Myoepithelial lesions of the breast. Myoepitheliosis, adenomyoepithelioma, and myoepithelial carcinoma

Adenomyoepithelial adenosis mimicking phylloides: A diagnostic dilemma

Benign proliferative breast diseases are well recognized in young females. Benign biphasic proliferation of epithelial and myoepithelial cells has been observed, among which adeno-myoepithelial adenosis is one of the rare morphologies published in the literature with the tendency to recur and poses a risk for low-grade malignant transformation. Here, we report a case of a young female who had a history of recurrent breast lump mimicking phyllodes tumor and eventually diagnosed as adeno-myoepithelial adenosis on histopathological examination. Benign proliferative breast diseases are well recognized in young females. Benign biphasic proliferation of epithelial and myoepithelial cells has been observed, among which adeno-myoepithelial adenosis is one of the rare morphologies published in the literature with the tendency to recur and poses a risk for low-grade malignant transformation. Here, we report a case of a young female who had a history of recurrent breast lump mimicking phyllodes tumor and eventually diagnosed as adeno-myoepithelial adenosis on histopathological examination.

Concurrence of Adenomyoepithelioma of the Breast and Gastrointestinal Stromal Tumor of the Stomach: A Case Report and Review of the Literature

Adenomyoepithelioma (AME) of the breast and gastrointestinal stromal tumors (GISTs) are rare benign (primarily) tumors observed in the breast and gastrointestinal tract, respectively. The coexistence of both of these rare tumors is extremely rare; therefore, the author describes the clinical presentation and pathophysiological findings of such a unique case in this study. A 56-year-old female patient with no medical history presented with a substantial right breast lump, severe nausea, and vomiting, and suffered from iron deficiency anemia. Radiological observation and a right breast excisional biopsy diagnosed the patient with AME associated with ductal carcinoma in situ (DCIS). Endoscopy and a CT scan of the stomach revealed the existence of GIST. This is the first reported case of concurrence of a huge mass of AME and GIST in a patient. Histological and immunohistochemistry tests using p63, SMA, calponin, and Ki67 markers for the breast tumor and DOG-1, CD34, and CD117 markers for the gastric tumor revealed the non-invasive benign state. The patient had a right breast mastectomy with a negative resection margin. AME of the breast and GIST pose diagnostic challenges due to their erratic morphological characteristics and can cause misinterpretation drawn solely from radiological tests. Effective and accurate diagnostics require assessing the histological and immunohistochemistry findings of the tumor to identify the invasiveness of the neoplasm and the associated risk levels. This report, thus, creates awareness among clinicians and pathologists for the consideration of such possibilities and, therefore, conducts the necessary diagnostics and prophylactic treatments.

Adenomyoepithelioma of the Breast in the Setting of Prior Contralateral Breast Malignancy

An 81-year-old female patient underwent a screening mammogram one year after completing treatment for right-sided estrogen receptor (ER)/progesterone receptor (PR)-negative ductal carcinoma in situ (DCIS). A new 1-cm mass was noted in the contralateral breast. Ultrasound and percutaneous core needle biopsy results were suggestive of an atypical papillary lesion. An excisional biopsy was performed, and the final pathology was consistent with a benign adenomyoepithelioma (AME). Surgical resection was considered her definitive treatment. AME of the breast is a rare clinical entity, with only a handful of case reports and case series available. In this case report, we review common clinical and radiologic presentations, methods of diagnosis, and recommendations for management based on current literature. The presence of an AME in the background of a previous or synchronous breast malignancy occurs in a very small percentage of cases. On review of available literature, we identified other cases with a past or current history of breast malignancy.

Malignant Adenomyoepithelial Tumour of the Breast - a Rare Diagnosis - Case Report

Breast adenomyoepithelioma is an unusual tumour characterized by a biphasic proliferation of epithelial and myoepithelial cells. Most of the breast adenomyoepitheliomas are considered to be benign and characterized by propensity for local recurrence. Malignant change can occur rarely in one or both cellular components. We here present a case of a 70-year-old previously healthy female who initially presented with a painless breast lump. The patient underwent wide local excision in view of suspicion of malignancy and sent for frozen section regarding the diagnosis and margins which surprisingly came as adenomyoepithelioma. Final histopathology came as low-grade malignant adenomyoepithelioma. The patient shows no sign of tumour recurrence in the follow up.

Breast lesions with myoepithelial phenotype

Myoepithelial cells (MECs) constitute a continuous layer of cells surrounding the breast glands, localised between the epithelial cells (ECs) and the basal membrane. MECs play important roles in normal mammary gland as they produce basal membrane and stimulate secretion. During neoplastic transformation, MECs act as a barrier preventing stromal invasion. MECs themselves can undergo a great variety of changes, ranging from hyperplastic to metaplastic, to neoplastic, and giving rise to a wide spectrum of morphological pictures sometimes difficult to interpret on routine diagnoses. Several benign and malignant breast tumours can present features of MECs differentiation. As these latter tumours are quite infrequent, the purpose of the present study is to offer a review of the morphological spectrum of MECs lesions, with correlations to prognosis.

Case report and literature review: Malignant adenomyoepithelioma after breast augmentation

Background

Breast malignant adenomyoepithelioma (MAME) after breast augmentation has never been reported.

Case summary

We reported a case of a 55-year-old woman who was diagnosed with breast MAME 16 years after breast augmentation. Breast augmentation was performed on the patient with two 200 ml round textured prostheses in the subpectoral plane through axillary incisions in 2004. However, a breast ultrasound in 2020 revealed a suspicious malignant lump in the right breast, which was finally confirmed as MAME by pathology. Skin-sparing modified radical mastectomy and immediate breast reconstruction with expander implantation were performed. Subsequently, the patient received three cycles of chemotherapy with the regimen of anthracycline and cyclophosphamide. In the following nearly 2 years of follow-up, no tumor recurrence and metastasis were found, and the overall treatment was satisfactory for the patient.

Conclusion

Here, we present a unique case in which a patient was diagnosed with breast MAME after breast augmentation. Skin-sparing modified radical mastectomy and immediate breast reconstruction with expander implantation are feasible approaches that yield at least short-term oncological safety and acceptable aesthetic results. However, whether there is a potential relationship between MAME and breast implants remains to be further explored. Meanwhile, due to the rarity of breast MAME, more authoritative strategies considering both oncological safety and aesthetics to seek better long-term therapeutic effects are needed.

Adenomyoepithelioma of the breast with unusual confounding diagnostic feature: a case report

Background

Adenomyoepithelioma of the breast is an uncommon subtype of breast neoplasm that occurs in adults over a wide age range but most commonly in middle-aged and older adults. It usually presents as a solitary palpable mass or is detected on breast radiographic images. Histologically, it is a biphasic tumor with proliferation of both the epithelial and myoepithelial components of the glands, with variable types of tissue metaplasia.

Case presentation

A 64-year-old Saudi woman who underwent regular breast screening (mammogram) presented to our hospital following radiographic detection of a suspicious grouped microcalcification in the upper outer quadrant of her right breast on the mammogram. A wide local excision of the right breast lump was performed. Following histopathological examination of the breast lump, the final diagnosis was breast adenomyoepithelioma with mucoepidermoid/divergent differentiation, with no evidence of malignancy. About two years after the operation, a clinical follow-up conducted outside our hospital showed the development of ductal carcinoma in situ in the same breast.

Conclusion

Although the prognosis and the plan of treatment remains the same, our case highlights the complexities in making an accurate diagnosis between the various types of metaplasia within adenomyoepithelioma on one hand and the presence of mucoepidermoid differentiation in adenomyoepithelioma on the other.

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.

Benign adenomyoepithelioma of the breast: a case report

The diagnosis of adenomyoepitheliomas is difficult and relies on the presence of a double component of epithelial and myoepithelial cells belonging to the breast lobules and ducts. The clinical and imaging characteristics are not specific; thus, the diagnosis is histological. In this article, we present a case of a young female who presented with a 2 cm lump in the breast without other clinical symptoms, which revealed a benign adenomyoepithelioma (AME). We performed a large excisional lumpectomy, and the patient recovered well with no complication or recurrence within two years follow-up. When it comes to adenomyoepitheliomas, the published literature is mainly composed of case reports, so much so that there are no evidence-based guidelines. Our case shows that an excisional lumpectomy is often enough when facing a small size tumor with no signs of malignancy, which contributes to the limited data on the subject.

Malignant Adenomyoepithelioma of the Breast and Associated Epithelial-Myoepithelial Carcinoma; A Rare Case Report

Adenomyoepithelioma comprises a spectrum of lesions with variable morphology and clinical behavior, presenting at a wide age range. The most common presenting symptom is palpable abnormality. Mammographic abnormalities include focal asymmetries, masses and microcalcifications. Adenomyoepithelioma is a biphasic neoplasm characterized by proliferation of epithelial and myoepithelial cells. Adenomyoepitheliomas can be benign, atypical and malignant (adenomyoepithelioma with carcinoma). Malignant transformation occurs in either one or both cellular components leading to the development of invasive carcinoma. Invasive carcinoma types include invasive breast carcinoma of no special type, invasive lobular carcinoma, invasive carcinoma of special types, myoepithelial carcinoma, metaplastic carcinoma and biphasic carcinoma such as epithelial-myoepithelial carcinoma. While the majority of classic adenomyoepitheliomas have a benign clinical course and can be treated by local excision, local recurrence and distant metastasis have been reported. In malignant cases, treatment is determined by the associated carcinoma to include radiotherapy after breast conserving surgery and sentinel lymph node biopsy or axillary lymph node dissection, as indicated. Herein we report a case of a 62 year old woman who was found to have focal asymmetry on screening mammogram. She underwent a core biopsy of the lesion which showed atypical epithelial-myoepithelial neoplasm and excision was recommended. Upon excision, a diagnosis of malignant adenomyoepithelioma with associated epithelial-myoepithelial carcinoma was rendered with negative margins. The patient declined additional surgery for sentinel lymph node biopsy and declined adjuvant therapy. Six months after surgery, the patient is doing well with no complains. A follow-up mammogram and ultrasound of the axilla showed no abnormalities.

Adenomyoepithelioma of the breast: a rare diagnosis complicated by surgical emergency and diagnostic uncertainty

A woman in her 80s was referred as an emergency case with a large oedematous and ulcerating lesion of the right breast. There was a 5-month history of increasing breast volume with new onset skin breakdown and discharge. Imaging revealed an extensive heterogeneous mass requiring drainage. No diagnosis was received from multiple biopsies and immediate surgical resection of the breast and axillary sampling was prioritised given the deteriorating patient condition. Postoperative histology identified a biphasic Adenomyoepithelioma of low malignant potential, a rare presentation compounding the complexity of management. The diagnostic uncertainty of this case highlighted the importance of MDT collaboration and the flexibility of current management pathways when dealing with cases requiring urgent surgical intervention. Axillary sampling in the context of unsuccessful preoperative biopsy represented a comprehensive means for assessing the need for further surgical or systemic management in the context of unconfirmed malignancy in a deteriorating patient.

Combination of Adenomyoepithelioma and Adenoid Cystic Carcinoma of the Breast: A Case Report of an Uncommon Histopathological Entity

BACKGROUND Adenomyoepithelioma and adenoid cystic carcinoma are uncommon types of breast tumors. Adenoid cystic carcinoma accounts for 0.1% of breast neoplasms and typically presents as a tender breast tumor, mostly in the subareolar area. Adenoid cystic carcinoma usually appears in women in the fifth or sixth decade of life and predominantly presents as a mixed tumor, with cribriform, tubular, and solid growth characteristics. Adenomyoepithelioma of the breast shows epithelial and smooth muscle characteristics. Adenomyoepithelioma rarely goes through malignant transformation and is an uncommon type of benign breast tumor. CASE REPORT Our study reviews the current published literature regarding the combination of these 2 rare neoplasms of the breast and shows a rare case of a 48-year-old woman with a combination of adenoid cystic carcinoma and adenomyoepithelioma. CONCLUSIONS The combination of adenoid cystic carcinoma and adenomyoepithelioma should be part of the differential diagnosis in breast cancer. More research is needed regarding the optimal therapy, which is currently surgical excision.

Malignant adenomyoepithelioma of the breast: Two case reports and review of the literature

BACKGROUND

Malignant adenomyoepithelioma (AME) of the breast is a rare tumor in which malignancy can arise from either epithelial or myoepithelial components, or from both cell types. The incidence and prognosis of malignant AME of the breast are difficult to assess due to its rarity. Therefore, the optimal treatment for this disease is still controversial.

CASE SUMMARY

We present two middle-aged women (48 and 56 years old) with malignant AME of the breast. Core needle biopsy was performed before surgery. However, breast adenoma and malignant tumors were observed. The preoperative diagnosis of malignant AME of the breast is still challenging for pathologists and clinicians. Both patients underwent mastectomy and sentinel lymph node biopsy, both of which were negative, followed by adjuvant chemotherapy.

CONCLUSION

The follow-up duration of the two patients was two years and four months, respectively. No signs of relapse or metastasis have been observed thus far.

Triple-negative breast carcinomas of low malignant potential: review on diagnostic criteria and differential diagnoses

Triple-negative breast carcinomas constitute a wide spectrum of lesions, mostly being highly aggressive. Nevertheless, some special histologic subtypes can have low malignant potential. The purpose of the present paper is to review diagnostic criteria and prognostic parameters of breast neoplasms of special histotypes. Specifically, adenoid cystic carcinoma, adenomyoepithelioma, acinic cell carcinoma, mucoepidermoid carcinoma, tall cell carcinoma with reverse polarity, and secretory carcinoma will be discussed. For each tumour, definition and morphological and molecular features, together with prognostic parameters, will be presented. Paradigmatic cases will be illustrated.

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.

Updates on Lobular Neoplasms, Papillary, Adenomyoepithelial, and Fibroepithelial Lesions of the Breast

CONTEXT.—

This review article is a result of the breast pathology lectures given at the Sixth Chinese American Pathologists Association annual diagnostic pathology course in October 2020 (held virtually due to the coronavirus disease 2019).

OBJECTIVE.—

To update recent developments, in this review article, the authors wrote minireviews in the following 4 areas: lobular neoplasm, adenomyoepithelial lesions, papillary lesions, and fibroepithelial lesions.

DATA SOURCES.—

The sources include extensive literature review, personal research, and experience.

CONCLUSIONS.—

With the wide practice of screening mammography, these lesions are not uncommon in image-guided core biopsies and excisional specimens. Many recent developments have emerged in understanding these lesions. We aim to provide readers with concise updates for each of these lesions with a focus on recent updates in definitions, diagnostic criteria, management, and molecular profiles that are most relevant to the daily practice of pathology and patient management.

Papillary neoplasms of the breast-reviewing the spectrum

Papillary neoplasms of the breast encompass a wide range of tumor types ranging from the benign intraductal papilloma to in situ and invasive papillary carcinomas. In this review, we considered each tumor entity listed under the Papillary Neoplasms category in the latest WHO Classification of Breast Tumors (5th edition), namely intraductal papilloma, papillary ductal carcinoma in situ, encapsulated papillary carcinoma, solid-papillary carcinoma, and invasive papillary carcinoma. We examined their pathological features, current issues pertaining to diagnosis and prognostication, as well as the latest molecular findings. We also briefly addressed adenomyoepithelioma and the newly included tall cell carcinoma with reversed polarity, highlighting areas where they overlap with papillary neoplasms.

Apocrine Hidradenoma and Adenomyoepithelioma: Entities on a Biological Continuum of Adnexal Neoplasia

Apocrine hidradenomas (AH) once believed to harbor myoepithelial cells are now considered pure epithelial neoplasms. They are categorized separately from adenomyoepitheliomas which consist of apocrine epithelial and myoepithelial components. Reports of myoepithelial tumors arising in AH have suggested a link between the 2. Our goal was to explore whether cases diagnosed on routine microscopy as AH harbored occult myoepithelial elements, which would be disclosed by an immunohistochemical evaluation. Twenty-nine such cases, derived from a teaching collection of one of the authors, formed the basis of the study. Clinical and demographic data were documented, and morphological details of the cases were recorded. A panel of immunohistochemistry (AE1AE3, CK8/18, epithelial membrane antigen, p63, S100 protein, glial fibrillary acid protein, calponin, alpha actin, and others), designed to identify myoepithelial cells, was used. The population consisted of 14 women and 15 men (mean age 55.8; range 26-82 years). The tumors, located on the head/neck (14), limbs (10), and trunk (5), were solid (2) and solid/cystic (27). They exhibited varied (often combined) cytological elements (clear, squamoid, polygonal, and mucinous cells). On immunohistochemistry, aggregates of myoepithelial cells were identified in 5 (17%) cases. Four were calponin+ and AE1AE3+; they occupied ≤30% of tumor volumes and exhibited fusiform cytomorphology. One was S100 protein+ and AE1AE3+; it occupied 70% of tumor volume and exhibited polygonal cytomorphology. The gradation in the volume of myoepithelial elements disclosed by immunohistochemistry in a subset of our cases suggests that AH and adenomyoepitheliomas exist on a biological continuum of adnexal neoplasia. The diagnostic categorization of lesions with dual elements requires further study, but we propose that the term adenomyoepithelioma be restricted to those in which myoepithelial cells constitute ≥25% of tumor volume.

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.

A Case of Adenomyoepithelioma With a Pleomorphic Adenoma-Like Component of the Male Breast

Adenomyoepithelioma (AME) of the male breast is a rare tumor characterized by biphasic proliferation of gland epithelial cells and myoepithelial cells. Though pleomorphic adenoma (PA) is also known to be an epithelial-myoepithelial tumor in the breast, and these tumors are considered to exist on the same spectrum by some authors, to the best of our knowledge, there have been no reports of a clear transition from AME to PA in the male breast. Therefore, the case of an 85-year-old man with AME with PA-like components is presented.

Adenomyoepithelioma with a human epidermal growth factor receptor 2-fluorescence in situ hybridization-confirmed ductal carcinoma in situ component: A case report and review of the literature

INTRODUCTION

Breast adenomyoepithelioma (AME) is a rare tumor composed of myoepithelial cells and ductal or luminal cells. Most cases of AME are benign, but rare cases in which either or both cell types exhibited malignant features have been reported. Due to its rarity, no diagnostic criteria for malignancy have been established for AME.

PATIENT CONCERNS

A 64-year-old woman presented with a mass in her right breast. Fine-needle aspiration cytology and biopsy examinations revealed lesions composed of spindle-shaped cells and round epithelial cells. AME was suspected, and partial mastectomy was performed.

DIAGNOSIS

The tumor specimen showed AME, which mainly consisted of spindle-shaped myoepithelial cells with slight atypia, admixed with tubular luminal cells and small areas of atypical intraductal proliferative lesions. No apparent features of malignancy, such as necrosis or invasion, were seen in the myoepithelial cells or the luminal or intraductal component. However, the atypical intraductal component exhibited focal nuclear atypia, a cribriform pattern, and moderate to strong membranous human epidermal growth factor receptor 2 (HER2) immunoreactivity. HER2 amplification was detected in focal regions of the atypical intraductal component by fluorescence in situ hybridization (FISH), which resulted in a diagnosis of AME with ductal carcinoma in situ.

OUTCOMES

The patient did not receive further therapy and was free from tumor recurrence at 23 months after the operation.

CONCLUSION

HER2 FISH might be useful for evaluating suspected AME tumors for malignancy when an atypical ductal lesion that lacks definitive features of malignancy is encountered.

Adenomyoepithelial tumors of the breast: molecular underpinnings of a rare entity

Adenomyoepitheliomas (AMEs) of the breast are uncommon and span the morphologic spectrum of benign, atypical, in situ, and invasive forms. In exceptionally rare cases, these tumors metastasize to regional lymph nodes or distant sites. In the era of genomic characterization, data is limited regarding AMEs. The aim of this study was to provide insight into the molecular underpinnings of a spectrum of AMEs. Seven cases of AMEs of the breast (benign-1, atypical-2, in situ-1, invasive-3) were identified in our files. The seven samples were interrogated using the Oncomine Comprehensive Assay v3 (ThermoFisher). Two atypical AMEs and the malignant in situ AME harbored the same gain-of-function PIK3CA mutation. The malignant in situ AME also showed EGFR amplification, not described previously. Both a benign AME and a malignant invasive AME shared the same gain-of-function AKT1 variant. The benign AME also showed a GNAS mutation. Moreover, the same gain-of-function HRAS mutation was present in an atypical AME and a malignant invasive AME. We also identified co-occurring HRAS and PIK3CA mutations in an ER-positive atypical AME, which has not been previously described. No fusion drivers were detected. We describe the molecular characteristics of the spectrum of AME tumors of the breast, which harbor alterations in the PI3K/AKT pathway. Our findings are clinically relevant with respect to the current options of targeted therapy in the rare instances where malignant AME tumors of the breast progress.

Malignant adenomyoepithelioma of the breast: A case report

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Malignant breast adenomyoepithelioma (AME), rare subtype of cancer that usually benign.

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Mastectomy and sentinel lymph node biopsy with no further recurrence.

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Inner epithelial cells revealed positivity for CK5/6.

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Myoepithelial layers were positive for P63, CK5/6, SMA and S100 protein.

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Metastases chance of 30–40% with malignant adenomyoepithelioma, generally haematogenous route. Whereas metastases to the axillary lymph nodes is rare.

Introduction

Malignant breast adenomyoepithelioma (AME) is a rare subtype of breast cancer. AME is mostly a benign disease that uncommonly undergoes malignant transformation.

Presentation of case

Here we present a case of a young, previously healthy female who initially presented with a painless breast lump. The patient underwent wide local excision for atypical cells with squamous metaplasia by core biopsy, but final histopathology showed AME with carcinoma. Thus, a mastectomy and a sentinel lymph node biopsy was undertaken. The patient had an uneventful recovery and no recurrence after the second surgery.

Discussion and conclusion

Malignant transformation of adenomyoepithelioma is reported in a small number of cases. Benign AME may be treated with wide local excision as recurrence is rare locally. Whereas malignant AME tends to be treated with simple mastectomy with or without lymph node biopsy.

Malignant adenomyoepithelioma of the breast

BACKGROUND

Adenomyoepithelioma (AME) of the breast is a very rare tumor and is generally considered to be benign. However, some show malignant transformation, which results in local recurrences or distant metastases. The morphological features of AME that might predict malignant potential have not been elucidated. Moreover, there is also no established multidisciplinary treatment for malignant AME aside from complete excision at an early stage.

CASE PRESENTATION

A 64-year-old female diagnosed with AME of the left breast underwent lumpectomy. The surgical margins were negative. Six months after the operation, however, malignant AME recurred locally in the left breast. MRI showed multiple masses, which invaded the skin. A left mastectomy with axillary lymph node dissection was performed. Additional areas of AME were found in about one third of the entire breast. Eight months after the mastectomy, lung metastases were detected. She underwent chemotherapy with fluorouracil, epirubicin, and cyclophosphamide (FEC) for 9 cycles with little response. Lung metastasectomy was performed. Nine months after lung metastasectomy, the metastases were widespread to the brain, heart, and kidney; she subsequently died 2 months later.

CONCLUSIONS

Malignant AME has various morphological features, and in this report, we characterize new findings from both imaging and pathology/autopsy. Malignant potency is related to the tumor size, tumor appearance, and mitoses, even if only a few. Given that ductal spread is one of the morphological features of malignant AME, it is of paramount importance to assess the surgical margins.

Genotype-phenotype associations in breast pathology: Achievements of the past quarter century

The first genotype-phenotype relationship in breast pathology developed in 1994 with the discovery of the CDH1 gene. This finding eventually provided biological insight into the characteristic morphology of invasive lobular carcinoma. Subsequent investigative efforts have uncovered additional molecular alterations largely responsible for the histology of several breast neoplasms including secretory carcinoma, adenoid cystic carcinoma, tall cell carcinoma with reversed polarity, fibroepithelial lesions, and most recently, adenomyoepithelioma. Evaluation of the genomic landscape of other special types of breast cancer with distinctive growth patterns, such as invasive mucinous carcinoma, have yet to uncover recurring cytogenetic and/or molecular alterations. Despite the lack of a hallmark alteration in mucinous carcinoma, it is important to note the relative decrease in PIK3CA mutations compared with invasive carcinoma of no special type. In this review, we describe the clinical and pathologic features of breast tumors with recognized genotype-phenotype correlations and summarize the molecular alterations of mucinous carcinoma.

Rapid Local Recurrence of Breast Myoepithelial Carcinoma Arising in Adenomyoepithelioma: A Case Report

Adenomyoepithelioma (AME) is a rare breast neoplasm composed of both epithelial and myoepithelial cells with biphasic proliferation. Although most AMEs are benign, malignant transformation of either or both cellular components may occur. This report describes an unusual rapid local tumor recurrence a month after excision of the myoepithelial carcinoma arising in an AME. Ultrasound and MRI showed small recurrent masses in the superficial part of a hematoma. This report suggests the benefit of immediate postoperative breast imaging in patients with malignant AME with potential for local recurrence, such as those with narrow resection margins or high mitotic activity.

Primary Cutaneous Adenomyoepithelioma Ex Spiradenoma With Malignant Histologic Features, Epithelial-Myoepithelial Carcinoma Type: A First Case Report With Molecular Studies

Adenomyoepithelioma is an extremely rare primary cutaneous neoplasm. Although there is ample evidence on the existence of malignant adenomyoepithelioma in the breast, a malignant counterpart in the skin has not been documented. We report a primary cutaneous adenomyoepithelioma (pcAME) with malignant features arising from a spiradenoma in a 39-year-old female patient. The tumor was solid-cystic in appearance and entirely located in the subcutaneous tissue. Histologically, the tumor displayed foci of adenomatous changes and adenomyoepitheliomatous hyperplasia adjacent to a minute spiradenoma. Gradual increase of architectural complexity, cytologic atypia, mitotic activity, and infiltrative growth were observed in a significant portion of the neoplasm, indicative of transformation to adenomyoepithelioma and subsequently low- to high-grade salivary-type epithelial-myoepithelial carcinoma (EMCA). The intimate dual populations of ductal and myoepithelial cells were highlighted by a panel of immunohistochemical stains in all different components of the tumor. Molecular studies revealed a PIKCA3 mutation, a genetic aberration that has been documented in EMCA, particularly of breast origin. The current case documents for the first time a pcAME with malignant features arising from a spiradenoma and suggests adenomyoepithelioma ex spiradenoma as a possible tumorigenesis pathway of this rare cutaneous tumor.

Malignant adenomyoepithelioma of the breast: A rare case report

INTRODUCTION

Adenomyoepithelioma of the breast is a rarely reported and mostly benign disease that seldom undergoes malignant transformation.

PRESENTATION OF THE CASE

Here, we present a case of malignant adenomyoepithelioma of the breast in a patient who initially presented with pain following an excision procedure at local clinic. The condition was finally diagnosed after a third surgical procedure, pathologic analysis with hematoxylin and eosin staining, and immunohistochemistry analysis to detect smooth muscle actin and S100 expression.

CONCLUSION

The patient developed no complications or recurrences after a total mastectomy with sentinel node dissection.

Adenomyoepithelioma With Myoepithelial Carcinoma of the Breast With Axillary Lymph Node Metastasis: Two Case Reports and Review of the Literature

Objectives

Adenomyoepithelioma (AME) of the breast exhibits characteristic proliferation of the epithelial and myoepithelial cells. Most AMEs are benign, but the 2 inherent cell types can become malignant. The present study reports 2 cases of AME with myoepithelial carcinoma of the breast, one with axillary lymph node metastasis.

Methods

A modified radical mastectomy was performed in a 67-year-old woman, because a sentinel lymph node biopsy revealed one metastatic lymph node composed of a myoepithelial carcinoma component. Despite receiving radiotherapy and chemotherapy, the patient died from lung and brain metastases 21 months later. In the second case, breast-conserving surgery with sentinel lymph node biopsy was performed in a 55-year-old woman. Following additional treatment with radiotherapy and chemotherapy, there were no signs of recurrence or metastasis.

Results

The tumors of the 2 patients were diagnosed as malignant, based on their high mitotic rate and severe nuclear atypia.

Conclusions

Based on previously reported cases with distant metastases, the prognosis of myoepithelial carcinoma is poor. Myoepithelial carcinoma should be followed up with careful screening and treated aggressively.

Adenomyoepithelioma of the Breast, Presenting as a Cancer

Aims and background

Adenomyoepithelioma is a rare lesion that can involve the breast tissue. The diagnostic appearance of the lesion can give raise to a difficult differential diagnosis with breast carcinoma.

Patients and methods

We report our experience with a case of adenomyoepithelioma whose differential diagnosis with a breast carcinoma was particularly difficult, leading to surgery for definitive histology.

Discussion

Few papers are available with evidence about adenomyoepithelioma. The difficult differential diagnosis and the potentiality of malignant evolution of this lesion could in principle justify a conservative surgical approach for final histology.

Adenomyoepithelioma of the Breast

Adenomyoepithelioma of the breast is an uncommon tumor characterized by the presence of both epithelial and myoepithelial cells; its first full description was published in 1970 by Hamperl.

A 45-year-old woman presented a left breast lump that had been palpable for 4 weeks. There was no family history of breast cancer. Neither axillary nor supraclavicular lymph nodes were palpable. Craniocaudal mammography showed a 1.6 cm, well-defined nodule with several punctate intranodular calcifications in the subareolar region of the left breast. Color Doppler sonogram showed an ovoid, well-defined, homogeneous hypoechoic subareolar nodule with prominent peripheral vessels in the 6 o'clock position of the left breast. Operation was arranged and intraoperative frozen section examination revealed proliferation of round, oval or tubular glandular elements with intervening islands and bands of polygonal myoepithelial cells. Adenomyoepithelioma of the breast was the impression. Wide excision with adequate removal of the tumor and preservation of the left breast contour was successfully achieved. The diagnosis of adenomyoepithelioma of the breast was confirmed by immunohistochemical studies.

Myoepithelial Differentiation in Breast Carcinoma

Background

The aim of presenting this work is to describe a matrix producing carcinoma with anaplastic myoepithelial cell foci, with the coexistence of in situ myoepithelial carcinoma which originated from a sclerosing adenosis.

Case report

A 51-year-old perimenopausal woman presented with a hard irregular lump in her left breast. After histological confirmation of malignancy the patient underwent a modified radical mastectomy. The tumor was composed of a sclerosed fibroadenoma and preexisting sclerosing adenosis with poorly differentiated overt carcinoma within the cartilaginous matrix. There were foci of ordinary intermediate-grade carcinoma in situ and myoepithelial carcinoma in situ.

Results

We performed immunohistochemistry by the streptavidin-biotin horseradish peroxidase method. Estrogen receptor and progesterone receptor were negative, and so was c-erbB-2. Both the invasive and the in situ components were positive for CK7, CK19, CK14, vimentin, smooth muscle actin, nerve growth factor receptor, and epidermal growth factor receptor. By contrast, CK5/6 immunoexpression was found only in the in situ component. Negativity was found for p63 and CD10 within the tumor. While cytoplasmic bcl-2 immunoexpression was detected in some of the tumor cells of the invasive component, intranuclear p53 expression was found to be positive not only in the invasive component but also in the in situ component of the tumor.

Conclusion

The histopathological findings and the immunohistochemistry results support the derivation of the tumor from myoepithelial cells.

Tubular variant of mammary adenomyoepithelioma: Diagnostic challenges and cytomorphological correlation in two cases

The authors describe the cytomorphologic features of two cases of tubular variant of adenomyoepithelioma of the breast that were first examined by fine-needle aspiration cytology (FNAC) and diagnosed as fibroadenoma. On retrospective review of the cytology, subtle features such as less cohesive epithelial clusters, intimate association of clusters of stromal cells with epithelial elements, a dominant population of plump-epithelioid naked (myoepithelial) cells, and occasional cells with intranuclear inclusions, were noted. Thus, these lesions can be diagnostically challenging and cannot be conclusively differentiated from either fibroadenoma or tubular adenoma cytologically and the pathologist may only be able to give a differential on FNAC. Recognition of the biphasic nature and the characteristic overall architecture of the tumors in combination with immunohistochemistry are essential to establish the correct diagnosis on biopsy. Although most tumors have a benign clinical course, rare instances of local recurrence, malignant transformation, and distant metastases have been reported. A complete excision with adequate margins would lower the chance of local recurrence.

[Adenomyoepithelioma of the breast: Report of four cases and literature review]

Adenomyoepitheliomas of the breast are infrequent tumors with a variable histological appearance, and they can mimic several epithelial, myoepithelial and biphasic lesions of the breast. We have reviewed four cases of adenomyoepithelioma of the breast diagnosed between 2005 and 2015 in our institution (Hospital Clínico San Carlos). Mean age was 57years. All lesions were solid irregular masses located in the upper quadrants (3 of them in the right breast and one in the left), with an average size of 13mm. Microscopically 2 of them were tubular and the remaining 2 were lobulated subtypes. Hyaline, myxoid and cystic areas, peripheral pseudoinfiltration and satellite nodules were occasionally seen. Myoepithelial cells were fusiform and immunohistochemically they were actin, calponin, p63, S100 and CD10 positive and CKAE1-AE3 negative, with variable CK23BE12 and CK5/6 staining. In all cases lumpectomy was curative, no recurrences or malignant degeneration were observed.

Radiotherapy in the Multidisciplinary Management of Adenomyoepithelioma of the Breast with an Axillary Lymph Node Metastasis: A Case Report and Review of the Literature

We describe a case of aggressive adenomyoepithelioma (AME) of the breast with a lymph node metastasis. A 63-year-old female presented with a fluctuating breast mass and clinically palpable lymph nodes. The patient underwent excisional biopsy followed by mastectomy with lymph node dissection and adjuvant radiotherapy (RT). Clinical behavior of both benign and malignant AME is described with the review of the literature and treatment recommendations.

Adenomyoepithelioma of the breast with late pulmonary metastases - case report and review of the literature

Background

Adenomyoepithelioma (AME) of the breast is a rare tumour of unpredictable clinical behaviour. Most of the tumours are benign with some giving local recurrences or distant metastases.

Case Presentation

We report a case of late lung metastases in a woman with a history of breast adenomyoepithelioma. Partial lobectomy was performed for lung lesions and initial diagnosis was epithelial-myoepithelial carcinoma.

Conclusion

Careful slide’s revision of both breast and pulmonary lesions showed identical microscopic appearance with lung tumour performing more malignant features. Tumour cells in both: breast and pulmonary lesions were positive for cytokeratin and EMA (epithelial cells) and also for SMA, S100 and vimentin (myoepithelial cells). Two years and 7 months follow-up showed no recurrent neoplastic disease in our patient.

Smooth Muscle and Nerve Sheath Tumors of the Breast

The clinical and pathological features of 22 smooth muscle tumors and 23 nerve sheath tumors of the breast are presented. The smooth muscle tumors included 18 leiomyomas and 4 leiomyosarcomas. Two types were found: those superficial in the nipple or in the skin overlying the breast and those located within the breast parenchyma. Superficial leiomyomas were small and had ill-defined, infiltrating margins. Leiomyomas located within the breast were circumscribed and larger than the superficial ones. Mitotic activity did not exceed 1 mitotic figure per 10 high-power field and only 2 of the 18 showed 1 + and 2 + atypia. None recurred after local excision. The four leiomyosarco mas had 2 + and 3 + nuclear atypia and mitotic activity ranging from 3 to 28 mitotic figures per 10 high-power field. Recurrences occurred in two, but none metastasized. Nerve sheath tumors included 5 neurilemomas, 15 neurofibromas and 3 malignant schwannomas. All neurilemomas were encapsulated and showed no mitotic activity or cytologic atypia. Of the 15 neurofibromas, 6 were encapsulated, 4 had circumscribed margins with focal infiltration, and 2 had infiltrative margins. Focal cytologic atypia was seen in 4. All 3 malignant shwannomas had infiltrative margins, nuclear atypia, and noticeable, often abnormal, mitotic figures. Two of the 11 patients with neurofi broma had von Recklinghausen's disease and developed recurrences. None of the 3 patients with malignant schwannoma developed a recurrence. Int J Surg Pathol 2(2): 85-92, 1994

[Adenomyoepithelioma with dominant myoepithelial contingent of the breast: A case report and literature review]

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.

Breast Adenomyoepithelioma: Ultrasonography, Elastography, Digital Mammography, Contrast-Enhanced Digital Mammography, and Pathology Findings of This Rare Type of Breast Tumor

Breast adenomyoepithelioma is considered as an uncommon breast tumor. It is evaluated as a variant of intraductal papilloma. The treatment of choice is local resection with free margins. It is the first case of breast adenomyoepithelioma reported with conventional ultrasonography, elastography (both free-hand and acoustic radiation force impulse imaging), digital mammography, contrast-enhanced digital mammography, and pathology findings. A 35-year-old white woman presented with a painless lump of the left breast. Treatment was local resection with free margins. There has been no recurrence for 6 months. Although breast adenomyoepithelioma is an uncommon breast tumor, its awareness is imperative because the differential diagnosis from other breast tumors is quite extensive.

Adenomyoepithelioma of the breast coexisting with ductal carcinoma in situ: a case report and review of the literature

We herein report a case of adenomyoepithelioma (AME) of the breast with ductal carcinoma in situ (DCIS) involving a 71-year-old Japanese woman. She presented with bloody discharge from the left nipple. Mammography and ultrasonography showed a well-defined polygonal tumor. Fine-needle aspiration cytology of the mass and stamp cytology of the bloody nipple discharge showed malignancy. Mastectomy and a sentinel lymph node biopsy were performed. The final diagnosis was AME of the breast with DCIS. There are no reports of AME of the breast presenting with bloody nipple discharge; upon a diagnosis of AME of the breast with bloody nipple discharge, the possibility of the coexistence of breast cancer should thus be considered when encountering such cases.