Colon tumor
Familial polyposis syndromes
Serrated polyposis

Author: Michael Feely, D.O. (see Authors page)
Editor: Raul S. Gonzalez, M.D.

Revised: 2 January 2017, last major update July 2016

Copyright: (c) 2003-2017, PathologyOutlines.com, Inc.

PubMed Search: Serrated polyposis [title] colon tumor
Cite this page: Serrated polyposis. PathologyOutlines.com website. http://pathologyoutlines.com/topic/colontumorserratedpolyposissx.html. Accessed January 23rd, 2017.
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
Terminology
  • Previously referred to as hyperplastic polyposis syndrome, although serrated polyposis is current preferred term by WHO
Sites
Pathophysiology
  • 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
Treatment
  • 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)
Micro 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
Micro 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