Breast cancer has become a hot topic nowadays. Breast cancer is a major problem for women. The treatment of breast cancer should be started as early as possible, therefore, early detection and diagnosis is especially important. Lumps are the first symptom of breast cancer. Most of the lumps are located in the upper outer quadrant, followed by the upper inner nipple and areola area, and less in the lower part. The size of the lump varies, with 2-3 cm being the most common size, mostly solitary and occasionally multiple. Most of the lumps are round or oval with unclear borders and are usually hard nodes with poor mobility. Most of the breast cancer patients lack pain symptoms. Because of the low occurrence of pain, breast cancer is not easily detected at an early stage. Pain is often manifested as tingling, swelling or hidden pain in the breast, and periodic pain may occur if the cancer is accompanied by cystic hyperplasia of the breast. The skin of breast is changed and the breast tissue is surrounded by the superficial fascia under the skin, which is connected by Cooper’s ligament. Since the superficial fascia is connected with the skin, when the breast cancer invades the Cooper’s ligament between the breast and shortens it, it will pull the skin and make the local skin sunken like a dimple, which is called “dimple sign”. In addition, the tumor may also adhere to the skin directly. The dimple sign can appear at the early stage of breast cancer and is more obvious when the affected arm moves up and down. (1) Redness and swelling can occur in larger tumors with faster growth, and superficial skin veins can become angry and local skin temperature of the tumor can increase. If the tumor is close to the skin surface, the skin may become red. If the cancer cells block the subcutaneous lymphatic vessels, the skin may become edematous and “orange peel-like changes” may occur. The skin of breast cancer is most typical for inflammatory breast cancer. The skin color is light red or dark red, and the tumor will soon expand from a limited area to most of the breast, or even to the whole breast. (2) Skin breakdown When the tumor develops to advanced stage, the mass grows up and can make the skin bulge. If the blood supply is insufficient, with the skin reddening and thinning, breakdown can occur. Patients are often accompanied by pain, sometimes severe pain is unbearable. Due to the large amount of necrotic tissue and bloody secretions exuding from the traumatic surface, patients often show signs of emaciation and anemia as a result. (3) Skin nodules are called satellite nodules when they are distributed in the skin around the lesion, which are caused by direct infiltration of cancer cells into the skin along lymphatic ducts, breast ducts or subcutaneous fascial cords. Satellite nodules may be single or several, and the latter are mostly scattered. (4) Armor carcinoma with several skin nodules fused into a sheet covering the whole affected chest wall, and may extend from the axilla to the back, or even beyond the midline of the sternum to the contralateral chest wall. The thick and hard skin resembles the armor worn by ancient soldiers, so it is called armor cancer. 4.Mammary rotunda change When the mass is large, there may be local elevation of the breast and enlargement of the breast. When the tumor involves the skin or pectoral muscle, it can make the breast harden and shrink. When the patient sits upright, the affected breast can be raised. Treatment of breast cancer should be carried out as early as possible, so correct diagnosis and early detection are especially important. These clinical symptoms are typical, and the clinical diagnosis of breast cancer must grasp these features and examine the symptoms carefully in order to make the correct diagnosis.