Papillary Carcinoma Of Breast Research Articles

Non-primary solid malignancies of breast in needle core biopsy: a clinicopathological analysis of 23 cases

Objective: To investigate the accurate diagnosis and differential diagnosis of non-primary solid malignant tumors in breast needle core biopsy. Methods: Twenty-three cases of breast, axilla or neck lymph nodes pathologically diagnosed as non-primary solid malignant tumors were collected at the First Affiliated Hospital of Nanjing Medical University, Nanjing, China from January 2013 to March 2023. The differential diagnoses and diagnostic features were analyzed, based on combining clinical data, histology, and expression characteristics of biomarkers. Results: All patients were female, with age ranging from 29 to 75 years (average 56 years). The average time from the diagnosis of primary tumor to the current diagnosis was 21 months (0 to 204 months).The primary sites included the ovary (9 cases), the lung (5 cases), the gastrointestinal tract (4 cases), the pancreas, intrahepatic bile duct, thyroid gland, nasal cavity and forearm skin (1 case each). No carcinoma in situ was found in any of the cases. The morphological differences were significant among the tumors, but similar to the primary tumors. The tumors of neuroendocrine and female reproductive tract had great morphological and immunophenotypic overlaps with breast cancer. Metastatic lung cancer cells showed obvious atypia and tumor giant cells. The morphology and immunophenotype of metastatic serous carcinoma of female reproductive system might resemble invasive micropapillary carcinoma of the breast. Metastatic adenocarcinoma of the gastrointestinal tract often had features of mucous secretion. Metastatic neuroendocrine tumors were bland in appearance and morphologically similar to solid papillary carcinoma of breast, but negative for ER. TRPS1 was mostly negative (18/23) and variably positive in ovarian (4/9) and intrahepatic bile duct (1/1) tumors. Conclusions: The diagnosis of breast needle core biopsy specimen should be combined with clinical history, imaging study, and careful examination of histological features, such as presence of in situ component, morphological similarity between the primary and metastatic tumors, and using appropriate markers to differentiate the primary from metastatic tumors.

Invasive solid papillary carcinoma of breast mimicking as a benign condition: Rare case report

Invasive papillary carcinomas of breast are rare tumors. They account for approximately 0.5% of all Invasive breast carcinomas. Invasive papillary carcinomas are commonly present in post-menopause women. These tumors lack the myoepithelial cell layer (MCL) within the papillae or at the periphery of the tumor. The diagnosis is difficult due to different clinical and radiological features. Immunohistochemistry (IHC) is really essential to confirming the diagnosis. We are here presenting one index case of a rare variety of invasive papillary carcinoma of the left breast. We present a case of invasive papillary carcinoma of the left breast in a 55-year-old female presented with a retroareolar lump without nipple discharge. Preoperative core biopsy showed fibroadenoma with a papillary configuration.But post-operative histopathological examination revealed it was an invasive papillary carcinoma. Invasive papillary carcinoma of breast even though a rare entity, making a diagnosis is very challenging. Thorough preoperative clinical and radiological examination should be done, so that timely management as well as proper treatment is possible.

Invasive Solid Papillary Carcinoma of breast in an elderly male: a rare entity in an uncommon gender - case report and review of literature

Abstract Introduction/Objective Male breast cancers (MBC) account for less than 1% of all breast cancers. Papillary cancers constitute less than 3% of MBCs. Solid papillary carcinoma (SPC) is a rare subtype of papillary cancer with a solid growth pattern associated with fibrovascular cores. SPC is an indolent disease that typically presents in a post- menopausal woman as a central breast mass. Neuroendocrine differentiation, ER/PR positive status and Her-2 neu negative status are characteristic. SPC can be in situ or have invasive components. SPC is a rare entity in men and so far, approximately less than 40 cases of SPC in men have been discussed in literature. Here, we report a rare case of SPC with multiple invasive foci in an elderly male. Methods/Case Report An 84-year-old white male presented with a painless mass in his left breast. Excision biopsy revealed Solid Papillary Carcinoma. He subsequently underwent a Left Modified Radical Mastectomy with Left Sentinel Lymph Node Excision. The final histopathology report showed a background of SPC with multiple invasive foci with largest focus measuring 2 mm. Margins were negative and lymph nodes were negative for malignancy. The tumor was ER and PR positive, Her-2 neu negative and had a Ki-67 proliferation index of 42%. Negative IHC staining for Cytokeratin AE1/AE3 confirmed the absence of metastatic epithelial cells in the examined lymph nodes. Results (if a Case Study enter NA) N/A Conclusion SPC is an uncommon subtype among the papillary lesions of breast. Furthermore, only a few cases of SPC have been reported in men. Despite its rarity, it has a good prognosis and lymph node positivity, distant metastasis and local recurrence are uncommon. However, there is limited data about SPC with invasive components which may behave like other invasive breast lesions leaving management a dilemma for clinicians. We believe this case will add to the scarce existing literature about invasive SPC in men.

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.

CLINICO PATHOLOGICAL ANALYSIS ON PAPILLARY CARCINOMA BREAST

Background : Papillary carcinoma of breast is rare and account for approximately 1-2% of newly diagnosed cases of breast cancers. The common age group of presentation is 6-7th decade. These tumours usually present with a painless retroareolar swelling associated with bloody nipple discharge in 50% cases. Case 1) 57 year old most Cases : menopausal woman presented with huge ulcerative lump in right breast over a period of 1 year. After confirming diagnosis with incisional biopsy, patient was proceeded with Neoadjuvant Chemotherapy (NACT) followed by Right MRM with SSG. Case 2) 66 year old male patient came with complaints of bloody discharge from nipple for past 1 year. A small subcentimetric lump present in retroareolar region on left breast was present, on which USG guided CNB revealed Invasive Ductal Carcinoma. Patient was proceeded with Left MRM. Case 3) 65 year old male patient presented with painless lump in left breast for 3 months. Clinical examination revealed a 1*2 cm lump in left breast with a single mobile ipsilateral axillary node. Image guided CNB revealed Invasive Papillary carcinoma. Patient was taken up for upfront Left MRM. All 3 patients are on regular follow-up for more than a year, and no recurrence is noted on followup

Tall Cell Variant of Invasive Papillary Breast Carcinoma.

Tall cell variant of invasive papillary breast carcinoma is exceedingly rare, with only 30 cases reported in the literature. This report describes a case of a 47-year-old woman who presented to the clinic with bilateral breast masses on a screening mammogram. The patient was lost to follow-up, but she presented again after 4 years when the right breast mass significantly grew in size over several months. Mammography showed a 1.9 cm right breast mass and a 2.3 cm left breast mass. Ultrasound-guided core biopsy revealed right breast triple negative invasive carcinoma of the tall cell papillary variant and left breast fibroadenomatoid nodules. She underwent bilateral lumpectomies with a right sentinel lymph node biopsy and was started on chemotherapy after surgical excision.

Intracystic Papillary Carcinoma of Breast - A Case Report

Intracystic Papillary Carcinoma of Breast - A Case Report

Papillary carcinoma of breast: An institutional overview of a rare histopathologic type.

Papillary carcinoma of the breast is a rare malignant tumor, constituting 1%-2% of all breast carcinomas in women. We studied a total of 6 cases of papillary cancer breast of which five were in female patients, and one was a male patient. Three were invasive papillary carcinoma while one was encapsulated papillary carcinoma without invasion, one was encapsulated papillary carcinoma with invasion and one was a solid type of papillary carcinoma. The median age of the patients was 45.5 years. All the tumors except one were seen in the left breast. Grossly, the size of the tumors ranged from 2 cm × 2 cm × 1.5 cm to as large as 6 cm × 10 cm × 4 cm. Three of the cases had positive axillary nodes. To conclude, papillary carcinoma is a rare tumor with a better prognosis as compared to Infiltrating duct carcinoma breast, and hence, it is important to be aware of the different subtypes and diagnostic pitfalls of this tumor to correctly diagnose it.

68 (PB-068) Poster - Papillary carcinoma of breast – Clinicopathological characteristics, management, and survival

68 (PB-068) Poster - Papillary carcinoma of breast – Clinicopathological characteristics, management, and survival

ODP042 Hereditary Pheochromocytoma with a Novel Mutation in the Succinate Dehydrogenase Subunit A gene

Abstract Pheochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumorswith a diverse clinical presentation. Pathogenic variants in the genes encoding different subunits of the succinate dehydrogenaseenzyme complex that plays a central role in energy metabolism,have been linked to hereditary PPGL syndromes. Here wereport a rare case of hereditary pheochromocytoma with a novel mutation in the succinate dehydrogenase subunit A (SDHA) gene. A middle aged woman presented with left sided abdominal pain and was incidentally found to have bilateral adrenal lesions on abdominal imaging. She denied any symptoms of catecholamine excess but her plasma metanephrines level was elevated. Family history was significant for breast cancer in her motherand sister. Computed tomography (CT) scan of the abdomen showed bilateralbulky adrenal glands with a lesion in theleft adrenal gland. Magnetic resonance imaging (MRI) abdomen was performed for further characterization, the lesion measured approximately 2.8×2.6 cm with imaging characteristics suggestive of pheochromocytoma. Iodine-131 Metaiodobenzylguanidine (MIBG) whole body scan showed abnormal focal radiotracer uptake at the left adrenal gland, and she then underwentleft sided robotic adrenalectomy. Following surgery, the patient had symptomatic relief. Histopathology confirmed the diagnosis of pheochromocytoma measuring 2×2×1.5 cm with PASS (Pheochromocytoma of the Adrenal gland Scaled Score) score of 1/10, due to cellular monotony. Genetic testing revealed that she was positive for a pathogenic mutation in the SDHA gene consistent with the diagnosis of hereditary PPGL syndrome. Genetic testing was performed for the patient due to her presentation with bilateral adrenal masses and family history of cancers. Guidelines recommend genetic testing for patients with features that indicate a high likelihood of a hereditary cause for PPGL, including positive family history, syndromic features, and multifocal, bilateral, or metastatic disease. SDHA mutated PPGLs have diverse phenotypes and may be at high risk of metastasis. They are also associated with extra-adrenal tumors, include gastrointestinal stromal tumours (GIST), pituitary adenomas, papillary thyroid carcinoma, renal carcinoma and breast carcinoma. The detection of susceptibility genes for hereditary PPGL syndromes has key implications, for surveillance to detectextra-adrenal disease and recurrent tumors, as well as for consideration of genetic testing forfamily members. Presentation: No date and time listed

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.

Intraductal papillary carcinoma of breast with invasion: A nomogram and survival from the analysis of the SEER database.

Intraductal papillary carcinoma (IPC) with invasion is a rare type of breast cancer. There have been few studies on its prognosis, and a nomogram that predicts the prognosis of the disease has not been described to date. Patients who were diagnosed with invasive IPC were screened from the Surveillance, Epidemiology, and End Results (SEER) database. The screened patients were randomly divided into a training cohort and a verification cohort at 7:3. A Cox proportional hazard regression model was performed to analyze the effects of different variables on the risk of death in invasive IPC. A nomogram was constructed to quantify the possibility of death. The concordance index (C-index), calibration plots, receiver operating characteristic (ROC) curves, and decision curves analysis (DCA) were used to verify the proposed model. We included a total of 803 patients diagnosed with invasive IPC, including 563 patients in the training cohort and 240 patients in the validation cohort. The median follow-up times in the training cohort and validation cohort were 63 months (range, 2-155 months) and 61 months (range, 1-154 months), respectively. For all patients, the probability of death with invasive IPC was 1.4% within 5 years and 5.4% within 10 years. In multivariate analysis, sex, race, tumor size, lymph node status, type of treatment, and chemotherapy were related to the prognosis of invasive IPC. We constructed a nomogram to predict the possibility of death in patients with invasive IPC. Patients with invasive IPC had a high survival rate. The proven nomogram was helpful to both patients and clinical decision makers.

Intracystic papillary carcinoma of the breast: Report case and literature review

Intracystic papillary carcinoma (IPC) of the breast is a rare malignant tumour, found mainly but not exclusively in elderly women. IPC may be asymptomatic or presents with a palpable mass or blood-stained nipple discharge. Radiologic manifestations of IPC are not specific. On ultrasonography, it can be a pure cyst, a mixed image, or a solid mass. Histologic features of the tumor include cellular proliferations surrounding fibrovascular cores, with or without invasion. The mainstay of treatment is breast-conserving surgery or mastectomy. Sentinel node biopsy could be considered in invasive cases. Adjuvant radiotherapy and/or endocrine therapy is considered in appropriate cases. Through the observation of a 58-year-old patient, we report the epidemiological, clinical and radiological data of papillary breast carcinoma.

Shedding Light on T2 Bright Masses on Breast MRI: Benign and Malignant Causes.

While T2 hyperintense masses on breast MRI are often benign, there are several malignant etiologies that can also be T2 hyperintense. Delineation between benign and malignant entities is important for the accurate interpretation of breast MRI. Common benign T2 hyperintense masses include cysts, fibroadenomas, and lymph nodes. Malignant processes that are T2 hyperintense include metastatic lymph nodes, mucinous breast carcinomas, papillary breast carcinomas, and breast cancers with central necrosis. Evaluation of the morphology and enhancement pattern of a T2 hyperintense mass can help to differentiate a benign process from a malignant one. This educational review will present both benign and malignant causes of T2 hyperintense masses on breast MRI and review common imaging findings and pertinent imaging characteristics that can be used to help accurately identify benign entities while also recognizing suspicious lesions that require additional evaluation.

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.

Comparison of ultrasonographic and mammographic features of extremely rare papillary carcinoma and invasive ductal carcinoma

This study aimed to investigate and compare ultrasonographic and mammographic findings of papillary breast carcinoma and invasive ductal carcinoma in breast masses that were diagnosed as pathological. This retrospective study included 88 patients with breast lesions, who underwent ultrasonography, mediolateral oblique-craniocaudal, and tomosynthesis imaging in the Picture Archiving and Communication System between January 2010 and March 2019. 44 histopathologically diagnosed papillary carcinoma patients and 44 invasive ductal carcinoma patients were divided into groups according to contour, shape, internal structure, calcific-cystic component, echogenicity, posterior acoustic change, skin orientation, and environmental echogenic halo. There was a statistically significant difference between the groups in mammography contour, U/S contour, U/S shape, U/S posterior acoustics, and U/S internal structure. Logistic regression analysis showed that the presence of homogenous appearance (p < 0.001) and absence of shading in the posterior acoustic U/S (p = 0.001) were the most pertinent findings for determining papillary carcinoma. In the U/S, the likelihood of a homogenous tumour being a papillary carcinoma was 16.869 times higher than that of invasive ductal carcinoma, whereas the same probability was 0.1101 times less for a tumour with posterior acoustic shadowing. It is challenging to differentiate between invasive ductal carcinoma and papillary carcinoma of the breast without histopathological diagnosis both on ultrasound and mammography. The results of our study demonstrated that the ultrasonographic and mammographic findings of invasive ductal carcinoma and papillary carcinoma were like each other. Therefore, it is still not possible to distinguish between these 2 types of cancer only in accordance with these 2 criteria.

Synchronous Bilateral Encapsulated Papillary Breast Carcinoma in a Male—A Case Report—

症例は69歳の男性．右乳房腫瘤の精査目的に当院へ紹介された．右乳房には嚢胞内腫瘤，左乳房には境界明瞭な充実性腫瘤を認めた．針生検にてともに乳頭状癌を認め，同時性両側乳癌と診断．両側乳房切除およびセンチネルリンパ節生検を施行した．病理検査では両側とも嚢胞内癌の形態をしていたが，免疫染色にて乳頭状部および嚢胞壁の筋上皮細胞が乏しく，両側とも被包型乳頭状癌と診断した．同時性両側男性被包型乳頭状癌という非常にまれな症例であったため，文献的考察を加え報告した．

Atypical Breast CarcinomaA Series of Six Cases

Breast cancer comprises 10.4% of all cancer among women world and it the second most common type of cancer. Increased public awareness and screening have led to earlier diagnosis at different stages. Surgical resection can be done earlier and complete cure of the disease can be achieved. As a result survival rates for breast cancer in young women have improved significantly. Six unusual type of breast carcinoma, presented to the Surgery Outpatient Department were referred to Pathology Department for further investigations. Patient age and sex, clinical characteristics of the tumour, the duration of the lesion, the size, radiological investigation, Fine Needle Aspiration Cytology (FNAC), trucut biopsy and histopathological examination were noted. Immunohistochemical examination also done in all the cases. Out of the six cases of breast carcinoma, one was the mucinous carcinoma of breast, two invasive papillary breast carcinoma, one apocrine carcinoma, one invasive Pleomorphic Lobular Carcinoma (PLC) of breast and one was fibromatosis like metaplastic carcinoma of breast. All the patients were female except, a 71-year-old male who presented with invasive papillary carcinoma. All the female patients were presented at postmenopausal age group. After careful examination of the cytology and histopathological slides the final diagnosis was made which helped the clinician for further treatment. Rare breast cancers do not differ from other types of breast cancer in their presentation. But they vary by treatment regimens and outcomes. So, proper diagnosis with imaging, FNAC, trucut biopsy and histopathological examination is a combined tool for proper diagnosis and treatment.

28154 Endocrine mucin-producing sweat gland carcinoma in a patient with metastatic melanoma

A 55-year-old male with metastatic melanoma recently off immunotherapy presented with a 1-year history of an asymptomatic, slow growing mass on his right eyelid. Examination revealed a 3-mm well-circumscribed flesh-colored papule on the right upper eyelid margin. Excision performed by oculoplastics showed a multinodular superficial cystic and deep solid dermal neoplasm. The cystic component was comprised of an epithelial lining two layers thick. The deep solid component had foci of papillary change. Lesional cells had nuclear contours with small nuceloli and sparse pale granular eosinophilic cytoplasm. Scattered mitoses were present and high-grade atypia was absent. The tumor was positive for chromogranin A, CK7, EMA, BerEp4, synaptophysin (patchy), ER, and PR. MelanA, CK20, and CD56 were negative. P63 highlighted myoepithelial cells around the tumor. Based on the histopathologic and immunohistochemical features, endocrine mucin-producing sweat gland carcinoma (EMPSGC) was diagnosed. EMPSGC is an uncommon low-grade carcinoma with histopathologic and immunohistochemical features of solid, papillary breast carcinoma. Diagnosis can be difficult given its rarity and broad clinical differential diagnosis. The key immunohistochemical feature is neuroendocrine expression; tumors also often co-express estrogen and progesterone receptors. Elaboration of a myoepithelial layer surrounding the tumor is prudent to evaluate for invasive tumor. Although EMPSGC is a low-grade carcinoma with no reported cases of metastases, complete surgical excision is recommended given local recurrence and concern for progression to invasive mucinous carcinoma. Our patient’s tumor was completely excised via Mohs micrographic surgery with closure by oculoplastics. To our knowledge, there is no known association between EMPSGC and melanoma.

Clinicopathologic and immunohistochemical study of breast angiosarcoma

Breast angiosarcoma (AS) is a rare malignancy which can be classified into primary or secondary as a result of breast cancer therapy. On histology, breast AS has a wide spectrum of morphologic presentations, and its diagnosis can be challenging based on morphologic evaluation alone. Here, we studied 10 cases of breast AS diagnosed at our institution during a 20-year period, in which 7 cases were radiation-associated AS (RA-AS) and 3 cases were primary AS (P-AS). The average latency between radiotherapy and RA-AS was 8.1 years. RA-AS mostly occurred in breast skin, while all P-AS involved breast parenchyma. All 10 AS cases were high grade, including 4 RA-AS cases demonstrating epithelioid morphology. Histologic morphologies of AS varied from confluent growth of atypical spindle or epithelioid cells to scattered marked pleomorphic cells. Some cases appeared deceptively bland or low grade, but the presence of areas of haemorrhage (‘blood lake’) or necrosis upgraded them to high grade lesions. Additionally, some epithelioid RA-AS cases with lymphatic differentiation (D2–40 positive) showed pseudopapillary morphology characterized by discohesive cells sloughing off at periphery of vascular cores, resembling papillary breast carcinoma. P-AS did not show prominent vesicular nuclei and/or conspicuous nucleoli, which were features observed in RA-AS. C-MYC immunostain results showed P-AS was completely negative or focal weakly positive in hypercellular areas. In comparison, RA-AS were consistently positive for c-MYC. Epithelioid RA-AS with lymphatic differentiation tended to show stronger and/or more diffuse c-MYC positivity than other AS cases. CD31 and ERG immunostains showed positivity in all cases, while CD34 were negative in some cases with lymphatic differentiation. This study offers a detailed morphologic and immunohistochemical assessment of a rare tumor of the breast that is important to recognize. Common differential diagnosis for breast AS, including post-radiation atypical vascular proliferation (AVP), are also reviewed and discussed.