GRAnulomatous MAstitis REGistry Study

Idiopathic granulomatous mastitis (IGM) is a rare benign inflammatory breast condition with unknown cause, affecting approximately 2.4 per 100,000 women aged 20-40 years. Patients experience severe local symptoms including pain, redness, and recurrent abscesses that can last weeks to months and often mimic inflammatory breast cancer. Due to its rarity, mostly case reports and case series exist in the literature, leading to limited knowledge about risk factors, optimal treatment strategies, and clinical outcomes. The GRAMAREG study is the first European registry for patients with histologically confirmed idiopathic granulomatous mastitis. This retrospective/prospective observational cohort study aims to systematically evaluate the incidence, diagnostic features, clinical course, treatment strategies, and patient outcomes of this uncommon disease. The study collects both retrospective data (from January 1, 2015 onwards) and prospective data from participating sites across Europe. All diagnostic and therapeutic procedures are conducted according to institutional standards in clinical routine, as this is a non-interventional study. Patients in the prospective cohort are followed for up to 5 years to document symptom duration and recurrence rates.