Idiopathic granulomatous mastitis: A diagnostic and therapeutic challenge

•Idiopathic granulomatous mastitis (IGM) is challenging to treat since the etiology is unclear.•Those diagnosed with IGM tend to be young, within five years post-partum, and present with a persistent painful mass.•Excision of the mass is successful in halting the process in approximately 85% of the patients.•Corticosteroids may conserve breast tissue in patients with a sterile abscess and no contraindications to immunosuppression.

BackgroundIdiopathic granulomatous mastitis is a rare benign breast disease of women of reproductive age. It usually presents as a painful mass. Since the etiology is unclear, directed diagnosis and management is lacking.MethodsThis is a retrospective chart review of 14 patients, over twelve years (2004-2016), identified through query of pathology findings.ResultsTwo asymptomatic patients were diagnosed after oncologic breast resection following neoadjuvant chemotherapy. The remaining twelve patients were young (31.7 years, range 23-43 years), predominantly non-white (50% African/African-American, 36% Hispanic, 7% Asian), pregnant within the last five years (86%), with no prior granulomatous disease. Evaluation included breast imaging, microbial cultures and staining, and biopsy. Treatment included antibiotics (57%), corticosteroids (21%), methotrexate (7%), and/or surgery (71%). Imaging suggests segmental masses, possibly abscess.ConclusionGranulomatous mastitis is uncommon, and difficult to diagnose and manage. We review our experience, the literature, and propose an algorithm for diagnosis and management.