If there is a shadow on the surface of the breast, the reasons are as follows: 1, black shadow may be caused by the accumulation of epidermal pigment in the breast; 2, the shadow is mauve or light red, which is formed due to the local blood coagulation; 3, the shadow with smooth surface, good mobility and soft appearance inside the breast may be caused by breast lumps and small polyps caused by hyperplasia of milk ducts, and it may be a shadow when it is visualized by ultrasonography or other examinations. If the boundary of the breast shadow is not very clear and the texture of the shadow looks hard after imaging, it may be the manifestation of breast papilloma and breast cancer; 5. Tumors of the chest wall or lung cancer, congenital developmental defects of the lungs and other diseases will be blocked and manifested as shadows in the breast.