Clinical characteristics and treatment approach of idiopathic granulomatous mastitis

Objectives: The purpose of this study was to evaluate the clinical characteristics, treatment approaches, and outcome of the patients with idiopathic granulomatous mastitis (IGM). Methods: The patients with IGM were reviewed retrospectively from 2011 to 2017. Event free follow up rate was estimated by using Kaplan-Meier analysis, and follow up differences for prognostic factors were compared by using the log-rank test. Multivariate analysis was performed by using Cox-regression method. Results: There were 69 patients with histologically proven IGM with median age 34 years (range, 21-68 years) at diagnosis. The majority of the symptoms and signs were breast lump, pain, erythema and axillary lymphadenopathy. The most common extramammary finding was eritema nodosum. The most common treatment approaches were only antibiotic or antibiotic plus drainage. The estimated event free follow up rate was 74.7%. It varied according to parity distribution, erythema, extramammary manifestation, and treatment modalities. Cox regression analysis showed that parity distribution, extramammary manifestation and treatment. Conclusion: This is one of the largest series in a single center. Factors affecting event free follow up rates were parity, erythema, extrammamary manifestations and treatment modalities.