Objectives <p>Idiopathic granulomatous mastitis is a rare, chronic, inflammatory breast disease that can mimic breast carcinoma. Histologicaly there are giant cells and epitheloid histiocytes forming non-caseating granulomas. Corticosteroids, methotrexate, azathioprine, intralesional corticosteroid injection can be used as the first step drugs in the treatment of patients with Idiopathic granulomatous mastitis, but the next step is unclear in a group of patients who are resistant to these treatments. Many of these patients also undergo unnecessary surgical interventions. Tumor necrosis factor-alpha (TNF-α) plays a role in maintaining the granuloma structure. There is few case reports and very limited data in the literature regarding TNF-α inhibitor treatment in resistant patients. Our aim is to show that TNF-α inhibitors may be an alternative for refractory patients in the treatment of idiopathic granulomatous mastitis.</p> Methods <p>The data of 25 female patients with idiopathic granulomatous mastitis who were refractory to conventional therapies and started TNF-α inhibitors were retrospectively analyzed. Pre- and post-treatment M scores of the patients were calculated.</p> Results <p>We observed that the M-scores of our patients decreased as the duration of TNF-α inhibitors use increased.</p> Conclusion <p>Our study contains the largest number of patients with data on the use of TNF-α inhibitors in the treatment of idiopathic granulomatous mastitis. We believe that our study will contribute to the development of idiopathic granulomatous mastitis treatment algorithms.</p> <p><Table Float="No" ID="Taba"> <tgroup cols="2"> <colspec align="left" colname="c1" colnum="1" /> <colspec align="left" colname="c2" colnum="2" /> <tbody> <row> <entry align="left" nameend="c2" namest="c1"> <p><b>Key Points</b></p> <p>• <i>TNF-α inhibitors may be an alternative for refractory patients in the treatment of idiopathic granulomatous mastitis.</i></p> </entry> </row> </tbody> </tgroup> </Table></p>