[A curious biphasic breast lesion]. / Une curieuse lésion biphasique du sein.

Adenomyoepithelioma represents 0.5% of breast tumors in postmenauposal women. Prognosis is good when the tumor is benign. However, its malignant variant is associated with a poor prognosis with local recurrences and metastatic potential. We present the case of a malignant adenomyoepithelioma, expose the 2019 WHO classification issues and propose a classification in three categories: benign, atypical and malignant adenomyoepitheliomas (in situ and invasive).

[Malignant Adenomyoepithelioma of the Breast:Report of One Case and Literature Review].

Malignant adenomyoepithelioma(MAME)of the breast is a rare tumor with an incidence less than 1% of primary breast cancer.The low incidence and diverse histomorphology pose challenges to the accurate diagnosis and clinical management of MAME.This paper reports a case of MAME of the breast with an intraductal papillary growth pattern and summarizes the clinical features,pathological features,diagnosis,treatment,and prognosis of MAME of the breast in the last 5 years.

Update on selective special types of breast neoplasms: Focusing on controversies, differential diagnosis, and molecular genetic advances.

Classification of breast tumors has been evolving in the last decade. Uncommon types of breast neoplasms have been increasingly recognized. While the pathogenesis of a subset of these tumors remains to be ascertained, integration of state-of-the-art knowledge from molecular advancements and clinical practice has enhanced our understanding of these diseases, be they unique to the breast or more frequently seen in other organs. Furthermore, these lesions may have diverse clinical outcomes despite of similar histopathologic and immunophenotypic characteristics or even molecular alterations, thus warranting different clinical management. Therefore, recognizing their salient histologic features and judicious use of ancillary studies is essential to reach the correct diagnosis in the pursuit of personalized medicine. This review provides an update on selective special types of breast neoplasms, with emphasis on their salient clinicopathologic features, diagnostic pitfalls, controversies, and recent molecular genetic advances.

Clinicopathological characteristics and outcomes of malignant adenomyoepithelioma of the breast: a single institution's experience.

BACKGROUND: Malignant adenomyoepithelioma of the breast is a rare tumor and most of relevant literature consists of individual case reports. This study objective was designed to evaluate clinicopathological features and treatment outcomes of 15 cases of malignant adenomyoepithelioma at a single institute. METHODS: A retrospective medical record review was performed for 15 subjects confirmed with malignant adenomyoepithelioma upon postoperative pathological diagnosis at the Asan Medical Center from January 2008 to June 2018. Data regarding age at diagnosis, preoperative biopsy results, operation methods, the status of hormone receptors and HER2, and clinical outcomes were collected. RESULTS: All cases were female patients diagnosed at median age of 50 years. Preoperative core needle biopsy results showed that 40% of the cases (6 out of 15) were benign which was in discordance with the final malignant pathology report. Thirteen cases underwent wide excision with or without sentinel lymph node biopsy (SLNB) and 2 cases had total mastectomy with SLNB. Five of 11 cases (45.5%) were triple negative. Ten of 15 cases underwent postoperative radiation therapy, 3 cases underwent chemotherapy, and 5 cases underwent endocrine therapy. During median follow-up of 55 months, the 5-year overall survival rate was 87.5% and the 5-year disease free survival rate was 91.7%. Two lung metastases developed. One case showed local recurrence 3 years after surgery and radiotherapy and subsequently developed lung metastasis 1 year late. Another case developed lung metastasis one and a half years after surgery in combination with endocrine therapy and neoadjuvant chemotherapy. CONCLUSION: Preoperative core needle biopsy showed inaccurate results for diagnosing malignant adenomyoepithelioma. Malignant adenomyoepithelioma has a high rate of triple negative subtype but has a relatively good prognosis although there is a risk of local and systemic recurrence.

Adenomyoepithelioma of the breast: a proposal for classification.

Breast lesions with a prominent myoepithelial cell component constitute a heterogeneous group of benign and malignant neoplastic proliferations. These lesions are often dual epithelial-myoepithelial, but may be purely myoepithelial cell in nature. Benign epithelial-myoepithelial lesions typically maintain the morphology and immunophenotype of the normal bilayer epithelial myoepithelial structures. However, the distinction between the two cell components is not always clear-cut in malignant lesions in which the histogenesis of myoepithelial cells remains uncertain. Neoplastic biphasic epithelial-myoepithelial lesions of the breast include adenomyoepithelioma (AME), pleomorphic adenoma and adenoid cystic carcinoma. Four histological patterns of classical AME have been described: tubular, lobulated, spindle-cell and adenosis variants. Overlapping patterns occur and some AMEs display an intraductal papillary pattern that may represent a fifth variant. AME can be benign or malignant. Classical AME may show atypical features, which are not sufficient for the diagnosis of malignancy (atypical AME). Atypical AME is recognised as a lesion of uncertain malignant potential with limited metastatic capability. Based on the histological features, we propose a classification of malignant AME (M-AME) into three variants: M-AME in situ, M-AME invasive and AME with invasive carcinoma. In this review, we provide an overview of myoepithelial lesions of the breast focusing on the classification of AME to improve not only the consistency of reporting but also help to guide further management decision-making.

Cutaneous adenomyoepithelioma with histopathological heterogeneity: A case report.

Some skin adnexal tumors display both epithelial and myoepithelial cell populations and can be broadly categorized as biphasic tumors. These include apocrine hidrocystoma, mixed tumor, adenomyoepithelioma (AME), and adenoid cystic carcinoma (ACC). Myoepithelioma is the myoepithelial cell-predominant type in this category. Cutaneous AME is exceedingly rare and usually has a benign prognosis, but it is considered to have the potential for local recurrence and metastasis. We report the case of a 57-year-old man with a 1-year history of an ulcerated nodule on his scalp. Microscopically, it was a defined cutaneous nodule with a focal lobulated architecture, composed of epithelial cells forming ducts and myoepithelial cells distributed around the ducts. In addition to these findings of typical AME, the present case focally revealed atypical features, such as increased mitotic activity (7/10 high power fields), invasive growth, and necrosis. However, cytological atypia was not significant. We conclusively diagnosed cutaneous AME with atypical features, suggesting malignant potential. Moreover, areas showing appearances similar to apocrine hidrocystoma, mixed tumor, myoepithelioma, and ACC were focally observed. We present a unique case of cutaneous AME exhibiting histopathological heterogeneity. The recognition of morphological variation could be helpful in appropriately diagnosing and treating AME of the skin.

Adenomyoepithelioma of the breast with prominent cystic changes: a case report.

BACKGROUND: Adenomyoepithelioma (AME) of the breast is a rare subtype of breast tumor. Most of AMEs reported are solid, however, cystic or prominent cystic changes are extremely rare. CASE PRESENTATION: A 51-year-old woman presented a lump in the upper outer quadrant of right breast, and it was accompanied by continuous breast pain and bilateral axillary itching for more than 2 months. There were no other symptoms found. Preoperative mammography and ultrasound examination were performed. Mammography showed a noncalcified lobulated mass, and it was considered to be a benign cyst with septum on ultrasound, but ductal carcinoma of breast, adenoid cystic carcinoma could not be excluded. At first, AME was not considered preoperatively, because the imaging features of this rare tumor may vary widely, which may result in an incorrect diagnosis. But eventually, AME was diagnosed by postoperative pathology and immunohistochemistry. CONCLUSION: We herein present a rare case of breast AME with prominent cystic changes. AME has no-specific imaging features, but the benign or malignant nature of the lesion might be suspected on imaging.

Immunohistochemical assessment of HRAS Q61R mutations in breast adenomyoepitheliomas.

AIMS: Breast adenomyoepitheliomas (AMEs) are uncommon tumours. Most oestrogen receptor (ER)-positive AMEs have mutations in phosphoinositide 3-kinase (PI3K) pathway genes, whereas ER-negative AMEs usually harbour concurrent mutations affecting the HRAS Q61 hotspot and PI3K pathway genes. Here, we sought to determine the sensitivity and specificity of RAS Q61R immunohistochemical (IHC) analysis for detection of HRAS Q61R mutations in AMEs. METHODS AND RESULTS: Twenty-six AMEs (14 ER-positive; 12 ER-negative) previously subjected to massively parallel sequencing (n = 21) or Sanger sequencing (n = 5) of the HRAS Q61 hotspot locus were included in this study. All AMEs were subjected to IHC analysis with a monoclonal (SP174) RAS Q61R-specific antibody, in addition to detailed histopathological analysis. Nine ER-negative AMEs harboured HRAS mutations, including Q61R (n = 7) and Q61K (n = 2) mutations. Five of seven (71%) AMEs with HRAS Q61R mutations were immunohistochemically positive, whereas none of the AMEs lacking HRAS Q61R mutations (n = 17) were immunoreactive. RAS Q61R immunoreactivity was restricted to the myoepithelium in 80% (4/5) of cases, whereas one case showed immunoreactivity in both the epithelial component and the myoepithelial component. RAS Q61R immunohistochemically positive AMEs were associated with infiltrative borders (P < 0.001), necrosis (P < 0.01) and mitotic index in the epithelial (P < 0.05) and myoepithelial (P < 0.01) components. RAS Q61R IHC assessment did not reveal Q61K mutations (0/2). CONCLUSIONS: IHC analysis of RAS Q61R shows high specificity (100%) and moderate sensitivity (71%) for detection of HRAS Q61R mutations in breast AMEs, and appears not to detect HRAS Q61K mutations. IHC analysis of RAS Q61R may constitute a useful technique in the diagnostic workup of ER-negative AMEs.

Clinical presentation, national practice patterns, and outcomes of breast adenomyoepithelioma.

Breast adenomyoepithelioma (AME) is a rare tumor with the published literature mainly in the form of case reports. Thus, there is currently only limited published data to guide evidence-based management. We sought to use a large, contemporary US database to evaluate how these patients are managed and describe expected outcomes. The National Cancer Database was queried (2004-2013) for women with AME. Statistics included multivariable logistic regression, Kaplan-Meier analysis to evaluate overall survival (OS) and Cox proportional hazards modeling. Overall, 110 patients were analyzed. At diagnosis, the median age was 67 years and the median tumor size was 2.0 cm. All but four patients had node-negative disease. A majority (55%) of tumors were estrogen receptor negative, and only one was positive for HER2/neu. The most common surgical procedure was lumpectomy (60%); a minority (10.9%) of subjects underwent complete axillary nodal dissection, with one-quarter not undergoing pathologic nodal sampling. Chemotherapy, hormonal therapy, and radiotherapy were utilized in a minority of patients (26%, 8%, and 36%, respectively), and none were associated with OS. At median follow-up of 52 months, the 5-year OS for the entire population was 74.4%. Disease-related characteristics and practice patterns are described for AME, the largest study of this rare tumor to date. Resection is the most important aspect of management, and based on this dataset the low rate of nodal involvement suggests that in some cases nodal sampling could be safely omitted. Adjuvant therapy may be considered on a case-by-case basis. Taken together, these data provide valuable insight into a rare neoplasm that may better inform management of these patients.

MYB rearrangement and immunohistochemical expression in adenomyoepithelioma of the breast: a comparison with adenoid cystic carcinoma.

AIMS: Adenomyoepithelioma (AME) and adenoid cystic carcinoma (ACC) of the breast have been noted to occur simultaneously, raising the possibility that AME may represent a related or precursor lesion to ACC. ACC frequently harbours genetic rearrangement of the MYB gene. We sought to clarify the relationship between AME and ACC by comparing their rates of MYB expression by IHC and MYB rearrangement by FISH. METHODS AND RESULTS: IHC and FISH for MYB rearrangement were performed on paraffin-embedded sections of 11 breast ACCs, 11 non-breast ACCs and 11 breast-AMEs. Using FISH, five of eight (63%) interpretable breast ACCs demonstrated MYB gene rearrangement. Nine of 11 (81%) breast ACCs demonstrated MYB expression (range = 20-95%). Of the three FISH-negative breast ACCs, two were solid variant and demonstrated strong MYB expression by IHC. Of the 10 interpretable non-breast ACCs, six showed MYB rearrangement, all of which were conventional type. Nine of these 11 (81%) cases showed MYB immunoexpression (range = 10-90%), including three solid-variant cases which were negative by FISH. No MYB rearrangements were detected by FISH in 10 interpretable AMEs. However, three of 11 cases (27%) showed weak to moderate MYB expression by IHC (range = 10-40%). CONCLUSIONS: Our results indicate that AMEs do not harbour MYB gene rearrangement. IHC for MYB may be helpful in diagnosing FISH-negative cases of ACC, particularly the diagnostically more difficult solid variants. However, weak to moderate MYB expression in a subset of AMEs highlights not only a potential diagnostic pitfall, but also shared pathophysiology with ACC worth investigating further at the genomic level.

A Case of Adenomyoepithelioma of the Breast Showing Strong Uptake of 18 F-Fluorodeoxyglucose on a Positron Emission Tomography.

An adenomyoepithelioma of the breast is a rare tumor characterized by biphasic proliferation of both epithelial and myoepithelial cells. This tumor is generally considered as a benign neoplasm, and there are few reports describing the imaging features of this tumor through 18 F-fluorodeoxyglucose positron emission tomography (FDG-PET). Here, we report a case of an adenomyoepithelioma that showed strong uptake of FDG on PET similar to that observed with a malignant tumor. A 73-year-old woman presented to our hospital with a 3.5-cm, mobile, and elastic hard tumor in the upper area of the left breast. Although the findings of mammography, ultrasonography, and contrast-enhanced magnetic resonance imaging suggested that the tumor was malignant, it was diagnosed as an adenomyoepithelioma by core needle biopsy. An invasive ductal carcinoma, 0.5-cm in size, was detected in the medial upper area of the ipsilateral breast during an examination. Although FDG-PET demonstrated no lymph node or distant metastases from the invasive ductal carcinoma, strong uptake of FDG was detected in the adenomyoepithelioma. Breast conserving surgery and sentinel lymph node biopsy for the invasive ductal carcinoma together with resection of the adenomyoepithelioma was performed. A diagnosis of adenomyoepithelioma was confirmed through histologic examination of the resected specimen. This case indicates that some adenomyoepitheliomas may show a strong uptake of FDG on PET, which resembles a malignant tumor.

Malignant adenomyoepithelioma of the breast: a review.

Malignant adenomyoepithelioma (MAME) of the breast is a rare lesion characterized by dual population of epithelial and myoepithelial cells which one or both components show malignant features. We report a case of MAME of the breast in a 46-year-old woman diagnosed by fine-needle aspiration with extensive review of the literature. Classification, clinical presentation, cyto-pathologic, and immunohistochemical features are described. This lesion showed both malignant components of epithelial and myoepithelial cells in cytology and histology. The malignancy was convincingly supported by high mitotic figures, pleomorphism, and invasion in tissue sections. This review of MAMEs showed that cyto-histologic diagnosis is difficult and should be supported by immunohistochemical study.

Adenomyoepithelioma of the breast with associated atypical lobular hyperplasia: a previously unrecognized association with management implications.

Adenomyoepitheliomas of breast are rare tumors. We report for the first time a case of an adenomyoepithelioma of the breast with associated lobular neoplasia. A 53-year-old woman had an annual screening mammogram, which identified areas of asymmetry in her left breast at 4-5-o'clock position. Resection of the masses revealed a well-circumscribed, gray-white, firm discrete nodule (0.8 × 0.4 × 0.3 cm). The tumor was composed of both adenomyoepithelial cell hyperplasia and focal atypical lobular hyperplasia. The 2 cell populations had some overlapping histologic features. Immunohistochemical analysis demonstrated a biphasic proliferation with approximately equal parts of luminal epithelial cells with clear and rounded appearance and myoepithelial cells. The myoepithelial component of the proliferation expressed myosin, p63, CK5/6, S-100, and dimly expressed E-cadherin. The epithelial component of the proliferation strongly expressed E-cadherin. In the areas of atypical lobular hyperplasia, there was distinct loss E-cadherin expression. Awareness of this association is highly important to provide these patients adequate follow-up and treatment.

[Adenomyoepithelioma with dominant myoepithelial contingent of the breast: A case report and literature review]. / Adénomyoépithéliome avec contingent myoépithélial prédominant du sein : à propos d'une observation et revue de la littérature.

We report a case of adenomyoepithelioma with predominant myoepithelial quota, a rare tumor of the breast due to proliferation of epithelial and myoepithelial cells in a patient of 71 years. This lesion, with difficult radiological and pathological diagnosis (biopsy) in the initial stage of the treatment, should benefit from surgical resection in healthy margin. In fact, this tumor is evolving in most cases on a benin mode, but cases of local or metastatic recurrences were reported. Histological and immunohistochemical arguments are important to reach the final diagnosis.

Benign Adenomyoepithelioma of the Breast: A Case Report and Review of Imaging Features.

Adenomyoepithelioma (AME) of the breast is a rare tumor that can be benign or malignant and has varied morphological features. We report a case of a 62-year-old female with a history of right breast cancer who presented with abnormal screening mammography. The detection, presentation, and varied imaging characteristics of AMEs are discussed. The nonspecific imaging and histologic appearance of AME are highlighted, emphasizing the need for representative biopsy samples and histopathological review for diagnosis. Our case underlines the importance of wide surgical excision with negative margins in the presence of diagnostic uncertainty, which corresponds with the current recommended treatment for AME to prevent recurrence.

Adenomyoepithelioma: A Case Report of a Rare Breast Lump.

Adenomyoepithelioma (AME) of the breast is a rare tumor characterized by biphasic differentiation into luminal and myoepithelial cells, with various histological patterns observed. This case report details a 35-year-old female with a progressively enlarging breast lump diagnosed initially as a fibroadenoma through ultrasonography (USG) and fine-needle aspiration cytology (FNAC). The patient underwent successful excision of the lump under general anesthesia, with histopathological examination confirming a benign tumor comprising epithelial and myoepithelial cells. This case underscores the importance of comprehensive clinical assessment and accurate diagnostic techniques in managing breast lumps, emphasizing the need for timely intervention for favorable outcomes.

Benign Adenomyoepithelioma: An Unrecognised Precursor of Ductal Carcinoma in Situ in Patient With Lynch Syndrome.

Currently, there is no robust evidence demonstrating a clear association between Lynch syndrome and non-malignant breast pathology such as adenomyoepithelioma. We report a case of benign breast adenomyoepithelioma, which after recurrence was associated with ductal carcinoma in-situ (DCIS) in a 41-year-old woman with Lynch syndrome, who lacked significant family history of breast or ovarian cancer. Both, the adenomyoepithelioma and DCIS were found to have nuclear loss of MSH2/MSH6 by immunohistochemistry, while germline testing confirmed MSH2 gene mutation. Concordant loss of MSH2 in both lesions in the context of a MSH2 pathogenic variant in this patient with Lynch syndrome illustrates that the benign adenomyoepithelioma behaved as a likely precursor of DCIS. Our report provides a novel perspective that in some patients with Lynch syndrome adenomyoepithelioma may represent a pre-malignant precursor lesion of DCIS.

Breast adenomyoepithelioma diagnosed on core needle biopsy: a diagnostic challenge.

Adenomyoepithelioma represents a rare tumor of the breast characterized by biphasic proliferation of epithelial and myoepithelial cells. Owing to its nonspecific clinical presentation, the rarity, and the morphological pitfalls in differential diagnosis, the diagnosis may be extremely difficult especially on limited samples such as core needle biopsy; thus, the diagnosis is histological, which is confirmed by the specificities of the immunohistochemical analyses. Here we report a case of a 64-year-old female who presented a benign adenomyoepithelioma diagnosed on core needle biopsy, review the clinicopathological features of breast adenomyoepithelioma diagnosed on core needle biopsy, and discuss the useful clues to prompt accurate diagnosis.

Benign Adenomyoepithelioma of the Breast: A Case Report.

Adenomyoepitheliomas of the breast are rare tumors that are characterized histologically as having both epithelial and myoepithelial components. While adenomyoepitheliomas are considered benign lesions, existing literature supports their potential for malignant transformation. These tumors also exhibit nonspecific and variable findings on noninvasive imaging, posing additional challenges in management. We present a rare case of an adenomyoepithelioma diagnosed in a 65-year-old female who was treated with surgical resection of her tumor, with histopathology negative for malignant transformation. By describing this patient's management course, we aim to contribute to existing literature analyzing adenomyoepitheliomas and help guide future treatment.