Cystic hyperplasia of breast, also known as chronic cystic breast disease, cystic desquamative breast hyperplasia, fibrocystic breast disease, etc. It is a disease characterized by cysts formed by highly dilated breast lobules, ductules and terminal ducts, accompanied by malformed breast structure. This disease is one of the common and frequently occurring diseases in women, more common in women aged 25 to 45. It is essentially a disorder of the normal structure of the breast caused by physiological hyperplasia and incomplete restoration. Compared with simple breast hyperplasia, this disease has coexistence of breast hyperplasia and atypical hyperplasia, and there is a risk of malignant transformation, which is the difference. It should be regarded as a precancerous lesion.