Idiopathic granulomatous mastitis: a medical or surgical disease of the breast?

Introduction Idiopathic granulomatous mastitis (IGM) is a rare benign breast disease, which can be protracted, disfiguring and may be linked to an underlying autoimmune disorder. The clinical presentation may mimic bacterial mastitis or carcinoma. Aims To review the mode of presentation, diagnosis, management, resolution and incidence of IGM in three tertiary breast centres and propose guidelines for management. Methods The breast and anatomical databases of three centres were reviewed from January 2000 to December 2013 to identify patients with histological diagnosis of IGM. Clinical and demographic characteristics were retrieved and treatment modalities and time to resolution were recorded. Results Seventeen patients were identified with a median age of 40. The majority of patients were premenopausal, multiparous and presented with a mass. All patients had initial treatment as infectious mastitis. The diagnosis was made by core biopsy in 71%. Eleven patients required immunosuppressive treatment with steroids and four of these patients required a steroid‐sparing agent because of steroidal side effects, recurrence or persistence of symptoms. The median time to resolution was 3 months (0–24 months). One patient had subsequent systemic Wegener's granulomatosis diagnosed. Conclusions Idiopathic granulomatosis mastitis requires histological confirmation, close monitoring, exclusion of underlying systemic autoimmune conditions and judicious use of steroids and steroid‐sparing agents such as methotrexate. It has a protracted course with some patients relapsing quickly upon cessation of steroids.