignant potential, but today these would likely be called SSA / Ps
Terminology
  • HPs have been divided into microvesicular, goblet cell and mucin poor types based on quantity of mucin and the presence or absence of dystrophic goblet cells; however, this has no clinical relevance
ICD-10 coding
Epidemiology
  • 75 - 90% of colon polyps
  • Usually detected in patients undergoing colonoscopies in their 50s but may be detected much earlier
  • Incidence increases with age
  • Factors associated with increased occurrence are similar to adenomatous polyps and include smoking, ethanol abuse, folate deficiency and obesity
  • Up to 35% of asymptomatic adults over 50 have colonic HPs
Sites
  • 90% occur in the left colon, most notably the rectum
  • They may be multiple or single
  • HPs in the proximal colon tend to be larger than more distal polyps
  • Microvesicular HPs are less restricted to the distal colon
Pathophysiology
  • HPs occur because of hyperproliferation in the basal portion of the crypts; colonocytes are produced faster than they are shed leading to a serrated appearance
Clinical features
  • Overwhelming majority of HPs are incidental findings during endoscopy appearing as pale nodular bumps
  • Their endoscopic appearance cannot be reliably distinguished from adenomatous polyps so they are biopsied and fulgurated
  • Rarely HPs may occur as part of MUTYH associated polyposis, Peutz-Jeghers syndrome, juvenile polyposis syndrome, hyperplastic polyposis syndrome, PTEN hamartoma syndrome, Birt-Hogg-Dube syndrome or hereditary hemorrhagic telangiectasia syndrome; however, individual HPs have no malignant potential
  • They are the most common colon polyp, estimated to comprise 75 - 90% of colon polyps, typically 1 - 5 mm in greatest dimension, rarely 1 cm or greater
  • They usually are found during endoscopies in patients starting in their 50s but may be found in much younger patients and the incidence increases with age
  • It is estimated that 35% of asymptomatic adults in the United States harbor HPs
  • Risk factors include smoking, alcohol consumption, folate deficiency, the Western diet and obesity
  • They are less common in the developing world
Case reports
Treatment
  • Typically are biopsied and fulgurated, although benign and asymptomatic, because they cannot be distinguished endoscopically from adenomatous polyps
Clinical images

Images hosted on PathOut server:

Images contributed by Elliot Weisenberg, M.D.:
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Descending colon

Gross description
  • Generally under 5 mm, usually on top of mucosal folds, may be multiple, same color as surrounding mucosa
Gross images

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Hyperplastic polyp

Microscopic (histologic) description
  • Microvesicular type shows admixed goblet and columnar cells with microvesicular mucin and inconspicuous nuclei showing prominent luminal serrations
    • Surface is mature and mitoses are only found at or near the base
  • Goblet cell rich type is less serrated and shows prominent goblet cells
  • Mucin poor type demonstrates micropapillary architecture, mucin depletion and an absence of goblet cells
    • Often described as having a regenerative appearance
Microscopic (histologic) images

Images hosted on PathOut server:

Images contributed by Elliot Weisenberg, M.D.:
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Hyperplastic polyp

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Typical hyperplastic polyps with superficial serrated architecture and absence of atypia



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Right sided vs. left sided polyps

Serrated crypts

Various images

Positive stains
  • Ki67 shows proliferation confined to the lower portions of the polyp
Molecular / cytogenetics description
  • BRAF or KRAS mutation may occur as well as DNA hypermethylation
Differential diagnosis
Board review question #1
    What is true of hyperplastic colonic polyps?

  1. They are usually over 2 cm in dimension
  2. They are usually right sided
  3. They have no malignant potential
  4. They typically are detected in young children by one of their parents
Board review answer #1
C. Hyperplastic colonic polyps have no malignant potential; while they may be present in some colonic polyposis syndromes, individual hyperplastic polyps have no malignant potential and they are not associated with familial adenomatosis polyposis. Hyperplastic polyps are most common in the distal colon, especially the rectum. They may occur in young patients but are typically found in patients starting in their 50s during colonoscopies; their incidence increases with age