Serrated Polyposis of the Colon and Rectum

Definition

• Syndrome characterized by multiple colorectal serrated polyps

Alternate/Historical Names

• Hyperplastic polyposis
• Metaplastic polyposis
• Sessile serrated adenomatosis

Covered Separately

• Sessile serrated adenoma / polyp
• Hyperplastic polyp

Diagnostic Criteria

• Originally defined by the number and location of hyperplastic polyps
  • It is now clear that most of the polyps of this entity are sessile serrated adenomas
    • Not all investigators accept this
• Multiple serrated polyps of any type (Rosty 2012)
  • (Note that criteria for SSA and HP are in a state of flux currently)
  • Most are sessile serrated adenomas or microvesicular hyperplastic polyps
    • See sessile serrated adenoma / polyp for complete description
      • Glands variably serrated throughout their length
      • Base of crypts show architectural disturbances
        • Dilation and flattening
      • Nuclear dysplasia is not a feature of pure sessile serrated adenoma
  • Some may have the appearance of goblet cell rich hyperplastic polyps or traditional serrated adenomas
  • Conventional adenomas have been reported
• Any of the following three:
  • ≥20 serrated polyps, any kind or size, anywhere in colorectum
    • Some investigators prefer ≥30
  • ≥5 serrated polyps proximal to sigmoid
    • ≥2 of which are ≥1 cm
  • Any serrated polyp proximal to sigmoid in a first degree relative of a patient with serrated polyposis
• Development of cytologic dysplasia (adenomatous change) may indicate increased risk for carcinoma
• Patients with syndrome are considered at risk for development of colorectal carcinoma (see Clinical at left)

Robert V Rouse MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342

Original posting/updates : 1/31/10, 11/12/11, 3/20/13, 9/1/13

Supplemental studies

Immunohistology

• Ki67 staining may demonstrate aberrant proliferative zones

Genetic Analysis

• MSI low in pure lesions
• MSI high in foci of dysplasia or carcinoma
• BRAF frequently mutated

Differential Diagnosis

• Familial adenomatous polyposis
• Hereditary non-polyposis colorectal cancer
• Juvenile polyposis
• Hereditary mixed polyposis

Clinical

• Patients with syndrome are considered at risk for development of colorectal carcinoma
  • Level of risk is unclear because of rarity of syndrome
    • 15-55% incidence of cancer has been reported
    • Referral bias may affect these numbers
  • Increased screening of patients and first degree relatives is indicated
  • Removal of lesions >1 cm is recommended
  • Total or partial colectomy may be indicated if numerous
• Colorectal carcinomas arising in serrated polyposis are diverse in genotype (Rosty 2013)
  • They are not restricted to microsatellite instability pathway
• Rare familial cases have been reported
  • Pattern of heredity is not consistent

Bibliography

• Bosman FT, Carneiro F, Hruban RH, Thiese ND (Eds). WHO Classifiication of Tumors of the Digestive System, IARC, Lyon 2010
• East JE, Saunders BP, Jass JR. Sporadic and syndromic hyperplastic polyps and serrated adenomas of the colon: classification, molecular genetics, natural history, and clinical management. Gastroenterol Clin North Am. 2008 Mar;37(1):25-46.
• Snover DC, Jass JR, Fenoglio-Preiser C, Batts KP. Serrated polyps of the large intestine: a morphologic and molecular review of an evolving concept. Am J Clin Pathol. 2005 Sep;124(3):380-91.
• Jeevaratnam P, Cottier DS, Browett PJ, Van De Water NS, Pokos V, Jass JR. Familial giant hyperplastic polyposis predisposing to colorectal cancer: a new hereditary bowel cancer syndrome. J Pathol. 1996 May;179(1):20-5.
• Chow E, Lipton L, Lynch E, D'Souza R, Aragona C, Hodgkin L, Brown G, Winship I, Barker M, Buchanan D, Cowie S, Nasioulas S, du Sart D, Young J, Leggett B, Jass J, Macrae F. Hyperplastic polyposis syndrome: phenotypic presentations and the role of MBD4 and MYH. Gastroenterology. 2006 Jul;131(1):30-9.
• Rex DK, Ahnen DJ, Baron JA, Batts KP, Burke CA, Burt RW, Goldblum JR, Guillem JG, Kahi CJ, Kalady MF, O'Brien MJ, Odze RD, Ogino S, Parry S, Snover DC, Torlakovic EE, Wise PE, Young J, Church J. Serrated lesions of the colorectum: review and recommendations from an expert panel. Am J Gastroenterol. 2012 Sep;107(9):1315-29
  
• Rosty C, Buchanan DD, Walsh MD, Pearson SA, Pavluk E, Walters RJ, Clendenning M, Spring KJ, Jenkins MA, Win AK, Hopper JL, Sweet K, Frankel WL, Aronson M, Gallinger S, Goldblatt J, Woodall S, Arnold J, Walker NI, Jass JR, Parry S, Young JP. Phenotype and polyp landscape in serrated polyposis syndrome: a series of 100 patients from genetics clinics. Am J Surg Pathol. 2012 Jun;36(6):876-82.
• Rosty C, Walsh MD, Walters RJ, Clendenning M, Pearson SA, Jenkins MA, Win AK, Hopper JL, Sweet K, Frankel WL, Aronson M, Gallinger S, Goldblatt J, Tucker K, Greening S, Gattas MR, Woodall S, Arnold J, Walker NI, Parry S, Young JP, Buchanan DD. Multiplicity and molecular heterogeneity of colorectal carcinomas in individuals with serrated polyposis. Am J Surg Pathol. 2013 Mar;37(3):434-42.