The main symptom of breast cancer is a lump in the breast, which is the first symptom of most patients. However, the clinical manifestations of breast cancer can be varied, and it is not always necessary to have a lump. In addition to the lump, there are also the following common clinical manifestations. 1. Nipple discharge: Although most nipple discharge is caused by benign lesions, about 10% of bloody discharge may be confirmed as breast cancer. Breast cancer occurring in large ducts or intraductal carcinoma is more often combined with nipple discharge, and most of them are accompanied by breast lumps, but there are still a small number of breast cancers manifested by nipple discharge only. The nature of overflow is mostly bloody, and a few of them can be plasma or watery, and most of them are unilateral single-ductal overflow. Paget’s disease: also known as eczema-like breast cancer, nipple erosion is a typical symptom of this disease, often accompanied by nipple itching and burning sensation. In the early stage, the skin of nipple can be thickened, reddened and rough, and then vesicles, flakes and scabs can be seen, just like eczema. Further development can form ulcers, and gradually invade the areola area skin, the whole nipple can be eroded and disappear. About 60% of patients are accompanied by breast lumps, and can cause axillary lymph node enlargement. Inflammatory breast cancer: its first symptom is often breast enlargement, accompanied by inflammatory changes. Typical clinical manifestations are diffuse enlargement of the whole breast, skin congestion and edema of 1/3 or more area of the breast (orange peel-like changes), and the boundary of the tumor is not clear on palpation. Invisible breast cancer: this is a rare and special type of breast cancer. It generally refers to the breast cancer which is metastasized in axillary lymph nodes or distant metastasis in other parts of the body, but clinical physical examination of the breast fails to detect the lump and imaging examination (including mammography, ultrasonography, etc.) fails to determine the breast cancer. Occult breast cancer is also different from breast cancer with no lump on clinical physical examination, which can be detected by various imaging examinations, such as tiny lesions in the breast and carcinoma in situ. Breast cancer without a lump on clinical physical examination: often asymptomatic, mostly detected by screening. If no lump can be detected by clinical physical examination, mammography may show calcification, structural distortion, focal asymmetric densification, isolated ductal dilatation, etc. Sometimes, mammography may also show the same pattern. Sometimes, molybdenum target examination is also negative, and breast magnetic resonance examination may show non-mass-like enhancement. Therefore, it is especially important to review breast ultrasound and mammogram regularly in the clinic.