Idiopathic granulomatous mastitis (IGM) is a rare inflammatory breast disease affecting women aged 20-40, and it can mimic infectious or neoplastic mastitis. This retrospective study at Saint-Louis Hospital (2010-2023) analyzed 19 histologically confirmed cases to refine clinicopathological features and evaluate treatments. Clinically, 89% of patients presented with one or more erythematous breast masses, often associated with abscesses, adenopathy, nipple retraction, edema, or fistulas. Histology showed large peri-lobular granulomas with polymorphic inflammation. Among 18 treated patients, NSAIDs achieved complete remission (CR) in 50% (6/12), corticosteroids in 40% (2/5), and surveillance alone in 60% of minimally symptomatic cases (5/8). Antibiotics led to partial remission (PR) in 23% but no CR. Surgery was not recommended due to its aesthetic impact. The median time to CR was six months, with three relapses. NSAIDs appear as an effective first-line treatment, while antibiotics showed limited efficacy. Further research is needed to standardize therapeutic protocols.
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