Observation Alone for Mild Non-Lactational Mastitis

The goal of this observational study is to investigate the disease progression rate and timing in patients with mild Non-Lactational Granulomatous Lobular / Periductal Mastitis (NL-GLM/PDM) during follow-up with observation alone strategy. The main questions it aims to answer are: What is the rate of disease progression in mild NL-GLM/PDM patients under observation, and what clinical and pathological factors are associated with this progression? Participants with diagnosis of mild NL-GLM/PDM will be monitored over a specified period, with data collected on their clinical outcomes and relevant factors influencing disease progression.

Inclusion Criteria: 1. Female, aged 18 to 65 years; 2. Clinically diagnosed with possible non-lactational (more than 6 months since stopping breastfeeding) granulomatous lobular mastitis or periductal mastitis. 3. Mscore ≤ 4 points; 4. Patients with ultrasound findings suggesting localized breast abscess formation must have undergone abscess drainage before enrollment; 5. After education, participants should have a strong willingness for observation and follow-up, and, after discussing with the primary physician, jointly decide to proceed with observation and follow-up; 6. Signed informed consent form. Exclusion Criteria: 1. Patients with confirmed or suspected breast malignancy; 2. Patients with bilateral mastitis (including those with bilateral simultaneous onset and those with sequential onset of non-lactational granulomatous mastitis); 3. Pregnant patients who are currently in the gestation period; 4. Patients who have had non-lactational mastitis in the same breast within the past year and have undergone treatments such as surgery, oral corticosteroids (for more than 2 weeks), anti-tuberculosis treatment (for more than 2 weeks), or ductal lavage therapy. 5. Patients who received surgery, oral corticosteroids, or anti-tuberculosis treatment for the non-lactational mastitis of the ipsilateral breast within 2 weeks before enrollment.