Idiopathic Granulomatous Mastitis: 784 Cases from a Single University Hospital Treated Between January 2001 and December 2024

Background/Aims: This research sought to characterize the clinical presentations, imaging features, and histopathological findings in patients presenting with idiopathic granulomatous mastitis (IGM) at a tertiary care center and to evaluate and compare outcomes across various therapeutic approaches.

Materials and Methods: A retrospective analysis was conducted reviewing medical records and clinical documentation for 784 individuals diagnosed with IGM over 24 years, spanning from January 2001 through July 2024. Demographic features, family histories, main complaints, physical findings, laboratory and radiological findings, medical and surgical treatments, complete clinical response rates, and recurrence rates were searched for the patients discussed earlier.

Results: A total of 784 patients (782 female, 2 male) with a mean age of 33.4 years were evaluated retrospectively. The diagnosis was confirmed by histopathologic examination of the lesions. Twenty patients were pregnant, and 25 were lactating; 650 patients (82.9%) were treated with intralesional corticosteroid therapy, 36 patients (4.6%) had systemic corticosteroid therapy, 48 patients (6.1%) were treated with a wait-and-see protocol, 5 patients (0.6%) were treated with mastectomy, 43 patients (5.5%) had surgical resection, and 2 patients (0.3%) were treated with methotrexate. While 98.2% of the patients had a complete response after intralesional steroid therapy, 50% of the patients had a complete response after systemic steroid therapy. Recurrence rates were 100% after methotrexate, 20.9% after surgical resection, 20% after mastectomy, 13.8% after systemic steroid therapy, 8.3% after wait-and-see protocol, and 4.3% after intralesional steroid injection. According to the data, a multi-group chisquare test revealed significant differences between treatment types in complete clinical response (P < .0001) and recurrence rates (P < .0001). Intralesional steroid treatment significantly improved the rate of complete clinical response across all groups (P < .0001) except the mastectomy group (P = .759). On the other hand, intralesional steroid treatment significantly reduced the recurrence rate across all groups (P < .0001), except in the mastectomy group (P = .089) and the wait-and-see protocol group (P = .268).

Conclusion: It was concluded that the most effective therapy is intralesional steroid injection. Surgical intervention must be limited to abscess drainage.

Cite this article as: Akçay MN, Kartal M, Karadeniz E, Alper F, Özmen S. Idiopathic granulomatous mastitis: 784 cases from a single university hospital treated between January 2001 and December 2024. ArchRheumatol. Published online July 9, 2026. doi: 10.5152/ArchRheumatol.2026.25172.