The breast is composed of the breast gland, fat and connective tissue. The breast is divided into 15 to 20 lobules by fatty tissue, and each lobe has a milk duct, which is centered on the nipple and arranged in a radial pattern. The development and secretion of the mammary glands are regulated by various hormones in the anterior pituitary gland, adrenal cortex and ovarian endocrine system. Non-lactating mastitis is a condition in which the large subareolar milk ducts become septic or blocked due to congenital nipple invagination, poor drainage, and intraductal infection, resulting in bacterial invasion and multiplication of the ducts. Because the disease is based on ductal dilatation, and the clinical manifestations and pathological features vary at different stages, it is also called ductal dilatation syndrome of the breast. In recent years, young and middle-aged women suffer from a chronic and limited breast-specific inflammation in the areola that is not related to childbirth or lactation. It is often treated clinically as a general inflammatory disease, such as anti-inflammatory, incision and drainage, but the wounds do not heal over time, or repeatedly become red and swollen and break down, resulting in multiple fistulas in the breast, which can last for several years. The disease is a chronic benign inflammatory disease characterized by marked dilation of the collecting ducts at the areola, periductal fibrosis, and complex and diverse lesions characterized by inflammatory cells, especially plasma cell infiltration, and is an autoimmune disease, also associated with endocrine disorders that can be seen at any age. The disease is divided into three types: breast lump type, nipple overflow type, and mixed type. 1, breast lump type: is the most common clinical manifestation of the disease, the lump is mostly about 2 cm in diameter, tough and hard, the border is unclear, adhesion with the skin, there is mild tenderness. Some patients have nipple invagination. This type is easily misdiagnosed as cancer and should be given high priority. 2. Nipple overflow type: The overflow is usually yellowish, creamy, bloody or purulent, and most patients are pale yellow paddle fluid. Some patients have this symptom as the first symptom. It can last from 1 week in short cases to several years in long cases. The overflow is squeezed out or spilled from one or more ducts, and some patients have slight pain. 3. Mixed type: Patients have both breast lumps and nipple discharge, and some patients also have pain in the areola area and enlarged axillary lymph nodes. The incidence of breast pain can be more than six months, and a small number of patients have nipple invagination or even orange peel-like changes. This type is easily misdiagnosed as a malignant lesion. In some patients, the disease comes and goes, and it is a chronic inflammatory process with recurrent attacks. The results of x-rays taken show a flame-like or filiform protrusion, while ultrasound shows a marked dilatation of the milk ducts in the lesioned area, with irregular beads and tiny punctate calcifications.