Idiopathic granulomatous mastitis: presentation, investigation and management.

Idiopathic granulomatous mastitis (IGM) is a rare chronic inflammatory condition of the breast which although benign can mimic carcinoma. Establishing a diagnosis can be challenging and requires a high index of suspicion with exclusion of infective and autoimmune breast diseases. IGM is characterized histologically by noncaseating granulomas which are of a lobulo-centric pattern and often associated with microabscess formation. Management of confirmed cases remains controversial with proponents of initial surgical or medical therapies - each has its associated problems which can be worse than the original symptoms of IGM. However, many patients require more than one modality of treatment to completely resolve IGM lesions and careful judgment is necessary to ensure optimal type and sequencing of treatments.