Breast 4b should refer to a breast BI-RADS result of 4B, with a 50% to 90% likelihood of being benign and a 10% to 50% likelihood of being malignant. Breast BI-RADS is an imaging classification of the degree of benign and malignant breast nodules, which can be categorized into 7 categories, the higher the category, the higher the probability of malignancy. 4 categories belong to the intermediate and high level, and 4 categories can be divided into 4A, 4B, 4C, 4B most of the benign nodules, but there is a probability of malignancy, malignancy probability is generally between 10% and 50%. Due to the probability of malignant transformation, it is necessary to take tissues for pathological examination in time, and the commonly used examination methods include surgical excision biopsy and hollow needle puncture examination. If the pathologic examination is benign nodules, regular examination is required to keep track of the development of the nodules. If the nodule is malignant, it should be treated by surgery, radiotherapy and chemotherapy. It is recommended that patients seek medical attention in time for further examination to clarify the degree of benign or malignant, and then follow the doctor’s instructions for treatment.