RATIONALE and PURPOSE: For non-lactational mastitis patients pathologically diagnosis of idiopathic granulomatous mastitis (IGM) or periductal mastitis (PD), the investigators hypothesized that ductal lavage is able to relieve the symptoms and achieve complete response, with shorter recovery time than oral intake of antibiotics or corticosteroids treatments. This single arm, observational, case series, pilot study is going to evaluate the effectiveness of ductal lavage in patients with non-lactational IGM or PD.

Inflammatory non-lactating breasts diseases encompasses a large spectrum of diseases ranging from infective diseases to autoimmune diseases, which cause considerable morbidity and difficulty in diagnosis. In daily practices, exclusion of possible diagnosis of breast carcinoma is the most important step. Aetiological factors for non-lactational mastitis include bacterial infection, tuberculosis, auto-immune disorders, etc. Treatments for these patients including antibiotics, anti-tuberculosis therapy, and corticosteroids treatments. Many of these patients were pathologically diagnosed as periductal mastitis (PD) or idiopathic granulomatous mastitis (IGM). The current treatment for PD or IGM include corticosteroids treatments, antibiotics and surgical treatments. Based on literature review, the complete response (CR) rate of corticosteroids and surgical treatment ranged between 63-87% and 89-100%, respectively. Time to CR ranged between 2-8 month for corticosteroid treatment.

Pathological findings of patients of IGM or PD revealed infiltrating inflammatory cells and neutrophilic microabscesses around the lobular units and partial ductal obstruction, we hypothesized that ductal lavage therapy will be able to relieve the symptom by dilating the lactiferous duct followed by irrigation solution flushing, with shorter recovery time and satisfactory CR rate. In our institution(Sun Yat-sen Memorial Hospital,Guangzhou, Guangdong, P.R.China), it is our routine practice to perform ductal lavage therapy to patients with non-lactating breasts diseases, especially for patients with IGM or PD, before we start corticosteroid or antibiotics treatments. For patients with evidence of bacterial infection, antibiotics was added into the irrigation solution. In our experience, many patients had short recovery time and low relapse rate, sparing the use of corticosteroid or antibiotics treatments. However, there is no concrete data to quantify the efficacy of ductal lavage therapy for IGM or PD patients. This observational study aims to prospectively enroll eligible patients and investigate the efficacy of ducal lavage therapy in IGM or PD patients.

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 year after the cessation of lactation.
• Never receive any treatments after the cessation of lactation.
• Good health, judged by clinicians, to receive ductal lavage.
• Pathologically diagnosed as idiopathic granulomatous mastitis (IGM) or periductal mastitis (PD).

Exclusion Criteria:

• Pathological diagnosis of breast carcinoma.
• Pregnant women.
• Evidences suggest possible diagnosis of systemic lupus erythematosus(SLE), rheumatic disorders or other systematic auto-immune diseases.
• Evidences suggest possible diagnosis of tuberculosis.
• Imaging examinations indicates foreign objects retained in the breast
• Evidences suggest possible diagnosis of fungus infection of the breast
• Patients with inappropriate coagulation function, cardiac function, pulmonary function, liver and renal function, that clinicians judges as not suitable to participate in this study.

Women with non-lactating mastitis, pathologically diagnosed as idiopathic granulomatous mastitis (IGM) or periductal mastitis (PD), were included in this study.

Individual patient data (de-identified) is available upon request.