There are several classification systems for hyperplastic polyposis, although most agree that this condition is defined as any one of the following:
- At least five histologically diagnosed hyperplastic polyps proximal to the sigmoid colon, of which two are >10 mm in diameter.
- Any number of hyperplastic polyps proximal to the sigmoid colon in individuals who have a first-degree relative with hyperplastic polyposis.
- More than 30 hyperplastic polyps of any size distributed throughout the colon (see Burt R, Jass JR. Hyperplastic Polyposis. In: Hamilton SR, Aaltonen LA, editors. Pathology and Genetics of Tumors of the Digestive System. World Health Organization Classification of Tumors. Third edition. Berlin: Springer-Verlag, 2000:135–6).