Clinicopathologic Features, Clinical Course and Outcomes of Idiopathic Granulomatous Mastitis

Abstract

Purpose: Idiopathic granulomatous mastitis (IGM) is a rare chronic inflammatory breast disease that mimics breast cancer in terms of clinical and radiological finding. The treatment of IGM remains controversial. We aim to evaluate the clinicopathological feature and outcomes of IGM. Methods: Fifty five pathologically confirmed IGM patients who were treated between 2005 and 2013 were enrolled. All patients were categorized into three groups according to treatment methods: conservative care including observation, aspiration, and antibiotics; steroid; surgical intervention groups. Results: The median age at time of diagnosis was 35.8 years (range, 20–49 years). The most common chief complaints were a palpable mass (40.0%) followed by painful mass (32.7%) and pain (21.8%). Thirty-one patients were treated with antibiotics for their initial treatment. Steroid treatment was initially performed in eighteen cases. The initial steroid treatment was changed to methotrexate treatment in six patients who developed side effects, such as steroid-induced diabetes mellitus and Cushing’s syndrome or showed no response to treatment. Surgical interventions were performed in six patients as the first-line treatment. Mean time to remission was 7.2±6.9 months and 1-year recurrence-free interval was 89%. Mean time to remission in conservative care group and steroid group was 5.3±5.6 months and 11.4±7.9 months, respectively, and it was significantly different (p=0.008). Conclusion: A multidisciplinary approach including close observation, antibiotics treatment, systemic steroid, methotrexate, and surgical intervention is the currently available treatment option for IGM. IGM should be closely followed up due to the frequency of disease recurrence.