Macromastia, also known as breast enlargement, large breasts or gigantomastia, is a condition in which a woman’s breasts are overdeveloped, containing excessive growth of glands and fatty connective tissues, and are oversized and significantly out of proportion to her torso. Chest compression, chronic mastitis, pain, heavy shoulder pain and skin erosion under the breast can occur. Breast enlargement is most common in adolescent girls or young women, and often occurs on both sides, occasionally limited to one side. Breast enlargement is caused by abnormal sensitivity of the glands and fatty connective tissue to estrogen. Multiple breast fibroids are the most common benign tumors of the breast and are most common in women of childbearing age. It is generally believed that the development of multiple breast fibroids is related to estrogen stimulation, which is mainly manifested by different degrees of hyperplasia of the epithelial and fibrous tissues of the breast. It is mostly benign and most patients have no obvious symptoms because it is painless or has only a slight swelling or dull pain, this pain and size is not related to menstrual cycle, the lump grows slowly and the surface is smooth. Breast tumor is a kind of excess new biological tissue in breast, which is divided into benign, junctional and malignant tumors. Common benign breast tumors include breast fibroadenoma, intraductal papilloma, atypical hyperplasia-like breast diseases, etc.; common lobular breast tumor is a kind of junctional breast tumor; common malignant breast tumors include breast cancer, etc. The nature of breast tumors differs, and the treatment and prognosis also have obvious differences.