Clinical characteristics and microbiota analysis of 44 patients with granulomatous mastitis

Unveiling the enigma: understanding the complex disease course of granulomatous mastitis and seeking ways to shorten it

Background

Granulomatous mastitis is an infrequent and intricate ailment. Limited knowledge exists regarding how granulomatous mastitis progresses and its impact on disease management. We aim to prospectively capture symptoms in the general population to accurately ascertain the duration of illness and the prevalence of long-lasting symptoms.

Methods

This study reports data from 169 prospectively enrolled real-world patients with pathologically confirmed granulomatous mastitis. Patients were enrolled after screening according to the inclusion and exclusion criteria. Patients were followed-up every 2-4 weeks during treatment, then every 3-6 months (Year 1) and 6-12 months (Year 2). Outcomes included symptom resolution, disease course, and relapse. Associations between clinical variables and outcomes were assessed using appropriate statistical models, with significance defined as P<0.05.

Results

The median disease course of granulomatous mastitis was 257 days (range, 55-1,500 days), with the majority of disease regression occurring within a span of 6 months subsequent to diagnosis; 72.78% of patients preferred steroids as the initial treatment. The use of steroids was associated with a shorter disease course after adjusting for age, lump size, abscess, and sinus formation (P=0.02). Abscess formation was observed in 58.57% of patients. Notably, abscess formation during disease progression contributed to a prolonged disease course (358.67 vs. 278.24 days, P=0.03).

Conclusions

Our findings highlighted the heterogeneity of granulomatous mastitis disease course and emphasized the importance of steroid usage in shortening disease course. Avoiding abscess and sinus formation, early steroid usage during granulomatous mastitis treatment might be beneficial. These evidences provide novel insights and supports the use of steroids in patients with granulomatous mastitis for modulating their immune response. Studies are urgently needed to further elucidate the role of steroid in granulomatous mastitis management.

A new stage for predicting the prognosis of granulomatous lobular mastitis

INTRODUCTION

The prognosis of granulomatous lobular mastitis (GLM) had been poor, primarily due to the lack of a unified disease assessment standard.

OBJECTIVE

The purpose of this cohort study was to establish a staging system for GLM to more accurately evaluate the prognosis of patients.

METHODS

This study retrospectively collected data from 264 GLM patients who visited our hospital between January 2017 and December 2023. Through logistic regression analysis, factors associated with prognosis were identified, which served as the basis for creating a new staging system.

RESULTS

Univariate and multivariate logistic regression analysis revealed that hyperlipidemia (HR: 2.031; 95% CI: 1.100-3.750) and microabscesses (HR: 2.087; 95% CI = 1.138-3.827) were significant independent risk factors affecting the prognosis of GLM patients. Based on the results of logistic analysis, three different stages were ultimately established, and it was found that stage C had the highest AUC value (AUC: 0.642), followed by stage B (AUC: 0.628), with stage A (AUC: 0.614) having the lowest. The Delong test revealed no significant difference in AUC values between stage A and stage B (P =  0.255), nor between stage B and stage C (P =  0.263). However, the AUC value of the stage C was found to be higher than that of stage A (P <  0.001). Given that stage C has the highest AUC value, this study selected stage C as the final stage for evaluating the prognosis of GLM patients and named it the 1st edition of GLM stage.

CONCLUSIONS

This study constructed a rigorous and widely applicable GLM staging system (the 1st edition of GLM stage). The system demonstrated good predictive outcomes and provided strong support for clinical decision-making.

Rat Model of Cystic Neutrophilic Granulomatous Mastitis by Corynebacterium Kroppenstedtii

Background

Cystic neutrophilic granulomatous mastitis (CNGM) poses a significant threat to the physical and mental health of women due to its increasing incidence, complex clinical manifestations. Developing an appropriate animal model will help further study the pathogenesis of CNGM.

Methods

Seventy-two rats were randomly assigned to seven groups: group A (n=12, tissue suspension 0.2mL), group B (n=12, 1×10^8 CFU/mL Corynebacterium kroppenstedtii (CK) suspension 0.1mL), group C (n=12, 1×10^9 CFU/mL CK suspension 0.1mL), group D (n=12, tissue suspension 0.1mL + 1×10^8 CFU/mL CK suspension 0.1mL), group E (n=12, tissue suspension 0.1mL + 1×10^9 CFU/mL CK suspension 0.1mL), group F (n=6, phosphate buffer saline solution 0.1mL), and group G (n=6, physiological saline 0.1mL + Complete Freund's adjuvant suspension 0.1mL). Groups A to E constitute the experimental groups with 12 rats each, while groups F and G served as control groups with 6 rats each. Tissue suspension of patients with granulomatous mastitis and different concentrations of CK solution were injected into the fourth pair of mammary glands of rats. Tissue samples were harvested on the 3rd, 7th, and 14th days post-implantation. The breast tissue specimens were stained with HE stain and Gram stain to observe the histopathological characteristics and the presence of Gram-positive bacteria. Bacterial culture was performed to observe the presence of CK. The expression levels of C-reactive protein and interleukin-1 beta were detected.

Results

Rats in groups A, D, and E exhibited breast masses with erythema, with some showing ulceration, and granulomatous structures in pathological. Lipid vacuoles and Gram-positive rods observed in groups D and E. Pus cultures from groups D and E showed growth of CK. Histopathology revealed minimal inflammatory cell infiltration and no granulomatous formation in groups B and C. Group F showed no masses or inflammatory cell infiltration. Rats in group G presented with masses without ulceration, only chronic and acute inflammatory cell infiltration in pathological. Levels of C-reactive protein and interleukin-1 beta were significantly elevated in groups A and E at day 14.

Conclusion

Components of pathological tissues from granulomatous mastitis patient combined with CK suspension, can successfully induce CNGM in rat models.

Integrating the milk microbiome signatures in mastitis: milk-omics and functional implications

Mammalian milk contains a variety of complex bioactive and nutritional components and microorganisms. These microorganisms have diverse compositions and functional roles that impact host health and disease pathophysiology, especially mastitis. The advent and use of high throughput omics technologies, including metagenomics, metatranscriptomics, metaproteomics, metametabolomics, as well as culturomics in milk microbiome studies suggest strong relationships between host phenotype and milk microbiome signatures in mastitis. While single omics studies have undoubtedly contributed to our current understanding of milk microbiome and mastitis, they often provide limited information, targeting only a single biological viewpoint which is insufficient to provide system-wide information necessary for elucidating the biological footprints and molecular mechanisms driving mastitis and milk microbiome dysbiosis. Therefore, integrating a multi-omics approach in milk microbiome research could generate new knowledge, improve the current understanding of the functional and structural signatures of the milk ecosystem, and provide insights for sustainable mastitis control and microbiome management.

Treatment of idiopathic granulomatous mastitis: a retrospective case series

Idiopathic granulomatous mastitis (IGM) is a rare inflammatory disease of the breast. Various clinical management approaches have been described, but their efficacy and optimal sequential order remain uncertain. We describe the first Canadian cohort of patients with IGM, discuss treatment outcomes and outline a practical management approach. This retrospective study included patients diagnosed with biopsy-confirmed IGM between 2014 and 2023, aged over 18 years. Based on a scoping review of the literature, a diagnostic and management approach was developed, and we present here the disease course and outcomes using this approach. 22 females were included, with a mean age of 40 (24-65) years, mostly presenting with a breast lump (n =22, 100%) and breast pain (n = 15, 68%). Mean rheumatology follow-up was 28.7 months (range 3-79). Mean time from first symptom to diagnosis was 3.5 months (range 1-13). Corynebacterium kroppenstedtii was found in 8 patients. Treatment including lipophilic antibiotics, corticosteroids and disease modifying anti-rheumatic drugs (DMARDs), led to complete remission in 95% of patients, in a mean time of 11.6 months (range 1-36), and relapse in only 1 patient. 11 patients required DMARDs (50%), most commonly methotrexate (n=9). We highlight the variable severity of IGM and the benefits of a severity-based treatment approach. A diligent evaluation and work-up is essential to manage IGM. The proposed severity-based management approach with medical treatment and less aggressive surgical intervention led to complete remission in 95%.

Immune Markers and Inflammatory Cytokines in Granulomatous Lobular Mastitis: A Case-Control Study

Purpose

Granulomatous lobular mastitis (GLM) has seen a rising incidence, though its pathogenesis remains unclear, posing challenges for treatment and contributing to high recurrence rates with conventional therapies. While the role of inflammatory and immune factors in GLM has been recognized, a comprehensive clinical evaluation of these markers is still lacking. This study aims to identify potential diagnostic markers and therapeutic targets by comparing immune markers and cytokine levels in GLM patients and healthy controls.

Methods

Conducted at Beijing Hospital of Traditional Chinese Medicine, Capital Medical University from July 2023 to May 2024, this study enrolled 30 GLM patients and 15 healthy female controls in a 2:1 ratio. Serum levels of immune markers and cytokines were analyzed to explore their potential association with GLM.

Results

The study population comprised 30 GLM patients with a mean age of 33.40 ± 4.12 years and 15 healthy female controls with a mean age of 32.13 ± 6.19 years. Significantly elevated levels of C-reactive protein (CRP), Immunoglobulin A (IgA), Complement Component 3 (C3), Complement Component 4 (C4), Compliment Component 1q (C1q), Alpha1-antit-rypsin (AAT), α1-acidglycoprotein (AGP), Anti-histone antibodies (Anti-HIS), Anti-Ro52 antibodies (Anti-Ro52), Anti-double stranded DNA antibodies (Anti-dsDNA), Interleukin-6 (IL-6), Interleukin-10 (IL-10), and Tumor Necrosis Factor-α (TNF-α) were observed in GLM patients compared to controls (all P < 0.05). Subgroup analysis revealed higher levels of CRP, C3, C1q, AAT, and AGP in patients with larger mass areas and those with erythema nodosum (all P < 0.05). No significant differences were found in subgroups based on disease duration or recurrence (both P > 0.05).

Conclusion

Serum levels of CRP, IgA, AAT, AGP, Anti-HIS, Anti-Ro52, Anti-dsDNA, C3, C4, C1q, IL-6, IL-10, and TNF-α may serve as diagnostic and prognostic indicators for GLM, with CRP, AAT, AGP, and C1q being particularly indicative of disease severity. These markers offer potential therapeutic targets for GLM.

Clinical characteristics of patients with granulomatous lobular mastitis associated with Corynebacterium parakroppenstedtii infection and drug sensitivity analysis of the isolated strains

BACKGROUND

It is presently considered that Corynebacterium especially Corynebacterium kroppenstedtii (CK) infection, is one of the important causes of granulomatous lobular mastitis (GLM). However, the pathogen of mastitis in the past two years has been identified as a newly discovered Corynebacterium. But it is unclear whether the pathogen associated with the occurrence of GLM is also this bacterium.

METHODS

GLM female patients with positive bacterial culture in pus specimens from February 2023 to February 2024 who were identified as CK infection by mass spectrometer were selected as the research objects in this study, and the clinical isolates were identified by 16S rDNA sequencing technology to identify the specific pathogen of GLM-related bacterial infection. Subsequently, the clinical characteristics of the patients were compared with those of GLM patients without bacterial infection during the same period, to explore the effect of this particular type of Corynebacterium infection on disease development in GLM patients. Finally, we tested the minimum inhibitory concentration (MIC) values of antibiotics when inhibiting these separation strains in vitro through the E-Test experiment, to evaluate their medicine sensitivity.

RESULTS

A total of 31 GLM patients initially diagnosed with Corynebacterium kroppenstedtii (CK) infection via MALDI-TOF MS were enrolled in the study. However, subsequent 16S rDNA sequencing revealed that 28 isolates (90.32%) were actually identified as the newly recognized Corynebacterium parakroppenstedtii (CPK). This discovery challenges the conventional belief that CK is the primary pathogen of GLM, suggesting instead that CPK is the predominant pathogen associated with GLM bacterial infections. Comparative analysis of the clinical characteristics between the two groups revealed a significantly higher recurrence rate among CPK-infected GLM patients compared to those without CPK infection, along with elevated prolactin levels (P < 0.05). The sensitivity test results indicated high sensitivity of the isolates to vancomycin, linezolid, and rifampicin.

CONCLUSION

In conclusion, this study highlights that Corynebacterium kroppenstedtii strains isolated from GLM specimens were Corynebacterium parakroppenstedtii, serving as the primary pathogen closely linked to GLM's occurrence. CPK infection significantly increases the risk of recurrence in GLM patients, with elevated prolactin levels potentially playing a pivotal role in this process. In clinical antimicrobial treatment, antimicrobials other than penicillin and ciprofloxacin may be empirically administered when sensitivity test results are inconclusive.

Corynebacterium parakroppenstedtii secretes a novel glycolipid to promote the development of granulomatous lobular mastitis

Granulomatous lobular mastitis (GLM) is a chronic idiopathic granulomatous mastitis of the mammary gland characterized by significant pain and a high propensity for recurrence, the incidence rate has gradually increased, and has become a serious breast disease that should not be ignored. GLM is highly suspected relative to microbial infections, especially those of Corynebacterium species; however, the mechanisms involved are unclear, and prevention and treatment are difficult. In this study, we demonstrated the pathogenicity of Corynebacterium parakroppenstedtii in GLM using Koch's postulates. Based on the drug sensitization results of C. parakroppenstedtii, and utilizing a retrospective study in conjunction with a comprehensive literature review, we suggested an efficacious, targeted antibiotic treatment strategy for GLM. Subsequently, we identified the pathogenic factor as a new type of glycolipid (named corynekropbactins) secreted by C. parakroppenstedtii. Corynekropbactins may chelate iron, cause the death of mammary cells and other mammary -gland-colonizing bacteria, and increase the levels of inflammatory cytokines. We further analyzed the prevalence of C. parakroppenstedtii infection in patients with GLM. Finally, we suggested that the lipophilicity of C. parakroppenstedtii may be associated with its infection route and proposed a possible model for the development of GLM. This research holds significant implications for the clinical diagnosis and therapeutic management of GLM, offering new insights into targeted treatment approaches.

Pathological manifestations of granulomatous lobular mastitis

Granulomatous lobular mastitis (GLM) is a rare inflammatory breast disease with unknown etiology, characterized by non-caseous granulomatous inflammation of the lobules, which infiltrate lymphocytes, neutrophils, plasma cells, monocytes, and eosinophils may accompany. GLM is often misdiagnosed as breast cancer due to the lack of specificity in clinical and imaging examinations, and therefore histopathology is the main basis for confirming the diagnosis. This review provides an overview of the pathological features of granulomatous lobular mastitis and cystic neutrophil granulomatous mastitis (CNGM, a pathologic subtype of GLM). As well as pathologic manifestations of other breast diseases that need to be differentiated from granulomatous lobular mastitis such as breast tuberculosis, lymphocytic mastopathy/diabetic mastopathy, IgG4-related sclerosing mastitis (IgG4-RSM), nodular disease, Wegener's granulomatosis, and plasma cell mastitis. Besides, discusses GLM and CNGM, GLM and breast cancer, emphasizing that their relationship deserves further in-depth exploration. The pathogenesis of GLM has not yet been clearly articulated and needs to be further explored, pathology enables direct observation of the microscopic manifestations of the disease and contributes to further investigation of the pathogenesis.

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.