In clinical practice, there is no such thing as breast cancer 4A, but usually a lump found in the breast is at grade 4A. Because it is difficult to distinguish benign or malignant breast lumps in the absence of pathological examination. Therefore, ultrasound examination is usually performed to classify a lump into grade 1-5 according to whether it has good blood supply, clear boundary, longitudinal to transverse diameter ratio over 1, and whether it is accompanied by calcification. If it is grade 4A, it usually indicates that the breast lump has some possibility of malignancy, and the probability of malignant disease in a 4A breast lump is usually about 5% in clinical practice. For small lumps of grade 4A can be closely observed and regularly reviewed. If there is progressive enlargement or increased grading, prompt surgical excision and pathological examination is usually required to rule out malignancy. If malignancy is confirmed, additional radical or modified radical treatment of breast cancer is usually required, together with comprehensive postoperative treatment.