Breast epithelial atypical hyperplasia mainly refers to the abnormal proliferation of epithelial cells. Breast epithelial atypical hyperplasia is characterized by proliferating cells of different sizes and morphologies, with increased but mostly normal karyorrhexis. The cells are disorganized and have increased cellular hierarchy, usually occurring in the overlying epithelium of the skin or mucosal surface, but may also occur in the location of the glandular epithelium. Breast cancer originates mainly in the ductal epithelium of the breast. Atypical hyperplasia is an intermediate station in the change from benign to malignant, and a critical point in the transition from quantitative to qualitative change. Therefore, atypical hyperplasia is called precancerous lesion. Atypical hyperplasia is a morphologic change in precancerous lesions, but there is a degree of heterogeneity in the morphologic structure of the proliferating epithelium that is insufficient to diagnose cancer. Not all ductal dysplasia necessarily transforms into cancer, and not all cancers have definite ductal dysplasia. When a patient has breast fibroma with ductal epithelial atypical hyperplasia, he should go to the hospital in time and be given appropriate treatment and therapy under the guidance of the doctor.