Table 1.

Comparison of 2010 and 2019 WHO Criteria for Serrated Polyposis Syndrome (SPS)

Major SPS Phenotypes	WHO Criteria 2010	WHO Criteria 2019
Type 1	I. At least 5 serrated polyps proximal to the sigmoid Colon, 2 of which are > 10 mm in diameter.α	I. ≥5 Serrated lesions/polyps proximal to the rectum, all being ≥5 mm in size, with at least 2 being ≥10 mm in size
	II. Any number of serrated polyps occurring proximal to the sigmoid Colon in an individual who has a first-degree relative with SPS.
Type 2	III. > 20 serrated polyps of any size distributed throughout the Colon.α	II. > 20 Serrated lesions/polyps of any size distributed throughout the large bowel, with ≥5 being proximal to the rectum.

^α criteria used to define SPS in this study