In mature breasts, the nipples protrude from the center of the areola, while both breasts are symmetrical to each other and at the same level. If the nipple recedes and changes its orientation, it is called nipple invagination. The causes can be divided into two categories: congenital and pathological. The congenital nipple invagination is a kind of abnormal breast development performance, the breast in the development stage, the nipple failed to grow out of the upright. (Women are more prone to nipple invagination during puberty if they are affected by the bad habit of breast binding) is a congenital malformation of the breast. The pathological ones can be caused by inflammation, trauma and cancer. Inflammation is mostly seen in acantholytic mastitis (ductal dilatation) as it is a chronic recurrent abscess that occurs under the areola, and repeated episodes can lead to twinning of the fibrous tissue of the duct under the nipple, resulting in a change in nipple orientation or invagination. Secondly, when the subcutaneous tissue is necrotic due to trauma to the breast and the necrotic fatty tissue is completely fibrotic, some patients may also experience nipple recession or change in orientation. In breast cancer that occurs in the central part of the breast, the growth of cancer cells causes the Cooper’s ligament fibers to contract. This results in nipple invagination and directional changes. At the same time, the sunken nipple often has a hard lump that can be palpated, and the sunken nipple cannot be lifted. Congenital nipple depression often leads to acute mastitis after pregnancy and childbirth due to the inability to breastfeed properly due to nipple depression. Therefore, once the nipple is found to be sunken during puberty, the sunken nipple should often be pinched with the fingers and gradually pulled outward (especially if there is sunkenness after pregnancy) to sometimes correct the deformity. For those who have complete nipple invagination and cannot be pinched and pulled out by hand, surgery should be performed, preferably during the unpregnant period. Surgical correction can also be performed electively after complete healing of the infected lesions of nipple invagination caused by inflammation or trauma. As for nipple indentation caused by advanced breast cancer, it should be removed as early as possible along with the breast cancer.