Granulomatous mastitis (GM) is a form of non-lactational breast inflammation that is closely associated with autoimmune processes, however its underlying pathogenesis remains elusive. In this study, we employed single-cell RNA sequencing (scRNA-seq) to conduct a comparative analysis of GM lesion tissues versus normal breast tissues, thereby unveiling the immune profile of GM tissues. Our investigation centered on T and NK cells, macrophages, epithelial cells, and endothelial cells. Notably, we observed a substantial infiltration of immune cells in GM tissues, accompanied by immune disorders, an elevation in Th1 cell counts, enrichment of the toll-like receptor (TLR) pathway, and upregulation of various factors including interferon-γ (IFN-γ), C-C motif chemokine ligand 3 (CCL3), CCL4, chemokine (C-X-C motif) ligand (CXCL) 13, CD69, signal transducer and activator of transcription 1 (STAT1), and heat shock protein family A member 1A (HSPA1A). Furthermore, the macrophage subpopulations in GM tissues exhibited a transition to a pro-inflammatory phenotype, enriched for pathways such as interferon-γ (IFN-γ), IFN-α, interleukin-6/janus kinase/signal transducer and activator of transcription 3 (IL-6/JAK/STAT3), and tumor necrosis factor-α/nuclear factor-κB (TNF-α/NF-κB). Mammary luminal cells demonstrated an impaired estrogenic profile yet displayed upregulation of prolactin downstream signaling pathways, namely the JAK/STAT and mitogen-activated protein kinase (MAPK) pathways. Additionally, vascular endothelial cells were found to recruit immune cells and exhibited a prominent angiogenic profile in GM tissues. Cellular interaction analysis unveiled an intricate network of interactions between mesenchymal and immune cells. This study provides a comprehensive immune landscape of granulomatous mastitis and offers some potential therapeutic targets for the disease.

Idiopathic granulomatous mastitis is a rare, chronic, inflammatory breast disease that can mimic breast carcinoma. Histologicaly there are giant cells and epitheloid histiocytes forming non-caseating granulomas. Corticosteroids, methotrexate, azathioprine, intralesional corticosteroid injection can be used as the first step drugs in the treatment of patients with Idiopathic granulomatous mastitis, but the next step is unclear in a group of patients who are resistant to these treatments. Many of these patients also undergo unnecessary surgical interventions. Tumor necrosis factor-alpha (TNF-α) plays a role in maintaining the granuloma structure. There is few case reports and very limited data in the literature regarding TNF-α inhibitor treatment in resistant patients. Our aim is to show that TNF-α inhibitors may be an alternative for refractory patients in the treatment of idiopathic granulomatous mastitis.

The data of 25 female patients with idiopathic granulomatous mastitis who were refractory to conventional therapies and started TNF-α inhibitors were retrospectively analyzed. Pre- and post-treatment M scores of the patients were calculated.

We observed that the M-scores of our patients decreased as the duration of TNF-α inhibitors use increased.

Our study contains the largest number of patients with data on the use of TNF-α inhibitors in the treatment of idiopathic granulomatous mastitis. We believe that our study will contribute to the development of idiopathic granulomatous mastitis treatment algorithms. Key Points • TNF-α inhibitors may be an alternative for refractory patients in the treatment of idiopathic granulomatous mastitis.

Granulomatous lobular mastitis (GLM) is a rare, benign inflammatory condition of the breast that is difficult to distinguish from breast cancer on the basis of clinical and imaging findings. GLM typically has a long disease course, and is difficult to treat and prone to recurrence. Furthermore, there is currently no standard treatment for GLM. The aim of this study was to compare the therapeutic effects and patient satisfaction scores of surgery, triple anti-tuberculosis drug therapy, and combination treatment against GLM.

The medical records and follow-up data of GLM patients who underwent treatment at our center were retrospectively analyzed. Patients were divided into the treatment groups of surgery (group A), triple anti-tuberculosis drug therapy (group B), and combination therapy (group C). The demographic and clinical data, treatment outcomes, and patient satisfaction scores were compared among the three groups.

Median follow-up duration of the patients was 35.43 months (range, 13.27-67.90 months). There were 106, 109, and 88 patients in groups A, B, and C respectively. The cure rates were similar among the groups (P = 0.220), although treatment duration was longest for group B, followed by group C and group A (P < 0.001). Group B had the highest patient satisfaction scores (P < 0.001),whereas the recurrence rate was highest in Group A (P < 0.001). Furthermore, no severe adverse drug reactions or major postoperative complications were observed in any of the patients.

Triple anti-tuberculosis drug therapy can effectively treat GLM patients with high patient satisfaction scores for potential application in clinical practice. The combination of surgery and triple anti-tuberculosis drug therapy is a suitable option for patients seeking rapid relief.

The study was registered at the Us Clinical Trial Registration Center (registration number: NCT06565845;date: 08/21/2024).

Idiopathic granulomatous mastitis (IGM) is a rare, benign, and chronic inflammatory breast disease with unclear etiology and no standardized treatment. It often presents as a painful breast mass that mimics breast cancer, necessitating thorough diagnostic evaluation.

This report discusses a case of a 39-year-old pregnant woman with IGM associated with erythema nodosum, a poorly understood co-occurrence. Initial treatment included antibiotics and surgical drainage for an abscess. Despite multiple interventions, including corticosteroids and methotrexate, the disease persisted with recurrent episodes.

This case underscores the complexities of managing IGM, highlighting its association with systemic manifestations such as erythema nodosum. Current therapeutic approaches range from conservative management to immunosuppressive therapy and surgery, with outcomes varying widely.

Further studies are needed to elucidate the pathophysiology and establish optimal treatment strategies for IGM, particularly in the context of systemic involvement.

Granulomatous lobular mastitis (GLM) is a chronic breast inflammation with low remission and high recurrence. This study aimed to investigate GLM patients' autoimmune profiles and their correlation with GLM etiopathogenesis.

Samples from GLM patients and fibroadenoma (FA) controls admitted to Shuguang Hospital between July 2021 and July 2022 were analyzed. Patients (107 GLM, 73 FA) underwent humoral immunity (C3, C4, IgG, IgM, IgE and IgA), cellular immunity (CD3+CD4+ T cells, CD3+CD8+ T cells, regulatory T cells and CD4/CD8 ratio) and cytokines (IL-1β, IL-6, IL-8, IL-10, IL-12 and TNF-α) tests. Immunohistochemical staining (10 GLM, 10 FA normal tissues) detected IL-1β, IL-6, CD86 and CD206, and immunofluorescence (3 GLM, 3 FA normal tissues) evaluated CD86 and CD206 expression. Multivariate analysis was done using logistic regression.

GLM featured granulomas with non-caseation necrosis and inflammatory cell infiltration. GLM patients showed higher C3 (P < 0.001), C4 (P < 0.001), IgE (P < 0.05), IgA (P < 0.05), IL-6 (P < 0.001), and IL-8 levels (P < 0.05). M1 (CD86) and M2 (CD206) macrophage markers were significantly higher in GLM than controls in both immunohistochemical and immunofluorescent staining (P < 0.05). The multivariate logistic regression analysis revealed that reproductive history (OR = 7.011, P < 0.01) and C3 expression level (OR = 5565.570, P < 0.001) were independent factors of GLM.

The results highlighted the crucial role of elevated M1 and M2 macrophages in GLM inflammation. GLM was associated with reproductive history, C3, C4, IgE, IgA, IL-6, and IL-8, with reproductive history and C3 as independent risks.

Cystic neutrophilic granulomatous mastitis (CNGM) is characterized by granulomas with cysts that sometimes contain bacteria in the lumen, a surrounding neutrophilic infiltrate, and Langhans giant cells. There are no universally accepted diagnostic criteria for CNGM. Corynebacterium kroppenstedtii, a Gram-positive bacillus, has been reported to cause several infections, but the exact cause remains unclear. We report our experience with a case of CNGM, thought to be due to a rare Mycobacteroides abscessus infection.

We report the case of a 36-year-old Japanese woman with granulomatous mastitis due to Mycobacteroides abscessus who had not undergone surgery and was not immunosuppressed. She presented with a chief complaint of pain and swelling in her left breast for 1 month. Mammography showed asymmetrical focal increased density, and ultrasonography showed an irregular hypoechoic area in the left 3 o'clock position. Contrast-enhanced magnetic resonance imaging showed segmental non-mass-enhancement. Ultrasound-guided vacuum-assisted biopsy with pathology revealed granulomatous mastitis. Ziehl-Neelsen staining revealed red-staining bacilli. The patient was followed up for observation because her breast pain had decreased after the examination, and there was no redness or fever. However, the breast pain has not completely disappeared, and intermittent purulent discharge from the biopsy site persisted for 5 months. Hence, two 12-Fr drains were inserted along the ductal dilatation-like hypoechoic area. Imipenem, amikacin, and clarithromycin were administered for 8 days. After 8 days of this therapy, the patient developed a drug-associated rash; therefore, antimicrobial therapy was discontinued, and the drains were removed. Her symptoms improved, and magnetic resonance imaging after 1 month showed that the previous imaging findings in her left breast had disappeared. At the time of writing, 18 months have passed since treatment, and no recurrence has been observed.

We experienced a rare case of CNGM associated with Mycobacteroides abscessus. This case suggests that a combination of drainage and antimicrobial therapy may shorten the duration of antimicrobial therapy in CNGM.

This network meta-analysis aims to evaluate the recurrence rates of various treatment options for granulomatous lobular mastitis.

We systematically searched and identified eligible studies in PubMed, EMBASE, Cochrane Library, and Web of Science databases until September 30, 2023. Original studies reporting the recurrence rates of various treatments were included. Subsequently, literature screening, data extraction, and network meta-analysis were conducted. This study was registered with PROSPERO (registration number CRD 42023434773).

Nineteen articles involving 1,095 patients were included in this study. The network meta-analysis revealed that several treatment combinations reduced the recurrence rate compared to observation: Surgery + Local steroid injection + Systemic steroids therapy (OR: 0.23, 95% CI 0.01 to 4.53), Local steroid injection (OR: 0.34, 95% CI 0.02 to 6.81), Surgery + Systemic steroids therapy (OR: 0.36, 95% CI 0.02 to 5.29), Surgery + Traditional Chinese Medicine (OR: 0.33, 95% CI 0.01 to 9.11), Systemic steroids therapy + MTX (OR: 0.62, 95% CI 0.01 to 34.59), and Systemic steroids therapy + drainage (OR: 0.76, 95% CI 0.05 to 10.67). Among these, Surgery + Local steroid injection + Systemic steroids therapy demonstrated superior efficacy. The surface under cumulative ranking curve (SUCRA) values were highest for Surgery + Local steroid injection + Systemic steroids therapy (0.85), followed by Local steroid injection (0.78) and Surgery + Systemic steroids therapy (0.77).

Steroid-based combination therapy may be the first choice for IGM patients, with a comprehensive strategy of local and systemic steroids combined with surgery having the best effect on IGM.

Background/Objectives: Despite its long-standing recognition, the etiopathogenesis of idiopathic granulomatous mastitis (IGM) remains poorly understood. This study aims to investigate the relationship between IGM and food intolerance, allergies, and immunological factors to shed light on its etiology. Materials and Methods: This case-control study included 32 patients with IGM and 32 healthy women. In order to examine their potential relevance to allergy and immunology, serum interleukin (IL)-4, IL-4 receptor, histamine, and histamine-releasing factor (HRF) were measured by ELISA. Furthermore, serum IgG antibodies against specific food allergens were measured to evaluate food intolerance. Results: The patient group exhibited significantly higher intolerance values for lentils and curry compared to the control group (p = 0.023 and p = 0.012, respectively). Histamine (p < 0.001) and IL-4 (p = 0.003) levels were elevated in IGM patients compared to the control group, while HRF and IL-4R outcomes did not show any significant differences (p > 0.05). Conclusions: Elevated histamine and IL-4 levels may suggest the involvement of allergy and immunological factors in IGM's etiopathogenesis. The integration of anti-histamine medications for IGM patients with elevated histamine levels could provide an alternative therapeutic strategy.

Cornus officinalis total glycosides (COTG) derived from the traditional Chinese medicine Cornus officinalis, is a natural immunosuppressant and has been extensively studied in immunomodulation and immunosuppression. This study aimed to explore the effects of COTG on granulomatous lobular mastitis (GLM) and its associated mechanisms. Compared to the model group, COTG effectively ameliorated histopathological damage to breast tissue, reduced mammary gland suppuration, and enhanced the blood-milk barrier. Additionally, COTG treatment reduced the total number of T cells and B cells in GLM rats, significantly improving clinical indicators such as P-selectin, E-selectin, and intercellular cell adhesion molecule-1. We also observed downregulation of CD28 and B7 expression levels, an upregulation of cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) expression, and a significant decrease in inflammatory marker levels in the COTG group. COTG exerts an anti-inflammatory effect in GLM by stimulating CTLA-4, inhibiting the B7-CD28 signaling pathway affecting T cell activation, and promoting the blood-milk barrier. These findings suggest that COTG could be a promising therapeutic option for managing GLM, potentially improving patient outcomes by modulating immune responses and reinforcing the blood-milk barrier.

Granulomatous mastitis (GM) is a rare, chronic, benign inflammatory disease of the breast. Here, we present a rare case of GM caused by brucellosis and present the first review to compile the cases in the literature. The diagnosis was confirmed by the patient's serological and histopathological results. The patient was successfully treated with doxycycline+rifampicin combination therapy for six weeks. In conclusion, infectious agents, especially brucellosis, should be considered in the differential diagnosis of GM in endemic regions. Diagnostic methods, such as tissue culture and serological tests, should be used to detect possible infectious agents if necessary.

We describe the demographics, clinical presentation, imaging findings, and treatment response among 235 cases of biopsy-proven idiopathic granulomatous mastitis (IGM) at a single institution.

An institutional review board-approved retrospective search of the breast imaging database was performed to select patients with biopsy-proven IGM between 2017 and 2022. Retrospective review evaluated clinical presentation, imaging findings with US and mammography, and treatment recommendations (antibiotics, nonsteroidal anti-inflammatory drugs [NSAIDs], warm compresses, or observation only). Response to treatment was evaluated on follow-up US. A favorable treatment response was a decrease in size or resolution of disease on follow-up imaging. Statistical analysis using Poisson regression was performed to evaluate the clinical outcomes associated with each treatment.

A total of 235 patients met the selection criteria with a mean age of 38 years (18 to 68). The majority of patients were Hispanic (95%, 223/235). Of all patients, 75.3% (177/235) received treatment (consisting of 1 or any combination of antibiotics, NSAIDs, warm compresses), 24.7% (58/235) were treated with observation, 78.7% (185/235) returned for follow-up imaging, and 21.3% (50/235) were lost to follow-up. Of those with follow-up imaging, disease improvement was seen in 70.3% (102/145) of patients who received treatment compared with 72.5% (29/40) of patients treated by observation alone. Multivariate analysis further showed no difference in clinical outcomes among the treatment of unifocal, multifocal, or recurrent IGM.

Nonsteroidal treatment of IGM showed no significant improvement on follow-up imaging compared to treatment with observation alone in a predominantly Hispanic patient population.

Introduction: Idiopathic granulomatous mastitis (IGM) is a benign, chronic inflammatory disease with no effective treatment and high relapse rate. The pathophysiology is poorly understood. Tinosporin, an immunomodulator obtained from Tinospora cordifolia, is known to be useful in treating immune-mediated diseases. We report our experience of using Tinosporin for IGM and the effectiveness of this "steroid-free" regimen. Methods: We analysed the clinicopathological characteristics of patients diagnosed with IGM on histopathology during January 2018 and December 2022. Tinosporin tablet (500 mg Guduchi stem extract) was prescribed for 3-6 months; data were collected from electronic medical records and analysed in SPSS v-29. Results: Of 315 patients, 132 had complete clinical records. Median age was 39 years (25-77), and 107 (81.7%) were premenopausal. Seventy-eight (59.09%) had clinical suspicion of malignancy. On imaging, 84 (63.64%) were BIRADS 4/5 lesions. Empirical broad-spectrum antibiotics were prescribed to 101 patients. Tinosporin tablets were prescribed to 91 patients. Symptomatic response was seen in 72 (79.12%). Five patients did not achieve response, while 14 patients (15.38%) were lost to follow-up. At a median follow-up of 36 months (14-62 months), only 2 patients on Tinosporin had recurrence. None of the patients needed surgical intervention other than diagnostic biopsy or control of infection, and none received steroids. Conclusion: IGM is a benign, often self-limiting disorder. However, it mimics malignancy in 60% cases, and histology clinches the diagnosis. We report the efficacy of steroid-free management of IGM with immunomodulatory herbal origin phytopharmaceutical drug Tinosporin. It is safe, inexpensive and effective. Large volume excisions or mastectomies can be reserved for severe and refractory cases.

Introduction: Although idiopathic granulomatous mastitis (GM) of the breast is a benign condition, it can be locally aggressive and frequently chronic, causing significant pain and distress to the patient. Treatment often involves multiple disciplines including general practice, breast surgery/physicians, rheumatology and/or immunology. Traditional options for treatment include observation, oral steroids, methotrexate and/or surgery, all with variable outcomes. A more recent alternative treatment option involves intralesional steroid injections. Methods: Using PRISMA methodology, a systematic review of intralesional steroid injection for the management of GM was conducted. Medline, PubMed, Embase and Cochrane databases were searched for original studies reporting treatment protocols and clinical outcomes, published up to the end of September 2023. Results: Nine eligible studies reported outcomes in 474 patients undergoing treatment of GM with intralesional injections. All studies reported success (improvement in clinical and/or imaging appearance) with intralesional injections. Studies that had a comparison group showed statistically significantly fewer side effects compared to oral steroids or surgical management. The recurrence rate was less for intralesional injections than for other treatments in all studies except one. No studies included patient-reported outcomes. Conclusion: There is consistent evidence for the safety, efficacy and low recurrence rate with intralesional steroid injections for GM. The existing literature is heterogenous with respect to injection protocols, and the optimal protocol is unclear. Future research should compare the various steroid agents and dose/frequency of administration. Future studies should include cost analysis and patient-reported outcomes to ensure that the treatment is cost-effective and acceptable to people with idiopathic GM.

Idiopathic granulomatous mastitis (IGM) is a rare, chronic inflammatory, and benign breast disease. Its unclear etiology may involve autoimmune reactions, secretion-related factors, and microorganisms.

To analyze data from our IGM patient series and compare potential etiological factors.

We prospectively collected data using follow-up forms for patients diagnosed with IGM at our breast clinic from September 2014 to December 2020 and analyzed it retrospectively.

The study cohort included 220 patients, with a median age of 34 years (range: 20-58). A majority, 217 patients (98.6%), reported a history of breastfeeding, with a median duration of 36 months (range: 0-156). The median interval between the last breastfeeding session and disease onset was 25 (25th-75th percentiles: 15-44) months. Additionally, 116 patients (53.5%) reported breastfeeding-related problems. In 41 surgical patients, dense milky-brown debris in the breast ducts was noted. Although no independent seasonal fluctuations in disease onset were detected, a reduction in IGM cases during the summer months was found to correlate with a general decrease in all breast clinic visits.

Most patients reported recent breastfeeding and half experienced related problems, supporting the secretion theory's relevance in IGM's etiology. The absence of seasonal fluctuations suggests that secretion-related factors may be more central to IGM development than autoimmunity or infections. These findings offer crucial insights for future research into IGM's complex causes.

Idiopathic Granulomatous Mastitis is a rare benign inflammatory disease of the breast.

We present a case of 45-year-old woman who was diagnosed with stage II invasive ductal carcinoma in the left breast. While receiving neoadjuvant chemotherapy, she developed idiopathic granulomatous mastitis (IGM) in the left breast after the second cycle. She underwent modified radical mastectomy and has been managed with steroids for IGM on the contralateral side, which developed later in the course of the disease. This is a unique finding with limited literature available on similar cases, to the best of our knowledge.

IGM poses a diagnostic challenge requiring histopathology for definitive diagnosis.

Treatment guidelines of IGM are not established making it difficult to manage.

The systemic immune-inflammation index (SII) comprehensively reflects the balance between immune status and host inflammation. We aimed to investigate the potential predictive value of the SII in the prognosis of granulomatous mastitis (GM).

We enrolled 245 patients with GM who underwent surgery between 2015 and 2020 in this study. Using the receiver operating characteristic (ROC) curve, we divided the patients into low SII groups (SII≤836×109/L) and high SII groups (SII>836×109/L). The associations between SII and clinical parameters were assessed using chi-squared or Fisher's exact tests. Kaplan-Meier plots and Log rank tests were performed to investigate the clinical outcomes of cumulative no-recurrence rates. Risk factors were analyzed by using logistic regression analysis.

We found a correlation between the recurrence of GM and the preoperative level of SII, and the high SII group exhibited a higher recurrence rate than the low SII group. To further explore the factors affecting the risk of recurrence, we found that young age at disease onset, skin rupture, and the postoperative use of corticosteroids could increase the risk of GM recurrence. Multivariate logistic regression analysis suggested that young age and postoperative corticosteroid use were the risk factors for disease recurrence.

As a noninvasive and readily available clinical parameter, the preoperative SII level has great significance in evaluating the efficacy and prognosis of surgical treatment for GM combined with age and postoperative corticosteroid use, which provides valuable insights for making treatment decisions.

This study aims to analyse the imaging manifestations of granulomatous mastitis (GM) and invasive ductal carcinoma (IDC) using conventional ultrasound (US) and contrast-enhanced ultrasound (CEUS). The objective is to investigate the clinical value of CEUS in differentiating between GM and IDC.

We retrospectively enrolled 39 GM patients and 64 IDC patients between January 2020 and June 2023. All diagnoses were confirmed via core needle biopsy or surgical pathology. The characteristics of both conventional US and CEUS in these patients were analysed to distinguish GM from IDC.

Based on CEUS features, GM lesions most commonly presented as hypoechoic areas (43.6%), followed by pseudocysts (28.2%), hypoechoic nodules (15.4%), and honeycomb cysts (12.8%). The diffuse enhancement pattern was an independent characteristic for distinguishing GM from IDC, with the ROC analysis revealing an area under the curve (AUC) value of 0.794.

US is the preferred initial examination for GM, and both its conventional and CEUS features can enhance diagnostic accuracy and guide clinical treatment. CEUS demonstrates high differential diagnostic value in distinguishing GM from IDC.

This study categorizes GM manifestations on CEUS into four types, each corresponding to different pathological stages of GM. We identified that the diffuse enhancement pattern on CEUS is a distinctive characteristic associated with GM, aiding in its differentiation from IDC.

Idiopathic granulomatous mastitis (IGM) is a benign inflammatory condition predominantly affecting women of reproductive age, particularly those with a history of breastfeeding. Although the precise etiology remains unknown, treatment strategies continue to be a subject of debate. This study aimed to compare the efficacy of intralesional steroid (ILS) injections with oral steroid (OS) therapy in managing IGM.

A total of 72 patients, clinically and histopathologically diagnosed with IGM, were treated with either ILSs (group ILS, n = 47) or OSs (group OS, n = 25) at a tertiary referral hospital between January 2022 and January 2024. The data were retrospectively analyzed.

The mean age of the patients was 33.5 years (range: 22-56). No statistically significant differences were observed between the two groups in terms of demographic characteristics, presenting symptoms, clinical findings, or laboratory results. The mean treatment duration was 6 months. There were no significant differences in treatment response or recurrence rates between the two groups. However, there was a statistically significant difference in the incidence of side effects, with 6.3% in the ILS group compared to 36% in the OS group (p = 0.001).

Given its ease of application, lower incidence of side effects, and comparable efficacy, ILS injections may be considered a first-line treatment option in the management of IGM.

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.

Idiopathic granulomatous mastitis (IGM) is a rare, benign, inflammatory breast disorder of unknown aetiology usually affecting women of reproductive age. It classically presents as a unilateral painful breast mass. It is frequently mistaken for carcinoma or other inflammatory breast diseases. Diagnostic investigations include clinical examination, appropriate imaging and tissue sampling. A link between IGM and infection with the Corynebacterium species in particular Corynebacterium kroppenstedtii has been described.

A retrospective single-centre cohort study was conducted over a 5-year period (2017-2022); all cases of IGM were identified.

Forty-one patients were diagnosed with IGM. Breast lump was the most common presenting complaint (n=29). The average age was 45 years. Eighteen patients had samples sent for culture and sensitivity, 11 of which had positive microbiology results indicative of Corynebacterium spp infection.An 82% resolution rate (27 of 33) was recorded in those who received either a short-antibiotic course or none at all. Eight patients reported persistent disease at 3 months, five of which had evidence of Corynebacterium spp.

This 5-year review highlights the impact of IGM in a tertiary centre in Dublin, Ireland. Although no treatment guidelines exist, options include antibiotics, immunomodulators and surgery. Due to risk of fistulae and unfavourable cosmetic outcomes, surgery should be reserved for refractory IGM. We suspect that there may be a subset of patients where prolonged antibiotic therapy should be considered. Defining this subgroup requires further study, but likely includes those with cystic neutrophilic granulomatous mastitis, relapsing disease and in whom Corynebacterium spp is recovered.

Granulomatous mastitis is a relatively rare benign inflammatory disease of the breast, but it is sometimes difficult to distinguish from breast cancer by imaging. We experienced a case that was definitively diagnosed as granulomatous mastitis from the surgical specimen. The mass appeared as a large cystic lesion on imaging, which is unusual for granulomatous mastitis, and was initially suspected to be an encapsulated papillary carcinoma.

A 43-year-old woman presented with a painful mass in her right breast. Ultrasonography revealed a cystic mass lesion with internal solid components, with partially indistinct cyst walls and abundant blood flow. Additionally, lymphadenopathy of one axillary lymph node was observed. Magnetic resonance imaging findings showed irregularly spreading enhanced nodules within the cystic lesion, raising the suspicion of encapsulated papillary carcinoma. Although the histological findings from a needle biopsy were consistent with granulomatous mastitis, the possibility of malignancy could not be ruled out based on imaging, prompting a diagnostic probe lumpectomy. However, the surgical specimens did not reveal any tumorous lesions, and we reached a final diagnosis of granulomatous mastitis. Postoperatively, the patient was followed-up without steroid therapy and has been free from recurrence of mastitis for 22 months after surgery.

We report a case of granulomatous mastitis that was detected as a large cystic lesion with a well-defined border on imaging and a definitive diagnosis was made from a surgical specimen.

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.

This systematic review aimed to summarize the evidence and evaluate the efficacy of DMARDs in the management of IGM.

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.

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.

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.

Granulomatous mastitis is a chronic inflammation of the breast, mostly of unknown etiology. The treatment would be definitive if the causative organism were isolated. It is characterized histologically by granulomas, formed mostly by polymorph nuclear neutrophils and central necrosis. Herein, we report a 46-year-old woman who presented with a non-responding to treatment right breast abscess of six months duration. The abscess was associated with multiple fistula formation. Radiological investigations were inconclusive. She needed incision and drainage many times. The diagnosis of granulomatous mastitis secondary to sporotrichosis can only be made after breast tissue biopsy and culture. She was started on itraconazole. She responded slowly and later needed resection of the remaining mass.

Oral corticosteroids represents the most prevalent treatment for idiopathic granulomatous mastitis. Ductal lavage with triamcinolone acetonide and antibiotics followed by observation (DL-OBS) has emerged as a novel strategy, but a comparison of them remains lacking. Here in this multicenter, open-label, non-inferiority, randomized trial (ClinicalTrials.gov identifier: NCT03724903), we assigned 140 patients to oral corticosteroids (N = 71) and DL-OBS (N = 69), stratified by baseline M-score. The primary outcome is complete Clinical Response rate at 1 year. The non-inferiority margin is -15%. The primary outcome is 85.5% in DL-OBS and 87.3% in oral corticosteroids (difference: -1.8%; 95%CI, 13.2 to 9.5; Pnon-inferiority = .01) in intention-to-treat population, and 92.6% vs 98.2% (difference -5.6%; 95%CI -13.4 to 2.2; Pnon-inferiority = .01) in per-protocol population, respectively. The most common (>15%) adverse events were Cushingoid, epigastric pain and arthralgia in oral corticosteroids, and irregular menstruation in DL-OBS, respectively. Here, we report that DL-OBS shows similar efficacy to oral corticosteroids but with better safety profile.

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.

Objective: The study aimed to use the systemic lupus erythematosus risk probability index (SLERPI) to assess if patients with idiopathic granulomatous mastitis (IGM) meet the criteria for systemic lupus erythematosus (SLE). Methods: A total of 62 patients with IGM and 55 age- and sex-matched healthy controls (HC) were enrolled. The study included patients who were over 18 years old and had been diagnosed with IGM using a true-cut biopsy. The participants' demographic, clinical, and laboratory data were recorded in detail. The presence of autoantibodies, such as RF, CCP, C3, C4, ANA, ENA profile, and Anti-dsDNA was documented. For the detection of SLE in IGM patients, we used the SLERPI (SLE risk probability index). Results: A total of 62 patients diagnosed with idiopathic granulomatous mastitis (age 35.22 ± 8.34, BMI 27.15 ± 3.41) were compared to 55 healthy controls (age 32.54 ± 8.67, BMI 26.97 ± 3.54). The present study assessed the performance of SLERPI in IGM, and SLERPI positivity was observed in 12 out of 62 (19.4%) IGM patients. There was a significant difference in arthritis and ANA levels in the SLERPI subgroups (p < 001). Conclusions: The SLERPI index can be utilized to identify patients suspected of having systemic lupus erythematosus (SLE) in the IGM cohort.

Patients with clinically cured granulomatous lobular mastitis (GLM) still face a high probability of recurrence and new occurrence.

To evaluate the long-term efficacy of traditional Chinese medicine (TCM) in treating GLM and to hypothesize potential risk factors for recurrence or new occurrence.

A retrospective analysis was conducted on GLM patients treated with TCM at Longhua Hospital affiliated with Shanghai University of Traditional Chinese Medicine from January 2016 to July 2021. We analyzed general data, two-year recurrence and new occurrence rates, and 12 risk factors associated with recurrence or new occurrence.

This cross-sectional study included 261 GLM patients with an average age at onset of 31.95 years (primarily aged 31-40). The two-year recurrence rate for GLM was 1.53%, and the new occurrence rate was 4.21%. Univariate and multivariate conditional logistic regression analyses revealed that a history of inverted nipples was associated with the risk of both recurrence and new occurrence of GLM (HR = 8.672, 5.375, P < 0.05), and menstrual irregularity was related to a higher risk of recurrence (HR = 13.172, P < 0.001).

A history of inverted nipples is identified as a potential risk factor associated with the long-term recurrence and new occurrence of GLM, while menstrual irregularity is associated with recurrence. Despite this, patients with GLM undergoing TCM demonstrate low rates of long-term recurrence and new occurrence after achieving clinical cure, underscoring the effectiveness of TCM. This study lays the groundwork for a long-term effectiveness strategy to guide future GLM treatments.

Granulomatous lobular mastitis (GLM) is a rare benign breast inflammatory disease that affects women of childbearing age. Corynebacterium species, especially Corynebacterium kroppenstedtii, was reported as the pathogen of GLM. A recent study showed that the C. kroppenstedtii complex is composed of C. kroppenstedtii and two novel species, C. parakroppenstedtii and C. pseudokroppenstedtii. The study presents seven C. kroppenstedtii-like strains isolated from GLM patients. However, they turned out to be six strains of C. parakroppenstedtii and one strain of C. pseudokroppenstedtii according to 16sRNA sequencing. In order to conduct a phylogenetic study, we further sequenced the fusA and rpoB genes, which were frequently employed in studies of Corynebacterium species. Novel Mass Spectral Peaks (MSPs) for C. parakroppenstedtii were created with Bruker MALDI-TOF MS. Then, the identification power of the MSPs was tested by C. parakroppenstedtii strains and remotely related Corynebacterum spp. The antibiotic sensitivity tests were performed according to the CLSI M45 guidelines. All of the strains were not resistant to β-lactams, vancomycin or linezolid. However, applying erythromycin and clindamycin could be fruitless. Phenotypic identification using a Vitek2 ANC ID card proved all of the C. parakroppenstedtii strains were identified as Actinomycete naeslundii. The test of Ala-Phe-Pro arylamidase and urease could be employed as the characteristics to distinguish C. pseudokroppenstedtii from C. parakroppenstedtii. Here, we present the identification, antibiotic sensitivity tests (ASTs) and epidemiological investigation of two novel C. kroppenstedtii-like species with the purpose of improving the understanding of C. kroppenstedtii-like species and related diseases.

Idiopathic granulomatous mastitis (IGM) is a rare, benign inflammatory breast condition often mistaken for inflammatory breast cancer and, therefore, requires a biopsy for accurate diagnosis. Although not cancerous, IGM can cause emotional distress because of severe pain and ensuing breast deformity. Differentiating IGM from other breast inflammations caused by infections is essential. IGM mostly affects premenopausal women and is potentially associated with recent pregnancies and breastfeeding. The risk factors, including smoking and contraceptive use, have inconsistent associations. Steroid responses suggest an autoimmune component, though specific markers are lacking.

We performed a narrative review on potential risk factors, diagnostics, and therapy of IGM.

Diagnostics and clinical management of IGM are challenging. The treatment options include NSAIDs, steroids, surgery, antibiotics, immunosuppressants, prolactin suppressants, and observation, each with varying effectiveness and side effects.

Current IGM treatment evidence is limited, based on case reports and small series. There is no consensus on the optimal management strategy for this disease. The GRAMAREG study by the EUBREAST Study Group aims to collect comprehensive data on IGM to improve diagnostic and treatment guidelines. By enrolling patients with confirmed IGM, the study seeks to develop evidence-based recommendations, enhancing patient care and understanding of this condition.

Granulomatous mastitis (GM) is an uncommon, chronic inflammatory breast disease, mostly idiopathic. Occasionally, the causative organism is isolated. It is characterized histologically by polymorph nuclear neutrophils' predominance and the absence of caseous necrosis. Idiopathic GM could be associated with other general conditions like autoimmune disorders, diabetes mellitus, and sarcoidosis. We report a case of a 41-year-old woman who presented with a left breast abscess of two weeks duration and a three-year history of intermittent attacks of painful breast swelling, which required multiple and extended empirical courses of antibiotics. Diagnosis as GM caused by Hafnia alvei bacteria was only confirmed by biopsy of the inflammatory mass and culture of the pus. The course of treatment was over three years, with three relapses.

This study focuses on granulomatous mastitis (GM), a rare inflammatory condition of the breast that has been increasingly diagnosed over the recent years. This research attempts to understand the incidence and prevalence of GM and its treatments.

This is a retrospective study over 9 y (January 2015-December 2023). We utilized the anonymized data collected by TriNetX Analytic Network, a global federated health research network. The database was queried for patients diagnosed with GM and 3058 patients were returned. The incidence and prevalence of GM by age, race, and ethnicity were analyzed. The most common treatments for GM (antibiotics, steroids, incision and drainage, breast excision, and methotrexate) were analyzed.

Hispanic and Latinos have a six-fold increased likelihood of developing GM compared to their non-Hispanic and non-Latino counterparts (0.006% compared to 0.001%). Treatment approaches reveal that antibiotics are the primary choice, while methotrexate is less commonly used. Antibiotics showed no significant differences between Hispanics and Latinos when compared to non-Hispanics and non-Latinos. Steroids showed a decreased prevalence in Hispanics and Latinos (P < 0.05). Incision and drainage showed an increased incidence in Hispanics and Latinos (P < 0.05). Excision showed no significant differences between the two groups. Methotrexate showed a higher incidence of usage among Hispanics and Latinos (P < 0.05).

GM has the highest incidence and prevalence among Hispanics and Latinos. Despite that, the treatments do not directly reflect these differences which underscore the need for personalized treatment strategies, particularly among Hispanic or Latino populations, and underscores the importance of further research to elucidate contributing factors to these differences.

The aim of the idiopathic granulomatous mastitis (IGM) consensus study was to evaluate the etiology, diagnostic steps, and differential diagnosis and propose a widely accepted clinical classification of this mysterious breast disease.

The organization of a national IGM consensus was decided by the joint evaluation of the Turkish Federation of Breast Diseases Societies, SENATURK, and the Society of Breast Surgery. First, a working group of 11 members was formed, and a survey and workshop were organized to reach a common consensus. The modified Delphi method was used in the consensus methodology. Voting rates of 80% and above were considered as acceptance.

The consensus was 45/50 (92%) that core needle biopsies are necessary for the diagnosis of IGM and 39/40 (97%) that a new clinical classification is needed. The proposed Turkish clinical classification of IGM was accepted by 94% in three rounds of voting.

This disease should be considered etiologically idiopathic. Tissue diagnosis and pathological evaluation are recommended for treatment. The proposed IGM Turkey classification was strongly accepted.

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.

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.

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).

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.

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.

Idiopathic granulomatous mastitis (IGM) is a benign inflammatory breast disease, commonly presented with a sensitive breast lump and developing scars. Currently, there is no definitive treatment for IGM but Antibiotics, steroids, immunosuppressive drugs or a surgical treatments are the usual options. This case series aimed to evaluate the effectiveness of cotrimoxazole in treatment of IGM as there is no clinical consensus on the best and most widely acknowledged therapeutic management for IGM.

All IGM patients were treated by Cotrimoxazole (800 mg BD for one week), and they were assessed at a month, 3 months, and 6 months after that. The primary outcome was an improvement in presenting complaints and symptoms such as palpable mass, bulging, pain, erythema and hypersensitivity of breast skin, breast discharge and fluctuation. The secondary outcome was the refractory rate within 6 months. Number of 20 patients were included. At the baseline, participants exhibited various symptoms such as bulging, pain and erythema (100 %), breast discharge (80 %), and fluctuation (30 %). After the intervention, there was a significant decrease in the prevalence of symptoms over the study period. The prevalence of bulging and pain, erythema, discharge, and fluctuation symptoms were decreasedto 5 %, 0 %, and 0 %, respectively. The refractory rate of IGM within six months of cotrimoxazole treatment was estimated 30 %.

In this study, the treatment approach did not involve corticosteroids and invasive procedures and the recurrence rate of IGM within the six months was lower than in similar studies that employed steroids alone or any more invasive treatments. Additionally, our study showed a high healing rate with resolution of inflammation, pain, discharge, and fluctuation. These results suggest that cotrimoxazole may be a more favorable option than high-dose corticosteroids and a comparable alternative to low-dose corticosteroids regarding recurrence rates.

Cotrimoxazole may be an effective treatment option for idiopathic granulomatous mastitis. However, further research is needed on different treatment options.

Granulomatous mastitis (GM) is a rare, benign inflammatory breast disease that predominantly affects women of childbearing age and often mimics breast carcinoma. The diagnosis requires histopathological examination due to nonspecific imaging findings. Treatment includes antibiotics, corticosteroids, and surgery, but no standardized protocols exist. This autobiographical case report describes a 34-year-old woman with a tender breast lump following trauma, initially misdiagnosed as a simple abscess. Despite incision and drainage, she developed erythema nodosum, persistent fever, and arthritis, which responded to corticosteroids. Further investigation, including an ultrasound-guided biopsy and MRI, confirmed GM. Recurrent symptoms were managed with prednisolone and doxycycline, leading to significant improvement. This case report aims to highlight the diagnostic challenges associated with GM, emphasizing the necessity for a detailed histopathological examination to achieve an accurate diagnosis. It also brings attention to the significant emotional impact on patients facing a rare and complex diagnosis. By presenting this case, we aim to highlight the critical importance of a comprehensive and multidisciplinary approach to patient care in managing GM effectively.

Idiopathic granulomatous mastitis (IGM) is an inflammatory-mediated rare disease that can be linked to rare manifestations. Erythema nodosum (EN) and polyarthritis, seen in a multitude of autoinflammatory and autoimmune diseases, have been rarely linked to IGM. Despite the cause of IGM being unclear, Corynebacterium infections are thought to play a role in the pathophysiology of IGM. Unusually, IGM has a relapsing and remitting course, which also applies to its systemic manifestations. As such, we present a case of IGM in a middle-aged lady who was initially thought to have Corynebacterium-containing unilateral abscesses for which drainage was performed. However, several abscesses devoid of bacterial growth started recurring, and the disease course was complicated by EN and polyarthritis. IGM, EN, and polyarthritis eventually resolved and were managed with symptomatic treatment.

Idiopathic granulomatous mastitis (IGM), a recurrent inflammation disease of the non-lactating breast, has had an increasing clinical morbidity rate in recent years, and its complicated symptoms and unclear etiology make it challenging to treat. This rare benign inflammatory breast disease, centered on the lobules, represents the most challenging type of non-puerperal mastitis (NPM), also known as non-lactating mastitis. In this study, patients diagnosed with IGM (M, n = 23) were recruited as cases, and patients with benign control breast disease (C, n = 17) were enrolled as controls. Cytokine microarray detection measured and analyzed the differentially expressed cytokine factors between IGM and control patients. Then, we verified the mRNA and protein expression levels of the significantly changed cytokine factors using Q-RT-PCR, ELISA, western blot, and IHC experiments. The cytokine factor expression levels significantly changed compared to the control group. We observed a significant increase between IGM and control patients in cytokine factors expression, such as interleukin-1β (IL-1β), monokine induced by gamma interferon (MIG), macrophage inflammatory protein (MIP)-1α, MIP-1β, tumor necrosis factor receptor 2 (TNF RII). Then, we verified the expression of these top five dysregulated factors in both mRNA and protein levels. Our results demonstrated the cytokine map in IGM and indicated that several cytokines, especially chemokines, were associated with and significantly dysregulated in IGM tissues compared to the control group. The chemokine factors involved might be essential in developing and treating IGM. These findings would be helpful for a better understanding of IGM and offer valuable insights for devising novel diagnostic and therapeutic strategies.

The BIRADS lexicon ensures a standard reporting terminology in breast imaging and serves as a means of smooth communication between the radiologist and the referring physician. BIRADS assessment categories 4 and 5 warrant a biopsy to rule out underlying malignancy. However, a substantial number of cases in these categories sometimes turn out to be benign on biopsy. These benign mimics encompass inflammatory, sclerosing, neoplastic and a few other miscellaneous conditions. Awareness of these various mimics of breast cancer can equip the radiologist to handle these apparent cases of radiologic-pathological (rad-path) discordance better, guide overall patient management, avoiding inadvertent excisional biopsies and help alleviate patient anxiety and confusion.

Granulomatous lobular mastitis (GLM) is a rare, benign inflammatory disease of the breast that shares some physical diagnostic features with breast cancer. GLM has been rarely reported to be associated with prolactinoma. In this report, we present a case of undiagnosed prolactinoma in a 37-year-old woman with its initial presentation as GLM. We discuss the underlying pathophysiologic mechanisms for the development of GLM and the potential immunomodulatory role of prolactin in the development of GLM. We also highlight the need to assess for possible prolactinoma in GLM, which might go undiagnosed as in the case of our patient who did not seek medical attention for her amenorrhea, which is likely due to hyperprolactinemia that might also have other clinical implications on cardiovascular and bone health due to consequent estrogen deficiency.

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.

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.

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.

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.

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.

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.

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.

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.