Chronic granulomatous mastitis occurs in women between 28 and 45 years of age after breastfeeding and is very difficult to treat. Although benign, the patient is very distressed during the consultation and treatment. Etiology The etiology is unclear and may be related to several factors: (1) high protein secretions that cannot be excreted; (2) ductal dilatation duct blockage leading to continuous retention of secretions stimulating an inflammatory response; (3) bacterial infections such as Mycobacterium aureus, Mycobacterium tuberculosis, Mycobacterium bovis, etc.; (4) oral contraceptives, antidepressants, etc.; (5) hyperprolactinemia; (6) smoking; (7) a1 antitrypsin deficiency ; Pathogenesis Non-specific ductal dilatation ductitis, causing an inflammatory response, massive infiltration of plasma cells and lymphocytes, release of inflammatory factors by inflammatory cells attacking the own duct, causing ductal degeneration and necrosis, self-repair granuloma formation, alternating with the formation of central necrotic lesions and abscesses and surrounding granuloma formation. To put it simply, self-inflammatory cells cause damage and tissue repair forms granulomas, with the two mechanisms alternating. Plasmacytoid mastitis and periductal mastitis Granulomatous mastitis and plasmacytoid mastitis are not clinically distinguishable from each other alone. Plasmacytoid mastitis is named because of the large number of plasma cells infiltrating the inflammation, and some people believe that ductal dilatation periductal mastitis plasmacytoid mastitis granulomatous mastitis is a different stage of the disease. However, some periductal mastitis plasma cell mastitis is still periductal mastitis plasma cell mastitis from the beginning to the end, whether it is a different disease or different stages of a disease is not really important in the current understanding because the treatment is basically the same. Treatment includes hormonal therapy, surgical treatment, and hormonal therapy does not reduce the recurrence rate, but helps to limit the lesions, make them smaller, and preserve the appearance of the breast as much as possible. Surgical treatment mainly involves removing 1 cm of tissue around the lesion, and the recurrence rate is extremely high, almost 100%, simply by cutting and draining the pus. However, in practice it is very difficult because chronic mastitis is often very extensive and if excision is done to 1cm of normal glandular tissue around the lesion, the only option may be to do a simple mastectomy, which is a very difficult choice for a benign disease.