Mimic Breast Carcinoma Research Articles

Outcome of Wide Local Excision in Idiopathic Granulomatous Mastitis-A Short Observational Study

Background: Idiopathic granulomatous mastitis is a rare disease of the breast. It is a benign inflammatory lesion characterized by lobulocentric granulomas. Clinically and radiologically it may mimic breast carcinoma.1 Awareness of surgeons, pathologists, and radiologists is essential to avoid unnecessary mastectomies. Objective: This study aimed to investigate the outcome of wide local excision in idiopathic granulomatous mastitis. Method: This hospital based prospective study was done in surgery unit of both govt. and private hospitals, Cumilla, Bangladesh. All patients who were diagnosed with idiopathic granulomatous mastitis during the period of July 2020 to July 2022 were included. Informed consent was taken from the patient before invasive procedures including surgery. Data was analyzed using the Statistical Package for Social Sciences version 24.0 wherever appropriate. Result: Among 17 patients no recurrence was observed in 94% patients who were treated with wide surgical excision during the median follow-up period of 12 months. Conclusion: Patients with idiopathic granulomatous mastitis can present with a wide variety of symptoms which mimic other more common conditions. Surgical management in the form of wide local excision appears to provide the best long term outcome in patients with idiopathic granulomatous mastitis. Central Medical College Journal Vol 8 No 1 January 2024 Page: 35-37

Hidradenocarcinoma of the Chest With Axillary Lymph Node Metastasis: Report of 2 Cases and Systematic Literature Review of a Breast Cancer Mimicker.

Hidradenocarcinoma (HAC) is a rare malignant neoplasm originating from eccrine sweat glands, often presenting diagnostic challenges because of its resemblance to other malignancies, particularly breast cancer when occurring in the chest region. This report describes 2 cases of HAC with axillary lymph node metastasis, both initially misinterpreted clinically. The first case involved a 63-year-old woman with a sternal mass, near the right breast, initially suspected to be a sebaceous cyst. Histologic examination revealed a solid-cystic epithelial tumor with features suggestive of HAC, confirmed by immunohistochemical analysis. The second case concerned an 81-year-old woman with a subcutaneous growth in the sternal area, also diagnosed as HAC after histopathologic and immunohistochemical assessment. Both cases demonstrated strong estrogen receptor positivity, leading to the recommendation of hormonal therapy. A systematic review of the literature identified 21 similar cases of HAC in the chest wall, highlighting the diagnostic complexities and the potential for these tumors to mimic breast carcinoma. This review underscores the need for careful histologic and immunohistochemical evaluation to differentiate HAC from other malignancies, particularly in the breast region. Given the rare and the potential aggressive nature of HAC, early and accurate diagnosis is crucial for guiding appropriate therapeutic strategies and improving patient outcomes.

Primary breast tuberculosis mimicking breast cancer: an original study of imaging findings and differential diagnosis challenges.

Breast tuberculosis is a rare extrapulmonary manifestation of Mycobacterium tuberculosis, representing less than 0.1% of all breast pathologies in developed countries. However, in regions with high tuberculosis prevalence, such as India and Africa, its incidence is higher. The disease poses diagnostic challenges due to its ability to mimic breast carcinoma, leading to potential misdiagnosis and unnecessary surgical interventions. This study investigates the clinical and imaging characteristics of breast tuberculosis in a large cohort, with a specific focus on a rare case in a postmenopausal woman. A retrospective observational study was conducted on 1704 women who presented for mammography at the Alessandrescu-Rusescu National Institute for Mother and Child Health between 2019 and 2021. Clinical presentation, imaging results, and histopathological findings were analyzed to identify cases of breast tuberculosis. The study includes a comparative analysis with other granulomatous diseases and malignant breast conditions to highlight key diagnostic features. Among the 1704 patients, 714 (41.9%) presented with symptoms such as pain (35.4%), palpable lumps (13.2%), nipple discharge (4.3%), and breast appearance changes (2.1%). A rare case of primary breast tuberculosis was identified in a 69-year-old postmenopausal woman, presenting with a painless, palpable mass in the upper outer quadrant. Imaging demonstrated a hypoechoic mass with fine granular content and posterior acoustic enhancement, categorized as BIRADS 4A. The biopsy confirmed the diagnosis of breast tuberculosis. This study underscores the diagnostic complexity of breast tuberculosis, particularly in its ability to mimic malignancy. Through detailed imaging and clinical analysis, we emphasize the importance of biopsy in differentiating tuberculosis from breast cancer. Given the potential for misdiagnosis, clinicians should consider breast tuberculosis in differential diagnoses, especially in regions with high tuberculosis prevalence. Further research is needed to develop specific imaging criteria for earlier and more accurate diagnosis.

Improving ultrasound diagnostic Precision for breast cancer and adenosis with modality-specific enhancement (MSE) - Breast Net

Adenosis is a benign breast condition whose lesions can mimic breast carcinoma and is evaluated for malignancy with the Breast Imaging–Reporting and Data System (BI-RADS). We construct and validate the performance of modality-specific enhancement (MSE)-Breast Net based on multimodal ultrasound images and compare it to the BI-RADS in differentiating adenosis from breast cancer.A total of 179 patients with breast carcinoma and 229 patients with adenosis were included in this retrospective, two-institution study, then divided into a training cohort (institution I, n = 292) and a validation cohort (institution II, n = 116). In the training cohort, the final model had a significantly greater AUC (0.82; P < 0.05) than B-mode–based model (0.69, 95% CI [0.49–0.90]). In the validation cohort, the AUC of the final model was 0.81, greater than that of the BI-RADS (0.75, P < 0.05). The multimodal model outperformed the individual and bimodal models, reaching a significantly greater AUC of 0.87 (95% CI = 0.69–1.0) (P < 0.05).MSE-Breast Net, based on multimodal ultrasound images, exhibited better diagnostic performance than the BI-RADS in differentiating adenosis from breast cancer and may contribute to clinical diagnosis and treatment.

Primary Cutaneous Apocrine Carcinoma: Diagnostic and Management Difficulties of an Uncommon Neoplasm

Primary cutaneous apocrine carcinoma (PCAC) is a rare adnexal neoplasm. Due to its clinical presentation, it can mimic other tumors, especially metastasis. We present a case of primary apocrine carcinoma of the axilla mimicking breast carcinoma metastasis in a 54-year-old woman. The patient presented with a painless, lobed, and erythematous nodule in the left axilla of one year duration. We suspected an adnexal neoplasm but also considered metastasis from breast carcinoma. Histological examination revealed apocrine proliferation. Immunohistochemistry stains of tumor cells were positive for AE1/AE3, and negative for CK7, CK20, p63 and GATA3. Radiological explorations did not reveal any signs of malignancy. Considering all these features, the conclusive diagnosis was primary cutaneous apocrine carcinoma. Treatment was wide excision without adjuvant therapy, and no recurrence was noted. Due to the rarity of this carcinoma, its various clinical presentations, and histological overlaps with breast cancer metastasis, making the diagnosis may be challenging. A comprehensive evaluation of all findings is necessary to rule out other tumors. There is any consensus on the management strategy. The standard treatment is surgical excision, but adjuvant therapies such as radiotherapy or chemotherapy can be proposed in advanced stage disease.

Diabetic mastopathy: A case report and literature review on a mimic of breast carcinoma in patients with diabetes

AbstractDiabetic mastopathy is a rare benign breast condition that mimics breast carcinoma in patients with diabetes. Clinicians must differentiate it from malignant causes because of differences in prognosis and management. This paper presents a case report of an 87‐year‐old lady with type 2 diabetes and diabetic mastopathy. We also review the literature on the pathogenesis, clinical presentation, diagnostic workup and management of diabetic mastopathy.

Male’s Primary Breast Lymphoma: Rare Entity of Breast Malignancy, Wad Madani Teaching Hospital, Gezira State, Sudan, August 2023

&amp;lt;i&amp;gt;Background&amp;lt;/i&amp;gt;: Primary breast lymphoma is a malignant lymphoma primarily involving breast in absence of previously detected lymphoma localizations. &amp;lt;i&amp;gt;Method&amp;lt;/i&amp;gt;: A male of forty years old admitted to Department of Surgery; Wad Madani Teaching Hospital; Gezira State; Sudan; complaining of left breast lump for three months. Condition observed as a painful swelling in left breast, increasing gradually in size, associated with continuous high-grade fever, no rigors and relieved by analgesia, no nipple discharges. Had significant weight loss, anorexia, fatigability, back pain, dry cough with no hemoptysis, no history of headache, and no past or family history of similar condition. Examination: patient looks ill, pale, and not jaundiced. Breast examination: Left breast was larger than right one. Left breast: no nipple destruction, nipple was directed downward medially, no skin changes or dimpling, and no ulceration. There was a mass in left upper outer quadrant, measuring 6*7 cm, smooth surface, hard in consistency with well-defined edges, and attached to muscles but not to skin. No palpable axillary lymph nodes. Right breast was normal. Chest and abdominal examination were unremarkable. Investigations: Fine needle aspiration cytology showed poorly differentiated carcinoma. Incisional biopsy revealed: high grade Non-Hodgkins Lymphomas (Diffuse Large B Cell Lymphoma). He was referred to oncological department for neoadjuvant chemoradiotherapy. Conclusion and &amp;lt;i&amp;gt;Recommendation&amp;lt;/i&amp;gt;: Primarily breast lymphoma is extremely rare among male, showing features mimicking breast carcinoma. Incisional biopsy was recommended for investigation of breast lump especially among males.

Diabetic mastopathy: A review of a breast carcinoma mimic

Abstract Diabetic mastopathy is a rare fibro-inflammatory breast disease that closely mimics breast carcinoma. The disease predominantly affects insulin-dependent diabetics, and the etiology is still unclear. A proper physical examination, imaging, and core-needle biopsy usually lead to a diagnosis. Management is conservative and revolves around counseling the patient to allay fears and regular follow-up. In this review, we highlight the recent information on diabetic mastopathy with emphasis on historical background, epidemiology, etiopathogenesis, diagnostic approaches, and treatment choices.

Unusual Benign Lesions of the Breast Mimicking Carcinoma: A Series of Six Cases

ABSTRACT Introduction: There has been a growing increase in the incidence of breast cancer, which is still the most significant cancer-related cause of female mortality. All breast lesions are not malignant, and all the benign lesions do not progress to cancer; however, the accuracy of diagnosis can be increased by a combination of preoperative tests (like physical examination, mammography, fine-needle aspiration cytology, and core-needle biopsy [CNB]). Aim: To study the breast mass which mimicks malignant lesion clinically and their further evaluation with the help of core needle biopsy and fine needle aspiration cytology. Materials and Methods: Prospective evaluation of the breast masses which mimicks malingnant lesion clinically at IPGME &amp;R and SSKM Hospital kolkata from January 2019 to June 2020 at department of pathology. We studied the cases of breast masses. This comprised patient age and sex, the clinical characteristics and location of the mass, the duration of the lesion, its size, the treatment provided, and the histopathological findings obtained from fine-needle aspiration cytology (FNAC) and CNB. Results: We present six clinical cases in which a diagnosis dilemma existed, in terms of ultrasound findings that were not clear and suspicious. The results of FNAC and CNB are used to distinguish between benign breast lesions mimicking carcinoma of breast. Our findings are compared with previously published cases. Furthermore, literature review regarding the case presentation and diagnosis has been discussed, as well as treatment options. Conclusion: Accurate preoperative diagnosis of carcinoma is necessary in screen-detected lesions so that patients may be counseled appropriately and a majority could have a single therapeutic operation. Benign breast lesion mimicking breast carcinoma should be differentiated. Combining FNAC and CNB for screening-detected breast cancers, the complete sensitivity increases from 93% for CNB only to 98% when both tests are combined.

Comparison of Interleukin-33 Serum Levels in Patients with Breast Cancer and Idiopathic Granulomatous Mastitis

Breast cancer (BC) is the main cause of cancer death in women. Idiopathic granulomatous mastitis (IGM), a rare chronic disease that clinically mimics breast carcinoma, and is associated with high mortality and morbidity, but an immediate and accurate diagnosis can substantially decrease these rates. Expressed by numerous human tissues, interleukin-33 (IL-33) has an inductive role in the network of pro-inflammatory cytokines. The aim of this study was to investigate the serum levels of IL-33 in BC and IGM patients in comparison with healthy women. This descriptive-analytical study was carried out on 28 patients with BC and 25 patients with IGM as the patient groups and 25 healthy volunteers with normal screening reports as the control group. Histopathological pattern of BC and IGM were confirmed by specialized pathologists. The serum concentration of IL-33 was measured using enzyme-linked immunosorbent assay (ELISA) kit according to the manufacturer's instructions. The mean age of the patients with BC and IGM and the control group was 49.1, 37.1, and 36.8 years, respectively. There was no significant difference in IL-33 expression among the participants with regard to age, marital status, body mass index (BMI), and menopausal status. IL-33 assay indicated a significant difference between the BC (P=0.011) and IGM (P=0.031) groups compared to the controls, although no substantial differences were observed between the IGM and BC groups. IL-33 can be considered a significant factor distinguishing IGM and BC patients from controls, although it cannot be applied to diagnose and differentiate BC from IGM patients.<br />.

Primary tuberculosis of the breast from mankweng hospital

Object of study: To share our experience with a rare case of Primary Tuberculosis of Breast.&#x0D; The problem to be solved: Tuberculosis of the breast is a rare type of extrapulmonary tuberculosis and usually affects young lactating multiparous women. It accounts for less than 0.1 % of all breast pathologies. Tuberculosis of the breast is often misdiagnosed. Therefore, a high index of suspicion is needed when evaluating cases of breast abscesses, fistulae, or mass.&#x0D; Main scientific results: A case of a 27-year-old female with no known co-morbidities, HIV negative who presented to our Surgical Outpatient Department with a 1-year history of a painless left breast lump. No previous history of pulmonary tuberculosis was reported. Breasts ultrasonography indicated BIRADS (Breast Imaging-Reporting and Data System) V: lesion highly suspicious of malignancy. Histopathological analysis of the core biopsy showed features of a necrotizing granulomatous mastitis with adjacent fat necrosis. Ziehl-Neelsen stain was negative though histological results were worrisome of a mycobacterial infection. Patient responded well to antitubercular therapy as evidenced by lump regression, ulceration healed, peau d’orage currently resolved, and the overall size of the breast is going back to its normal state.&#x0D; The area of practical use of research results: Family medicine physicians, Primary health care center, District level or regional level hospital.&#x0D; An innovative technological product: a high index of suspicion tuberculosis is needed when evaluating cases of breast abscesses, fistulae, or mass. Awareness of this condition is important as it can clinically, and radiologically mimic breast carcinoma.&#x0D; Scope of application of an innovative technological product: Family medicine physicians, Primary health care center.

Fibromatosis of the breast; another diagnosis of cancer like lesions: About 4 cases reports

Introduction and importanceDesmoid fibromatosis is a benign monoclonal fibroblastic tumor that was first reported in 1832 and arises from musculoaponeurotic structures. It is an uncommon tumor that can mimic breast carcinoma in both hits clinical and radiological presentation.This entity mainly affects patients in their fourth and fifth decades of life. Case presentationOur four patients were of young women in their 2nd and 3rd decade that consulted for masses of the breast.These lesions were suspicious for malignancy in both their clinical and radiological features despite not having any family history of breast carcinoma. Clinical discussionOnly histology provides the diagnosis, it is locally invasive, non-metastatic but with a high potential of recurrence and the sole treatment is complete and wide local excision with clear margins. ConclusionAlthough it is a rare clinical scenario, the presence of an unusual breast or chest wall tumor such as a desmoid tumor should be considered when obvious breast changes and history do not correlate with routine diagnostic measures.

Granulomatous Mastitis Masquerading as Breast Neoplasms- An Enigmatic Series of 14 Cases

Granulomatous Mastitis (GM) is a rare entity encountered in day-to-day practice. Aetiologies range from infections like tuberculosis, lactation, certain medications to being idiopathic. Clinical and radiological pictures in these cases often mimic breast carcinoma that poses diagnostic dilemmas to the treating physician. However, sometimes they may be asymptomatic. Definitive diagnosis is made using cytology followed by histomorphology by demonstration of granulomas, which are collections of histiocytes along with giant cells and inflammatory cells. Ancillary studies like Ziehl-neelsen (ZN) stain, Periodic Acid Schiff (PAS) stain, Cartridge Based Nucleic Acid Amplification Test (CBNAAT) are used to detect or rule out certain aetiologies of granulomatous inflammation. Idiopathic Granulomatous Mastitis (IGM) is mainly a diagnosis of exclusion, where all the possible aetiologies have been ruled out by detailed history and investigations. Treatment approaches are mainly conservative, depending on the cause or may be anti-inflammatory and steroids in case of IGM. Appropriate and timed diagnosis of such cases is essential to prevent over diagnosis of carcinoma and unnecessary mastectomies. This is a series of 14 such cases which were diagnosed using cytology or histology and ancillary tools. They belonged to four categories (namely-Tuberculous mastitis, IGM, Post-chemotherapy GM and sarcoid granuloma of breast). Tuberculous cases shared majority of the series, whereas, sarcoid granuloma was a single isolated entity. All these cases presented with lump in breast with other associated presentations. Immediate tissue diagnosis helped in ruling out malignancy and adopting a conservative approach for management.

A RARE CASE OF TUBERCULOSIS OF BREAST

Tuberculosis is caused by Mycobacterium tuberculosis and mainly affects the lungs. Breast tuberculosis (TB) is a rare localization of extra-pulmonary TB. Breast tuberculosis has a prevalence of 0.6% to 3.6% of all breast infective conditions in India. It appears mostly in women of reproductive, age, multiparous, lactating. It has been scarcely reported to infect male patients, mainly before puberty, as well as women of older age. Most commonly the disease presents as a lump in the central or upper-outer quadrant of the breast while multiple lumps appear less frequently. Often the presentation leads to misdiagnose breast tuberculosis with either breast carcinoma or abscess because lump can mimic breast carcinoma, being hard, with irregular border, xed to either the skin or the muscle or even to the chest wall. Treatment generally involves anti-TB medications with or without surgery

Radiomics Based on DCE-MRI Improved Diagnostic Performance Compared to BI-RADS Analysis in Identifying Sclerosing Adenosis of the Breast.

PurposeSclerosing adenosis (SA) is a benign lesion that could mimic breast carcinoma and be evaluated as malignancy by Breast Imaging-Reporting and Data System (BI-RADS) analysis. We aimed to construct and validate the performance of radiomic model based on dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) compared to BI-RADS analysis to identify SA.MethodsSixty-seven patients with invasive ductal carcinoma (IDC) and 58 patients with SA were included in this retrospective study from two institutions. The 125 patients were divided into a training cohort (n= 88) from institution I and a validation cohort from institution II (n=37). Dynamic contrast-enhanced sequences including one pre-contrast and five dynamic post-contrast series were obtained for all cases with different 3T scanners. Single-phase enhancement, multi-phase enhancement, and dynamic radiomic features were extracted from DCE-MRI. The least absolute shrinkage and selection operator (LASSO) logistic regression and cross-validation was performed to build the radscore of each single-phase enhancement and the final model combined multi-phase and dynamic radiomic features. The diagnostic performance of radiomics was evaluated by receiver operating characteristic (ROC) analysis and compared to the performance of BI-RADS analysis. The classification performance was tested using external validation.ResultsIn the training cohort, the AUCs of BI-RADS analysis were 0.71 (95%CI [0.60, 0.80]), 0.78 (95%CI [0.67, 0.86]), and 0.80 (95%CI [0.70, 0.88]), respectively. In single-phase analysis, the second enhanced phase radiomic signature achieved the highest AUC of 0.88 (95%CI [0.79, 0.94]) in distinguishing SA from IDC. Nine multi-phase radiomic features and two dynamic radiomic features showed the best predictive ability for final model building. The final model improved the AUC to 0.92 (95%CI [0.84, 0.97]), and showed statistically significant differences with BI-RADS analysis (p<0.05 for all). In the validation cohort, the AUC of the final model was 0.90 (95%CI [0.75, 0.97]), which was higher than all BI-RADS analyses and showed statistically significant differences with one of the BI-RADS analysis observers (p = 0.03).ConclusionsRadiomics based on DCE-MRI could show better diagnostic performance compared to BI-RADS analysis in differentiating SA from IDC, which may contribute to clinical diagnosis and treatment.

Clinicopathological features of idiopathic granulomatous mastitis: A retrospective study & educational lessons from Syria

Objectiveto determine the clinical presentations and histopathological findings of idiopathic granulomatous mastitis, and to evaluate clinical outcomes after management. Methodsbetween 2007 and 2021, the files and histopathology reports of 17 patients with idiopathic granulomatous mastitis at Tishreen University Hospital, Latakia, Syria were reviewed. The data were analyzed and a scan through relevant literature was carried out to review related cases. Resultsthe age of patients ranged from 23 years to 57 years, and the mean age was 37.2 ± 9.57 years. All patients were female. The most common clinical presentation was breast lumps and the most common mammographic finding was ill-defined masses, which mimics breast carcinoma. Multinucleated giant cells, polymorphonuclear leukocytes, lipogranuloma-like changes and lobulocentric abscesses were the most common histopathological findings. Treatment options include: drainage of abscess along with antibiotics, steroid administration, and surgical excision. Antibiotic treatment was associated with a higher rate of complications, while use of steroids showed complete remission of the disease. Conclusionidiopathic granulomatous mastitis is a spectrum of entities that should be differentiated from breast carcinoma and other mastitis conditions, the infectious or the non-infectious ones. The clinical and radiological features resemble those of breast carcinoma and infectious mastitis. The histopathological study is considered as the most crucial element in the multidisciplinary approach to diagnose idiopathic granulomatous mastitis (IGM) and determine the optimal management to be administered.

FDG PET/CT of Primary Breast Lymphoma in a Man.

Primary lymphoma of the male breast is extremely rare. We describe FDG PET/CT findings in a man with primary breast lymphoma in his right breast. The breast tumor showed intense FDG uptake mimicking breast carcinoma.

Out Come of Wide Local Excision with and without Corticosteroid Therapy in Management of Idiopathic Granulomatous Mastitis

Introduction: Idiopathic granulomatous mastitis is a rare benign breast disease. Initial reports from hospitals in Egypt from Departments of Pathology at Cancer Institutes of Cairo, Tanta and Mansoura Universities; indicate that the disease is not as rare as that in the developed countries. It often mimics breast carcinoma both clinically and radiologically. Histological examination is the gold standard for diagnosis. Management of Idiopathic granulomatous mastitis is still debatable. In our study, we aimed to evaluate the addition of corticosteroid therapy to surgical excision in management of idiopathic granulomatous mastitis. Patients and Methods: This is a comparative study was conducted at Ain-Shams University Hospital’s breast clinic on patients with idiopathic granulomatous mastitis from to August 2015 till September 2018. Thirty patients were divided into 2 groups. Group (A) includes patients who underwent surgical management only. Group (B) includes patients who received corticosteroid therapy according to the severity of the cases then surgical Excision was done for the residual lesion. Follow up of all cases up to 1-2 years was done to document the recurrence rate and compare the cosmetic outcome of both groups. Informed consent was obtained from all patients included in the study. Results: The mean age of the affected women was 38.80 and 33.13 in group (A) and group (B), respectively and it wasn’t statistically different (p value = 0.099). The most common presenting symptom was a palpable mass in the breast (66.7% and 93.3%) in group (A) and group (B) respectively. Recurrence rate was higher in group (A) (40%) with no recurrence documented in group (B) however 2 cases were omitted from the study due to steroid noncompliance and complications. Cosmetic outcome was excellent in 76.9% of group (B) and good in 53.3% of group (A). Conclusion: Systemic steroid therapy with surgical resection is the recommended as first-line treatment strategy for IGM as it shows less recurrence rate and surgical scarring. Increased awareness of IGM will increase their understanding and improve their management.

Isolated Primary Mammary Tuberculosis Mimicking Breast Carcinoma

Isolated Primary Mammary Tuberculosis Mimicking Breast Carcinoma

Pregnancy Associated Granulomatous Mastitis: Clinical Characteristics, Management, and Outcome

Background: We have already known that idiopathic granulomatous mastitis (IGM) is a rare benign chronic inflammatory disorder that can clinically mimic breast carcinoma, especially affects parous women of childbearing age, but there is little literature to report about pregnancy associated granulomatous mastitis (PAGM). The aim of our study is to report and describe the clinical signs, managements, clinical course, and clinical outcomes after treatment of PAGM in our hospital. Methods: We retrospectively analyzed 15 pregnant patients who were diagnosed as PAGM in our hospital collected from December 2018 to December 2020 by reviewing medical records and questionnaire survey, including the patients' characteristics, clinical presentations, microbiological workups, tissue pathology, treatment modalities, outcomes, and follow-up data. Results: The mean age of these patients at diagnosis was 30.5 (range 24-35) years. All patients had one birth before, and had at least two gravida times, 6 of them (40%) had three gravida times, and only one of them had four gravida times at diagnosis. The mean weeks of gestational age were 23.7 (range 4-37) weeks. Two patients' BMI were greater than 30, which were considered obese. The mean time to presentation since last delivery was 38.4 (range 19-78) months. All patients had a history of breastfeeding; the average breastfeeding time was 12.97 months. Just 2 of them were diagnosed with lactational mastitis before. One patient smoked before, 1 patient had oral contraceptive pills before, 4 patients had breast trauma recently, 5 patients had positive bacterial culture of pyogenic fluids, 3 patients had nipple retraction, 6 patients had abnormal humoral immunity, shown as elevated C3 or C4, and 2 patients had elevated serum prolactin. All patients presented as a breast mass with pain; two of them had erythema nodosum and oligoarthritis. Nearly all patients had unilateral lesion. The mean follow-up was 11 (range 1-24) months. Thirteen patients gave birth to a healthy baby, and all babies had a healthy growth and development. Almost all patients chose observation during pregnancy. Nine patients demonstrated complete remission, five of them underwent surgery after steroids and/or antibiotics, one patient had observation alone, two chose postpartum steroids alone, and the last one chose postpartum antibiotics alone. The average time to complete remission was 11.2 (range 7-18) months. Conclusions: In general, PAGM is a much rare disorder which has onset during pregnancy, and mainly happens in the second trimester and the third trimester. PAGM patients were all parous women and generally within 5 years of their last pregnancy, also with uncertain etiology and pathogenesis. Observational therapy during pregnancy for PAGM is reliable and feasible.