Serrated Polyps of the Colon
Aaron Sinclair, MD
University of Kansas School of Medicine – Wichita
Department of Family and Community Medicine
Wesley Family Medicine Residency
8/7/14
Learning Objectives:
• Distinguish the malignant potential of serrated
polyps and adenomas
• Identify when serrated polyps are considered
serrated polyposis syndrome
• Describe the relationship between
hyperplastic polyps and serrated polyps
Case Presentation
• 50 yo male presents for
screening colonoscopy.
• Diverticula noted
• 40 cm and 80 cm there
were 3-4 mm polyps
completely excised with
cold forceps biopsy.
• Operative Report
Recommendation at 10
years.
• Pathology: Sessile Serrated
Polyp – 2 days later.
• Treatment:?
Classification - Serrated Polyps
World Health Organization (WHO)
• Hyperplastic Polyps (HP)
• Sessile Serrated Adenomas/polyps (SSA/P)
• Traditional Serrated Adenomas (TSA)
Historical Context
• 1990 – First described in the literature
• 2005 - Pathological distinctions first appeared
• 2008 – First pathological diagnostic criteria and
nomenclature introduced.
• 2010 – WHO adopted criteria
Importance of Serrated Polyps
• Prevalence of Proximal Serrated Polyps of 5-8% of
all average risk screening colonoscopies
• 15-35% of all cancers are secondary to serrated
polyps
• The progression of dysplasia to cancer for Sessile
Serrated Adenomas and Polyps is 10-15 years.
• Only about 10% of all tubular adenomas progress
to cancer
• Typically tubular adenomas are larger, progress in
8-12 years to cancer.
Importance of Serrated Polyps
• How many Repeat Normal 10 year follow-up
Colonoscopies are you doing that quite
possibly were serrated polyps not hyperplastic
polyps?
• Figure 3. A, Sessile serrated adenoma (SSA). Arrows mark
edges of an SSA. B, An SSA with early carcinoma. The
erythematous/ulcerated area represents the early
carcinoma; the arrows indicate the edges of the residual SSA.
Bars: 20 mm.
The serrated pathway to colorectal carcinoma: current concepts and challenges. Bettington et al. Histopathology 2013, 62, 367–386.
Serrated Adenoma Pathway:
Sessile serrated adenomas frequently (78%) have BRAF mutations or K-ras mutations (11%)
Hyperplastic polyps which show frequent K-ras mutations (70%) with less common BRAF
mutations (20%)
MLH1 promoter methylation is frequent in serrated polyps, suggesting that they give rise to
sporadic colorectal carcinoma with MSI
Smoking and estrogen withdrawal may be associated with serrated pathway carcinoma
80%
Classification - Serrated Polyps
World Health Organization (WHO)
• Hyperplastic Polyps (HP)
• Sessile Serrated Adenomas/polyps (SSA/P)
• Traditional Serrated Adenomas (TSA)
Hyperplastic Polyps
•
•
•
•
•
80 - 90% of all Serrated Polyps
Malignant potential - <1%
Size: < 5mm
Typical Location is Recto-Sigmoid
Increases in number up to 50 years of age
then stable thereafter.
Hyperplastic Polyps
Mucosa is
typically paler
Size <5 mm
Sessile Serrated Adenomas/Polyps
• 8-15% of all Serrated Polyps
• Malignant Potential – uncertain but higher
than adenomatous polyps which is at least
25% over 10 years if larger than 2 cm.
• Size is variable
• Equally distributed between right and left
colon.
• Increases in number throughout life.
Sessile Serrated Polyp
Typically covered with a
“mucus cap”
Grow horizontally, flat,
sessile
Size is variable
50% >5mm
12-20% > 10 mm
Red and Puckered
appearance
Sessile Serrated Adenoma
Typically covered with a
“mucus cap”
Size is variable typically
greater than 5 mm
Red and Puckered
appearance
Traditional Serrated Adenomas
• 2-5% of all Serrated Polyps
• Malignant Potential – 3 fold increased risk
compared to Adenomatous Polyps
• Predominately Left Sided
• Increases in number throughout life
Traditional Serrated Adenoma
• Variable size up to
5 cm
• Often adenomatous
appearing
• Red appearance
How accurate are pathologist in depicting
a Serrated Polyp from a Hyperplastic Polyp?
The Clinical Significance of Serrated Polyps - Christopher S Huang, Francis A Farraye, Shi Yang and Michael J O'Brien American Journal of Gastroenterology
How Reliable is the Diagnosis
• Virchows Archives, 2012
– 70 cases using World Health Organization
Pathological Diagnostic Criteria/Worksheets
– 16 European Pathologists
•
•
•
•
28 Hyperplastic Polyps
25 Sessile Serrated Adenomas/Polyps
11 Traditional Serrated Adenomas
15 Mixed HP with SSP features
– How do you think the 16 pathologists do?
How Reliable is the Diagnosis
• Virchows Archives, 2012
– 16 European Pathologists
•
•
•
•
28 Hyperplastic Polyps – 44% got all 28
25 Sessile Serrated Adenomas/Polyps – 40% got all 20
11 Traditional Serrated Adenomas – 10% got all 11
15 Mixed HP with SSP features – 6% got all 15
– How do you think the 16 pathologists did?
• After 2 rounds and a conference reviewing the WHO
diagnostic criteria, they were able to come to near perfect
alignment on diagnosis.
• The authors of this study stated that at best reproducibility of
the histopathological diagnosis on a Serrated Polyp remains
imperfect.
Identification in the presence of the prep.
The Clinical Significance of Serrated Polyps Christopher S Huang, Francis A Farraye, Shi Yang and Michael J O'Brien
American Journal of Gastroenterology
Hyperplastic Polyps vs Serrated
Adenomas – are we missing them.
Polyp Miss Rates High for Colonoscopies Done After Poor Bowel
Preparation
• ScienceDaily (June 13, 2011)
• In the context of suboptimal bowel preparation, of all adenomas
identified, 42 percent were discovered only during a repeat
colonoscopy.
Current Recommendation for
Hyperplastic Polyps
• Remove all polyps when
technically possible
except for the small
(<5mm) distal
hyperplastic – appearing
polyps that can be sample
to confirm they are true
HP’s
Serrated Polyposis Syndrome
• At least 5 hyperplastic polyps proximal to the
sigmoid colon
– At least two of them greater than 10 mm
• More than 30 hyperplastic polyps evenly
distributed throughout the colon
• Any number of hyperplastic polyps proximal to
the sigmoid colon with a family member with
diagnosis of Serrated Polyposis Syndrome
Serrated Polyposis Syndrome
• Treatment is Colonoscopy every 1-3 years with
complete removal of ALL polyps.
• Start at age of 45 for first degree relatives or 5
years younger than the age of initial diagnosis
• 40% risk of lifetime cancer
• Not all that different from Colorectal Cancer
recommendations.
Surveillance Recommendations
• Every 5 years if the Sessile Serrated
Polyp/Adenoma are less than two in number
and/or greater than 1 cm in size.
• Every 3 years if the Sessile Serrated
Polyp/Adenoma are three or more in number
and/or greater than 1 cm in size
• If a Sessile Serrated Polyp/Adenoma is removed
and any comments of cytological dysplasia are
mentioned, perform a one year post removal to
ensure complete removal.
Surveillance Recommendations
• Traditional Serrated Adenomas – follow the
guidelines for typical adenomas.
Approach to the patient with colonic
polyps. www.utdol.com
Measuring Quality
• Current quality markers suggest Screening
Colonoscopy of Average Risk Patients
– Men – 25% Adenoma Detection Rate
– Women – 15% Adenoma Detection Rate
• Study of 15 Gastroenterologists between
2000-2009
– Showed a serrated adenoma detection risk of
4.5% (Expected Prevalence Rate of 5-8%)
– Correlated with quality marker expectations of the
Adenoma Detection Rate
High colonoscopic prevalence of proximal colon serrated polyps in average-risk men and women. Kahi et al. Gastrointestinal Endoscopy 2012. 75.3
References
High colonoscopic prevalence of proximal colon serrated polyps in average-risk
men and women. Kahi et al. Gastrointestinal Endoscopy 2012. 75.3
The Clinical Significance of Serrated Polyps - Christopher S Huang, Francis A
Farraye, Shi Yang and Michael J O'Brien. American Journal of Gastroenterology
Serrated Polyps of the colon and rectum, and serrated polyposis. Snover DC,
Ahnen DJ et al. (2010)In: Bosman Et al. WHO Classification of tumours of the
digestive system, 4th edition. pp 160-165
The serrated pathway to colorectal carcinoma: current concepts and challenges.
Bettington et al. 22 JAN 2013
Serrated plyps of the colon and rectum – proposal for diagnostic criteria. Daniela
E. Aust and Gustavo B. Baretto. Virchows Arch (2010) 457:291-297.
Cancer risks for relatives of patients with serrated polyposis. Win AK et al. Am j
Gastroenterol. 2012 May; 107 (5): 770-778.
Screening, management and surveillance for the sessile serrated
adenomas/polyps. Xiangshen Fu, Ye Qiu, Yali Zhang. Int J Clin Exp Pathol 2014; 7
(4) 1275-1285.
Serrated lesions of the colorectum, a new entity: What should a
clinician/endoscopist know about it? A. Jouret-Mourin, K Geboes. Acta GastroEnterolgica Belgica, Vol. LXXV, April-June 2012
Serrated polyps of the colon: how reproducible is their classification? Ensari A et
al. Virchows Arch (2012) 461:495-504.