病理組織學上息肉主要有三種類型：HP, AP, SSP。意義是不一樣的。

Generally, colorectal polyps could be classified according to the histological types into hyperplastic polyps (HPs), adenomatous polyps (APs), and sessile serrated polyps (SSPs) Among them, APs and some subtypes of HP have been considered as precancerous lesions for colorectal cancer (CRC)