The orange peel sign of breast cancer looks like edema of the breast skin but forms dense punctate depressions at the hair follicles, similar to the skin pattern of “orange peel”. The subcutaneous lymphatic network of the breast is very well developed, so when the cancer is close to the skin, it often invades and blocks the subcutaneous lymphatic vessels, resulting in impaired circulation of lymphatic fluid. The skin of the breast is edematous and higher than normal skin due to lymphatic fluid retention. However, the skin at the hair follicles is more closely connected to the subcutaneous tissue and does not swell, so dense punctate depressions are formed at the hair follicles, making the breast skin look like orange peel. The edematous skin with orange peel sign will not only be thickened, but also the elasticity of the skin will be significantly reduced. The skin with orange peel sign is usually pale white, but when a large number of cancer cells enter the subcutaneous lymphatic network and rapidly expand, the skin can also be red or dark red, similar to the skin manifestation of acute mastitis. If patients find their breasts have changes in appearance, it is recommended that they should actively seek medical treatment and be diagnosed or excluded by professional doctors through physical examination combined with breast ultrasound or molybdenum target, etc. Patients should not diagnose on their own in order to avoid delaying their condition.