Long-term outcome in idiopathic granulomatous mastitis: a western multicentre study.

Aim: To investigate the presentation, disease course and long-term outcome of a western cohort of idiopathic granulomatous mastitis (IGM) and to analyse the impact of different therapeutic strategies.
Methods: Multicentre retrospective study of 23 women followed over an extended period. Patients were recruited in nine French internal medicine departments.
Results: The median follow-up was 6 years. IGM presented commonly as a single inflammatory unilateral extra-areolar lump of varying size. Clinical course was heterogeneous and frequently remitting/relapsing. Most patients had at least one recurrence (18/23, 78%). The mean number of recurrences was 1.3 ± 1.5. Seven women had a bilateral evolution. Twelve women received steroids (corticosteroids). Only two of these did not respond to corticosteroids, whereas six relapsed when dose was tapered off. Nine patients received colchicine and/or hydroxychloroquine. First-line treatment consisted of excisional surgery in eight cases. At the date of last interview, 91% of the patients declared to be healed, 15 being free of treatment. However, 12/21 (57%) reported significant sequelae (unsightly scars: eight and/or lasting pain: six). Unsightly scars were not more prevalent in patients who had received steroids whereas they tended to be more frequent after breast excisional surgery. In addition, we found that excisional surgery did not prevent recurrences more successfully than a conservative approach.
Conclusions: Despite its retrospective nature, this Caucasian series provides novel information regarding long-term outcomes in IGM and argues in favour of conservative approaches. The value of immunomodulatory drugs such as colchicine or hydroxychloroquine deserves further investigation.