Idiopathic Granulomatous Mastitis: Cytologic and Histologic Study of 65 Egyptian Patients

Diagnostic Challenges and Insights Into Granulomatous Mastitis: A Systematic Review

Granulomatous mastitis (GM) is a chronic inflammatory breast condition that presents significant diagnostic challenges due to its clinical and imaging similarities to malignancies. Accurate diagnosis is crucial to avoid unnecessary interventions and ensure effective management. A total of 1,216 articles were initially identified through a comprehensive database search. After removing duplicates and conducting a systematic review, 73 studies were shortlisted for full-text evaluation, with 31 studies meeting the inclusion criteria. These studies were analyzed to extract data on diagnostic methodologies, sample sizes, accuracy, and limitations. The review highlights the central role of histopathology in the definitive diagnosis of GM, supported by adjunctive tools such as contrast-enhanced ultrasound, magnetic resonance imaging, and polymerase chain reaction. Imaging modalities, while valuable, often lack specificity and require histological confirmation. Emerging techniques, including quantitative imaging parameters and molecular diagnostics, offer promise in enhancing diagnostic precision. A multidisciplinary approach integrating clinical, radiological, and histopathological findings remains critical. GM diagnosis requires a nuanced approach combining traditional and emerging techniques. Histopathology remains the gold standard, but advancements in imaging and molecular diagnostics provide new avenues for improving accuracy and guiding management. The findings emphasize the need for further research and standardized diagnostic protocols to address the complexities of GM.

Periductal Mastitis, a Disease with Distinct Clinicopathological Features from Granulomatous Lobular Mastitis

Purpose

Periductal mastitis (PDM) is a chronic inflammatory lesion of the breast with an unknown etiology, and it is difficult for clinicians to differentiate it from granulomatous lobular mastitis (GLM), although they have different treatment strategies and prognosis. This study aimed to investigate the differences in their clinicopathologic features to inform treatment strategies.

Patients and Methods

Between 2011 and 2020, 121 patients diagnosed with PDM and 57 patients with GLM were retrospective analysis. Patient data were extracted on demographics, clinical presentation, pathologic characteristics, treatments and clinical response. Histopathological evaluations were performed on core needle biopsy specimens. Immunohistochemical stains using antibodies against CD3, CD4, CD8, CD20, and CD138 was performed to define immune cell infiltration.

Results

PDM patients had a higher median age compared to GLM patients (38 vs 32, p<0.001). PDM was primarily located in the areolar area, while GLM predominantly affected the peripheral quadrant of the breast (56.20% vs 75.44%, p<0.001). Histopathologically, more ductal dilatation (90.08% vs 3.51%, p<0.001), ductal wall thickening (47.93% vs 1.75%, p<0.001), and ductal rupture (44.63% vs 5.26%, p<0.001) were observed in PDM. GLM presented with significantly more granuloma (94.74% vs 10.74%, p<0.001), microabscess (68.42% vs 28.93%, p<0.001), and lipid vacuole (40.35% vs 8.26%, p<0.001) formation than PDM. Immunohistochemical analysis revealed a significant presence of CD20+ B lymphocytes in PDM and a higher prevalence of CD8+ T lymphocytes in GLM, indicating differing immune responses. Treatment outcomes varied, with PDM patients responding well to surgery and anti-mycobacterial therapy, while GLM patients showed favorable responses to steroid therapy.

Conclusion

PDM is a specific entity with a similar clinical presentation but distinct histopathological features and immune profiles to GLM. Further research is needed to elucidate the pathogenesis and optimize therapeutic approaches for these breast inflammatory conditions.

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.

The discriminatory diagnostic value of multimodal ultrasound combined with blood cell analysis for granulomatous lobular mastitis and invasive ductal carcinoma of the breast

OBJECTIVE

To explore the discriminatory diagnostic value of multimodal ultrasound(US) combined with blood cell analysis (BCA) for Granulomatous Lobular Mastitis (GLM) and Invasive Ductal Carcinoma (IDC) of the breast.

METHODS

A total of 157 breast disease patients were collected and divided into two groups based on postoperative pathological results: the GLM group (57 cases with 57 lesions) and the IDC group (100 cases with 100 lesions). Differences in multimodal ultrasound features and the presence of BCA were compared between the two groups. The receiver operating characteristic (ROC) curve was used to calculate the optimal cutoff values, sensitivity, specificity, 95% confidence interval (CI), and the area under the curve (AUC) for patient age, lesion size, lesion resistive index (RI), and white blood cell (WBC) count in BCA. Sensitivity, specificity, positive predictive value, negative predictive value, diagnostic accuracy, and AUC were calculated for different diagnostic methods.

RESULTS

There were statistically significant differences (P < 0.05) observed between GLM and IDC patients in terms of age, breast pain, the factors in Conventional US (lesion size, RI, nipple delineation, solitary/multiple lesions, margin, liquefaction area, growth direction, microcalcifications, posterior echogenicity and abnormal axillary lymph nodes), the factors in CEUS (contrast agent enhancement intensity, enhancement pattern, enhancement range, and crab-like enhancement) and the factors in BCA (white blood cells, neutrophils, lymphocytes and monocytes). ROC curve analysis results showed that the optimal cutoff values for distinguishing GLM from IDC were 40.5 years for age, 7.15 cm for lesion size, 0.655 for lesion RI, and 10.525*109/L for white blood cells. The diagnostic accuracy of conventional US combined with CEUS (US-CEUS) was the highest (97.45%). The diagnostic performance AUCs for US-CEUS, CEUS, and US were 0.965, 0.921 and 0.832, respectively.

CONCLUSION

Multifactorial analysis of multimodal ultrasound features and BCA had high clinical application value in the differential diagnosis of GLM and IDC.

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.

Demographic and Socioeconomic Risk Factors for Granulomatous Mastitis in the United States: A Case-Control Study

OBJECTIVE

Granulomatous mastitis (GM) is a benign breast disease that can have an extended clinical course impacting quality of life and causing breast disfigurement. Granulomatous mastitis has been studied throughout the world; however, less is known about GM patients in the United States. We aim to identify demographic and socioeconomic factors associated with GM in the United States.

METHODS

An IRB-approved retrospective case-control study was performed of 92 patients with biopsy-proven GM at two institutions in Los Angeles, California: a safety-net hospital and an academic institution. Age-matched controls were selected from patients presenting for diagnostic breast imaging. Demographic and socioeconomic characteristics were collected. Data were analyzed using univariable test for odds ratios (ORs) with 95% confidence intervals (CIs) and multivariable conditional logistic regression.

RESULTS

Patients with GM were more likely to prefer Spanish language (OR 6.20, 95% CI: 2.71%-14.18%), identify as Hispanic/Latina (OR 5.18, 95% CI: 2.38%-11.30%), and be born in Mexico (OR 3.85, 95% CI: 1.23%-12.02%). Cases were more likely to have no primary care provider (OR 3.76, 95% CI: 1.97%-7.14%) and use California Medicaid for undocumented adults (OR 3.65, 95% CI: 1.89%-7.08%). In the multivariable analysis, participants who preferred Spanish language had four times higher odds of GM versus those who preferred English language (OR 4.32, 95% CI: 1.38%-13.54%).

CONCLUSION

Patients with GM may have barriers to health care access, such as preferring Spanish language, being an undocumented immigrant, and not having a primary care provider. Given these health care disparities, further research is needed to identify risk factors, etiologies, and treatments for this subset of GM patients.

A case management model for patients with granulomatous mastitis: a prospective study

Background

Granulomatous mastitis (GM) is a chronic inflammatory mastitis disease that requires long-term treatment and has a high recurrence rate. Case management has been proven to be an effective mechanism in assisting patients with chronic illness to receive regular and targeted disease monitoring and health care service. The aim of this study was to investigate the application of a hospital-to-community model of case management for granulomatous mastitis and explore the related factors associated with its recurrence.

Methods

This was a prospective study on patients with granulomatous mastitis based on a case management model. Data on demographic, clinical and laboratory information, treatment methods, follow-up time, and recurrence were collected and analyzed. The eight-item Morisky Medication Adherence Scale (MMAS-8) was used to investigate patients' adherence to medications. Logistic regression models were built for analysis of risk factors for the recurrence of granulomatous mastitis.

Results

By October 2021, a total of 152 female patients with a mean age of 32 years had undergone the entire case management process. The mean total course of case management was 24.54 (range 15–45) months. Almost all the patients received medication treatment, except for one pregnant patient who received observation therapy, and approximately 53.9% of the patients received medication and surgery. The overall recurrence rate was 11.2%, and “high” medication adherence (RR = 0.428, 95% CI 0.224–0.867, P = 0.015) was significantly associated with a lower rate of recurrence, while the rate of recurrence with a surgical procedure + medication was higher than that with medication alone (RR = 4.128, 95% CI 1.026–16.610, P = 0.046).

Conclusion

A case management model for patients with granulomatous mastitis was applied to effectively monitor changes in the disease and to identify factors associated with disease recurrence. “Low” medication adherence was a significant risk factor for the recurrence of granulomatous mastitis. Patients treated with medication and surgery were more likely to experience recurrence than those treated with medication alone. The optimal treatment approach should be planned for granulomatous mastitis patients, and patient medication adherence should be of concern to medical staff.

New Insights of Corynebacterium kroppenstedtii in Granulomatous Lobular Mastitis based on Nanopore Sequencing

BACKGROUND

The etiology of granulomatous lobular mastitis (GLM) remains unknown. This study aimed to detect bacteria in GLM using Nanopore sequencing and identify the relationship between GLM and Corynebacterium kroppenstedtii.

METHODS AND MATERIALS

The bacterial detection on fresh samples (including breast pus and tissue) of 50 GLM patients using nanopore sequencing and culture methods. The bacterial detection rate of participants with different stages were compared and analyzed. Formalin-fixed and paraffin-embedded (FFPE) tissues from 39 patients were performed on Gram staining to identify Gram-positive bacilli (GPB) within lipid vacuoles. Moreover, the clinicopathological characteristics of GLM patients in different bacterial subgroups were also conducted.

RESULTS

In 50 GLM patients, the detection rate of bacteria was 78% using nanopore sequencing method, especially in the early stage of GLM (over 80%), which was significantly higher than that using culture methods (24%, p < 0.001). The dominant bacteria were Corynebacterium species (64%), especially for the Corynebacterium kroppenstedtii. The detection rate of C. kroppenstedtii in nanopore sequencing method (56%) was higher than that in culture methods (16%, p < 0.001). Gram staining positive of bacteria in 7 patients, and 5 of them were C. kroppenstedtii. Thirty-one patients (31/39, 79.5%) exhibited typical histological structure of cystic neutrophilic granulomatous mastitis (CNGM), and eighteen patients detected with C. kroppenstedtii.

CONCLUSION

Nanopore sequencing showed rapid and accurate bacteria detection over culture method in GLM patients. GLM is not sterile inflammation and closely related to C. kroppenstedtii. CNGM was associated with Corynebacterium infection, especially for C. kroppenstedtii.

The effect of methotrexate monotherapy on treatment-resistant idiopathic granulomatous mastitis patients

BACKGROUND

Idiopathic granulomatous mastitis (IGM) is a disease of unknown etiology, involving a chronic inflammatory process, characterized by noncaseating granuloma formation. IGM can mimic a tumor clinically and radiologically. Since we are a tertiary referral center, most of our patients (n = 56, 87.5%) are secondary admissions who have previously had antibiotics and steroid treatments; therefore, we accept these patients as resistant cases. Here, we aim to present our single-center series of 64 patients with resistant IGM who underwent methotrexate monotherapy. To the best of our knowledge, our study includes the highest number of patients described in the literature with IGM who have undergone this treatment.

METHODS

This study included 64 patients, 56 of which were resistant cases, diagnosed with IGM between January 2013 and January 2020 at Istanbul University Cerrahpasa, Cerrahpasa Medical Faculty, General Surgery Breast Outpatient Clinic that were followed-up at least once. These patients were administered oral methotrexate monotherapy 15 mg/week for 24 weeks, and in relapsed cases, the treatment was up to 20 mg/week for 1 year. Folic acid 10 mg/week was given as a supplement to all patients.

RESULTS

Complete recovery was observed in 52 (81.25%) of the 64 patients. Follow-up was discontinued by 4 patients. The dose was increased and the duration of treatment was extended up to 1 year when relapse was observed in 8 patients and complete response was then obtained in these cases. Only 3 patients (4.69%) experienced side effects and were switched to subcutaneous treatment due to nausea.

CONCLUSION

Considering the high patient compliance, low recurrence, minimal side effects, and overall success of the treatment, we believe that methotrexate monotherapy may be used in treatment-resistant IGM patients and may also be the first choice for first-line treatment in the future.

Bacteria Associated with Granulomatous Lobular Mastitis and the Potential for Personalized Therapy

Granulomatous lobular mastitis (GLM), also known as idiopathic granulomatous mastitis (IGM), is a chronic inflammatory lesion of the breast. The incidence of GLM has been increasing in recent years, especially among young women. The etiologies of GLM have not been fully elucidated but are associated with autoimmunity and bacterial infection. Bacteria, especially Corynebacterium species, play important roles in GLM. In this article, we review research progress regarding the bacteriology of GLM attained with the application of several new high-throughput detection techniques. Accurate detection might be important for deepening our understanding of the pathogenesis of GLM and hold promise for personalized GLM therapy.

Mastitis in Autoimmune Diseases: Review of the Literature, Diagnostic Pathway, and Pathophysiological Key Players

Mastitis frequently affects women of childbearing age. Of all the pathological breast conditions requiring specific management, autoimmune mastitis is in the third position after infection and breast cancer. The aim of this literature review was to make a comprehensive description of autoimmune diseases targeting the mammary gland. Four main histological patterns of autoimmune mastitis are described: (i) lymphocytic infiltrates; (ii) ductal ectasia; (iii) granulomatous mastitis; and (iv) vasculitis. Our literature search found that all types of autoimmune disease may target the mammary gland: organ-specific diseases (diabetes, thyroiditis); connective tissue diseases (such as systemic erythematosus lupus or Sjögren’s syndrome); vasculitides (granulomatosis with polyangiitis, eosinophilic granulomatosis with polyangiitis, giant cell arteritis, polyarteritis nodosa, Behçet’s disease); granulomatous diseases (sarcoidosis, Crohn’s disease); and IgG4-related disease. Cases of breast-specific autoimmune diseases have also been reported, including idiopathic granulomatous mastitis. These breast-limited inflammatory diseases are sometimes the first symptom of a systemic autoimmune disease. Although autoimmune mastitis is rare, it is probably underdiagnosed or misdiagnosed. Early diagnosis may allow us to detect systemic diseases at an earlier stage, which could help to initiate a prompt, appropriate therapeutic strategy. In case of suspected autoimmune mastitis, we hereby propose a diagnostic pathway and discuss the potential pathophysiological pathways leading to autoimmune breast damage.

Cystic neutrophilic granulomatous mastitis: an update

Cystic neutrophilic granulomatous mastitis (CNGM) is a rare subtype of granulomatous mastitis with a highly distinct histological pattern often associated with Corynebacterium species. CNGM is characterised by suppurative lipogranulomas that are composed of central lipid vacuoles rimmed by neutrophils and an outer cuff of epithelioid histiocytes. Some of the lipid vacuoles may contain sparse, rod-shaped, gram-positive bacilli that can be easily missed or dismissed. The surrounding mixed inflammatory infiltrate contains Langhans-type giant cells, lymphocytes and neutrophils. CNGM occurs in reproductive age women with a history of pregnancy and typically presents as a palpable mass that can be painful. CNGM has many mimickers, most significantly breast carcinoma. In many cases, CNGM has significant pathological and clinical overlap with other forms of granulomatous mastitis. Given the association with Corynebacterium species, early diagnosis of CNGM is essential in offering patients the most appropriate treatment. Prolonged antibiotic therapy specifically directed to corynebacteria is required, sometimes even beyond resolution of clinical symptoms. This comprehensive review of the existing literature on CNGM describes clinical-pathological features, microbiological findings, challenges associated with the microscopic differential diagnosis, clinical implications of this diagnosis and emerging treatment options. Morphological criteria and suggested comments to convey the degree of diagnostic certainty are also proposed for standard pathology reporting.

Clinical study on surgical treatment of granulomatous lobular mastitis

Background

The etiology and pathogenesis of granulomatous lobular mastitis (GLM) remain unknown, with no unified evaluation criteria or standard treatments. This study aimed to assess the etiology and features of GLM, as well as the effects of surgery (lesion excision + stage I breast reconstruction; LE + BR) for GLM.

Methods

This study evaluated 178 female GLM patients retrospectively in 2006-2015. The surgery and non-surgery groups included 164 and 14 patients, respectively. All patients received conservative therapy (traditional Chinese medicine combined with regional wet compress and pus drainage). In addition, the surgery group (n=164) underwent LE + BR. Clinical data, including disease course, causes, lesion size, marital status, and treatment approaches, were assessed.

Results

Follow-up was 13-117 months. Seventy-five of the 178 patients had no overt causes (42.1%); meanwhile, 63 (35.4%) and 16 (9.0%) had congenital nipple retraction and a history of psychotropic drugs for >1 year, respectively. The surgery group showed lesions significantly shrunk (≤1 quadrant) with acute inflammation fully controlled; 8 showed recurrence, indicating a cure rate of 95.1% (156/164). In the non-surgery group, 4 cases showed relapse after 6-14 months (cure rate =71.4%; 10/14). Therefore, surgical treatment was significantly more efficient than non-surgical treatment (P=0.001). Kaplan-Meier survival curves for the two treatment types showed a significant difference in recurrence (log rank =11.84, P<0.001).

Conclusions

In GLM patients, LE + BR is safe and effective with respect to cosmetic results, recovery time, and recurrence. Successful surgery should be performed for patients whose lesions ≤1 quadrant, aim to achieve optimal GLM treatment.

Methotrexate in the Treatment of Idiopathic Granulomatous Mastitis

Objective.

Idiopathic granulomatous mastitis (IGM) is a disfiguring inflammatory breast disease without effective treatment. We report the largest IGM cohort treated with methotrexate (MTX) monotherapy.

Methods.

Chart review was performed on patients evaluated by the Stanford Immunology and Rheumatology Clinic, with histopathologically established IGM treated with MTX, and at least 1 followup appointment.

Results.

Nineteen female patients with a mean age of 33.5 years were identified. Most failed treatment with antibiotics, prednisone, and surgical intervention. By 15 months of treatment with MTX, 94% had disease improvement and 75% achieved disease remission.

Conclusion.

MTX monotherapy is an effective treatment for IGM.

Idiopathic Granulomatous Mastitis Presenting as a Breast Pseudotumor: Case Reports with Review of the Literature

Idiopathic granulomatous mastitis is a rare benign inflammatory breast disease that affects women of childbearing age with a history of breastfeeding. It usually presents as an enlarging breast mass that can greatly mimic breast cancer. Moreover, it does not have a specific radiographic finding, so the only way to reach a definitive diagnosis is by core biopsy and histology. Furthermore, a consensus regarding the best treatment modality has not been reached yet. In this report, we describe the cases of two patients who suffered from this disease, and to our knowledge, such a report is the first of its kind to address this topic in this region. Therefore, because of its uncommon nature and obscure presentation, we hereby report two cases of idiopathic granulomatous mastitis. The clinical presentation, treatment, and pathological findings are described, and a literature review on idiopathic granulomatous mastitis will be reported.

Clinical and Cytological Spectrum of Granulomatous Mastitis and Utility of FNAC in Picking up Tubercular Mastitis: An Eight-Year Study

INTRODUCTION

Granulomatous Mastitis (GM) is a rare, benign, inflammatory disease of the breast. It is a well known mimicker of malignancy, clinically and radiologically. Patients are often subjected to number of tests for the right diagnosis. Non-specific Granulomatous Mastitis (NGM) and Tubercular Mastitis (TBM) are chief among the various causes of GM. They are important to be diagnosed early as their treatment varies significantly. Fine Needle Aspiration Cytology (FNAC) is simple, patient friendly and primary investigation modality in cases of lump in breast.

AIM

To find out the utility of FNAC in differentiating NGM and TBM.

MATERIALS AND METHODS

All cases of granulomatous mastitis diagnosed on cytology over eight years were retrospectively retrieved. The clinical and radiological history was obtained from the patient file. The slides were stained with haematoxylin and eosin stain as well as Leishman stains. Special stains like Periodic Acid Schiff (PAS) and Ziehl Neelsen (ZN) stain were used for fungus and Mycobacteriumtuberculosis respectively. Histopathological correlation of the available cases was done. Clinical presentation and cytological morphology of individual cases was studied in detail.

RESULTS

Twenty one cases of GM obtained, of which 16 were NGM and five were TBM. Both diseases were common among young reproductive women who presented with unilateral breast lump of varying duration. Almost 25% of NGM and 60% of TBM has clinical suspicion of malignancy. About 30% had radiological suspicion of malignancy. Nearly 62.5% of NGM patients had painful swelling and none of tubercular mastitis patients had pain. About 31% of NGM patients underwent prior abscess drainage and 40% of TBM patients gave history of tuberculosis. Almost 6.25% of NGM and 60% of TBM had axillary lymphadenopathy. Cytologically epithelioid cells were identified in 100% of patients whereas, granulomas were seen in 62.5% and 80% of NGM and TBM smears respectively. Langhans giant cells were frequent among TBM and foreign body giant cell among NGM. Caseous necrosis was seen in 60% of TBM and absent in NGM smears.

CONCLUSION

Though, NGM and TBM is said to have overlapping features, our study highlights few clinical and cytological differences which aid in differentiating the two entities at primary level. FNAC along with special stain must be advocated as the primary tool of diagnosis in cases of GM.