Treatment of Idiopathic Granulomatous Mastitis: Local Steroid Administration vs. Systemic (Oral) Steroid

Idiopathic granulomatous mastitis is characterized by non-caseating granuloma and microabscess formation limited to mammary gland lobules. It is a form of chronic mastitis of unknown pathogenesis. In this study, the effectiveness of intralesional steroid injection with topical steroids is compared to systemic steroid therapy in the treatment of idiopathic granulomatous mastitis. Between June 2017 and December 2020, patients were collected and assessed. Idiopathic granulomatous mastitis was diagnosed histopathologically by tru-cut biopsy in patients with breast mass, pain, and erythema with suspicion of idiopathic granulomatous mastitis. Included in the study were one hundred and eleven patients who were diagnosed with idiopathic granulomatous mastitis and were treated with local or oral administration of corticosteroids, with at least 6 months of follow-up. The patients were divided into 2 groups: a local corticosteroid–treatment group (n = 57) and a peroral corticosteroid–treatment group (n = 54). Demographic characteristics, treatment responses, recurrence rates, side effects of the steroid, and the need for surgery were compared. The rate of smoking was 12.3% in the local corticosteroid–treatment group and 20.4% in the peroral corticosteroid–treatment group. There was no history of oral contraceptive use in either group. Previous steroid use was significantly lower in the local corticosteroid–treatment group (10.5%) compared to the peroral corticosteroid–treatment group (55.6%) (p = 0.001). Previous antibiotic use was significantly lower in the local corticosteroid–treatment group (75.4%) compared to the peroral corticosteroid–treatment group (100%) (p = 0.001). Those who responded after the first course of treatment were 96.5% in the local corticosteroid–treatment group versus 75.9% in the peroral corticosteroid–treatment group (p = 0.001). Complete responders after the third course of treatment was 98.2% in the local corticosteroid–treatment group versus 87.0% in the peroral corticosteroid–treatment group (p = 0.003). Recurrence had been 7% of the patients in the local corticosteroid–treatment group compared to 37% in the peroral corticosteroid–treatment group (p = 0.001). Steroid-related side effects were lower in the local corticosteroid–treatment group (0 compared to the peroral corticosteroid–treatment group (11.1%) (p = 0.010). Surgery was performed in 3.5% of the local corticosteroid–treatment group and in 57.3% of the peroral corticosteroid–treatment group (p = 0.001). A comparative open-label study in idiopathic granulamatous mastitis between local infiltration of corticosteroid compared to oral methyl prednisilone both used as single modality therapy has shown better and sustained response to local infiltration of corticosteroids.