Mammogram 4a, regardless of the type of imaging of the breast, is now standardized for imaging physicians with BI-RADS training. Therefore, all imaging abnormalities must be classified and described uniformly in the BI-RADS grading system. BI-RADS grade 4a represents a low degree of malignant potential, and a lesion that has reached grade 4a has a probability of malignancy of approximately 5-15%. Therefore, with an indication for biopsy, it is best to perform a puncture or excisional biopsy as soon as possible to clarify the nature.