The term intraepithelial neoplasia was first used by Richard in 1960 for precancerous changes in the squamous epithelium of the cervical mucosa, and its proper meaning is to emphasize that the essence of this precancerous lesion is the formation of an intraepithelial tumor. And this intraepithelial tumor formation contains a twofold meaning. One is not cancer, and the other is that tumor formation is still a process, so it is called ” neoplastic change rather than tumor. In the International Histological Classification of Tumors published by WHO in 2000, the term “intraepithelial neoplasia” was used to replace the term “heterogeneous hyperplasia” for tumors in the colorectum, cervix, vagina, stomach, urinary tract, prostate, breast and other organs. The term “intraepithelial neoplasia” has been adopted instead of “anaplastic hyperplasia”. This means that the terms “intraepithelial neoplasia” and “heterogeneous hyperplasia” are synonymous and have the same meaning. In colorectal tumors, there are two main grades, namely low intraepithelial neoplasia (LIN) and high intraepithelial neoplasia (HIN). The original mild and moderate heterogeneous hyperplasia are classified as low-grade intraepithelial neoplasia, while the severe heterogeneous hyperplasia is classified as high-grade intraepithelial neoplasia. High-grade intraepithelial neoplasia is the same thing as severe heterogeneous hyperplasia, carcinoma in situ, focal carcinoma, intramucosal carcinoma, and other carcinoma suspicion, carcinoma trend, etc. There should be only one term, which is high-grade intraepithelial neoplasia. The term “intraepithelial neoplasia” was adopted to reflect more accurately the nature and scientific concept of morphological changes of epithelial cells in precancerous lesions before they develop into invasive carcinoma, thus correcting the overtreatment and adverse effects caused by the use of terms such as severe heterogeneous hyperplasia, suspicious carcinoma, carcinoma in situ, focal carcinoma, intra-mucosal carcinoma, and carcinoma trend. In short, complete endoscopic removal or local excision of intraepithelial neoplasia, whether low-grade or high-grade, is sufficient.