Granulomatous mastitis

Granulomatous mastitis (GM), also known as idiopathic granulomatous mastitis (IGM), is a rare, benign, chronic inflammatory condition of the breast. It is characterized by the formation of non-caseating granulomas within the breast lobules, in the absence of identifiable infectious, autoimmune, or foreign body causes. The condition predominantly affects women of childbearing age, typically within a few years of pregnancy and breastfeeding, though it can occur in nulliparous women and, very rarely, in men. The disease primarily affects the breast tissue and may present as a firm, painful breast mass that can mimic breast carcinoma on clinical examination and imaging. Key symptoms include a unilateral breast lump, pain, skin erythema, abscess formation, draining sinus tracts, nipple retraction, and fistulae. Axillary lymphadenopathy may also be present. The condition can follow a relapsing and remitting course, causing significant morbidity and distress. Diagnosis is made by exclusion after histopathological examination of a biopsy specimen reveals characteristic granulomatous inflammation, and other causes such as tuberculosis, sarcoidosis, and fungal infections have been ruled out. The treatment landscape for granulomatous mastitis remains challenging and somewhat controversial due to the lack of large randomized controlled trials. Management options include observation (as some cases resolve spontaneously), corticosteroids (the most commonly used first-line medical therapy), immunosuppressive agents such as methotrexate (often used as steroid-sparing agents or for refractory cases), and surgical excision. Antibiotics are used when secondary bacterial infection is present. Recurrence rates can be significant regardless of the treatment approach chosen. A multidisciplinary approach involving breast surgeons, pathologists, and sometimes rheumatologists is often recommended for optimal management.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

Common questions about Granulomatous mastitis