Idiopathic granulomatous mastitis: clinical, histopathological, and radiological characteristics and management approaches

>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.

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.

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.

Construction of a Multi-Indicator Model for Abscess Prediction in Granulomatous Lobular Mastitis Using Inflammatory Indicators

Background

Granulomatous lobular mastitis (GLM) is a chronic inflammatory breast disease, and abscess formation is a common complication of GLM. The process of abscess formation is accompanied by changes in multiple inflammatory markers. The present study aimed to construct a diagnosis model for the early of GLM abscess formation based on multiple inflammatory parameters.

Methods

Based on the presence or absence of abscess formation on breast magnetic resonance imaging (MRI), 126 patients with GLM were categorised into an abscess group (85 patients) and a non-abscess group (41 patients). Demographic characteristics and the related laboratory results for the 9 inflammatory markers were collected. Logistics univariate analysis and collinearity test were used for selecting independent variables. A regression model to predict abscess formation was constructed using Logistics multivariate analysis.

Results

The univariate and multivariate analysis showed that the N, ESR, IL-4, IL-10 and INF-α were independent diagnostic factors of abscess formation in GLM (P<0. 05). The nomogram was drawn on the basis of the logistics regression model. The area under the curve (AUC) of the model was 0.890, which was significantly better than that of a single indicator and the sensitivity and specificity of the model were high (81.2% and 85.40%, respectively). These results predicted by the model were highly consistent with the actual diagnostic results. The results of this calibration curve indicated that the model had a good value and stability in predicting abscess formation in GLM. The decision curve analysis (DCA) demonstrated a satisfactory positive net benefit of the model.

Conclusion

A predictive model for abscess formation in GLM based on inflammatory markers was constructed in our study, which may provide a new strategy for early diagnosis and treatment of the abscess stage of GLM.