Endometrial thickening is divided into simple endometrial thickening, and atypical endometrial thickening, i.e. endometrial intraepithelial neoplasia, as follows: 1. Simple endometrial hyperplasia: it can be cured, and the chance of cancer is small, only 10% of patients will progress to endometrial cancer; 2. Atypical endometrial hyperplasia or endometrial intraepithelial neoplasia: the chance of cancer is larger, 30% of patients will develop into endometrial cancer, but patients with such precancerous lesions can be cured if they are treated in time.