IGM mostly occurs in young women in childbearing age with history of pregnancy and lactation, and most commonly present with a breast mass 2,3,4,5,6,7,8,10. In our study, mean age of patients was 35.27±7.82 years and most had history of pregnancy and lactation; the most common presentation both at first episode and at recurrence was breast mass or thickening.
There is no consensus regarding the best treatment for this disease. Different treatments consist of: observation; surgical treatment which includes mass excision, abscess drainage, and even mastectomy, which is less common today; medical treatment with antibiotics, anti-inflammatory and immunosuppressive agents like NSAIDS, corticosteroids, methotrexate, and azathioprine. Treatment modality is chosen according to patient’s symptoms and its severity, ranging from observation for mild limited disease to immunosuppressive drugs and surgical excision for more severe and refractory cases2,3,6,7,11,13.
Use of Corticosteroids as an anti-inflammatory and immunosuppressive agent to treat IGM was first reported in 1980 by DeHertogh et al16. Since then, it’s been widely used, mostly with good responses, although some study have reported high recurrence rates after its cessation5,6,8,12,14. Topical and intralesional administration of these agents have been reported with good results and low recurrence rates too8,17. In our study, most of patients(more than 80%) in both groups respond to corticosteroids with 21.9% recurrence, which confirms good response with slightly lower recurrence compared with other studies6,18.
Corticosteroids are generally prescribed as 0.5-1mg/kg/day(30-60mg), although treatment with different doses(ranging from 5-60mg)have been reported9,12,14,15.
In a retrospective study by Kaviani et al on 374 patients with IGM, treatment modalities were evaluated. Patients were treated with observation only, Non-Steroidal Anti-Inflammatory Drugs, corticosteroids, antibiotics, Methotrexate, and surgical interventions. Prednisolone was used in 41.7% of patients which 67.8% of them showed complete or partial response (P-value < 0.001); the recurrence rate following cessation of prednisolone was significantly high(24.8%)6.
In another retrospective study by Mizrakli et al on 49 patients with IGM, 44 cases received 0.5 mg/kg/day; 40 (81.6%) patients were successfully treated with no recurrence in six months follow up. only two patients showed corticosteroid side effects14.
In a case series by Velidedeoglu et al, Ten cases of bilateral IGM were evaluated. four cases were treated with oral prednisolone at an initial dose of 0.5 mg/kg/day. In one patient, disease recurred as the corticosteroid was tapered, two others developed recurrence after a complete recovery following cessation of steroid therapy, and just one patient had complete recovery with no recurrence7.
In a prospective non-randomized study by Karanlik et al, outcome of patients with IGM treated with methylprednisolone (starting at a dose of 0.5 mg/kg/day )alone vs treatment with corticosteroid followed by surgery was compared. Twenty three patients were treated in the corticosteroid group(control group) and 37 patients in corticosteroid and surgery(combined) group. Clinical and radiological regression was reported in all patients with steroid therapy. No recurrence was observed in patients who were treated in combined group during the median follow-up period of 38 (22–78) months. In control group, 30% of patients experienced recurrence (p < 0.001). The authors suggested that as IGM is a possible autoimmune disease with an immune response against breast ductal epithelial, and the residual area or previous lesion bed that is excised after steroid therapy may be the area responsible for the autoimmunity against breast cells, leading to IGM relapses. They finally concluded that combined therapy was superior to steroid therapy or surgical excision alone18.
In a retrospective study by Gurleyik et al on 19 cases with IGM, patients were treated with oral methyl-prednisolone starting at 0.8 mg/kg/day, tapered gradually during 8 weeks. At the end of the eighth week, patients were clinically and radiologically evaluated. No one displayed complete clinical response. Local excision of the remaining lesions was done in all patients. During the follow-up period(median 20 months), recurrence was observed in one patient. Recurrent lesions were treated with surgical re-excision. The authors claimed that initial treatment with steroids leads to disease regression, allowing more limited surgery15.
Despite good reported responses, the administration of corticosteroids-especially in higher doses- is limited by their inherent side effects, including increased blood pressure, impaired glucose homeostasis, weight gain, cushingoid appearance, edema, cataract, depression, immunosuppression, and gastritis8,18; so, lower doses are more favorable, given that therapeutic efficacy is not influenced. As mentioned above, most of studies are evaluating the effect of high dose(0.5-1mg/kg) corticosteroids, and there are not much reports regarding effect of low dose corticosteroid on IGM improvement.
In a retrospective study by Jeon et al, corticosteroids with initial dose of 0.4 mg/kg/day was administered to 36 patients; 75% of patients responded to treatment; no one experienced side effects such as glucose intolerance or Cushing syndrome19.
The efficacy of low dose prednisolone(5mg) versus high dose(50 mg for three days, then 25 mg for the next three days, 12.5 mg for three days and 5 mg daily afterwards)prednisolone in the treatment of IGM was evaluated on 30 patients in a randomized clinical trial by Montazer et al. Each group included 15 patients; all patients received antibiotic and were followed for more than 12 months. No corticosteroid side effects were reported. Patients receiving high dose prednisolone had significantly higher rate of remission compared to low dose group(93.3% vs 53.3%). In high dose group, one patient underwent lumpectomy due to the resistance to treatment. In low dose group, 5 patients progressed to abscess and fistula and underwent lumpectomy. In resolved cases, recurrence was significantly higher in the low dose group (37.3% vs 0%, p = 0.04). The authors concluded that high dose prednisolone has high success rates with lower recurrence in the treatment of IGM and could reduce the need for surgery9.
According to our results, the response to treatment was high with an acceptable recurrence rate in all patients treated with corticosteroid (both high and low dose); these findings are against Montazer et al which reported remarkable difference in response and recurrence between low and high dose groups; however, the prednisolone dose of low dose group in their study was substantially lower than our study(5mg vs mean 14.74mg ).
Although our results were not statistically significant, corticosteroid dose did not influence response and recurrence much in our patients; this finding can be promising as it suggests that lower safe doses of corticosteroids may be used to treat IGM patients without influencing treatment efficacy.
The strength of this study is limited by retrospective design and relatively small sample size, which prohibited achieving significant results. Apart from that, unmatched case and control groups(especially in the severity of disease), and lack of some data, like corticosteroid side effects, are other drawbacks of this study.