Breast Node 4A is not treated, it may lead to missed diagnosis of breast cancer, miss the better time for treatment, and affect the mortality rate and prognosis of patients. Breast nodule 4A is mainly obtained through color ultrasound or mammogram and BI-RADS classification. According to the BI-RADS classification standard, the higher the grade of breast nodule, the higher the possibility of malignancy, and the chance of malignancy of breast nodule 4A is 2%-10%. According to the Chinese Anti-Cancer Society Breast Cancer Diagnostic and Treatment Guidelines and Specifications 2021 Edition, 4A nodules may include fibroadenomas with irregular borders, intraductal lesions with nipple fluid or blood overflow, and unspecified mastitis, etc. Pathologic examination is recommended for all ≥4-grade nodules, and if the pathology is benign results the nodules still need to be reassessed by ultrasound after 6 months. Although the probability of 4A breast nodules is benign, it is still necessary to check for malignancy, and early detection and treatment of breast cancer can significantly improve the survival rate and prognosis of patients.