Colon (tumor & nontumor)
Serrated polyposis

Topic Completed: 1 July 2016

Minor changes: 31 July 2020

Copyright: 2003-2019,, Inc.

PubMed Search: Serrated polyposis [title] colon tumor

Michael Feely, D.O.
Raul S. Gonzalez, M.D.
Page views in 2019: 871
Page views in 2020 to date: 556
Cite this page: Feely M. Serrated polyposis. website. Accessed August 8th, 2020.
Definition / general
  • Polyposis syndrome defined by the development of numerous sessile serrated polyps in the colon
Essential features
  • WHO diagnostic criteria: (a) at least five serrated polyps proximal to the sigmoid colon with two or more of these being > 10 mm; or (b) any number of serrated polyps proximal to the sigmoid colon in an individual who has a first degree relative with serrated polyposis; or (c) > 20 serrated polyps of any size, distributed throughout the colon
  • Significantly increased risk for colorectal carcinoma (Gut 2010;59:1094) and possibly extracolonic malignancies (Dis Colon Rectum 2011;54:164)
  • Family members also at increased risk for colorectal malignancies, suggesting an inherited component (Am J Gastroenterol 2012;107:770)
  • Likely represents a heterogeneous group of patients that includes several phenotypes of serrated polyposis
  • Previously referred to as hyperplastic polyposis syndrome, although serrated polyposis is current preferred term by WHO
  • Likely consists of at least two groups: (Type 1) patients with BRAF mutations and relatively few large right sided polyps, and (Type 2) patients with KRAS mutations and many small left sided polyps (J Pathol 2007;212:378)
  • Awaiting more definitive molecular genetic studies
Clinical features
  • Mean age at diagnosis is 55 years, with overall equal distribution in males and females
  • Type 1 patients (with BRAF mutations) typically female smokers (United European Gastroenterol J 2016;4:305)
  • Typically asymptomatic and encountered on screening colonoscopy, although larger polyps may bleed
  • Most cases appear de novo, although a few familial cases have been described
  • Colonoscopy for polyp removal every 1 - 3 years, depending on polyps present
  • Colectomy with ileorectal anastomosis in cases of advanced lesions or those not amenable to colonoscopic management
  • Some recommend screening colonoscopy in first degree family members (Am J Gastroenterol 2012;107:770)
Microscopic (histologic) description
  • Lesions typically consist of sessile serrated adenomas / polyps that may have cytologic dysplasia
  • Hyperplastic polyps, typically of the microvesicular type, are also encountered and may be large
  • Conventional adenomas are occasionally present and may represent sessile serrated adenomas / polyps with cytologic dysplasia
Microscopic (histologic) images

Images hosted on other servers:

Syndromic sessile serrated
polyps, with no cytologic
dysplasia (left) and low
grade cytologic dysplasia (right)

Molecular / cytogenetics description
Differential diagnosis
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