Simple epithelial hyperplasia of mammary glands is an early lesion of mammary gland dysplasia. It is a common disease in women of childbearing age. It can occur in any age group from puberty to menopause, especially unmarried women or married women without children, or women with strong sexual function who have children but are not breastfeeding. The peak age of onset of this disease is 30 to 40 years old. Clinically, 50% of women have symptoms of mammary gland hyperplasia, and histologically, 90% of women can see symptoms of mammary gland dysplasia. Bloodgood first described it in 1922, and Semb noticed in 1928 that the disease manifested as breast pain and lumps, and named it simple glandular fibromatosis. Beatle called it simple desquamative epithelial hyperplasia of the breast in 1931, and Gescnickter called it mastodynia in 1948. It has been used until now.