Abstract
Idiopathic granulomatous mastitis (IGM) is a rare benign breast condition with a course that is often rapidly progressive and slow to resolve. There is no consensus on management, especially during pregnancy and lactation. A 30-year-old at 33 weeks presented with mastalgia, induration and galactorrhoea in the left breast. There was no improvement with antibiotics. Initial workup was negative, and a core needle biopsy showed findings consistent with the diagnosis of IGM. She was treated with steroids antepartum. She was co-managed by rheumatology and her obstetrician/breastfeeding medicine specialist postpartum. She was treated with azathioprine, breastfed exclusively for 6 months and continued breastfeeding through the first year. A multidisciplinary team approach is crucial in diagnosing, treating, and facilitating successful breastfeeding in patients with IGM.