GRAnulomatous MAstitis REGistry Study

Background:

Idiopathic granulomatous mastitis was first described by Kessler and Wolloch in 1972. The etiology remains largely unknown due to its rare occurrence. Valid prevalence data in Europe are lacking, though incidence appears higher in low-income countries compared to Western Europe. IGM predominantly occurs in women of childbearing age, mostly parous and more frequently of non-white ethnicity.

The diagnosis is confirmed only by histological evaluation, typically using core needle biopsy. Patients commonly develop recurrent breast abscesses that do not improve with antibacterial medication and often require repeat incisions or drainages. IGM must be differentiated from granulomatous inflammation associated with duct ectasia, foreign material reactions, specific infections (tuberculosis, fungi, parasites), systemic granulomatous diseases (sarcoidosis), and cystic neutrophilic granulomatous mastitis (CNGM) linked to Corynebacterium species.

Treatment strategies described in literature include high-dose steroids, immunosuppressive agents, bromocriptine, antibiotics, surgical resection, or even mastectomy. However, no evidence-based treatment recommendations are currently available.

Study Design:

This is an investigator-initiated non-interventional observational international prospective/retrospective cohort study with unlimited accrual and open registry duration due to disease rarity.

Data Collection Methods:

Retrospective Phase:

Collection and analysis via anonymized electronic database maintained by EUBREAST e.V. Participating Study Sites identify and document patients with histologically confirmed IGM treated between January 1, 2015, and Study Site activation. No patient identifying information is disclosed or documented. Data are fully anonymous without prospective follow-up.

Prospective Phase:

Patients with histologically confirmed IGM presenting after Study Site activation are informed about possible participation. Written informed consent is obtained. Diagnostic management and treatment follow institutional standards without protocol deviation. Follow-up occurs at 1, 3, and 5 years after first diagnosis to evaluate current symptoms and document potential recurrence.

• Type and Duration of Systemic Treatment [Срок оценки: From initial diagnosis through completion of treatment, up to 5 years]
• Number of Surgeries Performed [Срок оценки: From initial diagnosis through 5 years follow-up]
• Recurrence Rate [Срок оценки: At 1, 3, and 5 years after first diagnosis]
• Risk Factors Associated with Recurrence [Срок оценки: At 1, 3, and 5 years follow-up]
• Time to Histological Confirmation [Срок оценки: At baseline (from retrospective chart review or patient recall)]
• Presentation on Breast Imaging [Срок оценки: At initial diagnosis]