Ductal Lavage Versus Corticosteroids Therapy for Idiopathic Granulomatous Mastitis

Inclusion Criteria: * Female, age between 18 and 65 years old. * Inform consent signed. * Clinical diagnosis of non-lactating mastitis, defined as mastitis occurred more than 1 month after the cessation of lactation. * Clinical and pathological diagnosis of idiopathic granulomatous mastitis. * Never receive surgical treatments, or corticosteroids therapy after the cessation of lactation. Core needle biopsy is allowed. * Good health, judged by clinicians, to receive ductal lavage. * M score \>=2 Exclusion Criteria: * Grade III inverted nipple(Plastic. Reconstruction. Surgery. 104: 389, 1999.) * Lactational mastitis patients. * Bilateral IGM patients. * Clinically diagnosis of periductal mastitis. * Pathological diagnosis of breast carcinoma. * Pregnant women. * Evidences suggest possible diagnosis of SLE(systemic lupus erythematosus), rheumatic disorders or other systematic auto-immune diseases. * Evidences suggest possible diagnosis of tuberculosis. * Evidences suggest possible diagnosis of fungus infection of the breast * History of breast trauma. * History of taking oral corticosteroids or anti-tuberculosis treatment. * Imaging examinations indicates foreign objects retained in the breast * Presence of sepsis or severe inflammation caused by IGM, for which surgery is likely required. * Patients with inappropriate coagulation function, cardiac function, pulmonary function, liver and renal function, that clinicians judges as not suitable to participate in this study.