Breast dcis is carcinoma in situ confined to the ducts of the breast and is an early malignant tumor. Breast dcis, which mostly occurs in the terminal ducts, is a carcinoma in situ confined to the ducts of the breast. X-ray examination may suggest that the breast shows clusters of tiny calcified foci without masses. Clinically, dcis is categorized into three grades: low-grade, intermediate-grade and high-grade. Low-grade dcis consists of small cells of uniform size. Intermediate grade has a variety of structural manifestations, and high grade dcis consists of pleomorphic cells that may be accompanied by necrosis in the lumen. The mainstay of treatment for breast dcis is surgery, which involves removal of the breast mass, breast and lymph node dissection, followed by radiotherapy, targeted and endocrine therapy on a case-by-case basis. If breast dcis exists, you should go to the hospital in time to find out the cause of the disease and treat the symptoms.