Today a big brother gastroscopy came out with a pathology report of low-grade endomorphic lesions, and was very stressed and consulted me. The explanation I gave is for reference only. In 2000, the concept of intraepithelial neoplasia (GIN) was introduced in the new World Health Organization (WHO) classification of tumors. LGIN corresponds to mild and moderate heterogeneous hyperplasia of the gastric mucosa; HGIN corresponds to severe heterogeneous hyperplasia and carcinoma in situ, replacing the previous terms of atypical hyperplasia and carcinoma in situ. Low-grade intraepithelial neoplasia refers to structural and cytologic abnormalities limited to the lower half of the epithelium and corresponds to mild and moderate heterogeneous hyperplasia. High-grade intraepithelial neoplasia refers to structural and cytologic abnormalities extending to the upper half of the epithelium and even to the whole layer, corresponding to severe heterogeneous hyperplasia and carcinoma in situ. Those cancers that morphologically lack a basis for infiltration into the submucosa are classified as high-grade intraepithelial neoplasia. High-grade intraepithelial neoplasia has biological characteristics similar to tumor cells and has the potential tendency to develop into tumor cells, but it is still a benign lesion, and its development can be stopped or even reversed with appropriate interventions. The name high-grade intraepithelial neoplasia is more appropriate than adenocarcinoma in situ, and intra-mucosal neoplasia is more appropriate than intra-mucosal adenocarcinoma. The aim is to avoid overtreatment and prevent unnecessary damage to the body that may affect the prognosis and quality of survival. To summarize, it is not cancerous at present, but there is a trend that treatment can reverse it. Regular review is needed.