If a tumor develops in the breast, it can invade the skin, glands, lymphatic vessels and blood vessels of the breast, resulting in skin abnormalities of the breast. Some skin changes can appear before the mass is clinically palpable and can be one of the most important signs in diagnosing a tumor. Different breast skin abnormalities may indicate different stages of the tumor. Between the lobes of breast glands, there are fiber bundles perpendicular to the skin, connecting the skin and the deep surface of the pleural fascia, which play the role of supporting and fixing the breast, maintaining the appearance of the breast and maintaining a certain degree of elasticity and tension, known as the suspensory ligament of the breast, or Cooper’s ligament. If the breast tumor violates the suspensory ligament, the ligament can be shortened and lose elasticity, and the skin in the corresponding area will be pulled towards the chest wall, forming a dimple-like skin depression, which is called the “dimple sign”. “Dimple sign” is the early clinical manifestation of breast cancer. When the tumor is small, it causes very slight skin adhesion, which is not easy to be detected without careful examination. This slight skin adhesion is one of the important signs to identify benign and malignant breast tumors. “Orange peel-like change” refers to the breast skin showing orange peel, the breast subcutaneous lymphatic network is rich, if the tumor is close to the skin, it can invade or block the subcutaneous lymphatic vessels, or due to the tumor is located in the central region of the breast, resulting in superficial lymphatic return obstruction, resulting in localized edema of the skin of the breast. Due to the close connection between skin and subcutaneous tissue at hair follicles and sebaceous glands, the skin edema shows pitting depression, i.e. “orange peel”, which is a clinical sign of advanced breast cancer. “Satellite nodule” is due to the infiltration of cancer cells along lymphatic ducts, glandular ducts or fibrous tissues into the skin and growth, forming scattered hard nodules in the skin around the main cancerous foci, which may be a few or a dozen, with diameters ranging from several millimeters to a few centimeters, and with reddish or dark red color, which is a clinical sign of breast cancer in advanced stage. Widespread skin nodules caused by recurrent breast cancer due to obstruction of lymphatic reflux and retrograde spread of cancer embolus in lymphatic vessels often appear around the scar in the operation area, and can also be manifested as a majority of small nodules in patches, accompanied by redness and swelling of the skin, which is clinically referred to as “armor-like lesions”. In advanced stage, breast cancer invades the skin, which breaks down and forms ulcers, accompanied by different degrees of bleeding and blood seepage, mostly complicated by bacterial infection, producing strange odor. Inflammatory breast cancer breast skin redness, swelling, heat, pain, cool acute inflammatory changes, but the body temperature is normal, the white blood cell count is not high, diagnosed as breast cancer by pathology, and most of the patients are found to have metastasis in axillary or supraclavicular lymph nodes at the time of diagnosis. Breast skin varicose veins, occurring in patients with faster tumor growth and larger size, this sign of breast cancer is rare, mostly seen in breast giant fibroadenoma, lobular tumor and fibrosarcoma.