Therapeutic strategies for idiopathic granulomatous mastitis: an umbrella review of systematic reviews and meta-analyses

Background Idiopathic granulomatous mastitis (IGM) is a rare chronic inflammatory breast disease characterized by a prolonged clinical course with recurrent episodes, and the optimal treatment remains controversial. Multiple systematic reviews and meta-analyses have evaluated medical, surgical, and combined treatment strategies, but their conclusions remain inconsistent. Methods We systematically searched PubMed, Embase, the Cochrane Library, and Web of Science for systematic reviews or meta-analyses evaluating remission, recurrence, and safety in patients with IGM or related granulomatous mastitis. The search period extended from database inception to 13 March 2026. The methodological quality of the included reviews was assessed using AMSTAR-2. Additionally, the overlap of primary studies across the reviews was evaluated using a citation matrix and the Corrected Covered Area (CCA). Results Six reviews published between 2017 and 2026 were included, comprising five conventional systematic reviews/meta-analyses and one network meta-analysis. Overall methodological quality was suboptimal, with three reviews rated as low and three as critically low. Across the included reviews, steroid-based combination therapy showed the most consistent favorable signal, particularly for recurrence reduction. In the network meta-analysis, triple therapy consisting of surgery, local steroid injection, and systemic corticosteroids ranked most favorably for recurrence control. Local steroid therapy and methotrexate-based therapy also appeared promising, particularly as better-tolerated alternatives or adjuncts to systemic corticosteroids. In contrast, systemic corticosteroid monotherapy and conservative approaches appeared less favorable for long-term recurrence control. Across the six reviews, 97 unique primary studies and 113 total study occurrences were identified, yielding a CCA of 3.30%, indicating slight overlap. Conclusion Steroid-based combination therapy showed the most consistent favorable signal, particularly for recurrence reduction. Local steroid therapy and methotrexate-based therapy also appeared promising in selected clinical contexts. However, the overall certainty of the evidence remains limited because of methodological weaknesses in the included reviews and the predominantly observational nature of the underlying literature. Further high-quality comparative research is needed before firm treatment recommendations can be established. Systematic review registration PROSPERO, identifier [CRD420261337622].