Effect of Topical Steroid Treatment on Idiopathic Granulomatous Mastitis: Clinical and Radiologic Evaluation

Idiopathic granulomatous mastitis (IGM) is a rare inflammatory, noncaseating, chronic granulomatous benign disease. The etiology of IGM is still unknown. It is postulated to be an autoimmune localized response. The use of a course of oral steroids provides an important regression of breast mass and skin lesions. Topical corticosteroids are used to treat many skin diseases, but no study is available on the sole use of topical steroids for treating IGM. Eleven women with IGM were treated with topical steroid and evaluated using mammography, ultrasonography, and dynamic MRI. At the end of the 12th week, patients were clinically and radiologically evaluated for the regression of breast and skin lesions. Pre- and post-treatment time-intensity curve patterns (TICs) were also compared. During the topical steroid treatment, the inflammation signs in the affected breast had markedly disappeared, the fistulas had become inactive, and the fistula orifices and/or skin erosions had closed in nine patients. The median follow-up period was 17months (range: 12-48months). Recurrence was observed in two patients (2/11) at 5 and 8months, which were treated again topically. The inflammatory findings of the breast skin completely resolved after 8weeks of treatment, and no side effects or steroid-related complications occurred. In the pretreatment period, TICs from enhancing areas showed a Type 1 pattern in three cases, a Type 2 pattern in five cases, and a Type 3 pattern in three cases. After topical steroid treatment, TIC was not changed only in one patient (Type 2). Type 1 patterns were determined in seven cases and Type 2 patterns in two cases. In addition, in two patients, TICs were not determined due to complete healing. Our MRI findings showed that topical steroid therapy may be useful because it affects mammary parenchyma as well as mammary skin. Further studies with a greater number of patients are needed to determine the topical steroid therapy dosing and duration, and to better understand the efficacy for treating IGM.