Inflammatory Granulomatous Mastitis: A Comprehensive Review

Idiopathic Granulomatous Mastitis (IGM) is an inflammatory condition of the breast often characterized by pain, mass, erythema, and recurrent wounds. It usually affects women of childbearing age with a history of breastfeeding. The initial steps to evaluate such lesions are a mammogram followed by an ultrasound, as it can be difficult to distinguish IGM from breast malignancies. Concurrent infection with bacteria, such as Corynebacterium, further confounds diagnosis of IGM. The pathogenesis of IGM is poorly understood, despite reported cases as early as the 1970s. It is theorized that ductal epithelial cell damage, caused for example by milk stasis, triggers an inflammatory cascade affecting lobular connective tissue in the breast, resulting in a painful mass. The gold standard for diagnosis is histology, which can reveal non-specific inflammation around lobules of breast tissue and non-caseating granulomas. While IGM is considered a benign condition, it can cause discomfort and distress to patients along with potential disfigurement. There are currently no consensus treatment guidelines for IGM, necessitating an individualized approach. Treatment varies from clinical observation, surgical intervention, antibiotics, glucocorticoids either given systemically or intralesional, and in some refractory cases, disease modifying antirheumatic drugs. Early recognition and a multidisciplinary approach involving rheumatology in addition to obstetrics and gynecology and breast surgery are important for optimal patient care. This review explores the history, pathophysiology, clinical symptoms, diagnosis, and treatment of IGM.