High-grade intraductal carcinoma of the breast refers to grade III breast ductal intraepithelial tumor. Compared with low-grade and intermediate-grade, high-grade intraductal carcinoma has a higher number of nuclear divisions, lower differentiation of tumor cells, poorer prognosis, and a higher chance of developing infiltration. High-grade intraductal carcinoma of the breast belongs to early stage cancer, which is a kind of precancerous lesion of invasive cancer. At this time, the cancerous tissue is located in the ductal epithelium, no infiltration has occurred, and it has not broken through the basement membrane. Patients with intraductal breast cancer may have symptoms such as breast lumps, nipple overflow, and local skin color changes in the breast. High-grade ductal carcinoma of the breast describes the patient’s current type of pathology. In the early stage, breast-conserving surgery is possible, and if the cancer is intraductal, the surgery can be cured, and targeted therapy is usually not needed; in the middle stage, the doctor needs to remove the lesion by radical mastectomy, extended radical mastectomy, or modified radical mastectomy according to the patient’s condition; and in the late stage, the treatment is mainly conservative and tries to improve the patient’s quality of life as much as possible. If patients have symptoms of high-grade intraductal breast cancer, it is recommended that they go to the hospital in time for diagnosis and treatment under the judgment of professional doctors.