Serrated Polyposis of the Colon and Rectum

Definition

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