A Systematic Narrative Review of Idiopathic Granulomatous Mastitis: Evidence, Management Challenges, and Recurrence Patterns

Idiopathic granulomatous mastitis (IGM), also known as granulomatous lobular mastitis, is a rare, benign, chronic inflammatory breast disease that primarily affects women of reproductive age and frequently mimics breast carcinoma clinically and radiologically, making diagnosis challenging. Its aetiology remains poorly understood, and treatment is not standardised. This systematic narrative review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and included English-language studies published between January 2009 and March 2026 identified through PubMed, Ovid MEDLINE, Scopus, Google Scholar, and Cumulative Index to Nursing and Allied Health Literature (CINAHL). Studies addressing the aetiology, clinical features, diagnosis, management, or outcomes of IGM were eligible, and data were extracted using a standardised Microsoft Excel form (Microsoft Corp., Redmond, WA, USA). A total of 271 studies were included, with publication trends demonstrating increasing research activity over time and the highest volume of studies published between 2023 and 2025. Most studies were retrospective observational studies (29.7%; n = 81) or case reports (22.3%; n = 61), while prospective studies (8.8%; n = 24) and interventional trials (4.8%; n = 13) were limited. Thematic analysis showed that treatment and therapeutics were the most frequently studied areas (31%; n = 120), followed by diagnosis and diagnostic methods (25%; n = 95). Recurring findings included diagnostic uncertainty, a lack of standardised treatment protocols, variable recurrence risk, and inconsistent predictors of treatment escalation, while common limitations included small sample sizes, retrospective study designs, single-centre data, and methodological heterogeneity. Overall, IGM remains a diagnostically difficult condition with uncertain aetiology and heterogeneous management; despite growing research interest, the overall level of evidence remains low, highlighting the need for multicentre prospective studies and standardised diagnostic and treatment guidelines to improve evidence-based care and patient outcomes.