Risk Factors for Idiopathic Granulomatous Mastitis Recurrence after Patient-Tailored Treatment: Do We Need an Escalating Treatment Algorithm?

Presentation and Management of Granulomatous Mastitis in the United States: Results of an American Society of Breast Surgeons Registry Study

BACKGROUND

Granulomatous mastitis (GM) is a benign, chronic, inflammatory disease lacking clear treatment guidelines. The purpose of this American Society of Breast Surgeons (ASBrS) prospective, multisite registry was to characterize the presentation of GM and identify treatment strategies associated with symptom resolution and optimal cosmesis.

METHODS

ASBrS members entered data into a registry on patient demographics, treatment, symptoms, and cosmesis over a 1-year period. Initial symptoms were graded as mild, moderate, or severe. The Chi-square test and logistic regression were used to identify factors related to symptom improvement and cosmesis.

RESULTS

Overall, 112 patients with a mean age of 36 years were included. More patients were Hispanic (49.1%) and from the Southwest (41.1%), and management included observation (4.5%), medical (70.5%), surgical (5.4%), or combination treatment (19.6%). Immunosuppression was used in 83 patients (74.1%), including 43 patients who received intralesional steroid injections. Patients with severe symptoms were more likely to undergo surgical intervention compared with those with mild or moderate symptoms (21.4% vs. 0% and 7.5%, respectively; p = 0.004). Within 1 year, 85 patients (75.9%) experienced symptom improvement and/or resolution at a median of 3 months. Receipt of immunosuppressive therapy was predictive of improvement or resolution at 1 month (odds ratio 4.22; p = 0.045). One-year physician-assessed cosmesis was excellent or good for 20/35 patients (57.1%) and was not associated with type of treatment or symptom severity.

CONCLUSION

Although GM can have a protracted course, the majority of patients in this registry resolved within 1 year, with good cosmetic result. Treatment with immunosuppression appears to be most beneficial, and a symptom-based algorithm may be helpful to guide treatment.

Relationship of post-treatment radiological findings with relapses in idiopathic granulomatous mastitis patients

OBJECTIVE

The aim of this study is to investigate the relationship between post-treatment radiological findings and recurrences in idiopathic granulomatous mastitis (IGM).

METHODS

Clinical data, ultrasound (US) and magnetic resonance imaging (MRI) examinations of 160 patients with IGM (mean age 34.6±7 years; range 20-56 years) who received only steroid or steroid+surgical treatment were evaluated retrospectively. Patients were grouped as radiological complete response (RCR) or radiological incomplete response (RIR).

RESULTS

Only in the steroid group, 79 (54.1%) patients were in the RCR group and 67 (45.9%) patients were in the RIR group. Recurrence occurred in 42 (26.3%) patients, 27 (16.9%) in the same breast and 15 (9.4%) in the contralateral breast. Most of the recurrences in the same breast had residual lesions up to recurrence (74.1%).

CONCLUSION

Residual lesion after treatment is a risk factor for recurrence, and treatment can significantly reduce recurrences until the lesions disappear. The lesion size on MRI after treatment is not associated with recurrence.

Promoting Standardization of Clinical Evidence With Severity-Guided Treatments for Idiopathic Granulomatous Mastitis: A Narrative Review

Idiopathic granulomatous mastitis (IGM) is a benign disease of the breast which causes a great deal of discomfort for patients. More comparable data and greater consensus in treatment are needed to better understand the disease and help with evidence-based clinical decision making. This narrative review aims to discuss the literature available on IGM and illustrate the need for consensus on treatment. We highlight the existing severity scores for this disease in the literature and discuss the value of severity-guided treatment. In our review, 81 studies out of 319 reviewed publications met established criteria. With the selected results from our search results, the available research on IGM etiology, risk factors, diagnosis, and treatment is summarized with an emphasis on the existing severity scores. A total of four proposed severity scores were found in our review. Consensus on the treatment of IGM must be established. There are varying severity scores on IGM severity. We suggest using an established standardized severity score to guide treatment and recommend one such score.

Genomic Insights into Idiopathic Granulomatous Mastitis through Whole-Exome Sequencing: A Case Report of Eight Patients

Idiopathic granulomatous mastitis (IGM) is a rare condition characterised by chronic inflammation and granuloma formation in the breast. The aetiology of IGM is unclear. By focusing on the protein-coding regions of the genome, where most disease-related mutations often occur, whole-exome sequencing (WES) is a powerful approach for investigating rare and complex conditions, like IGM. We report WES results on paired blood and tissue samples from eight IGM patients. Samples were processed using standard genomic protocols. Somatic variants were called with two analytical pipelines: nf-core/sarek with Strelka2 and GATK4 with Mutect2. Our WES study of eight patients did not find evidence supporting a clear genetic component. The discrepancies between variant calling algorithms, along with the considerable genetic heterogeneity observed amongst the eight IGM cases, indicate that common genetic drivers are not readily identifiable. With only three genes, CHIT1, CEP170, and CTR9, recurrently altering in multiple cases, the genetic basis of IGM remains uncertain. The absence of validation for somatic variants by Sanger sequencing raises further questions about the role of genetic mutations in the disease. Other potential contributors to the disease should be explored.

Novel insights: crosstalk with non-puerperal mastitis and immunity

The two primary types of non-puerperal mastitis (NPM) are granulomatous lobular mastitis (GLM) and plasma cell mastitis (PCM). Existing research indicates that immune inflammatory response is considered to be the core of the pathogenesis of GLM and PCM, and both innate and adaptive immune responses play an important role in the pathophysiology of PCM and GLM. However, the regulatory balance between various immune cells in these diseases is still unclear. Consequently, we present a comprehensive summary of the immune-related variables and recent advances in GLM and PCM.

A meta-analysis of idiopathic granulomatous mastitis treatments for remission and recurrence prevention

Purpose

The major aim of our meta-analysis was to review the effectiveness of various treatment modalities for achieving successful remission and preventing recurrence for women with idiopathic granulomatous mastitis (IGM). This knowledge is instrumental in developing evidence-based guidelines for clinicians to improve management strategies and outcomes for patients with IGM.

Methods

A systematic literature search was performed on MEDLINE (Ovid), Embase (Elsevier), PubMed, Cochrane Library, Web of Science, and Google Scholar; studies published to 19 January 2022 were included. A meta-analysis of 57 observational studies was performed. The results of two randomized controlled trials were also examined.

Results

There were 3,035 IGM patients across the observational and randomised studies. Overall recurrence and remission rates across all treatment strategies in 59 studies are 87.9% (2,667/3035) and 13.5% (359/2667), respectively. The studies reported 19 different treatment strategies, comprising observation, medical monotherapies, surgery, and combinations involving medical therapies, with and without surgery. Among monotherapy treatment, surgical management had the highest pooled remission rate (0.99 [95% confidence interval (CI) = 0.97-1.00]); among combination therapy, this was steroids and surgery (0.99 [0.94-1.00]). Antibiotic monotherapy had the lowest remission rate (0.72 [0.37-0.96]). The highest recurrence rates belonged to treatments that combined antibiotics and surgery (0.54 [0.02-1.00]), and antibiotics, steroids, and surgery (0.57 [0.00-1.00]). Most successful for preventing recurrence were observation (0.03 [0.00-0.10]), methotrexate (0.08 [0.00-0.24]), and steroids and surgery (0.05 [0.01-0.12]). There is a significant association between longer follow-up duration and recurrence rate reported, p = 0.002.

Conclusion

Combination therapies, especially those incorporating antibiotics, steroids, and surgery, have demonstrated higher remission rates, challenging the use of antibiotic monotherapy. There is an increased emphasis on the need for personalised, multi-pronged approach for preventing IGM recurrence, with longer follow-up care. More prospective future work in IGM research, with standardised diagnostic criteria, treatment protocols, and reporting guidelines will be important for developing treatment protocols and guidelines clinicians can adhere to in the clinical management of IGM patients.Systematic review registration: PROSPERO (CRD42022301386).

Clinical features and risk factors of bilateral granulomatous lobular mastitis

Granulomatous lobular mastitis (GLM) is an idiopathic inflammatory breast disease that tends to recur on the same side. With the accumulation of clinical cases, it has been observed that GLM can also occur contralaterally. Currently, most studies on GLM focus on treatment methods and risk factors for ipsilateral recurrence, and there are few reports on bilateral GLM. The study aimed to summarize the clinical characteristics of patients with bilateral GLM by reviewing their clinical data, and to discuss the risk factors affecting the occurrence of bilateral GLM. A retrospective study of the medical records database of patients with GLM admitted between May 2019 and August 2022 was performed. Patients were divided into bilateral GLM group (bilateral GLM group) and unilateral GLM patients (unilateral GLM group). Demographic and clinical characteristics, treatment, and follow-up were collected and analyzed. In this study, by reviewing the clinical data of 59 cases of bilateral GLM, we found that the median time between the onset of bilateral GLM on both sides was 6.63 (0-18) months. Additionally, because of the simultaneous or interval onset on both sides, the duration of the disease was longer compared to unilateral cases. Regarding the history of external hospital treatment, it was found that about 57.63% of patients with bilateral GLM received 2 or more treatment modalities, with a higher involvement of herbal medicine. Meanwhile, by counting the clinical data of the 2 groups of patients with bilateral GLM and unilateral GLM, it was shown by univariate analysis that fertility, nipple development, absolute CD4 value, and CD4/CD8 ratio were associated with contralateral onset of GLM in both groups, with inverted nipple being an independent risk factor.

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.

Clinical, histological features, and predictors of relapse in patients with idiopathic granulomatous mastitis

Idiopathic granulomatous mastitis is a benign, inflammatory disease of breasts characterized by non-caseating granulomas. Our study aims to identify distinguishing clinical and histopathological features of relapsing disease compared to those in complete remission. We queried databases at our institution (1990-2021) to include females ≥18 years with biopsy-proven diagnosis of idiopathic granulomatous mastitis, excluding patients with breast cancer, lymphoproliferative disorders, solid organ malignancy, foreign body reaction in breast, plasma cell mastitis, and ductal ectasia. Remission was defined as a 3-month period without recurrence of symptoms or imaging findings. Relapse was defined as recurrence after 3 months of remission. Clinical and histopathological features were compared using 2-sample t tests and chi-squared tests. Of the 27 patients that met our inclusion criteria, the mean age at diagnosis was 35.8 years (± standard deviation 9.4 years) with a mean body mass index of 31.7 kg/m2 (± standard deviation 6.7 kg/m2). 11 (41%) were Hispanic, 25 (93%) had at least one previous full-term pregnancy prior to diagnosis and 8 (30%) were on oral contraceptives. Remission was seen in 18 patients (66%) and 9 (33%) had relapse. Six of these patients received steroids after antibiotics, while 5 patients received methotrexate. Three (33%) patients with relapse and 14 (77%) with remission, had abscess formation confirmed on histopathology (P = .04). Patients with remission had a higher number of abscesses on histopathology and history of oral contraceptive use was associated with more relapse. By identifying key clinical and histopathological findings in this population may guide prognosis and treatment of these patients.

Ozone therapy as a novel complementary therapeutic approach in refractory idiopathic granulomatous mastitis

Background

Autoimmunity may play a major role in the pathogenesis of idiopathic granulomatous mastitis (IGM). The therapeutic potential of ozone therapy has recently been shown in rheumatological diseases, and this study aimed to assess the clinical efficacy of ozone therapy (OT) in refractory IGM.

Methods

Patients with biopsy-verified IGM and incomplete response after steroid therapy (n = 47) between 2018 and 2021 were enrolled. Of these, 23 cases in cohort A had standard treatment with further steroid therapy (ST), and 24 were treated with systemic OT via autohemotherapy (AHT) in addition to steroid therapy (cohort B).

Results

The median age was 33 years (range, 24-45). Patients in cohort B had a higher complete response rate after completion of a four-month ozone therapy than those in the ST-group (OT-group, 37.5% vs. ST-group, 0%; p = 0.002). At a median follow-up of 12 months (range, 12-35), the patients treated with OT had a lower one-year recurrence in the affected breast than cases in cohort A treated with ST (OT-group, 21% vs. ST-group, 70%; p = 0.001). No significant side effects were observed in patients in cohort B related to AHT. Furthermore, OT significantly decreased the total steroid treatment duration (median week of steroid use; 26  weeks in cohort A vs. 12 weeks in cohort B; p = 0.001).

Conclusion

Systemic OT increases the complete response rate and decreases the duration of steroid treatment in patients with refractory IGM. Therefore, ozone therapy is an effective, well-tolerated, and safe novel complementary therapeutic modality.

Profiling Microbial Communities in Idiopathic Granulomatous Mastitis

Idiopathic granulomatous mastitis (IGM) is a rare and benign inflammatory breast disease with ambiguous aetiology. Contrastingly, lactational mastitis (LM) is commonly diagnosed in breastfeeding women. To investigate IGM aetiology, we profiled the microbial flora of pus and skin in patients with IGM and LM. A total of 26 patients with IGM and 6 patients with LM were included in the study. The 16S rRNA sequencing libraries were constructed from 16S rRNA gene amplified from total DNA extracted from pus and skin swabs in patients with IGM and LM controls. Constructed libraries were multiplexed and paired-end sequenced on HiSeq4000. Metagenomic analysis was conducted using modified microbiome abundance analysis suite customised R-resource for paired pus and skin samples. Microbiome multivariable association analyses were performed using linear models. A total of 21 IGM and 3 LM paired pus and skin samples underwent metagenomic analysis. Bray−Curtis ecological dissimilarity distance showed dissimilarity across four sample types (IGM pus, IGM skin, LM pus, and LM skin; PERMANOVA, p < 0.001). No characteristic dominant genus was observed across the IGM samples. The IGM pus samples were more diverse than corresponding IGM skin samples (Shannon and Simpson index; Wilcoxon paired signed-rank tests, p = 0.022 and p = 0.07). Corynebacterium kroppenstedtii, reportedly associated with IGM in the literature, was higher in IGM pus samples than paired skin samples (Wilcoxon, p = 0.022). Three other species and nineteen genera were statistically significant in paired IGM pus−skin comparison after antibiotic treatment adjustment and multiple comparisons correction. Microbial profiles are unique between patients with IGM and LM. Inter-patient variability and polymicrobial IGM pus samples cannot implicate specific genus or species as an infectious cause for IGM.

Risk Factors and the Role of the Albumin-to-Globulin Ratio in Predicting Recurrence Among Patients with Idiopathic Granulomatous Mastitis

Background

Idiopathic granulomatous mastitis (IGM) is a rare inflammatory disease of the breast with a high recurrence rate. The serum albumin to globulin ratio (AGR) is a relatively novel biomarker in inflammatory diseases, and one whose role in the recurrence of IGM remains unknown. This study primarily investigated the potential risk factors for IGM recurrence and whether AGR can be used as a predictive factor.

Methods

Patients diagnosed with IGM from pathology reports between 2016 and 2021 were enrolled in the study, and their medical records were analyzed retrospectively. The patients were divided into two groups – recurrence and non-recurrence. Clinical, demographic characteristics, and laboratory parameters were compared.

Results

Eighty-five patients were included in the study, recurrence being detected in 16 (18.8%) of these, with a median follow-up time of 39.99±18.93 months. No relationship was determined between childbearing, breastfeeding, disease severity, or therapeutic approaches and IGM recurrence. While AGR was significantly lower in the recurrence group (p < 0.001), neutrophil to lymphocyte ratio (NLR) and platelet to lymphocyte ratio (PLR) results were comparable in the two groups (p = 0.472 and p = 0.421, respectively). Multivariate analysis identified low AGR (odds ratio (OR): 50.7, 95% CI 5.93–434.1 P < 0.001) and smoking (OR: 4.45, 95% CI 1.04–18.9 P = 0.044) as independent risk factors for IGM recurrence.

Conclusion

The study findings indicated that AGR at a cut-off value of ≤1.179 at diagnosis and smoking exhibited a remarkable performance in predicting the recurrence of IGM. Developing new risk stratification systems for IGM recurrences and using AGR in these classifications may increase the success of treatment.

Trial Registration

This study was registered with ClinicalTrials.gov, NCT05409586.