Table 1.

Classification of Common Colorectal Polyps (adapted from Jass, 2005⁹ and O'Brien et al, 2006¹⁰). Advanced serrated polyp sub-types are shown in bold. Note the difference in frequency of somatic BRAF mutation between the adenoma (<1%) and serrated polyps (up to 83%).

Polyp Name	Alternative Terminology	Key features
Adenoma	Adenomatous polyp	Neoplastic polyp with malignant potential.Somatic BRAF mutation in < 1%
Serrated polyp		A term that encompasses all polyps listed below
Hyperplastic polyp	Metaplastic polyp	General term for common lesion with glandular serration.Somatic BRAF mutation in up to 50%
Serrated adenoma	Mixed hyperplastic adenomatous polyp Atypical hyperplastic polyp Traditional serrated adenoma	Neoplastic polyp having a serrated architecture reminiscent of hyperplastic polyp but with traditional adenomatous dysplasia Somatic BRAF mutation in 62%
Mixed polyp	Admixed serrated polyp	Polyp that includes two separate morphologic components; usually dysplastic and non-dysplastic
Sessile serrated adenoma	Sessile serrated polyp Serrated polyp with atypical proliferation.	Type of serrated polyp with abnormalities of architecture and proliferation but lacking the classical features of epithelial dysplasia (intraepithelial neoplasia)Somatic BRAF mutation in 83%