Occult metastasis of hormone receptor-positive breast cancer to the ovary: A case report and literature review.

BackgroundBreast cancer is one of the most common malignancies among women, and more than 90% of breast cancer-related deaths attributed to metastasis. Cutaneous metastases are relatively uncommon, and scalp involvement is exceedingly rare. Because of its atypical clinical presentation, scalp metastasis is often recognized and diagnosed only after a delay.Case presentationWe report the case of a 45-year-old woman diagnosed with invasive ductal carcinoma (IDC) of the right breast with ipsilateral axillary lymph node involvement (clinical stage cT4bN3M0). The patient received six cycles of neoadjuvant chemotherapy and achieved a partial response (PR) according to RECIST 1.1 criteria. Subsequently, she underwent a right simple mastectomy with axillary lymph node dissection. Pathology demonstrated a Miller–Payne grade 3 response, with metastases identified in all 13 dissected axillary lymph nodes (13/13). Immunohistochemistry (IHC) revealed estrogen receptors (ER) and progesterone receptors (PR) positivity, human epidermal growth factor receptor-2 (HER2) expression of 0, and Ki-67 expression of 20%. She subsequently received adjuvant radiotherapy and endocrine therapy. Surveillance imaging during follow-up showed no evidence of recurrence or distant metastasis. In December 2023, the patient developed a painless, round, skin-colored nodule on the left frontal scalp, accompanied by diffuse right periorbital edema and headache. Over the following year, she was evaluated in dermatology, neurosurgery, and oncology clinics. However, breast cancer metastasis was not initially suspected, resulting in misdiagnosis and delayed treatment. In April 2025, fine-needle aspiration of the scalp nodule confirmed metastatic carcinoma. IHC showed ER and PR positivity, HER2 expression of 1+, and Ki-67 expression of 35%. No additional metastatic lesions were identified. The patient was started on systemic therapy with fulvestrant plus dalpiciclib, and after four cycles, she achieved marked regression of the scalp lesion along with resolution of periorbital edema. The most recent examination, however, detected meningeal and calvarial metastases. Consequently, the patient received localized radiotherapy to these sites while continuing the original treatment protocol.ConclusionThis case highlights the diagnostic challenges of atypical scalp metastases in breast cancer and underscores the importance of early detection and prompt initiation of comprehensive treatment.

The hormone receptor, human epidermal growth factor receptor 2, and molecular subtype status of individual tumor foci in multifocal/multicentric invasive ductal carcinoma of breast

Introduction: MammaPrint, a 70-gene assay used to predict breast cancer recurrence, is typically obtained on the surgical specimen to guide the use of adjuvant chemotherapy. However, MammaPrint results obtained at the time of diagnosis on core biopsy specimen could allow consideration of neoadjuvant chemotherapy (NAC), particularly for tumors that may not traditionally be considered for NAC such as invasive lobular carcinoma (ILC). We hypothesized that MammaPrint scores correlate with pathologic complete response (pCR) and can predict NAC response independent of histology type. Methods: The National Cancer Database was used to identify patients with AJCC Stage I-III unilateral HR+/HER2- breast cancer with MammaPrint scores treated 2010-2018. Patients were stratified by histology: invasive ductal carcinoma (IDC) and ILC; and by MammaPrint score for 5-year breast cancer recurrence: Low Risk (1%) and High Risk (12%). Descriptive statistics identified clinical and treatment differences between groups. Logistic regression was used to identify factors associated with chemotherapy receipt and sequence. A subset analysis of patients receiving NAC compared pCR rates by MammaPrint score and histology type. Results: Of 10,999 patients, 9,351 (85%) were diagnosed with IDC and 1,648 (15%) with ILC. ILC were larger at presentation: 40% of ILC were cT2 or greater vs. 29% of IDC (p< 0.001). However, 90% of patients in both groups had cN0 disease. The majority of ILC were grade II (67% ILC vs. 52% IDC, p< 0.001). High Risk MammaPrint scores were significantly more common in IDC tumors: 44% IDC vs 25% ILC (p< 0.001). Mastectomy and axillary lymph node dissection (ALND) were performed more often for ILC than IDC (unilateral mastectomy 32% vs. 21%, bilateral mastectomy 17% vs. 12%, ALND 29% vs. 24%; all p< 0.001). Conversely, chemotherapy (38% vs. 30%, p< 0.001) and radiation (69% vs. 64%, p< 0.001) were more frequently used to treat IDC than ILC. In the subset analysis of patients who received NAC (n = 715), tumors with High Risk MammaPrint scores had more favorable in-breast and axillary responses than those with Low Risk scores for both ILC and IDC (Table 1). Furthermore, only tumors with High Risk Mammaprint scores achieved an overall pCR: 7% IDC and 5% ILC. There were no significant differences in pCR rates by histology type. On multivariable logistic regression, High Risk MammaPrint score was positively associated with the receipt of NAC (OR 4.3, p< 0.001) and adjuvant chemotherapy (OR 24.8, p< 0.001). NAC, adjuvant chemotherapy, and any chemotherapy were also strongly associated with node-positive disease and tumor size >2cm, but not IDC vs. ILC histology. Conclusions: Superior response to NAC was observed in tumors with High Risk MammaPrint score regardless of histology type, indicating a correlation between pCR rates and genomic assay results. Greater use of NAC guided by High Risk Mammaprint score obtained on core needle biopsy may allow patients with invasive breast cancer to undergo less extensive breast and axillary surgery. Further prospective studies using MammaPrint testing on core biopsy specimens could validate these findings in clinical practice. Table 1. Response to neoadjuvant chemotherapy by MammaPrint score for patients with Invasive breast carcinoma, NCDB 2010–2018 Citation Format: Lauren M. Drapalik, Rashi Singh, Ashley Simpson, Lisa Rock, Robert Shenk, Amanda L. Amin, Megan E. Miller. Using MammaPrint on Core Needle Biopsy to Guide Neoadjuvant Chemotherapy for Invasive Breast Carcinoma [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P6-01-02.

The most common sites of metastasis for breast cancer are the soft tissues, bones, lungs, liver and brain; however, metastases to the gastrointestinal tract and thyroid gland from breast cancer rarely occur. The present study describes the case of a 30-year-old woman who developed gastric and thyroid metastases 5 years after her initial diagnosis of invasive ductal breast carcinoma. The initial pathological diagnosis when receiving modified radical mastectomy was invasive ductal carcinoma, and further immunohistochemical examination revealed the cancer to be estrogen receptor (-), progesterone receptor (-), human epidermal growth factor receptor 2 (HER2; ++) and Ki-67 (70%). Genetic testing indicated the HER2 amplification mutation, whereas BRCA1/2 testing was negative. A total of 21 months after surgery, during regular follow-up, the patient was revealed to have developed an enlarged lymph node in the left side of the neck and the first recurrence was confirmed. Approximately 5 years after surgery, the patient gradually developed multi-site metastasis, and developed metastases to the thyroid gland and stomach confirmed by pathology and imaging. Combined chemotherapy and targeted therapy were administered and exhibited good efficacy; however, the patient subsequently died due to heart failure. This case report describes the occurrence of gastric and thyroid metastases from breast cancer, and highlights the importance of distinguishing between metastatic and primary tumors. Distinguishing between a metastatic and primary tumor is crucial as treatment protocols vary significantly for these two types of tumors. For patients with a history of breast cancer it should first be considered whether they have metastasis of the primary disease or discomfort caused by treatment; however, the possibility of a second primary tumor cannot be ignored. If the patient has symptoms such as loss of appetite, nausea, vomiting, stomach pain and stomach discomfort, a gastroscopy should be performed in a timely manner.

Accurate determination of estrogen receptor (ER), progesterone receptor (PgR), and human epidermal growth factor receptor-2 (HER2) status was very important in selecting breast cancer treatment. Discordance of ER, PR, and HER2 status between core needle biopsy (CNB) and open excision biopsy (OEB) varied among reported studies. We performed a meta-analysis to compare the accuracy of CNB with that of OEB for ER, PgR, and HER2 status detection in breast cancer. Medical subject heading (MeSH) terms (Breast Neoplasm) and key words (biopsy OR mammotome) AND (incision OR excision OR surgery) AND (estrogen OR progesterone OR HER2 OR hormone). Patients with HER2 immunohistochemical 3+ or fluorescence in situ hybridization positive were classified into HER2[b] group. A total of 27 studies were eligible in this study. Aggregate positive ER and PgR rate was 80.0 and 69.5% for CNB; and 77.7 and 66.2% for OEB, respectively. The HER2 positive rate difference between CNB and OEB was only 0.2%. The pooled sensitivity of evaluating ER, PgR, and HER2 status in CNB compared with OEB was 0.970, 0.911, and 0.799 (0.813 for HER2[b]), respectively. All of AUC values for these status determination were larger than 0.9. Heterogeneity between studies was introduced by various factors in PgR and HER2[b] analysis. Subgroup analysis showed that the specificity and OR of CNB in studies with ER positive rate >78% was lower than studies with ER positive rate ≤78% (P < 0.05). This meta-analysis indicated that CNB had high diagnostic accuracy in evaluating ER, PgR, and HER2 status compared with OBE in breast cancer patients. In terms of 2-3% positive rate difference, ER and PgR status should be detected both on CNB and OEB samples, especially to retest their expression on CNB in patients with hormonal receptor negative tumors in OEB.

Utility of Breast Magnetic Resonance Imaging in Determining Candidacy for Partial Breast Irradiation

Isolated adrenal metastases of invasive ductal breast carcinoma are extremely rare. We report a case with isolated left adrenal metastases, verified three years after diagnosed breast carcinoma. A 58-year-old female patient with a right breast tumor, clinically staged as IIIA (T2N2M0) started neoadjuvant anthracycline chemotherapy after biopsy which revealed invasive ductal breast carcinoma. Immunohistochemical findings of tumor biopsy showed hormonal steroid receptors for estrogen and progesterone negative, and human epidermal growth factor receptor 2 (HER2) positive. After 4 cycles of chemotherapy and partial tumor regression the patient underwent radical mastectomy. Definite histopathological analysis confirmed the diagnosis of invasive ductal carcinoma. The patient continued treatment with adjuvant chemotherapy to cumulative dose of anthracyclines, postoperative radiotherapy and adjuvant trastuzumab for one year. Three years later abdominal computerized tomography showed tumor in the left adrenal gland as the only metastatic site. Left adrenalectomy was performed and histopathological finding confirmed breast cancer metastases. Postoperatively, the patient received 6 cycles of docetaxel with trastuzumab and continued trastuzumab until disease progression. One year after left adrenalectomy control abdominal computerized tomography showed a right adrenal tumor with retroperitoneal lymphadenopathy. Treatment with capecitabine was continued for one year, but eventually she developed brain metastasis causing lethal outcome. In order to better understand metastatic pathways of invasive ductal breast carcinoma, publications of individual patient cases diagnosed with rare metastatic sites should be encouraged. This might improve our understanding of metastatic behavior of breast cancer and stimulate further clinical research.

Background: Worldwide, biopsy is the gold standard for pathological assessment of cancer. Routinely, immunohistochemistry (IHC) can be performed to evaluate various tumor markers on serial sections of formalin-fixed paraffin-embedded (FFPE) tissue. Comprehensive molecular analysis of biopsy is limited by the microscopic size of samples and the scarcity of quantitative tools for FFPE tissue examination. Development of the new tools for molecular analysis of biopsy is needed to stratify, as early as possible, a patient’s individual risk for tumor aggressiveness and sensitivity to therapy to avoid potential over- and under treatment. Objective: To assess the feasibility of direct mRNA expression profiling of all three classic clinical markers of cancer progression - estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2) in routinely collected FFPE core needle biopsy (CNB) of the breast. Methods: We obtained tissue from the Department of Pathology and Laboratory Medicine at the University of Pennsylvania, the University of Pennsylvania Tumor Tissue and Biospecimen Bank and the Cooperative Human Tissue Network. Steroid hormone receptor and HER2 status, determined by FDA-approved methods, was obtained from the surgical pathology reports. For direct (i.e. without amplification) mRNA profiling, we ran the Panomics/Affymetrix QuantiGene Plex 2.0 assay on Luminex according to manufacturer’s protocol. After the removal of low-abundance housekeeping genes expressing samples, the relative activity of target genes, ERS1, PGR, ERBB2 encoding ER alpha, PR and HER2 was detected. mRNA profiling was completed in 107 breast samples: 6 clinically normal (N) cases from reduction mammoplasty, 17 ductal carcinoma in situ ( DCIS) on CNB , 42 invasive ductal carcinoma (IDC) and 42 non-malignant matched tissue from surgical excisions. Groups were compared using one-way analysis of variance (ANOVA). Results: A pair-wise comparison among tissue groups revealed 3-fold higher expression levels of ERS1 in ER+ DCIS on CNB (P=. 055), and statistically significantly higher expression levels of ERS1 in the ER+/PR+ (P= .021) and ER+/PR- (P= .004) subgroups of IDC than in the N group. Remarkably, compared with N tissue, ERS1 levels were already decreased in non-malignant tissue adjacent to ER-/PR-/HER2- subgroup of IDC and were further significantly decreased in ER-/PR-/HER2- IDC itself (P= .023). Compared to the N group, significant decreases in PGR levels were found only in ER-/PR-/HER2- subgroup of IDC (P= .003), whereas significant increases in ERBB2 levels were found in both HER2+ DCIS on CNB (P= . 037) and HER2+IDC in excisions (P= .005). Conclusions: Our study, for the first time, proved the feasibility of using FFPE CNB as an RNA source for direct mRNA expression profiling. These findings support the notion that IHC evaluation of ER, PR, and HER2 status in the CNB DCIS may be complemented by concurrent detection of ESR1/PGR/ERBB2 mRNA levels. Citation Format: Indira Prabakaran, Paul J. Zhang, Marina Guvakova. The diagnostic power of direct mRNA profiling in breast cancer core biopsy. [abstract]. In: Proceedings of the Fourth AACR International Conference on Frontiers in Basic Cancer Research; 2015 Oct 23-26; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2016;76(3 Suppl):Abstract nr B24.

Breast cancer (BC) ranks the highest among all cancers of women worldwide. Mammography is the most widely utilized imaging tool for evaluation of breast cancer and the final diagnosis of BC is made on histopathology. This study aimed at describing the demographic, clinical and mammographic characteristics of proven invasive ductal carcinoma (IDC) of breast in a group of Sri Lankan women. The study was carried out using a database on mammography maintained by the principal investigator. Study sample was consisted of 177 subjects with histologically proven invasive ductal carcinoma of breast. The mean age of subjects was 52.2 years (SD ± 1.1). Majority (63.8%) of the subjects were post menopausal. 93% of them presented with symptomatic breast disease, and among them the commonest symptom was a palpable mass (90.7%). Presentation for mammography after observing symptoms showed a median delay of 28 days. BC was found mostly in involuting type of breasts. Commonest mammography characteristic was a mass (86.4%). Size of the mass was between 2 cm to 5 cm in majority (84.3%) with T stage II disease. In conclusion, mean age of the subjects was comparable to other Asian countries but relatively lower than that of the west. Majority of patients presented with a palpable mass within four weeks from the onset of symptoms. The size of the mass did not show a significant correlation with the duration of symptoms and the age. This study did not find a significant association between mammographic breast density with IDC.

In 1973, the European Institute of Oncology performed the first prospective neoadjuvant chemotherapy study in locally advanced, inoperable breast cancer. The original purpose was to downstage the primary tumor in order to achieve surgical resection. This approach has subsequently increased in popularity, and in the last 10 years, randomized controlled trials of neoadjuvant chemotherapy have been performed with a view to further downstage the primary tumor and lymph nodes in order to achieve greater rates of breast-conserving surgery and to test whether systemic therapy given earlier would confer a survival benefit. Although the net result of these trials did demonstrate a higher rate of breast conservation, no overall survival benefit was seen. However, in subgroup analysis, there was a significant survival benefit in patients in whom a complete pathologic response (pCR) was achieved. In the National Surgical Adjuvant Breast and Bowel Project B-18 trial of neoadjuvant chemotherapy, at 9 years median follow-up, the overall survival rate for patients achieving a pCR was 85% compared with 73% in those in whom residual cancer was detected on histopathologic examination. For disease-free survival, the respective rates were 75% and 58%. After adjustment for other prognostic factors, achievement of a pCR was associated with a 50% reduction in deaths compared with the group as a whole. Mauri et al evaluated nine randomized studies, with a total of 3,946 patients with breast cancer in whom neoadjuvant therapy was compared with adjuvant systemic therapy. They found no statistically or clinically significant difference between neoadjuvant therapy and adjuvant therapy arms with regard to overall survival, disease progression, or distant disease recurrence. However, they observed that neoadjuvant therapy was associated with an increased risk of locoregional disease recurrence compared with adjuvant therapy, especially in trials where more patients in the neoadjuvant arm received radiation therapy without surgery. In several retrospective studies, the pCR rates in invasive ductal breast carcinoma (no special type) have been shown to be approximately 15% or less, whereas the pCR rates in invasive lobular carcinoma have been shown to be 2% or less. Katz et al reviewed randomized trials of neoadjuvant chemotherapy and noted that the pCR rate was 1.7% in invasive lobular carcinoma and 11.6% in invasive ductal breast carcinoma (no special type). Regarding invasive lobular carcinoma, they concluded: “the benefit from systemic chemotherapy for individuals with this form of breast disease is unclear.” Similarly, two retrospective studies have demonstrated low rates of successful breast conservation for patients with lobular carcinoma who underwent neoadjuvant chemotherapy. In patients who received breast-conserving surgery after neoadjuvant therapy, Soucy et al found surgical margin involvement in 43% of patients with lobular carcinoma compared with 16% of patients with invasive ductal carcinoma (no special type). Another study, from the M. D. Anderson Cancer Center, of 284 consecutive patients diagnosed with pure invasive lobular carcinoma between 1998 and 2006 compared patients who received neoadjuvant chemotherapy with those who received primary surgery as first-line treatment and concluded that neoadjuvant chemotherapy did not increase the rates of breast conservation in this morphologic subtype. It should be noted that the above studies are retrospective, not randomized, trials. In the three randomized trials of neoadjuvant endocrine therapy (P024 conducted by the Letrozole Neoadjuvant Breast Cancer Study Group, IMPACT [Immediate Preoperative Anastrozole, Tamoxifen, or Combined with Tamoxifen], and PROACT [Pre-Operative “Arimidex” Compared to Tamoxifen]) for women with estrogen receptor (ER) –positive disease, none of which carried out analysis of histological tumor type (ie, lobular v ductal [no special type]), a higher rate of breast conservation was observed in women who received preoperative endocrine treatment. The lack of subgroup analysis in these three studies does not allow one to draw conclusions regarding histologic type-specific effectiveness of neoadjuvant endocrine treatment, although classical lobular carcinoma is well recognized as more often being ER positive than ductal tumors (no special type). JOURNAL OF CLINICAL ONCOLOGY COMMENTS AND CONTROVERSIES VOLUME 28 NUMBER 22 AUGUST 1 2010

Management of classic lobular neoplasia (cLN) diagnosed on core needle biopsy (CNB) is controversial. Our aim in this study was to review cases of cLN diagnosed on CNB to determine the rate and risk factors of an upgrade to ductal carcinoma in situ (DCIS) or invasive carcinoma on excision. All breast CNBs with a diagnosis of atypical lobular hyperplasia (ALH) or classic lobular carcinoma in situ (cLCIS) from three different institutions within a single health care system between 2013 and 2018 were retrieved. Cases with any additional high-risk lesions in the same CNB or discordant radiological-pathological correlation were excluded. Information about age, personal history of prior or concurrent breast cancer (P/CBC), and radiological and histological findings were recorded. A total of 287 cLN cases underwent surgical excision. Analysis of these 287 cLN cases showed 11 (3.8%) upgrade lesions on excision. Among the 172 ALH cases, there were 3 (1.7%) upgrades, which were all invasive lobular carcinomas (ILCs). On the other hand, 8 of 115 (7%) cLCIS cases revealed upgrade on excision (2 ILC, 5 DCIS. and 1 ILC + DCIS). Statistical analysis revealed that cLN cases with P/CBC, radiological asymmetry, or architectural distortion had a statistically significant higher upgrade rate on excision. Our findings revealed a low upgrade rate (3.8%) on the excision of classic lobular neoplasia diagnosed on breast core needle biopsy. Clinicoradiological surveillance can be appropriate when lobular neoplasia is identified on core biopsy with pathological radiological concordance in patients without a history of breast cancer, with the caveat that radiological asymmetry and architectural distortion are associated with a significant increase in an upgrade on excision.

Breast cancer is a serious health problem. It is the most common cancer in women. The aim of this study was to estimate the concordance between ER, PR receptor and HER-2 immunohistochemistry assessment scores in pared CNB (core needle biopsy) and surgical specimens. Histological grade, oestrogen receptor (ER) status, progesterone receptor (PR) status, and human epidermal growth factor receptor-2 (HER2) status were evaluated in a blinded fashion in CNB and in surgical excision specimens. Absolute concordance rate between core needle biopsies and surgical specimens for histological grade was 50% with κ value (0,15) for ER 92% with κ value (0,79), PR 88% with κ value (0,73) and for HER2 96% with κ value (0,91). CNB can provide reliable information in evaluation of ER, PR and HER2 status in an invasive breast carcinoma.

600 Background: When pathological complete response (pCR) is achieved in node-positive breast cancer after neoadjuvant chemotherapy (NAC), identifying traces of the previous lesion becomes challenging which makes accurate surgery difficult. We conducted targeted axillary surgery (TAS) in node-positive breast cancer after NAC, which involves accurately targeting the lymph nodes where metastasis occurred and performing surgery using a less extensive method. The 10-year outcomes were compared with those of patients who underwent conventional axillary lymph node dissection (ALND). Methods: We conducted a retrospective analysis of 235 patients with cT1-3N1-2 breast cancer who received NAC from 2012 to 2017. In this cohort, 78 patients underwent TAS only, and 157 underwent conventional ALND, including 31 patients who initially received TAS followed by additional ALND. Oncologic results, including locoregional recurrence-free survival (LRFS), distant metastasis-free survival (DMFS), and overall survival (OS), were assessed over a 10-year follow-up period. Survival outcomes for all patients and each subtype were analyzed using Kaplan-Meier survival methods. Results: The TAS group had significantly more postmenopausal patients (p=0.022), and the most common type of breast cancer was invasive ductal carcinoma [TAS: 75 (96.2%); ALND: 157 (100.0%)]. There was no statistical difference in the T stage and the number of lymph nodes suspected of metastasis at diagnosis (p=0.062, 0.985). Mastectomy was performed in 60.3% of patients in the TAS group and 93.0% in the ALND group (p&lt;0.001), and 68 (87.2%) of the TAS group and 41 (26.1%) of the ALND group received additional axillary radiotherapy (p=0.019). There was no significant difference in oncologic outcomes between the TAS and ALND groups in all patients (LRFS, p=0.673; DMFS, p=0.729; OS, p=0.396) and based on subtypes, including hormone receptor (HR)-positive, HER2-positive, and triple-negative breast cancer (TNBC). In the HR-positive breast cancer group, the TAS and ALND groups showed very similar trends (LRFS, p=0.954; DMFS, p=0.993; OS, p=0.617). In HER2-positive breast cancer, although not statistically significant, the survival outcomes were better in the TAS group than in the ALND group (LRFS, p=0.967; DMFS, p=0.999; OS, p=0.423). However, the OS in the TAS group for TNBC was lower than that in the ALND group, though not significantly (LRFS, p=0.411; DMFS, p=0.697; OS, p=0.210). Conclusions: This study demonstrates that TAS is comparable to ALND in terms of 10-year oncological outcomes across different types of node-positive breast cancer, suggesting its potential as a viable alternative. However, further research focusing on patient quality of life and postoperative complications is essential to establish TAS as a superior surgical option to ALND.

Removed.

Breast carcinoma with osteoclast-like stromal giant cells (OCGC) is a rare histological variant of invasive breast carcinoma. While it typically presents as a unilateral disease, its clinicopathological significance and the mechanisms underlying its formation remain incompletely understood. To our knowledge, a case of synchronous bilateral primary invasive ductal carcinoma with OCGCs has not been previously reported. A 44-year-old premenopausal woman was diagnosed with synchronous bilateral invasive ductal carcinoma with OCGCs. Imaging revealed small masses in both breasts, and core needle biopsies demonstrated invasive carcinoma with associated non-invasive components and numerous OCGCs in the tumor stroma. Both tumors were hormone receptor-positive and human epidermal growth factor receptor 2 (HER2)-negative (luminal A-like). The patient underwent bilateral mastectomy and sentinel lymph node biopsy, which showed no lymph node metastasis. The postoperative course was uneventful, and the patient has remained recurrence-free for six months after surgery.Notably, final pathological examination confirmed independent ductal carcinoma in situ (DCIS) components with OCGCs in both breasts, supporting the diagnosis of bilateral primary tumors rather than metastatic disease.Immunohistochemically, the OCGCs were CD68-positive, confirming their macrophage lineage.Genetic testing showed no pathogenicBRCA1/2variants. This report highlights an extremely rare, pathologically confirmed case of synchronous bilateral primary breast carcinoma with OCGCs. The presence of OCGCs in both invasive and in situ components suggests that their formation can be induced at early stages of tumor development, likely reflecting a distinct immune-reactive tumor microenvironment driven by host-related factors.