Idiopathic granulomatous mastitis (IGM) is a benign breast disease that was first described by Kessler and Wolloch in 1978. A rare inflammatory condition of the breast, it usually occurs in young parous women with a history of breast-feeding. The most common clinical presentation is a firm, unilateral, and discrete breast mass that is often associated with inflammation of the overlying skin. In ≥50% of reported cases, the initial diagnosis was considered malignant or was suspected to be breast cancer. Other causes of mammary granuloma formation must be excluded before a confirmative diagnosis can be made, including sarcoidosis, Wegener’s granulomatosis, tuberculosis, and a fungal infection because they require completely different treatments. Microbiological investigation is, therefore, very important. Cytological features can be difficult to distinguish from those of carcinoma and other granulomatous mastitis such as tuberculosis of the breast. Tuberculous mastitis (TM) is an uncommon disease that is often difficult to differentiate from IGM and breast cancer when it presents as a lump. Breast tuberculosis should be considered a differential diagnosis in people with clinically suspicious breast lumps in high-risk populations or endemic areas. Use of corticosteroids and surgical wide excision of the lesions have been reported for the treatment of IGM. TM is an important differential diagnosis because of the implications of corticosteroid therapy.
This article was published in the Journal of Breast Cancer and is free to access online.