Hypoechoic nodule category 3 in the left breast refers to the grade of the lesion found in the breast during the mammogram, which is determined by the nature of the lesion and other comprehensive classification. Breast ultrasound hypoechoic nodule category 3 refers to a nodule that is initially considered to be more likely to be benign and less likely to be malignant, and refers to a nodule with clear borders and an aspect ratio of less than one. For breast nodule category 3, if the nodule is small, it is the first case, and there is no family history of nodule size and nature changes can be regularly observed. If the mammogram suggests hypoechoic nodule category 3 in the left breast, the patient has a family history or the patient is anxious, and the solid mass or mass is large, further management is recommended, such as puncture biopsy or direct surgical excision with intraoperative rapid frozen section. If the lesion is benign, local excision is sufficient. If the lesion is malignant, expanded surgical treatment is required.