The male nipple is lined with connective tissue, blood vessels and nerves; the female nipple is lined with milk ducts, blood vessels and nerves, and is susceptible to lesions due to the complexity of the female structure. Breast tissue such as the male nipple stops developing before puberty and is lined with connective tissue, vascular nerves, and very few glands. Enlargement of the male breast may be due to physiologic factors such as obesity or estrogen abnormalities due to testicular disease. Inside the female nipple are ducts, sebaceous glands, some areola glands, blood vessels and nerves, and the nipple is the structure that secretes milk. When obstruction of the nipple milk ducts occurs, it may lead to diseases such as mastitis, with manifestations such as breast pain, redness and swelling of the skin. It is recommended to go to the hospital in time when symptoms of these diseases appear.