BACKGROUND: 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.
METHODS: 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.
RESULTS: 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).
CONCLUSIONS: 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.

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.

Idiopathic granulomatous mastitis (IGM) is a rare condition characterised by chronic inflammation and granuloma formation in the breast. The aetiology of IGM is unclear. By focusing on the protein-coding regions of the genome, where most disease-related mutations often occur, whole-exome sequencing (WES) is a powerful approach for investigating rare and complex conditions, like IGM. We report WES results on paired blood and tissue samples from eight IGM patients. Samples were processed using standard genomic protocols. Somatic variants were called with two analytical pipelines: nf-core/sarek with Strelka2 and GATK4 with Mutect2. Our WES study of eight patients did not find evidence supporting a clear genetic component. The discrepancies between variant calling algorithms, along with the considerable genetic heterogeneity observed amongst the eight IGM cases, indicate that common genetic drivers are not readily identifiable. With only three genes, CHIT1, CEP170, and CTR9, recurrently altering in multiple cases, the genetic basis of IGM remains uncertain. The absence of validation for somatic variants by Sanger sequencing raises further questions about the role of genetic mutations in the disease. Other potential contributors to the disease should be explored.

Granulomatous mastitis (GM), a benign inflammatory disease of the breast, often mimics breast cancer on presentation. We present a case of GM during pregnancy manifesting as a breast mass, sudden onset of plantar pain, and erythema nodosum (EN). A 31-year-old pregnant Japanese woman, gravida 2, para 1, was referred to our hospital with severe plantar pain on both soles, causing difficulty walking. This pain worsened and EN appeared on both lower legs, followed by a left breast mass. Ultrasound findings suggested malignancy; however, aspiration biopsy confirmed GM. Her arthritis and EN resolved 2 days after commencing oral prednisolone and her walking improved. EN with/without arthritis is commonly associated with GM, especially during pregnancy. The described manifestations with a breast mass are suggestive of this diagnosis.

BACKGROUND: 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.
OBJECTIVE: 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.
METHODS: This is a retrospective observational study, analysing the clinical, radiological, and histopathological data from 65 patients with mastitis between February 2023 and February 2024.
RESULTS: 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.
CONCLUSIONS: 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 (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.

The two primary types of non-puerperal mastitis (NPM) are granulomatous lobular mastitis (GLM) and plasma cell mastitis (PCM). Existing research indicates that immune inflammatory response is considered to be the core of the pathogenesis of GLM and PCM, and both innate and adaptive immune responses play an important role in the pathophysiology of PCM and GLM. However, the regulatory balance between various immune cells in these diseases is still unclear. Consequently, we present a comprehensive summary of the immune-related variables and recent advances in GLM and PCM.

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.

BACKGROUND: Tuberculous mastitis (TBM), is an uncommon form of extra-pulmonary tuberculosis. Clinical and radiological overlap of tuberculous mastitis with malignancy and other granulomatous conditions, along with its paucibacillary nature, make it a diagnostic challenge. In our study, we aim to assess the radiological response of microbiologically negative granulomatous mastitis cases to anti-tuberculous treatment (ATT) in an endemic country.
METHODS: Eighty-seven cases demonstrating granulomatous lesions on breast biopsy were identified. Of these, 49 patients who were treated with ATT and had at least two serial ultrasound follow-ups were included in our study. Mammogram and ultrasound were used for initial imaging. Subsequently, ultrasound was used for serial follow-up. Mantoux skin test, acid fast staining and histological examination of tissue sample were the other investigations used.
RESULTS: Radiologically, on ultrasound, well-circumscribed hypoechoic masses were noted in 18 patients, followed by ill-defined collections with tubular extensions in 15 cases, abscesses in 8, and a focal heterogeneity in 8 patients. Following ATT, 17 patients showed radiological resolution in 4 weeks, 18 of them at 3 months, and nine of them in 6 months.
CONCLUSIONS: Excellent and prompt radiological response to ATT, indicates the need for a high degree of suspicion for tuberculous mastitis (TBM), in endemic countries, even though microbiological tests may turn out negative.

BACKGROUND: Granulomatous lobular mastitis (GLM) is a rare benign inflammatory disease of the breast and is classified under comedo mastitis in traditional Chinese medicine (TCM). The etiology of this disease is unknown, and it mainly occurs in women of childbearing age. The diagnosis depends on histopathological biopsy. At present, there is no systematic and standardized treatment plan for GLM. In the absence of evidence supporting an infectious etiology, affected patients might continue to receive multiple courses of antibiotics and unnecessary surgery.
METHODS: A 37-year-old Chinese woman with a history of coronavirus disease 2019 infection presented with swelling and pain in the left breast. She also had erythema, nodules in the lower extremities, arthritis in both knees, cough, and headache. In the early stage of GLM, the mass was not significantly reduced by conservative treatment with internal application of TCM; hence, surgical treatment was carried out. The aim of postoperative treatment was to drain the pus, eliminate the necrosed tissue, and expand the muscles; fumigation and washing using TCM was applied.
CONCLUSIONS: Combined internal and external treatment with TCM, following the principle of \"Prioritize internal treatment before ulceration and emphasize external treatment after ulceration\" was effective in our patient with GLM. The prognosis was good. We believe that TCM offered valuable therapeutic benefits in this disease.