Granulomatous Mastitis Research Articles

EP363 - Idiopathic Granulomatous Mastits

Abstract Aim Idiopathic granulomatous mastitis (IGM) of breast is a rare condition with unknown aetiology with an incidence of 2.4 per 10,000. Treating this condition has often been a challenge and hence, this study aims at comparing the different treatment outcomes of recurrent IGM. Method A prospective study was conducted in our hospital. All the recurrent breast abscess with induration and biopsy proven granulomatous mastitis were included in this study for a study period of 2 years. Result 12 patients were included in the study and were divided into two groups : recurrent breast abscess with induration of size A) less than 3 cms and B) ones with size more than 3 cms. Patients in group A underwent Wide local excision of the abscess along with induration and patients in group B underwent surgery followed by steroid therapy. Both the groups were followed up for a year and group B showed no recurrence while group A came with recurrent abscess again and had to undergo surgery followed by steroid therapy after which no recurrence was seen after one year follow up. Conclusion All patients of IGM require steroid therapy along with surgery for better outcome.

Idiopathic Granulomatous Mastitis: Imaging Findings and Outcomes with Nonsteroidal Treatment in a Predominantly Hispanic Population.

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.

False Alarms: The Intriguing Cases of Granulomatous Mastitis Mimicking Malignancy along with Review of the Literature

Abstract Background: Granulomatous mastitis is a rare and challenging condition that can mimic malignancy in the breast. This condition often presents with clinical and radiological features that overlap with those of breast cancer, making it difficult to differentiate between the two based solely on clinical assessment. Aims and Objective: The objective of this study is to highlight the diagnostic dilemmas, the clinico-pathological profile of such cases and what enables a correct diagnosis in such cases. Materials and Methods: A retrospective study of 5 patients with histologically proven granulomatous mastitis attending OPD/IPD at a tertiary care center in south India during a period of 18 months from Jan 2022 – Jul 23. We present five cases of granulomatous mastitis highlighting the inconsistency of the clinical, imaging and initial biopsy findings, briefly review the relevant literature and discuss the challenges associated with its diagnosis. Results and Conclusion: This study highlights the importance of awareness of granulomatous mastitis and its clinicopathological characterstics. The study also emphasizes that a multidisciplinary approach involving Surgeons, radiologists, pathologists, and medical oncologists is crucial to accurately diagnose and manage this condition. Review of literature revealed few studies highlighting the clinic-radiological and histopathological profile of such cases of granulomatous mastitis mimicking malignancy however such studies are far less and encompass only isolated single case reports or occasional series of 2-3 cases. To our knowledge this is one of the largest case series with 5 cases highlighting the clinicopathological details and the diagnostic dilemmas.

Diagnostic Efficacy of Multimodal Ultrasound for Mass and Non-Mass Enhancements in Dynamic Contrast-Enhanced MRI of Idiopathic Granulomatous Mastitis and Breast Cancer

PurposeIdiopathic granulomatous mastitis (IGM) poses diagnostic challenges due to its diverse clinical and radiological presentations, often mimicking malignancies. This study aimed to assess the diagnostic efficacy of multimodal ultrasound for mass and non-mass enhancements in Dynamic Contrast-Enhanced MRI (DCE-MRI) of IGM and breast cancer. MethodsA retrospective analysis involved patients confirmed histopathologically with IGM and BC. All patients underwent conventional ultrasound (C-US), ultrasound elastography (UE), contrast-enhanced ultrasound (CEUS), and DCE-MR examinations. Blind experienced radiologists assessed imaging findings. Diagnostic accuracy, sensitivity, and specificity were calculated for mass and non-mass enhancements. ResultsFor mass enhancements (ME), multimodal ultrasound demonstrated strong efficacy (AUC = 0.8651, 95% CI: 0.7431 to 0.9871), exhibiting high sensitivity (83.3%) and specificity (92.4%) in differentiating IGM from breast cancer. However, for non-mass enhancements (NME), multimodal ultrasound showed limited accuracy (AUC = 0.6306) with lower sensitivity (65.6%) and specificity (81.2%) in distinguishing between IGM and breast cancer. ConclusionMultimodal ultrasound displayed good diagnostic efficacy for mass enhancements in DCE-MRI for idiopathic granulomatous mastitis and breast cancer, while for non-mass enhancement patterns, DCE-MRI remains the most valuable radiological modality for comprehensively assessing this condition's complexities.

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

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

Imaging Enigma in Mastitis: A Comprehensive study of Multifaceted Causes, Clinical and Radiological Presentations

Mastitis is an inflammatory condition of the breast which represents an array of underlying etiologies encompassing both infectious and non-infectious causes. Exacerbating factors include endemic infections, lack of awareness and suboptimal breastfeeding practices. Neglected cases lead to prolonged morbidity, recurrent episodes, and complications such as abscess or sinus formation, resulting in permanent breast disfigurement. Its overlapping clinical presentation with breast cancer necessitates an integrated multidisciplinary approach for diagnosis and treatment. The primary aim was to investigate demographic, radiological, and histopathological characteristics of mastitis. Objectives included correlating radiological and histopathological findings, classifying mastitis by etiology, identifying the clinical and imaging patterns across diverse clinical settings to enhance the understanding of mastitis. This is a retrospective observational study, analysing the clinical, radiological, and histopathological data from 65 patients with mastitis between February 2023 and February 2024. The study included 65 patients, aged 18 to 65 years, with breast pain as the most prevalent clinical presentation. Cases were classified as infectious (47.6%) and non-infectious (52%). Acute puerperal mastitis (26.15%) and granulomatous mastitis (30%) were the most common subtypes. The commonest mammographic finding was focal asymmetry. On ultrasound, infectious mastitis showed oedema with other inflammatory changes, including diffuse skin thickening and collections; while non-infectious mastitis typically presented as solitary or multiple breast masses (p < 0.001). Surprisingly, idiopathic granulomatous mastitis constituted the largest percentage amongst various histopathological causes of mastitis in our study. An integrated multidisciplinary approach with understanding of the pathogenesis is imperative for prompt diagnosis and optimizing treatment strategies, thereby improving patient outcome. Radiological imaging is critical for diagnosis, evaluating disease extent, conducting guided interventions, and monitoring treatment response.

Idiopathic Granulomatous Mastitis: A Retrospective Cohort Study of Treatment Modalities in 83 Patients From Southern Thailand

Objective: Idiopathic granulomatous mastitis (IGM) is a rare condition that mimics breast cancer. Current treatment strategies include both surgical and medical therapy. This study aimed to report and describe the clinical signs, radiological findings, management, clinical course, and outcomes after treatment of IGM, from a major tertiary care institute in southern Thailand.Material and Methods: The medical records of 83 patients with IGM treated at our institute between January 2001 and April 2022 were retrospectively studied. Patient characteristics, clinical presentations, radiological findings, microbiological workups, tissue pathologies, treatment modalities, outcomes and follow-up data were reviewed and analyzed. The success rate, recurrence rate, and time to heal were compared between the different treatment modalities. Results: Overall, 83 patients were diagnosed with IGM. Due to insufficient follow-up periods, data from only 50 patients were used for the analysis. Initially, 34,3,8, and 5 were treated surgically, with steroids, anti-tuberculosis (TB) drugs, or other treatments, respectively; 32 (64%) achieved disease resolution. The median time to heal was 472 days, while the median time to heal after surgery, steroid therapy, anti-TB therapy, and others was 614.5, 333, 208.5, and 406 days, respectively. Surgery resulted in the longest time to heal; however, the difference was not statistically significant (p-value=0.23). Eighteen (36%) patients experienced recurrence.Conclusion: There was no significant difference among the treatment modalities in terms of time to heal and recurrence. Surgery resulted in the longest healing time, the highest incidence of complications, and a recurrence rate of approximately 50%. Surgical treatment should be reserved for aggressive diseases.

Granulomatous mastitis and other inflammatory mastitis simulating breast neoplasms – A retrospective study in the fine needle aspiration cytology clinic of a tertiary care center in eastern India

Background: Fine needle aspiration cytology (FNAC) is an important diagnostic modality in palpable breast lesions. This together with imaging modality is important in distinguishing benign from malignant lesions of the breast. Granulomatous/inflammatory mastitis forms a small subset of breast lesions that may present as a breast lump. Clinical and radiological features in these cases may mimic malignant breast pathology. Aims and Objectives: The aim of this study was to study the frequency of granulomatous mastitis and other inflammatory mastitis with respect to other neoplastic lesions of the breast, presented in FNAC clinics and to correlate the cytological findings with the clinical presentation of granulomatous and other inflammatory mastitis. Materials and Methods: A retrospective study was conducted in the Department of Pathology in a tertiary care center in Eastern India for duration of 4 years 5 months. Details of all patients who underwent FNAC for breast lesions during the study period were recorded in terms of their clinical presentation, cytological findings, imaging, and ancillary investigations. The findings were then tabulated in a master sheet and analysis done by descriptive statistics using SPSS 25. Results: A total of 154 cases were included with 5 cases (3.2%) of granulomatous and 12 cases (7.8%) of inflammatory mastitis. Age range for granulomatous/inflammatory mastitis was 20–70 years. Lump and pain were the most common complaints followed by inflammatory skin changes and nipple discharge. Very few cases also showed nipple retractions and very occasional systemic symptoms like fever. History of lactation was seen among five cases. Three cases showed positive acid-fast bacilli in Ziehl–Neelsen stain. Radiology was discordant with cytological findings in three cases, where the former suggested a breast neoplastic process. Conclusion: Granulomatous/inflammatory mastitis is a rarely diagnosed entity in breast cytopathology with no standard guidelines for management. Antibiotics antitubercular therapy and corticosteroids are some proposed lines of medical management. In treatment-resistant cases, wide local excision may be done depending on available resources and surveillance opportunities.

The role of tissue IgG4 levels in steroid therapy in patients with idiopathic granulomatous mastitis

Idiopathic granulomatous mastitis (IGM) is a benign, chronic inflammatory lesion of the breast. Immunoglobulin G4 (IgG4) associated disease is rare in the breast. In our study, we aimed to evaluate the efficacy of steroid treatment on IgG4 levels in tissue in patients diagnosed with IGM. Between 2008 and 2017, 55 patients diagnosed with IGM in our clinic were included in the study. Demographic, clinical, microbiologic and histopathologic characteristics, treatment modality and recovery time were evaluated retrospectively. Patients were divided into 3 groups according to tissue IgG4 levels: negative (Group I), infrequently and slightly positive (Group II), and highly positive (Group III). Group I patients had a complete response rate of 77.8%. In the rest of the patients (22.2%), insufficient response was detected from the beginning of the treatment. In Group II, the response rate was 91.3% and the permanent success rate after treatment was 87.0%. Although group III patients had a complete response at the beginning (95.65%), they relapsed in a short period of time (26.1%) after discontinuation of steroid treatment. At least one steroid-related side effect was observed in 47 (85.8%) patients in all groups. There is no consensus on the dose and duration of immunosuppressive treatment in IGM. In this study, responses to steroid treatment according to IgG4 concentration in pathologic breast tissue and recurrences after the end of treatment were determined. We think that high IgG4 concentration in the tissue is associated with recurrence and other immunosuppressive drugs should be added as maintenance after steroid treatment.

ASO Visual Abstract: Presentation and Management of Granulomatous Mastitis in the United States-Results of an American Society of Breast Surgeons Registry Study.

ASO Visual Abstract: Presentation and Management of Granulomatous Mastitis in the United States-Results of an American Society of Breast Surgeons Registry Study.

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

BackgroundGranulomatous mastitis (GM) is a benign, chronic, inflammatory disease lacking clear treatment guidelines. The purpose of this American Society of Breast Surgeons (ASBrS) prospective, multisite registry was to characterize the presentation of GM and identify treatment strategies associated with symptom resolution and optimal cosmesis.MethodsASBrS members entered data into a registry on patient demographics, treatment, symptoms, and cosmesis over a 1-year period. Initial symptoms were graded as mild, moderate, or severe. The Chi-square test and logistic regression were used to identify factors related to symptom improvement and cosmesis.ResultsOverall, 112 patients with a mean age of 36 years were included. More patients were Hispanic (49.1%) and from the Southwest (41.1%), and management included observation (4.5%), medical (70.5%), surgical (5.4%), or combination treatment (19.6%). Immunosuppression was used in 83 patients (74.1%), including 43 patients who received intralesional steroid injections. Patients with severe symptoms were more likely to undergo surgical intervention compared with those with mild or moderate symptoms (21.4% vs. 0% and 7.5%, respectively; p = 0.004). Within 1 year, 85 patients (75.9%) experienced symptom improvement and/or resolution at a median of 3 months. Receipt of immunosuppressive therapy was predictive of improvement or resolution at 1 month (odds ratio 4.22; p = 0.045). One-year physician-assessed cosmesis was excellent or good for 20/35 patients (57.1%) and was not associated with type of treatment or symptom severity.ConclusionAlthough GM can have a protracted course, the majority of patients in this registry resolved within 1 year, with good cosmetic result. Treatment with immunosuppression appears to be most beneficial, and a symptom-based algorithm may be helpful to guide treatment.

The impact of cotrimoxazole in idiopathic granulomatous mastitis treatment

Introduction and importanceIdiopathic 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. Case presentationAll 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 %. Clinical discussionIn 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. ConclusionCotrimoxazole may be an effective treatment option for idiopathic granulomatous mastitis. However, further research is needed on different treatment options.

Evaluation of significantly changed chemokine factors of idiopathic granulomatous mastitis in non‐puerperal patients

AbstractIdiopathic 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.

Rare and Complicated Granulomatous Lobular Mastitis (2000-2023): A Bibliometrics Study and Visualization Analysis.

Granulomatous mastitis (GLM) is a rare and complex chronic inflammatory disease of the breast with an unknown cause and a tendency to recur. As medical science advances, the cause, treatment strategies, and comprehensive management of GLM have increasingly attracted widespread attention. The aim of this study is to assess the development trends and research focal points in the GLM field over the past 24 years using bibliometric analysis. Using GLM, Granulomatous mastitis (GM), Idiopathic granulomatous lobular mastitis (IGLM), and Idiopathic granulomatous mastitis (IGM) as keywords, we retrieved publications related to GLM from 2000 to 2023 from the Web of Science, excluding articles irrelevant to this study. Citespace and VOSviewer were employed for data analysis and visualization. A total of 347 publications were included in this analysis. Over the past 24 years, the number of publications has steadily increased, with Turkey being the leading contributor in terms of publications and citations. The University of Health Sciences, Istanbul University, and Istanbul University Cerrahpasa were the most influential institutions. The Breast Journal, Breast Care, and Journal of Investigative Surgery were the journals that published the most on this topic. The research primarily focused on the cause, differential diagnosis, treatment, and comprehensive management of GLM. Issues related to recurrence, hyperprolactinemia, and Corynebacterium emerged as current research hotspots. Our bibliometric study outlines the historical development of the GLM field and identifies recent research focuses and trends, which may aid researchers in identifying research hotspots and directions, thereby advancing the study of GLM.

Comparison of Fine Needle Aspiration and Core Needle Biopsy in Diagnosis of Granulomatous Mastitis Presenting with Breast Lump

Granulomatous mastitis is a chronic inflammatory disease of the breast with unknown etiology mostly seen in parous women shortly after their last pregnancy. It is crucial to differentiate granulomatous mastitis from cancer and definite diagnosis is established by histopathological examination. Its treatment is variable and the most appropriate treatment protocol is yet to be identified. Aim of the study was to compare the performances of fine needle aspiration and Core biopsy of breast lump verified by histopathological examination as “Gold standard”. 227 women presenting with breast lump were included in this study. After selection, fine needle aspiration and core biopsy were done at same sitting and follow-up resection histopathology with 122 cases (53.74%) were performed in the laboratory. 40(17.62%) cases were diagnosed granulomatous mastitis by either fine needle aspiration or core biopsy, the reports of 23 cases (57.5%) were concordant in both the procedures and discrepancy was observed in reporting of 17 cases (42.5%). 36 cases (90%) were resected for histopathology and 33 (82.5%) breast lumps were diagnosed granulomatous mastitis. Diagnostic accuracy, sensitivity, specificity, negative and positive predictive values of fine needle aspiration cytology and Core biopsy were calculated. The diagnostic accuracy of core biopsy was 97.54% and that of fine needle aspiration cytology was 89.34%. Specificity, sensitivity, positive and negative predictive values of core biopsy were 97.77%, 97.29%, 94.73% and 98.87% respectively. The specificity, sensitivity, positive and negative predictive values of fine needle aspiration were 97.77%, 70.27%, 92.85% and 88.88% respectively. The accuracy of core biopsy was much higher than that of fine needle aspiration and also the performances of the combination of two procedures were superior to the individual test alone.

General practitioners’ management of mastitis in breastfeeding women: a mixed method study in Australia

BackgroundMastitis is a common reason new mothers visit their general practitioner (GP). In Australia, the Therapeutic Guidelines: Antibiotic provides practical advice to GPs managing a range of infections, including mastitis. It is not known if Australian GPs prescribe antibiotics and order investigations as recommended for the management of mastitis.MethodsA convergent mixed methods design integrated quantitative analysis of a general practice dataset with analysis of interviews with GPs. Using the large-scale primary care dataset, MedicineInsight, (2021–2022), antibiotics prescribed and investigations ordered for mastitis encounters were extracted. Mastitis encounters were identified by searching ‘Encounter reason’, ‘Test reason’ and ‘Prescription reason’ free text field for the term ‘mastitis’; ‘granulomatous mastitis’ was excluded. Clinical encounters for mastitis occurring within 14 days of a previous mastitis encounter were defined as belonging to the same treatment episode. Semi-structured interviews were conducted with 14 Australian GPs using Zoom or telephone in 2021–2022, and analysed thematically. The Pillar Integration Process was used to develop a joint display table; qualitative codes and themes were matched with the quantitative items to illustrate similarities/contrasts in findings.ResultsDuring an encounter for mastitis, 3122 (91.7%) women received a prescription for an oral antibiotic; most commonly di/flucloxacillin ([59.4%]) or cefalexin (937 [27.5%]). Investigations recorded ultrasound in 303 (8.9%), blood tests (full blood examination [FBE]: 170 [5.0%]; C-reactive protein [CRP]: 71 [2.1%]; erythrocyte sedimentation rate [ESR]: 34 [1.0%]) and breast milk or nipple swab cultures in approximately 1% of encounters. Analysis using pillar integration showed consistency between quantitative and qualitative data regarding mastitis management. The following themes were identified:- GPs support continued breastfeeding.- Antibiotics are central to GPs' management.- Antibiotics are mostly prescribed according to Therapeutic Guidelines.- Analgesia is a gap in the Therapeutic Guidelines.- Low use of breast milk culture.ConclusionsPrescribing antibiotics for mastitis remains central to Australian GPs’ management of mastitis. Interview data clarified that GPs were aware that antibiotics might not be needed in all cases of mastitis and that delayed prescribing was not uncommon. Overall, GPs followed principles of antibiotic stewardship, however there is a need to train GPs about when to consider ordering investigations.

Drug-induced hyperprolactinemia and granulomatous mastitis: a case report and literature review

Drug-induced hyperprolactinemia and granulomatous mastitis: a case report and literature review

Chronic granulomatous mastitis in a patient with microprolactinoma

Chronic granulomatous mastitis in a patient with microprolactinoma

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

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

Abstract PO1-22-08: Ductal Lavage versus Oral Corticosteroids in Patients with Idiopathic Granulomatous Mastitis: A Multicenter, Open-label, Randomized, Controlled, Non-inferiority Study

Abstract Background: Idiopathic granulomatous mastitis (IGM) is an inflammatory breast disease characterized by the presence of mass, erythema and fistula. Various treatments have been proposed, including steroids, surgery, immunosuppressants, and observation alone. However, most of the reported studies are single-center, retrospective, single-arm with limited sample sizes, leaving the optimal treatment strategy unknown. In a previous single-arm study, we reported the efficacy and safety of ductal lavage as a novel treatment. This presentation presents the results of a multicenter, open-label, randomized controlled, non-inferiority trial that compares the efficacy and safety of ductal lavage with oral corticosteroids as the first-line treatment for IGM patients. Methods: Eligible IGM patients were randomized 1:1 to receive either ductal lavage or oral corticosteroids, stratified by M-score status. The M-score quantitatively evaluates IGM symptom severity as reported in our previous studies. Ductal lavage involved the intraductal infusion of lidocaine, triamcinolone acetonide, and ceftriaxone with saline, a total 5 times within 2 weeks. Oral corticosteroids were administered using prednisone or methylprednisolone at an initial dose of 20-40mg per day, decreased by 5mg every 2 weeks, and then maintained at 20mg per day for at least 1 month. The primary outcome was the rate of complete Clinical Response (cCR), which was defined as achieving M-score≤1 during any follow-up visit. Secondary outcomes included median time to first cCR, treatment failure, relapse, adverse events, and protocol compliance rate. If the lower limit of 95%CI of the absolute difference between ductal lavage and oral corticosteroids was greater than -15%, the non-inferiority was met. This trial was approved by the ethical committee of Sun Yat-sen Memorial Hospital and registered with ClinicalTrials.gov (NCT03724903). Results: Recruitment for this trial began in March 2019 and follow-up ended in May 2023 at 3 hospitals in China. In the intention-to-treat set (N=140), 69 patients were randomly assigned to the ductal lavage group and 71 patients to the oral corticosteroids group. The cCR rates after treatment were 85.51% (95% CI 77.20 ~ 93.81%) and 87.32% (95% CI 79.59 ~ 95.06%) in the ductal lavage and oral corticosteroids groups, respectively. The rate difference was -1.82% (95% CI -13.17 ~ 9.54%), not exceeding the non-inferiority margin (Non-inferiority P=0.011). In the per-protocol set (N=111), the cCR rate difference was -5.32%(ductal lavage: 92.86% vs. oral corticosteroids: 98.18%),with a 95%CI of -12.94% to 2.29%,also not exceeding the non-inferiority margin(Non-inferiority P=0.006).No significant differences were observed between groups in median time to first cCR (34.0 vs. 32.5 days, P= 0.878), treatment failure rate (14.49% vs. 11.27%, P=0.569), or relapse rate (10.14% vs. 4.23%, P=0.302).In the safety analysis set (N=129), the most frequently reported adverse events ( &amp;gt;15%) in the ductal lavage group were irregular menstruation (46.27%), while in the oral corticosteroids group, they were Cushingoid (79.03%), epigastric pain (17.74%), and arthralgia (16.13%). Conclusions: Ductal lavage demonstrates non-inferiority to oral corticosteroids in terms of efficacy as a first-line treatment for IGM patients. Furthermore, ductal lavage exhibits a significantly favorable adverse events profile. Primary endpoint in ITT and PP set *P value for non-inferiority comparison. Secondary endpoint in PP set §P value calculated by chi-square test. Adverse event in safety set No adverse event exceeding Grade3 have been recorded. Citation Format: Kai Chen, Xiaolin Chen, Shunrong Li, Liling Zhu, Jian Zhang, Tingting Hu, Hui Huang, Heng Huang, Lili Chen, Qiaozhen Xiao, Linhong Su. Ductal Lavage versus Oral Corticosteroids in Patients with Idiopathic Granulomatous Mastitis: A Multicenter, Open-label, Randomized, Controlled, Non-inferiority Study [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-22-08.