Background: The aim of this study is to compare the clinical course of idiopathic granulomatous mastitis (IGM) treated with low-dose oral corticosteroid therapy alone as opposed to treatment with low-dose corticosteroid therapy followed by surgery. Patients and Methods: 37 patients were treated with an approach that consisted of methylprednisolone at a dose of 0.5 mg/kg/day followed by wide excision, and 23 patients were treated with an approach that consisted only of methylprednisolone. The treatment efficacy was compared between the two groups. Results: Clinical and radiological regression was reported in all patients with steroid therapy, and the regression rate had a median of 75% (25-100%). No recurrence was observed in patients who were treated with wide surgical excision after steroid therapy during the median follow-up period of 38 (22-78) months. The control group of 23 patients was treated only with steroid therapy, and 7 (30%) of these patients experienced recurrence in the follow-up period (p < 0.001). Conclusions: Steroid therapy was effective in the treatment of IGM by reducing the lesion size and extent. With regard to the current treatment options available for IGM, surgical excision after steroid therapy seems the better treatment option compared to steroid therapy without surgical excision. This treatment sequence reduces the rate of recurrence.