Encapsulated Papillary Carcinoma Research Articles

Encapsulated papillary carcinoma of breast: Comparative study of multimodal ultrasound manifestations and pathological features.

To investigate the conventional ultrasound (US), contrast-enhanced ultrasound (CEUS) manifestations and the corresponding histopathological characteristics of patients diagnosed with breast encapsulated papillary carcinoma (EPC) and to explore the value of CEUS in diagnosis of EPC. The clinical, pathological, US, and CEUS features of 16 patients (17 lesions) with EPC confirmed by postoperative histopathology were retrospectively analyzed. EPC was prevalent in the postmenopausal women. The majority of conventional US images of EPC showed complex cystic and solid masses with circumscribed margins (70.6%), enhanced posterior echo (94.1%), no sonographic calcification (88.2%), rich blood flow in the solid components within lesions (70.6%) on Color Doppler flow imaging, and high resistance index of blood flow (94.1%). Moreover, CEUS showed mainly centripetal hyperenhancement of the solid components within the lesions with irregular outline, and the enhancement area of the whole masses was essentially the same as the B-mode US area. EPC typically presents as a complex cystic and solid mass. CEUS is helpful to clarify the extent of the solid component and facilitate preoperative core-needle biopsy. A comprehensive evaluation by CEUS is valuable for diagnosing EPC and combining it with clinical features are helpful to further improve the diagnosis of this rare kind of breast cancer.

Controversies regarding encapsulated papillary carcinoma of the breast: an approach to evaluation and categorisation.

Malignant papillary lesions, and in particular, encapsulated papillary carcinoma (EPC) of the breast, continue to present diagnostic challenges for the practising pathologist. In addition to the relative rarity of these lesions, the lack of evidence-based diagnostic criteria, differences in the biological characteristics, and the clinical behaviour of in situ and invasive forms, variable use of immunohistochemical markers, and overlap with other tumour types including high-grade circumscribed forms of invasive breast carcinomas has resulted in diagnostic discordance with potentially significant clinical and management implications. Pathologists should be familiar with the range of morphology observed in malignant papillary tumours, EPC, and EPC-like tumours and the existence of tumours with overlapping features. In this review we summarize the common diagnostic pitfalls in malignant papillary tumours and provide an approach to the diagnostic evaluation and categorisation of these enigmatic entities.

Encapsulated papillary carcinoma of the breast clinicopathological features and management: Could sentinel lymph node biopsy be exempted?

Papillary lesions in the breast pose diagnostic and therapeutic challenges. Encapsulated papillary carcinoma (EPC) is a rare breast cancer. However, evidence-based guidelines are limited. For this reason, there is no complete clarity in diagnosis and treatment management, and there are insufficient studies in the literature. This study aimed to examine the necessity of sentinel lymph node sampling in the management of EPC, in line with patients' clinicopathological data. We retrospectively screened patients with EPC in our clinic between January 2012 and March 2022. We recorded and statistically evaluated patients' demographic, clinical, radiological, pathological, and treatment management. Sixty-four patients with EPCs were identified. The final pathologic evaluation revealed that 19 patients (18.7%) had pure EPC, 27 patients (43.7%) had EPC with associated ductal carcinoma in situ and 18 patients (37.5%) had EPC associated with invasion. The mean age was 61 years, and two patients were male. Breast-conserving surgery was performed in 62 patients, and simple mastectomy was performed in two patients. Sentinel lymph node biopsy (SLNB) was positive in only one patient. Sixty-three patients with EPC were hormone receptor-positive, and one patient was triple-negative and was associated with invasion. None of the patients died, one had a local recurrence, and a mastectomy was performed. The overall prognosis and long-term survival of patients with EPC were excellent. Our study and the current literature indicate that routine SLNB is overtreatment because surgical excision with negative margins is sufficient in EPC cases and lymph node metastasis is rare, even with an invasive component.

Abstract PO1-21-01: A Case of High Grade Metastatic Encapsulated Papillary Carcinoma and a Look at Current Treatment Guidelines

Abstract Background: Encapsulated papillary carcinoma is a well-documented malignancy in the world of breast surgery. It is often described as a less invasive form of breast cancer, with a more indolent clinical course. Most EPC pathology demonstrates low grade tumors, with rare findings of metastases at time of diagnosis. EPC currently accounts for 1-2% of all breast cancers. It is distinguished by its fibrovascular core, which is covered with epithelium with or without a myoepithelial layer. Despite EPC being well-recognized, current management remains controversial. Most commonly, however, it is treated and managed as an in-situ disease. Case Presentation: We present a case of a 64-year-old female who initially presented with a painless lump in her left breast, which on biopsy demonstrated DCIS involved with a papillary lesion. On excision, the patient was upstaged to IDC in a background of EPC. She then underwent re-excision with confirmed negative margins. Despite this, over the following months, the patient continued to have increased pain, swelling, and an episode of superficial thrombophlebitis. She was taken back to the OR at this time and was found to have a new mass with a large feeding vein. Pathology was significant for high grade multifocal EPC with small and large vessel lympho-vascular invasion. Lesion noted to be metachronous. Additionally, metastases to the axilla were identified, requiring an axillary dissection. Conclusion: High grade encapsulated papillary carcinoma is a rare member of the indolent papillary breast cancer family. This unusually invasive type of cancer should be treated and managed in a more aggressive fashion, like its clinically similar cousin invasive ductal carcinoma. The current management standard of treating EPC as in situ disease is not robust enough and can lead to disease recurrence and need for repeat resection and treatment. Citation Format: Nicholas Gore MD, Madeline Silva MD, Carissia Calvo-Strube MD. A Case of High Grade Metastatic Encapsulated Papillary Carcinoma and a Look at Current Treatment Guidelines [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 PO1-21-01.

Rare Presentations of Encapsulated Papillary Carcinoma: A Case Report in Male Breast and a Case of Upfront Metastatic Presentation

Encapsulated papillary carcinoma (EPC) of the breast, while rare, presents unique diagnostic and management challenges. This report sheds light on two exceptional cases of EPC, diverging from typical clinical presentations. The first case involves a male patient, while the second exhibits an unusual upfront manifestation with metastasis. Through detailed clinical examinations, imaging modalities, and histopathological analyses, both cases underscore the importance of thorough evaluation and tailored treatment strategies in managing this rare malignancy. Additionally, insights from epidemiological data and treatment paradigms further elucidate the complexities surrounding EPC diagnosis and management, emphasizing the need for individualized approaches to optimize patient outcomes.

Encapsulated Papillary Carcinoma of the Breast: A Review of Clinicopathologic Characteristics, Molecular Mechanisms, and Patient Management.

Encapsulated papillary carcinoma (EPC) represents a distinct entity within the spectrum of breast papillary tumors, typically manifesting as a retroareolar mass. This rare subtype can be effectively visualized using ultrasound and magnetic resonance imaging, which reveal characteristic cystic-solid nodules. Histopathologically, EPC is defined by a papillary tumor structure with a well-defined fibrous capsule, devoid of myoepithelial cells both within and around the capsule. Immunohistochemical staining for myoepithelial markers is essential to confirm the absence of these cells, thereby validating the diagnosis of EPC. At the molecular level, EPC exhibits feature similar to estrogen receptor-positive invasive ductal carcinoma (IDC), with a biological behavior that lies between ductal carcinoma in situ (DCIS) and IDC. Generally, EPC has a favorable prognosis, associated with minimal recurrence and metastatic potential. Therapeutic strategies for EPC may parallel those for DCIS, including surgical excision. Adjuvant radiotherapy is recommended following surgery for patients with concurrent DCIS or those who have undergone breast-conserving therapy. In cases with associated IDC, management prioritizes the treatment of the invasive component. High-grade EPC often requires systemic therapies due to its poorer prognosis and increased risk of lymph node involvement.

Bilateral multicentric encapsulated papillary carcinoma of the breast: A rare case report

Bilateral multicentric encapsulated papillary carcinoma of the breast: A rare case report

Large encapsulated papillary carcinoma presenting as an arteriovenous malformation

Encapsulated papillary carcinomas (EPCs) are a rare breast tumour that carry a good prognosis. They are typically 0.5-8.0 cm in size and commonly present with a painless mass and bloody nipple discharge. We present an 80-year-old female with a 15.0 cm EPC, the largest reported in literature, that presented with an expanding breast haematoma and a distant history of breast trauma. Anaemic symptoms post initial aspiration, previous arterial injury to the same breast and prominent feeding vessels to the mass seen on both imaging, and at time of mastectomy, raise the differential of underlying vascular malformation.

Application of ultrasound-based radiomics models of breast masses to predict invasive components of encapsulated papillary carcinoma.

Axillary lymph node (ALN) metastasis is seen in encapsulated papillary carcinoma (EPC), mostly with an invasive component (INV). Radiomics can offer more information beyond subjective grayscale and color Doppler ultrasound (US) image interpretation. This study aimed to develop radiomics models for predicting an INV of EPC in the breast based on US images. This study retrospectively enrolled 105 patients (107 masses) with a pathological diagnosis of EPC from January 2016 to April 2021, and all masses had preoperative US images. Of the 107 masses, 64 were randomized to a training set and 43 to a test set. US and clinical features were analyzed to identify features associated with INVs. Then, based on the manually segmented US images to obtain radiomics features, the models to predict INVs were built with 5 ensemble machine learning classifiers. We estimated the performance of the predictive models using accuracy, the area under the receiver operating characteristic (ROC) curve (AUC), sensitivity, and specificity. The mean age was 63.71 years (range, 31 to 85 years); the mean size of tumors was 23.40 mm (range, 9 to 120 mm). Among all clinical and US features, only shape was statistically different between EPC with INVs and those without (P<0.05). In this study, the models based on Random Under Sampling (RUS) Boost, Random Forest, XGBoost, AdaBoost, and Easy Ensemble methods had good performance, among which RUS Boost had the best performance with an AUC of 0.875 [95% confidence interval (CI): 0.750-0.974] in the test set. Radiomics prediction models were effective in predicting the INV of EPC, whereas clinical and US features demonstrated relatively decreased predictive utility.

Encapsulated papillary carcinoma of the breast: A single institution experience.

Encapsulated papillary carcinoma (EPC) is a relatively rare form of breast cancer. To date, no evidence-based guidelines for the treatment of EPC have been established. Between January 2015 and December 2021, patients with histologically confirmed EPC of the breast were recorded in a database by The Third Hospital of Nanchang City (Nanchang, China). A total of 46 patients with EPC were retrieved from the database. Age at diagnosis ranged from 41-88 years (median age, 62 years). A total of 21 of these patients had pure EPC, 6 patients had EPC associated with ductal carcinoma in situ and 19 patients had EPC associated with invasive carcinoma. The majority of EPC cases were low nuclear grade, hormone receptor-positive and human epidermal growth factor receptor-2-negative. Additionally, myoepithelial cells were always absent in the papillae of the EPC. All patients underwent lumpectomy or mastectomy with sentinel lymph node biopsy, and almost all of the patients received adjuvant hormonal therapy. Adjuvant chemotherapy was only suggested to 4 patients who were diagnosed with axillary lymph node involvement. Subsequently, the clinicopathological features of non-invasive EPC were compared with invasive EPC. The results indicated that larger tumor sizes and axillary lymph node metastases were more common in invasive tumors. During the follow-up, only 2 patients with invasive EPC experienced recurrence or metastasis. In conclusion, a substantial proportion of invasive EPC cases display aggressive characteristics and metastatic potential, despite it being considered a subtype of carcinoma in situ with excellent prognosis, and local surgical resection is the initial method of treatment. Therefore, adjuvant endocrine therapy, radiotherapy and chemotherapy should be considered in select patients, especially in those diagnosed with invasive EPC tumors.

Encapsulated Papillary Carcinoma of the Breast.

Encapsulated Papillary Carcinoma of the Breast.

Encapsulated Papillary Carcinoma of The Breast: A Case Report of Rare Male Breast Cancer Clinically Presented as Soft Tissue Tumor

BACKGROUND: Male breast cancer is a rare condition, accounting for less than 1% of all breast cancers, and infiltrating ductal carcinoma is the most common type. However, Encapsulated Papillary Carcinoma (EPC) in males is a rare type of breast cancer, and the exact etiology is unknown. CASE REPORT: A 66-year-old male presented with a 15x10 cm mobile swelling over the left side of the anterior chest wall, which was clinically and radiologically diagnosed as a soft tissue tumor. Wide local excision of the swelling of the anterior chest wall was performed. Grossly, it was an encapsulated tumor with solid and cystic areas filled with gelatinous material, papillary excrescences, hemorrhage, and necrosis. Microscopic examination revealed Grade 2 encapsulated papillary carcinoma of the left breast. CONCLUSION: This case report highlights the importance of considering male breast cancer as a differential diagnosis in patients presenting with anterior chest wall soft tissue swelling. Keywords: Male breast cancer, encapsulated papillary carcinoma, anterior chest wall swelling.

Demographic characteristics of encapsulated papillary carcinoma.

e12562 Background: Encapsulated papillary carcinoma (EPC) is a very rare form of breast cancer characterized by fibrous encapsulation and expansile growth, causing 1-2% of all cases. A summary of 25 case reports found that although two-thirds of cases had invasive growth, EPC responded well to local therapy and is considered a favorable diagnosis as a result. Because classification and diagnostic criteria for EPC continues to be debated, examination of the demographics could prove useful in determining trends. Methods: A retrospective cohort study done using data from the National Cancer Database (NCDB) from 2004–2020 found 314 patients with an EPC diagnosis through histology. The following demographics were considered: age, sex, race, Hispanic identity, distance from residence to treatment facility, insurance coverage, type of facility, and Charleson-Deyo score. These variables were then analyzed through descriptive statistics. Results: 314 patients were identified with a steadily increasing number of cases diagnosed per year until 2018, when cases per year dropped from 46 to 6 or below for the remaining 3 years (2018, 2019, 2020). Of these 314 patients, 16 were male and 298 were female. (5.1% and 94.9%, respectively). The average age of diagnosis was 69.6 years with a standard deviation of 11.8 and a range of 30 to &gt; 90 years. The majority (99.7%) were found in the breast, with the remaining found in the endometrium. The majority of individuals (82.2%) had Charlson-Deyo comorbidity scores of 0. The majority of patients were non-Hispanic White, accounting for 88.9% of the total. A higher number of patients belonged to the highest income bracket, with 35.0% in the top quartile compared to those in other quartiles. The majority of patients had Medicare insurance, making up 63.1% of the total. More patients resided in counties with over 1 million people (56.7%) compared to those living in counties with a population below 1 million (43.3%). Most patients were treated at non-academic cancer centers (65.6%). On average, patients lived 19.8 miles (SD = 74.7, range = 1.8 – 370) from the treatment facility. Conclusions: Based on our literature review, this is the first NCDB analysis on EPC and thus addresses a significant knowledge gap on the topic. With an average age of diagnosis at 69.6 years, it is not surprising that the majority of patients were insured through Medicare. Male cases, while rare, support previous literature. Most commonly, EPC patients were most diagnosed in metropolitan areas. The majority of cases were diagnosed in the breast and most patients were treated at non-academic medical centers. While the vast majority of cases occurred in non-Hispanic white patients, it is unclear how much is due to race and how much is related to disparities in healthcare access and underdiagnosis in non-white races. Thus, further research is needed to understand which demographic factors prove to be the strongest predictors of EPC.

Encapsulated papillary carcinoma of the breast: does it have a native basement membrane?

Encapsulated papillary carcinoma (EPC) is surrounded by a thick fibrous capsule-like structure, which is interpreted as a thickened basement membrane (BM). This study aimed to describe the geometric characteristics of the EPC capsule and to refine whether it is an expansion of the BM or a stromal reactive process. In all, 100 cases were divided into four groups: EPC, ductal carcinoma in situ (DCIS), normal breast tissue and invasive tumours, with an additional encapsulated papillary thyroid carcinoma (EPTC) control group. Representative slides from each case were stained with picrosirius red (PSR) stain and examined using polarised microscopy. Images were analysed using ImageJ, CT-FIRE, and Curve align image analysis programmes. Compared to the normal and DCIS BM, the EPC group showed a significant increase of collagen fibre width, straightness, and density, and a decrease of fibre length. The EPC capsule showed less alignment of fibres with a more perpendicular arrangement, and it was enriched with disorganised collagen type I (stromal collagen) fibres. Compared to other groups, the EPC capsule showed significant variation in the thickness, evenness, distribution of collagen fibres, and significant intracapsular heterogeneity. Compared to BM-like material in the invasive group, the EPC capsule showed a higher density of collagen fibres with longer, straighter, and more aligned fibres, but there was no difference in the distribution of both collagen types I and III. Conversely, compared to EPTC, there were no differences between both EPC and EPTC capsules except that the fibres in the EPC capsule were straighter. Although differences between normal ducts and lobules and DCIS BM collagen fibre density, straightness, orientation, and alignment were detected, both were significantly different from EPC capsule. This study provided evidence that the EPC capsule is a reactive process rather than a thickened native BM characteristic of normal and in situ lesions, which provides further evidence that EPC is an indolent invasive carcinoma based on capsule characteristics.

Papillary Carcinoma of Breast: Clinicopathological Characteristics, Management, and Survival.

Objective To study clinicopathological features, treatment strategies, and prognosis of papillary carcinoma of breast. Material and Methods. Data from 58 patients were retrospectively reviewed from January 2010 to December 2016. Four types of papillary carcinoma (on final resected specimen) were included, i.e., invasive papillary carcinoma (IPC), intracystic (encapsulated) papillary carcinoma (EPC), solid papillary carcinoma (SPC), and papillary DCIS (ductal carcinoma in situ). Various features of the four types were observed and compared. Results Of the 58 patients, 8 were males (13.7%). The mean age at presentation was 61 years; the mean tumor size was 33 mm. The frequency of each histological type was as follows: IPC (n = 22/38%), EPC (n = 22/38%), SPC (n = 12/20.6%), and papillary DCIS (n = 2/3.4%). Only two patients were ER negative (both IPC). HER-2 Neu was positive in 3 patients only, out of which 2 died of progressive disease (one EPC and one IPC). LN metastasis was present in 3 (5%) patients (one in each of 1st three types) and only one died of bone metastasis that was also Her-2Neu positive. All patients underwent upfront surgery except two patients who had synchronous IDC on the contralateral side. Breast conservation surgery (BCS) was performed in 34 (58.6%) and mastectomy in 22 (37.9%) patients. 13 patients did not undergo invasive axillary staging; the rest of 43 (74%) patients did (32 sentinel biopsy and 11 axillary dissection). Chemotherapy was given to 18 patients (31%), mostly to IPC (n = 12). Only 2 patients had bone metastasis (one was IPC and one EPC). Cancer-related death was observed in 3 patients. For all groups combined, 5-year OS was 98% and DFS was 92%. Conclusion Overall, papillary carcinoma of the breast has an excellent prognosis, even though less intense treatment modalities were used. It is still difficult to define the optimum management and avoid overtreatment, given the limited data in the literature.

Significance of Myoepithelial Cell Layer in Breast Ductal Carcinoma in situ With Papillary Architecture With and Without Associated Invasive Carcinoma

IntroductionThe significance of absence of myoepithelial cells in circumscribed papillary breast lesions is controversial. When the DCIS with papillary architecture is associated with adjacent conventional invasive carcinoma, the size and stage of the carcinoma could vary substantially depending on whether the intraductal papillary component lacking a periductal ME cell layer is interpreted as invasive or intraepithelial/in situ. DesignIn a retrospective search of the pathology database at our institution for papillary DCIS (PDCIS), solid papillary carcinoma (SPC), and encapsulated papillary carcinoma (EPC) from 2001 to 2014, 73 lesions (42 PDCIS, 19 SPC, 12 EPC) with and without associated invasive carcinoma were identified and reviewed. Forty-five lesions (22 PDCIS, 14 SPC, and 9 EPC) were associated with invasive carcinoma. ResultsMajority of PDCISs (37 of 42) demonstrated retained myoepithelial cells around periphery of the ducts. Three cases showed discontinuous staining and 2 cases showed absent myoepithelial cells in the periphery of the ducts. No lymph node metastases were seen in DCIS in the absence of histologic evidence of invasion regardless of absence of ME cells around foci of DCIS. With a median follow-up period of 107 months, six distant metastases occurred, all in patients with invasive carcinoma. ConclusionsThe absence of ME cells around ducts harboring the PDCIS, SPC, or EPC is not indicative of an invasive process. The prudent use of morphologic criteria is critical to avoid overstaging and overtreatment.

Encapsulated Papillary Carcinoma: A Rare Case Report and Its Imaging Features.

Papillary lesions in the breasts are uncommon and have a wide range of pathologies. Due to diverse non-specific findings radiologically and histologically, papillary neoplasms are always a challenge to radiologists. Encapsulated papillary carcinomas (EPCs) of the breast, also known as intracystic papillary carcinomas, are a subgroup of intraductal papillary lesions of the breast. We present a case of a painless right breast lump with the aim to describe a rare encapsulated papillary carcinoma and its imaging features.

Invasive Lobular Carcinoma Mimicking Encapsulated Papillary Carcinoma with a Literature Review: A Rare Variant Detected Serendipitously.

Invasive lobular carcinoma with papillary features is a newly proposed variant which presents as a relatively well-circumscribed mass lesion with at least partial peripheral thickened fibrous capsule and central delicate fibrovascular cores, morphologically mimicking encapsulated papillary carcinoma or solid papillary carcinoma. There are only 5 cases described in literature. We here report an interesting example of invasive lobular carcinoma with papillary growth pattern surrounded by a thick fibrous capsule, mimicking encapsulated papillary carcinoma (EPC). The lobular nature of the tumor was confirmed by the absence of membranous expression of E-cadherin and p120 catenin. The lobular cytological features are subtle in this variant and may be overlooked. Differentiation of this variant from papillary carcinomas is crucial for correct tumor categorization, staging and most importantly, proper treatment.

Digital Mammography, Ultrasound and Magnetic Resonance Imaging Characteristics in Differential Diagnosis of Papillary Carcinoma Subtypes of the Breast and Diagnostic Challenges.

We aimed to investigate mammography (MG), ultrasound (US), and magnetic resonance imaging (MRI) findings of papillary breast carcinoma subtypes and to compare the diagnostic features and performance of the imaging method in distinguishing subtypes. Forty-two patients presenting with pathological diagnosis of 45 papillary carcinoma lesions, between 2014 and 2019, were included. Cases were assigned to five subgroups according to the latest World Health Organization (WHO) classification. The clinical characteristics (n = 45) and imaging features of each pathological subgroup were retrospectively related to imaging findings from US (n = 45), MG (n = 37), and breast MRI (n = 23), and further compared. The finding of a palpable mass in all subgroups was more common than nipple discharge on clinical breast evaluation, and no significant difference was found between the subgroups. Irregular shape on MG (10/12, 83.3%, p = 0.039) and US (11/12, 91.7%, p = 0.039) was found more frequently in invasive micropapillary carcinoma (IMPC) compared to other subgroups. Circumscribed margins (4/5, 80%, p = 0.002) occurred more frequently in papillary ductal carcinoma in situ (pDCIS) and encapsulated papillary carcinoma (EPC) than in other subgroups (6/8, 75%, p = 0.002). Lower apparent diffusion coefficient (ADC) values were found in solid papillary cancer (SPC) than in other subgroups (ADC = 0.35 x 10-3, p = 0.017). Radiological findings of papillary carcinomas overlap with each other. US and MRI are complementary when revealing specific morphological characteristics.

The Importance of Metastatic Papillary Serous Carcinoma in Cases of High-grade Encapsulated Papillary Carcinoma of the Breast: An Extremely Rare Case and a Possible Pitfall

Background: Encapsulated papillary carcinoma (EPC) of the breast has a favorable prognosis. High-grade EPCs, triple-negative or HER-2-positive, are dealt with as invasive carcinomas. Breast metastasis associated with serous carcinoma is a late-stage event. The discrimination between the two diagnoses can be very challenging.Case Presentation: A 79-year-old woman with a history of well controlled high-grade serous papillary carcinoma of the peritoneum went through a total left mastectomy and sentinel lymph node biopsy (SLNB) because of an invasive carcinoma in her left breast. In the lab, a peripheral nodular mass of 4cm was found. Microscopically, large intracystic papillary stalks, with high nuclear grade, surrounded by collagenous tissue were identified compatible with invasive encapsulated papillary carcinoma with positive estrogen receptor. A few months later, the patient was diagnosed with a supraclavicular cervical mass, which on FNB was indicative of metastatic serous papillary carcinoma. Immunohistochemical stains were similar in breast and previously treated peritoneal tumor showed ER+, PAX8+, p53+ (wild type) and high Ki-67 (80%). WT1 was positive only in peritoneal serous carcinoma. GATA-3 was weakly, scarcely expressed in both specimens. The findings pointed to metastatic SPC in the breast, mimicking primary carcinoma of the EPC type. Conclusion: Pathology of breast metastases and distincion from primary breast cancers is done by a combination of morphological and IHC features. In our case, the lack of clinical history, the type of surgical approach (mastectomy and SLNB), the solitary lesion, the EPC pattern of growth and the diffuse ER+ staining, were indicative of primary breast lesion. Various morphologic growth patterns of metastatic PSC have been described, among which EPC-like needs to be considered.