>Efficacy of disease-modifying antirheumatic drugs in the treatment of granulomatous mastitis: a systematic review.

INTRODUCTION: Idiopathic granulomatous mastitis (IGM) is an inflammatory breast disorder of unknown etiology. This benign condition can mimic the clinical presentation of breast cancer and is characterized by symptoms such as breast pain, erythema, and swelling. Over the past few years, Disease-Modifying Antirheumatic Drugs (DMARDs) have been increasingly used to manage this condition. However, strong evidence to support their use is lacking. OBJECTIVES: This systematic review aimed to summarize the evidence and evaluate the efficacy of DMARDs in the management of IGM. METHODS: A systematic literature review, adhering to PRISMA guidelines, was conducted across electronic databases, including PubMed, EMBASE, SCOPUS, directory of open access journals (DOAJ) and Cochrane Library from their inception until May 2024. We included retrospective and prospective studies while excluding case reports and case series of less than 10 patients. RESULTS: Eighteen studies met our eligibility criteria. Fifteen studies were retrospective, while 2 were prospective. No randomized controlled trials were identified. Of these, 16 papers examined the effect of methotrexate on IGM, revealing significant disease improvement in most cases. Several of the studies indicated that patients treated with azathioprine and mycophenolate mofetil also achieved favorable responses. CONCLUSION: Given the rarity of IGM, only a limited number of studies have explored the use of DMARDs as a pharmacological treatment option. A significant barrier to advancing our understanding is the substantial heterogeneity in the quality and volume of data provided by these studies. Therefore, there is a need for well-designed, randomized, placebo-controlled trials to rigorously assess the efficacy of DMARDs in the treatment of IGM.

Radiological response of non-specific granulomatous mastitis to anti-tuberculous treatment: A single centre study in an endemic nation.

BACKGROUND: Tuberculous mastitis (TBM), is an uncommon form of extra-pulmonary tuberculosis. Clinical and radiological overlap of tuberculous mastitis with malignancy and other granulomatous conditions, along with its paucibacillary nature, make it a diagnostic challenge. In our study, we aim to assess the radiological response of microbiologically negative granulomatous mastitis cases to anti-tuberculous treatment (ATT) in an endemic country. METHODS: Eighty-seven cases demonstrating granulomatous lesions on breast biopsy were identified. Of these, 49 patients who were treated with ATT and had at least two serial ultrasound follow-ups were included in our study. Mammogram and ultrasound were used for initial imaging. Subsequently, ultrasound was used for serial follow-up. Mantoux skin test, acid fast staining and histological examination of tissue sample were the other investigations used. RESULTS: Radiologically, on ultrasound, well-circumscribed hypoechoic masses were noted in 18 patients, followed by ill-defined collections with tubular extensions in 15 cases, abscesses in 8, and a focal heterogeneity in 8 patients. Following ATT, 17 patients showed radiological resolution in 4 weeks, 18 of them at 3 months, and nine of them in 6 months. CONCLUSION: Excellent and prompt radiological response to ATT, indicates the need for a high degree of suspicion for tuberculous mastitis (TBM), in endemic countries, even though microbiological tests may turn out negative.

Sarcoidosis Presenting as Granulomatous Mastitis, Erythema Nodosum, and Arthritis Syndrome: A Case Report and Comprehensive Review of the Literature.

Granulomatous mastitis (GM) is a long-term inflammatory disease of the breast that usually occurs in women of reproductive age. Autoimmune mastitis is one of the most common pathological breast conditions necessitating tailored treatment. However, GM as a first clinical manifestation of sarcoidosis is uncommon. Simultaneous occurrence of GM, erythema nodosum (EN), and arthritis, termed "GMENA" syndrome, is a rare clinical entity associated with autoimmune rheumatic diseases. Herein, we report the case of a 31-year-old female patient with GMENA syndrome, who presented with a painful nodule of the left breast. Initial treatment entailed antibiotics under the presumption of a breast abscess, yielding negligible improvement. During this period, the patient developed polyarthritis and bilateral EN on the lower extremities. Histopathologic examination of the breast tissue exhibited noncaseating granulomas. The patient responded positively to prednisolone and methotrexate treatment. Literature review revealed a coherent pattern across GMENA cases. Our findings suggest that the "GMENA" syndrome represents a unique acute manifestation of sarcoidosis and highlight the necessity for heightened awareness, accurate diagnosis, and tailored therapeutic approaches for GMENA syndrome. Further research is warranted to elucidate its cause and optimize patient management. This case highlights the importance of identifying and effectively managing such interrelated clinical presentations.

The role of tissue IgG4 levels in steroid therapy in patients with idiopathic granulomatous mastitis.

Idiopathic granulomatous mastitis (IGM) is a benign, chronic inflammatory lesion of the breast. Immunoglobulin G4 (IgG4) associated disease is rare in the breast. In our study, we aimed to evaluate the efficacy of steroid treatment on IgG4 levels in tissue in patients diagnosed with IGM. Between 2008 and 2017, 55 patients diagnosed with IGM in our clinic were included in the study. Demographic, clinical, microbiologic and histopathologic characteristics, treatment modality and recovery time were evaluated retrospectively. Patients were divided into 3 groups according to tissue IgG4 levels: negative (Group I), infrequently and slightly positive (Group II), and highly positive (Group III). Group I patients had a complete response rate of 77.8%. In the rest of the patients (22.2%), insufficient response was detected from the beginning of the treatment. In Group II, the response rate was 91.3% and the permanent success rate after treatment was 87.0%. Although group III patients had a complete response at the beginning (95.65%), they relapsed in a short period of time (26.1%) after discontinuation of steroid treatment. At least one steroid-related side effect was observed in 47 (85.8%) patients in all groups. There is no consensus on the dose and duration of immunosuppressive treatment in IGM. In this study, responses to steroid treatment according to IgG4 concentration in pathologic breast tissue and recurrences after the end of treatment were determined. We think that high IgG4 concentration in the tissue is associated with recurrence and other immunosuppressive drugs should be added as maintenance after steroid treatment.

Evaluation of clinical profiles, imaging findings and antituberculosis treatment outcome in granulomatous mastitis: An Indian scenario.

BACKGROUND: The management of choice for granulomatous mastitis (GM) has yet to be determined but few studies have demonstrated that anti-tubercular treatment (ATT) could be an effective alternative therapeutic option. Hence, the objective of the current study is to determine the clinical feature, radiological imaging findings, and histopathological examination results exhibited by GM and tuberculosis (TB)-proven GM as well as to evaluate the ATT clinical outcome in GM patients. METHODS: The study was performed on 68 GM patients who were referred to the department of pulmonology by the breast clinic (from January 2018 to August 2021). Study populations were categorized into two groups GM and TB-proven GM patients and all were prescribed with standard ATT regimen and were continuously followed up. SPSS version 25 was employed for statistical assessment. RESULTS: Our study showed that 6 patients from GM and 4 patients from the TB-proven GM group got relapsed. For patients who displayed partial remission, ATT treatment was started after assessing the side effects potential. 14.6% (n = 6) and 7.4% (n = 2) patients who initially demonstrated partial remission were also completely cured. ATT treatment curable rate was determined to be 90% (n = 37) and 81.5% (n = 22) for GM and TB-proven GM patients correspondingly. Therefore, the current study demonstrated nil significant differences between groups. CONCLUSION: The current study warrants that ATT therapy could be an effective and better treatment of choice for GM patients irrespective of their clinical condition.

Ultrasonography-based staging of inflammatory granulomatous mastitis and estimation of steroid response.

OBJECTIVES: The aim of this study is to present novel diagnostic ultrasonography (USG)-based classification of inflammatory granulomatous mastitis (IGM) and to assess and compare dosage responses of locoregional steroid therapy. METHODS: From January 2017 through March 2023, total of 230 biopsy-proven IGM patients were reclassified (grades I, II, and III) according to USG-based morphological features. The injection applications were grouped in Group1 (40 mg/mL between years 2017 and 2019) versus Group2 (80 mg/mL between years 2019 and 2023), and effectiveness was analysed for each grade in between groups. RESULTS: The mean age was 31 years old (range: 19-60) with median follow-up period of 7 months. The most common clinical presentation was breast mass accompanying draining skin sinuses of the affected skin and hypoechogenic mass with tubular extensions was the most prevalent feature on USG examination. As per USG-based features, 79 (34.3%) patients were redefined as grade I, 64 (27.8%) as grade II, and 87 (37.8%) as grade III. All patients underwent locoregional steroid injection only. The average number of treatments in the first group was 6 (±3 SD) with an effective dose of 40 mg/mL in the first group, and 4 (±2 SD) with an effective dose of 80 mg/mL in the second group. The generalized linear mixed model was used to investigate effects between groups (P < .05). CONCLUSIONS: High-dose steroid treatment was effective in burnout lesions (grades II and III), and it was found to be statistically significant in lowering number of treatments irrespective of grade. ADVANCES IN KNOWLEDGE: This novel classification could be a convenient tool in terms of common language between radiologists and clinicians. In addition, our study is a pioneer in comparing steroid dosage with no relapse in IGM patients.

Treatment modalities for granulomatous mastitis, seeking the most appropriate treatment with the least recurrence rate: a systematic review and meta-analysis.

BACKGROUND: Granulomatous mastitis (GM) is a rare, benign, inflammatory breast disease with an unknown etiology that predominantly affects women of reproductive age. The definitive treatment of GM is currently controversial; an appropriate therapeutic strategy has yet to be identified, and the disease's high recurrence rate remains. This study aims to determine the recurrence rate for each GM treatment strategy to identify the most appropriate treatment modality. METHODS: The search for relevant articles was undertaken using three international databases, including Medline, Scopus, and Web of Science. Articles published in English until the end of 2021 evaluating the recurrence rate of GM were included. Using Stata 13.0, the pooled incidence and 95% confidence interval (CI) for the recurrence rate were determined. RESULTS: Sixty-five eligible studies were included in our study. The recurrence rates of systemic steroid use, topical steroid use, antibiotic use, methotrexate use, observation, drainage, excision, antibiotic use and surgery, steroid use and surgery, antibiotic and steroid use, methotrexate and steroid use were 24% (95% CI: 21-27%), 11% (95% CI: 6-21%), 18% (95% CI: 14-22%), 13% (95% CI: 7-22%), 11% (95% CI: 7-17%), 65% (95% CI: 50-78%), 13% (95% CI: 10-16%), 23% (95% CI: 14-36%), 7% (95% CI: 5-11%), 11% (95% CI: 6-18%), and 4% (95% CI: 2-8%), respectively. Drainage had the highest recurrence rate, while combined methotrexate and steroid treatment had the lowest rate. CONCLUSION: The optimal treatment strategy for GM depends on the disease's severity, consequences, and the patient's features. The study results indicate that combination therapy is preferable for minimizing the risk of relapse and reducing treatment complications.

Refractory and Recurrent Idiopathic Granulomatous Mastitis Treatment: Adaptive, Randomized Clinical Trial.

BACKGROUND: Idiopathic granulomatous mastitis (IGM) is mostly described as an autoimmune disease with higher prevalence among Middle Eastern childbearing-age women. This study aimed to evaluate the best treatment of choice in patients with resistant or recurrent IGM. STUDY DESIGN: Patients with established recurrent or resistant IGM who were referred to the Breast Cancer Research Center from 2017 to 2020 were randomly assigned to either one of the following treatment groups: A (best supportive care), B (corticosteroids: prednisolone), and C (methotrexate and low-dose corticosteroids). This adaptive clinical trial evaluated radiological and clinical responses, as well as the potential side effects, on a regular basis in each group, with patients followed up for a minimum of 2 years. RESULTS: A total of 318 participants, with a mean age of 33.52 ± 6.77 years, were divided into groups A (10 patients), B (78 patients), and C (230 patients). In group A, no therapeutic response was observed; group B exhibited a mixed response, with 14.1% experiencing complete or partial responses, 7.7% maintaining stability, and 78.2% experiencing disease progression. Accordingly, groups A and B were terminated due to inadequate response. In group C, 94.3% achieved complete response, 3% showed partial remission, and 2.7% had no response to therapy. Among the entire patient cohort, 11.6% tested positive for antinuclear antibodies, 3.5% for angiotensin-converting enzyme, and 12.3% for erythema nodosum. Notably, hypothyroidism was a prevalent condition among the patients, affecting 7.2% of the cohort. The incidence of common side effects was consistent across all groups. CONCLUSIONS: The most effective treatment option for patients with recurrent or resistant IGM is a combination therapy involving steroids and disease-modifying antirheumatic drugs such as methotrexate.

Idiopathic Granulomatous Mastitis.

Idiopathic granulomatous mastitis (IGM) is a rare, benign inflammatory disorder of the breast that is often underrecognized. The exact etiology and pathophysiology are unknown, but milk stasis is felt to play a role. Classically, this condition is noninfectious, but many cases are noted to be associated with Corynebacterium species. Most patients affected are parous women with a mean age of 35, and many have breastfed within five years of diagnosis. Patients typically present with a painful mass and symptoms of inflammation, and these features can sometimes mimic breast cancer. Biopsy is needed to make a definitive diagnosis, and noncaseating granulomas are found on core biopsy. Many patients have a waxing and waning course over a period of six months to two years. Goal of treatment is to avoid surgery given poor wound healing, high risk of recurrence, and poor cosmetic outcomes. Medical treatment is preferred and includes observation, antibiotics, steroids, and immune modulators such as methotrexate. In more recent years, topical and intralesional steroids have become the treatment of choice, with similar outcomes to oral steroids.

The Effect of Local Steroid Administration on Idiopathic Granulomatous Mastitis: A Systematic Review andMeta-Analysis.

INTRODUCTION: Idiopathic granulomatous mastitis (IGM) is a rare, benign inflammatory breast disease. Corticosteroids and surgery are the primary treatment options, and a growing number of publications have shown the effectiveness of local steroid administration (intralesional injection and topical corticosteroids). However, less is known about the specific details and effects of this treatment approach. The purpose of this meta-analysis was to summarize the details and evaluate the efficacy of local steroid administration for IGM. METHODS: The PubMed, Embase, Cochrane Library, and SinoMed databases were systematically searched from inception to July 2023 to identify relevant randomized controlled trials. The quality of the included studies was assessed, and meta-analysis and subgroup analysis were conducted to obtain the pooled effect sizes of the outcomes of interest. RESULTS: Eight trials comprising 613 patients were included. Local steroid administration included intralesional injection and topical steroid ointment, and control groups were mainly given systemic therapy (oral steroid) and surgical treatment. The meta-analysis showed that local steroid administration had a significant effect on the response rate (risk ratio [RR] = 1.35, 95% CI = [1.14-1.59], P = 0.0004). The incidence of side effects was also lower than that of systemic treatment (RR = 0.24, 95% CI = [0.13-0.43], P＜0.0001). There was no difference in the recurrence rate (RR = 0.8, 95% CI = [1.42-1.51], P = 0.48). CONCLUSIONS: Local steroid administration can increase the RR and decrease the incidence of side effects for IGM patients. There is no significant difference in the recurrence rate between the local steroid administration group and the control group. Further studies are needed to identify the effect in different stages and among pregnant women.

Imiquimod as a new treatment in refractory idiopathic granulomatous mastitis: report of two cases.

INTRODUCTION: Idiopathic granulomatous mastitis (IGM) is a rare chronic inflammatory lesion of the breast that mimics breast cancer or infection. Immunological pathogenesis is strongly suggested for the disease. REASON FOR THE REPORT: The treatment remains controversial, comprising a spectrum from observation or NSAIDs to immunosuppressive agents and surgery. Intractable cases are not uncommon and represent a major treatment challenge. Therefore in this study, we examine the effect of a topical immunomodulator agent, imiquimod, on refractory IGM. Patient 1 had IGM for 9 months and had not responded to the existing treatments. She responded to a 7-week course of imiquimod. In patient 2, the disease had begun 4 months sooner and had been resistant to all treatments; it responded to imiquimod after 4 weeks. Ulcers appeared on the skin of both patients but resolved safely. OUTCOME: Both patients were very satisfied with the results. Imiquimod can be an appropriate local treatment with limited adverse effects in refractory IGM. We propose similar studies to assess the efficacy of imiquimod in IGM further, paying attention to the possibility of developing skin wounds.

Evaluation of early results of triamcinolone acetonide treatment in the treatment of idiopathic granulomatous mastitis introduction.

OBJECTIVE: Idiopathic granulomatous mastitis (IGM) is a rare, benign, chronic inflammatory breast disease with an unknown etiology. IGM patients may develop painful or painless masses, palpable lymph nodes, and skin findings that can mimic breast cancer, including retractions, skin edema, ulceration, and fistula formation. This presents a significant diagnostic challenge in clinical practice. The present study aimed to assess the early outcomes of triamcinolone acetonide treatment in patients with idiopathic granulomatous mastitis. PATIENTS AND METHODS: After obtaining the necessary approvals from the ethics committee, patients who were admitted to the breast endocrine department of the general surgery clinic of our hospital between 2014 and 2022 with complaints of a mass, discharge, and fistula formation and who were histopathologically diagnosed with granulomatous mastitis after radiological examination by tru-cut biopsy were prospectively enrolled in the study. RESULTS: Among the 136 patients with granulomatous mastitis, the mean age was 30.09±4.14 years, the symptom duration averaged 3 weeks (range: 1-5), the follow-up period extended for 20 weeks (range: 3-72), and the mean recurrence duration was 1.08±0.28 months. Complaints included discharge (52.2%), mass (51.5%), redness (45.6%), and pain (27.2%). Masses were predominantly on the left side (61.0%) compared to the right side (38.0%). CONCLUSIONS: In conclusion, the heterogeneous phenotype of IGM and the lack of randomized controlled trials pose challenges. Long-acting triamcinolone acetonide proves effective in managing IGM by resolving the inflammatory process and the disease itself. Its low side effects and ease of use make it a valuable treatment modality.

Framework and guide for intralesional steroid injections in idiopathic granulomatous mastitis.

PURPOSE: Literature on how to perform intralesional steroid injections, a valuable therapy for idiopathic granulomatous mastitis (IGM), is limited. This technical note offers a detailed technical guide on intralesional steroid injections for IGM and provides a framework for long-term follow-up. METHODS: Ultrasound characterization of IGM severity considering breadth, depth, and ancillary findings was used to guide steroid dosing and injection frequency. Clinical and sonographic breast diagrams were designed for accurate longitudinal tracking of IGM. A step-by-step guide for ultrasound-guided IGM aspirations and intralesional steroid injections was developed. RESULTS: A detailed approach for ultrasound-guided IGM interventions with clinical and sonographic breast diagrams for longitudinal follow-up is now in practice. CONCLUSIONS: The treatment approach described provides a framework for multidisciplinary treatment of IGM and offers insights that may contribute to the ongoing development and improvement of management strategies for this challenging disease.

Factors Affecting Recurrence of Idiopathic Granulomatous Mastitis: A Systematic Review.

Idiopathic granulomatous mastitis is a rare and benign disease that primarily affects young women of reproductive age. Various factors have been suggested as possible causes, including pregnancy, breastfeeding, history of taking birth control pills, hyperprolactinemia, smoking, and history of trauma. Due to unknown etiology, opinions on its treatment have varied, resulting in differing recurrence rates and side effects. Therefore, conducting a comprehensive systematic review and meta-analysis can aid in understanding the causes and recurrence of the disease, thereby assisting in the selection of effective treatment and improving the quality of life. A systematic literature review was conducted using predefined search terms to identify eligible studies related to risk factors and recurrence up to June 2022 from electronic databases. Data were extracted and subjected to meta-analysis when applicable. A total of 71 studies with 4735 patients were included. The mean age of the patients was 34.98 years, and the average mass size was 4.64 cm. About 3749 of these patients (79.17%) were Caucasian. Patients who mentioned a history of pregnancy were 92.65% with 76.57%, 22.7%, and 19.7% having a history of breastfeeding, taking contraceptive pills, and high prolactin levels, respectively. Around 5.6% of patients had previous trauma. The overall recurrence rate was 17.18%, with recurrence rates for treatments as follows: surgery (22.5%), immunosuppressive treatment (14.7%), combined treatment (14.9%), antibiotic treatment (6.74%), and observation (9.4%). Only antibiotic and expectant treatments had significant differences in recurrence rates compared to other treatments (p value = 0.023). In conclusion, factors such as Caucasian race, pregnancy and breastfeeding history, and use of contraceptive hormone are commonly associated with the disease recurrence. Treatment should be tailored based on symptom severity and patient preference, with surgery or immunosuppressive options for recurrence.

Efficacy of preoperative Shugan Sanjie decoction combined with mammotome-assisted minimally invasive surgery in the treatment of idiopathic granulomatous mastitis: A retrospective cohort study.

The management of idiopathic granulomatous mastitis (IGM) poses a significant challenge because of its ambiguous etiology. This study aimed to investigate the efficacy of traditional Chinese medicine (TCM) combined with mammotome-assisted minimally invasive surgery (MAMIS) for the treatment of IGM. This retrospective cohort study included patients with IGM who underwent treatment at our hospital between January 2017 and June 2022. Patients treated with Shugan Sanjie decoction alone and preoperative Shugan Sanjie decoction combined with MAMIS were included in Groups A and B, respectively. We focused on the demographics, clinical characteristics, and outcomes of the patients in the 2 groups. A total of 124 female patients with an average age of 33.9 ± 3.6 years were included in the study. The demographic and clinical characteristics of patients in Groups A (n = 55) and B (n = 69) were similar (P > .05). However, there were significant differences between the 2 groups in terms of treatment duration, 1-year complete remission (CR), and recurrence. Group B showed shorter treatment time (11.7 ± 5.1 vs 15.3 ± 6.4 months, P = .001), higher 1-year CR (72.5% vs 45.5%, P = .002), and lower recurrence (7.2% vs 21.8%, P = .019) in comparison to Group A. Shugan Sanjie decoction promoted the shrinkage of breast lesions in patients with IGM. Combined with MAMIS, this treatment regimen shortened the treatment duration, accelerated the recovery process, and reduced the recurrence rate.

Is it tuberculosis mastitis or granulomatous mastitis? A thirteen-year experience at a university hospital.

BACKGROUND: Granulomatous mastitis (GM) is a rare inflammatory disease of the breast. Tuberculosis mastitis (TM), one of the causes of GM, is a rare form of extrapulmonary tuberculosis. The clinical, radiological, and histopathological findings of TM and GM are similar, and sometimes it is difficult to make a distinction between these disease states. In this study, we aimed to evaluate the clinical and radiological features, diagnostic techniques, treatment modalities and treatment outcomes of the patients with GM and TM. METHODS: The data of the patients with confirmed GM by histopathologic examination of biopsy specimens between 2007 and 2020 were retrospectively analyzed. Demographic features, main complaints, physical findings, radiological and laboratory data, treatment modalities, and treatment outcomes were recorded. RESULTS: Sixty-eight GM patients with a mean age of 35.8 (18-63) years were evaluated. The patients had a mass lesion, pain, ulceration,and abscess in their breasts. All of the cases were female. Ultrasonographic examinations were performed on 62 cases. Abscess and/or sinus tract formation was detected in 34, heterogeneous hypoechoic mass in 15, heterogeneous parenchyma or parenchymal edema in 15, axillary lymphadenopathy in 18 and cysts in 13 patients. A total of 10 patients were lost to follow-up. Twenty-six patients underwent surgery for their breast lesions or had antibiotherapy (n = 13) or corticosteroid therapy (n = 7). Eleven (16.1%) patients were diagnosed with TM. These patients were evaluated by clinical examination, chest radiography, and tuberculin skin test. Acid-fast bacilli (AFB) staining and culture were negative in all cases. The diagnosis of TM was based on histopathological evaluation results. Eight of the 11 patients achieved complete remission with antituberculosis treatment. DISCUSSION: The etiological diagnosis of GM must be based on a multidisciplinary approach. Tuberculosis mastitis should become a part of differential diagnosis of breast diseases in populations with high incidence of tuberculosis.

Clinical characteristics and therapeutic strategy of granulomatous mastitis accompanied by Corynebacterium kroppenstedtii: a retrospective cohort study.

BACKGROUND: Increasing evidence has suggested that Corynebacterium kroppenstedtii is associated with some cases of granulomatous mastitis, mostly based on pathology or microbiology. We aimed to identify the clinical characteristics and treatment regimens for granulomatous mastitis with Corynebacterium kroppenstedtii infection. Understanding these clinical features is essential for patient care. METHODS: We retrospectively collected data on 201 patients who were pathologically diagnosed with granulomatous mastitis and had microbiological results of either Corynebacterium kroppenstedtii or no bacterial growth and recorded and analysed their demographics, clinical characteristics, and clinical outcomes. RESULTS: There were 107 patients in the CK group and 94 patients in the negative group. Sinus formation (x2 = 13.028, p = 0.000), time to complete remission at the first treatment period (Z = -3.027, p = 0.002), diameter of breast mass at first-time medical consultancy (Z = -2.539, p = 0.011) and recurrence (x2 = 4.953, p = 0.026) were statistically significant. Age (Z = -1.046, p = 0.295), laterality (x2 = 4.217, p = 0.121), time to presentation since the last delivery (x2 = 0.028, p = 0.868), BMI (Z = -0.947, p = 0.344), lactation time (Z = -1.378, p = 0.168), parity (x2 = 1.799, p = 0.180), gravida (Z = -0.144, p = 0.885), history of lactational mastitis or abscess (x2 = 0.115, p = 0.734), local trauma (x2 = 0.982, p = 0.322), hyperprolactinemia (x2 = 0.706, p = 0.401), erythema nodosum (x2 = 0.292, p = 0.589), and nipple discharge (x2 = 0.281, p = 0.596) did not demonstrate statistical significance. Regarding recurrence related to therapeutic strategy, except for surgery combined with immunosuppressants (x2 = 9.110, p = 0.003), which was statistically significant, none of the other treatment regimens reached statistical significance. The recurrence rate of patients in the CK group using rifampicin in their treatment course was 22.0% (x2 = 4.892, p = 0.027). CONCLUSIONS: Granulomatous mastitis accompanied by Corynebacterium kroppenstedtii more easily forms sinuses and has a higher recurrence rate. Both of the clinical characteristics may indicate that Corynebacterium kroppenstedtii plays an important role in the development and progression of granulomatous mastitis. Lipophilic antibiotics may be essential for granulomatous mastitis with Corynebacterium kroppenstedtii infection.