Clinicopathologic analysis of solid papillary carcinoma of the breast and associated invasive carcinomas

Pleomorphic Lobular Carcinoma In Situ Composed of Signet-Ring Cells Mimicking Ductal Carcinoma In Situ with A Papillary Pattern: A Case Report

While some forms of invasive or in situ carcinoma of the breast may be partly composed of signet-ring cells, signet-ring cells rarely become a prominent feature of pleomorphic lobular carcinoma in situ (LCIS). We report a rare example of pleomorphic LCIS composed predominantly of signet-ring cells with a papillary pattern mimicking ductal carcinoma in situ (DCIS). A 58-year-old woman presented with a mass in the left breast detected by ultrasonography. Fourteen years previously, the patient underwent right breast-conserving surgery for invasive breast carcinoma of no special type. Ultrasonography revealed an irregular parallel, angular hypoechoic mass measuring 1.5 cm in the left breast. An ultrasound-guided core needle core biopsy was conducted. Microscopically, the lesion was composed of epithelial cells supported by a fibrovascular stroma. The majority (> 70%) of the lesional cells between the fibrovascular stalks showed signet-ring cell features. Some of the nuclei of the signet-ring cells showed intermediate-grade atypia. A mucicarmine stain showed intracytoplasmic mucin in the signet-ring cells. Immunohistochemistry for E-cadherin was negative in the tumor cells. After surgical excision, the final diagnosis was a pleomorphic LCIS. To our knowledge, there have been no previous reports of pleomorphic LCIS consisting primarily of signet-ring cells with a papillary pattern.

A Preliminary Investigation into Search and Matching for Tumor Discrimination in World Health Organization Breast Taxonomy Using Deep Networks

Breast cancer is one of the most common cancers affecting women worldwide. It includes a group of malignant neoplasms with a variety of biological, clinical, and histopathologic characteristics. There are more than 35 different histologic forms of breast lesions that can be classified and diagnosed histologically according to cell morphology, growth, and architecture patterns. Recently, deep learning, in the field of artificial intelligence, has drawn a lot of attention for the computerized representation of medical images. Searchable digital atlases can provide pathologists with patch-matching tools, allowing them to search among evidently diagnosed and treated archival cases, a technology that may be regarded as computational second opinion. In this study, we indexed and analyzed the World Health Organization breast taxonomy (Classification of Tumors fifth ed.) spanning 35 tumor types. We visualized all tumor types using deep features extracted from a state-of-the-art deep-learning model, pretrained on millions of diagnostic histopathology images from the Cancer Genome Atlas repository. Furthermore, we tested the concept of a digital "atlas" as a reference for search and matching with rare test cases. The patch similarity search within the World Health Organization breast taxonomy data reached >88% accuracy when validating through "majority vote" and >91% accuracy when validating using top n tumor types. These results show for the first time that complex relationships among common and rare breast lesions can be investigated using an indexed digital archive.

Spectrum of Mucin-containing Lesions of the Breast: Multimodality Imaging Review with Pathologic Correlation

Mucin-containing lesions of the breast encompass a wide range of benign and malignant processes. The spectrum of histologic findings includes incidental mucus-filled benign cysts or ducts, mucocele-like lesions (MLLs), mucin-producing ductal carcinoma in situ, and invasive mucinous carcinoma. MLL is characterized by the presence of mucin-containing cysts that are typically associated with extravasated stromal mucin. MLL is often benign but can be associated with epithelial atypia or malignancy. Mucinous carcinoma represents the malignant end of the spectrum of mucinous lesions of the breast. Evidence-based literature supports a conservative approach for benign MLLs without associated atypia or malignancy, reserving excision for those lesions exhibiting such pathologic features. The most common imaging finding for MLL is microcalcifications at mammography. No specific imaging feature is predictive of malignant outcome at surgical excision. Invasive mucinous carcinoma is a heterogeneous breast tumor subtype, as defined according to the World Health Organization criteria. Mucinous carcinomas are categorized into pure (>90% mucinous component) or mixed (10%-90% mucinous component) subtypes. Pure mucinous carcinomas are generally associated with excellent prognosis and survival, with a few exceptions. Mixed mucinous carcinomas do not have the same favorable prognosis and instead behave similarly to invasive breast carcinomas of no special type. Characteristic diagnostic imaging features can be identified for mucinous carcinoma based on its mucinous and nonmucinous contents. ©RSNA, 2023 Online supplemental material is available for this article. Quiz questions for this article are available through the Online Learning Center.

Cytological study of 44 cases with solid papillary carcinoma and a systemic review of solid papillary carcinoma and neuroendocrine tumor of the breast

BACKGROUND

Solid-papillary carcinoma (SPC) of the breast is a rare variant of low-grade in situ and invasive carcinoma but there are only a few of the cytologic studies.

METHODS

We examined 44 cases of SPC of the breast to define the cytologic features. We also made a systemic review of reported cases of SPC and neuroendocrine tumor (NET) of the breast.

RESULTS

Both of our and the reviewed cases with SPC were very similar in the cytologic finding. It included hypercellularity, highly discohesive clusters, numerous isolated cells, small nuclei, finely granular chromatin of salt-and-pepper appearance, inconspicuous nucleoli, low nuclear-cytoplasmic ratio, and a plasmacytoid appearance. Moreover, SPC and NET had frequently all of these features in common. Capillary vessels structures and mucinous substance were not frequently seen in our and the reviewed cases with SPC. Rosette and pseudorosette were very rare in the cytologic specimen. The immunocytochemistry with our 9 cases with SPC indicated diffuse positivity for chromogranin A and/or synaptophysin.

CONCLUSION

Many cytologic features are frequently shared by SPC and NET of the breast. However, the vascular structure may not be a precise criterion for SPC. Rosette and pseudorosette are rarely helpful for the cytologic diagnosis.

A large-scale clinicopathological and long-term follow-up study of solid papillary carcinoma of the breast

Solid papillary carcinoma of the breast (SPC) is a rare tumor of the breast with the unique histology and frequent neuroendocrine differentiation. However, a real nature and diagnostic importance of the neuroendocrine differentiation have not been properly handled. And relationship between SPC and the other types of invasive breast carcinoma, especially neuroendocrine tumor of the breast (NETb), has not been fully explained. We conducted a clinicopathological study of SPC to tackle these problems.In the study, we included 127 cases of SPC with long-term follow-ups of up to 30 years. The incidence in the breast carcinoma was 2.0%. The patients with SPC had a significantly better prognosis and no patients died of the tumor. The 35 cases had only SPC in situ (SPC-IS), while the 92 cases had both SPC-IS and SPC with invasion (SPC-INV). Immunohistochemically, 123 of the 127 cases exhibited diffuse expression of one or more neuroendocrine markers. Fifty of the 92 cases had exclusively invasive SPC (iSPC) as the invasive component. Twenty-two cases of iSPC were combined with NETb and the 18 cases with MUC. Six of 8 cases with metastatic SPC-INV disclosed iSPC in the axillary lymph node.This study suggests that SPC is immunohistochemically compatible with NET of the systemic organs (NETs). And the unique morphology of SPC may represent a traditional histology of NETs. The study also indicates that SPC has close relationship between NETb and type B MUC. And SPC and NETb may represent a spectrum of the same disease.

The Spectrum of Mucinous Lesions of the Breast

CONTEXT.—

Mucinous lesions of the breast encompass many entities ranging from benign to malignant and nonneoplastic to neoplastic. Lesions discussed under this category are mucocele-like lesion, mucinous carcinoma, mucinous micropapillary carcinoma, solid papillary carcinoma, mucinous cystadenocarcinoma, mucoepidermoid carcinoma, invasive lobular carcinoma with extracellular mucin, mucinous ductal carcinoma in situ, and metastasis.

OBJECTIVE.—

To review clinical, pathologic, and molecular features of mucinous lesions of the breast, their differential diagnoses, and challenging features on core needle biopsies.

DATA SOURCES.—

The existing scientific and clinical literature as of December 2021.

CONCLUSIONS.—

The category of mucinous lesions of the breast is vast and the differential diagnosis can be challenging, especially on core needle biopsies. In all cases, clinical, radiologic, and pathologic correlation is necessary to reach a comprehensive diagnosis. Given that the prognosis and management of each entity is different, being aware of these entities and their nuances is critical for a pathologist to guide accurate management.

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.

Papillary lesions of the breast - review and practical issues

Papillary lesions of the breast represent a heterogeneous group of neoplasm featuring fibrovascular cores covered by epithelial cells with or without intervening myoepithelial cells. According to the World Health Organization classification of breast tumors, papillary lesions of the breast are further classified into intraductal papilloma (including intraductal papilloma with atypical ductal hyperplasia /ductal carcinoma in situ), papillary ductal carcinoma in situ, encapsulated papillary carcinoma, solid papillary carcinoma (in situ and invasive) and invasive papillary carcinoma. The overlapping morphological features and immunohistochemical profiles make accurate diagnosis of breast papillary lesion a challenge for pathologists. In this review, the morphological and relevant immunohistochemical features of papillary lesions are discussed, with further emphasis on some commonly encountered practical diagnostic issues. A simple diagnostic algorithm will be established. The relevant molecular characteristics will be discussed as well.

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

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

Factors associated with upgrade, malignant upgrade, and subsequent breast cancer occurrence of papillary breast lesions diagnosed on core needle biopsy

AIM

In this study, we analyzed the upgrade rate and associated factors for upgrade, malignant upgrade, and subsequent breast cancer occurrence of papillary breast lesions diagnosed on core needle biopsy (CNB).

METHODS

One hundred sixty-nine patients who underwent surgery for the treatment of papillary breast lesions diagnosed on CNB were included in this study. Medical records including radiological and pathological reports were retrospectively reviewed.

RESULTS

The overall upgrade rate was 29.6%, and upgrade rate to malignancy was 16.6%. Age over 45 years, preoperative tumor size ≥0.7 cm on breast ultrasound, pathologic tumor size ≥0.4 cm, breast imaging reporting and data system (BIRADS) category 4b or 4c, and personal history of breast cancer were associated with upgrade. In addition, age over 45 years, preoperative tumor size ≥0.9 cm, pathologic tumor size ≥0.6 cm, atypia in CNB, and BIRADS category 4b or 4c were associated with malignancy. The risk of subsequent breast cancer occurrence was increased in preoperative tumor size ≥0.8 cm, pathologic tumor size ≥0.5 cm, multiple and recurrent lesions.

CONCLUSION

Our study showed high upgrade rate of papillary breast lesions diagnosed on CNB. Our findings suggest that surgical excision is recommended for papillary breast lesions diagnosed on CNB in selected patients.

Papillary Neoplasms of the Breast: Diagnostic Features and Molecular Insights

Papillary neoplasms of the breast are a heterogeneous group of tumors characterized by fibrovascular cores lined by epithelium, with or without myoepithelial cells. Papillary neoplasms include benign, atypical, and malignant tumors that show varying histopathologic features and clinical outcomes. Appropriate pathologic classification is crucial to guide clinical treatment. Classification of papillary neoplasms is largely based on morphology, with immunohistochemistry playing an ancillary role to establish diagnoses. Recent molecular studies have provided insight into the genomics of these lesions. This review summarizes the histologic, immunohistochemical, and molecular features of papillary neoplasms of the breast that are important for diagnosis and treatment.

Breast carcinomas of low malignant potential

Some breast carcinomas have a very low likelihood of metastasis to regional lymph nodes and distant sites and may be considered carcinomas of low malignant potential. In this article, we review the clinical, pathologic, immunophenotypic, and molecular features of selected breast carcinomas of low malignant potential including low-grade adenosquamous carcinoma, fibromatosis-like metaplastic carcinoma, encapsulated papillary carcinoma, solid papillary carcinoma, and tall cell carcinoma with reversed polarity.

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.

Solid Papillary Carcinoma and Encapsulated Papillary Carcinoma of the Breast: Clinical-Pathologic Features and Basement Membrane Studies of 50 Cases

INTRODUCTION

Solid papillary carcinoma (SPC) and encapsulated papillary carcinoma (EPC) of the breast are usually considered in situ lesions due to favorable prognosis, despite the variable presence of myoepithelial cells. We aimed to describe clinical-pathologic features including basement membrane (BM) studies in these tumors.

METHODS

Patients diagnosed with SPC and EPC in 2000-2019 were retrospectively identified. Microscopic slides and clinical history were reviewed. Immunohistochemical stains for BM and myoepithelial markers were performed.

RESULTS

Of 23 SPCs and 27 EPCs, there were 5/23 (21.7%) pure SPCs and 9/27 (33.3%) pure EPCs, while 4/23 (17.4%) and 12/27 (44.5%) were associated with ductal carcinoma in situ (DCIS), and 6/23 (26.1%) and 6/27 (22.2%) with invasive carcinoma, respectively; 8/23 (34.8%) SPCs were considered invasive. The median tumor size was 1.7 cm (range 0.1-16). All tumors were positive for hormone receptors and negative for HER2. Myoepithelial cells were absent in 20 tumors (40%) and focally present in 30 (60%). Collagen IV and laminin were negative in most invasive lesions, but they were expressed in 21/21 (100%) and 18/21 (85.7%) of EPCs without invasion, and 16/17 (94.1%) and 10/17 (58.8%) SPCs, including invasive SPCs, respectively. Lymph node involvement was identified in 3/26 (11.5%) patients, including micrometastasis in 1 EPC associated with DCIS, macrometastasis in 1 EPC associated with invasive carcinoma, and isolated tumor cells in 1 invasive SPC. Of 31 patients with outcome data (median follow-up 35 months, range 1-85), 2 (6.5%; 1 SPC, 1 EPC) developed local recurrence, both associated with invasive carcinoma. No distant recurrences or deaths were observed.

CONCLUSIONS

Our study confirms favorable prognosis of SPCs and EPCs, with 2 local recurrences occurring in the presence of invasion. SPCs are more commonly associated with invasive carcinoma or considered invasive compared to EPCs (60.9 vs. 22.2%). The presence of BM material and lack of lymph node involvement in most cases indicates that the majority of these tumors may represent in situ lesions; however, some may behave as low-grade invasive malignancy with metastatic potential even in the absence of conventional invasion.

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.

Papillary neoplasms of the breast including upgrade rates and management of intraductal papilloma without atypia diagnosed at core needle biopsy

Papillary neoplasms of the breast are a heterogeneous group of epithelial tumors nearly entirely composed of papillae. Their classification rests on the characteristics of the epithelium and the presence and distribution of the myoepithelial cells along the papillae and around the tumor. Papillary neoplasms of the breast can be diagnostically challenging, especially if only core needle biopsy (CNB) material is available. This review summarizes salient morphological and immunohistochemical features, clinical presentation, and differential diagnoses of papillary neoplasms of the breast. We include a contemporary appraisal of the upgrade rate to carcinoma (invasive carcinoma and ductal carcinoma in situ [DCIS]) and atypical hyperplasias in surgical excision specimens obtained following CNB diagnosis of papilloma without atypia, and a review of the available follow-up data in cases without immediate surgical excision.

INSM1 immunostaining in solid papillary carcinoma of the breast

Solid papillary carcinoma (SPC) is a histological subtype of breast carcinomas. At least 50% of SPC show neuroendocrine differentiation. Insulinoma-associated protein 1 (INSM1) is a transcription factor now employed as a useful neuroendocrine marker. It is suppressed by the Notch signaling pathway in other neuroendocrine tumors. However, the usefulness of INSM1 as a neuroendocrine marker and the relationships between INSM1 and NOTCH receptors in SPC of the breast currently remain unclear. To clarify the usefulness of INSM1 as a neuroendocrine marker and the relationships between INSM1 and NOTCH receptors in SPC, we performed immunohistochemistry using 19 tissue specimens of SPC of the breast. We complementarily analyzed public RNA sequencing data on breast carcinomas. Immunohistochemical examinations revealed that the staining intensity of INSM1 was significantly higher in the neuroendocrine group than in the non-neuroendocrine group. Positive correlations were observed between INSM1 and synaptophysin (SYP), or chromogranin-A (CHGA). In all cases, NOTCH 2 and 3 were positive, while NOTCH 1 and 4 were negative. According to public RNA data analyses, there were positive correlations between INSM1 and SYP, or CHGA, and negative correlations between INSM1 and NOTCH1-3. INSM1 is useful as a diagnostic marker for SPC with neuroendocrine differentiation in the breast.

Special subtypes with favorable prognosis in breast cancer: A registry-based cohort study and network meta-analysis

BACKGROUND

We aimed to explore whether cribriform and adenoid cystic carcinoma had comparable prognoses to mucinous, tubular and papillary carcinoma, which were long recognized as favorable histologies by NCCN guidelines.

METHODS

A retrospective analysis based on the Surveillance, Epidemiology, and End Results Study (SEER) database (1994-2014) was conducted. The prognostic significance of all clinicopathological factors was calculated using univariate and multivariate analyses. A systematic review based on PubMed and network meta-analysis was conducted.

RESULTS

From the SEER database, the histologic subtypes of breast cancer (tubular, cribriform, adenoid cystic, mucinous, and papillary) were sorted by overall survival (OS) (94.4%, 91.6%, 90.8%, 87.6%, and 84.2%, respectively) and tubular, cribriform, mucinous, papillary, and adenoid cystic carcinoma by breast cancer-specific survival (BCSS) (99.4%, 98.4%, 97.7%, 95.2%, and 94.9%, respectively). A network meta-analysis combining 11 studies (886,649 patients) was conducted, which demonstrated consistent outcomes. SEER-based analyses revealed that, among the favorable subtypes, systemic chemotherapy did not improve OS or BCSS in hormone receptor-positive, node-negative patients, validating that these subtypes are generally associated with excellent outcomes, for which systemic chemotherapy may not be warranted.

CONCLUSIONS

Our data are consistent with guidelines suggesting that the mucinous, tubular, and papillary subtypes of breast cancer have favorable histologies. SEER data and meta-analysis supports this favorable category to include adenoid cystic and cribriform carcinoma, whose OS and BCSS outcomes are comparable to the former three. These findings add to the body of data, suggesting that patients with these histologic subtypes confer excellent prognosis, which may guide optimal therapeutic management strategies.

Invasive solid papillary carcinoma with neuroendocrine differentiation of the breast: a case report and literature review

Background

Solid papillary carcinoma (SPC) of the breast is a rare breast cancer that accounts for less than 1% of all breast cancers. The optimal clinical management of SPC remains controversial. Here, we report a case of invasive SPC with neuroendocrine differentiation in addition to review of the current literature.

Case presentation

A premenopausal 46-year-old female presented with a mass in her left breast that tended to increase in size over a 10-month period. Mammography and ultrasonography revealed a mass in the left upper-inner quadrant. The resulting images suggested a category 3 breast tumor according to the Breast Imaging Reporting and Data System (BI-RADS). A core needle biopsy (CNB) was performed, and the pathological findings showed a solid papillary pattern and atypical cells suggestive of noninvasive SPC. After a left partial mastectomy and sentinel lymph node biopsy (SLNB), the specimens were sent for histopathological analysis for further investigation. Postoperative pathological findings suggested invasive SPC. Whole-breast radiation therapy and adjuvant hormonal therapy were performed as postoperative treatments. Three years after surgery, multiple lung metastases were detected, and the patient was treated with a gonadotropin-releasing hormone agonist and an aromatase inhibitor. Five months later, multiple liver metastases and bone metastases appeared, and oral 5-fluorouracil was chosen for the subsequent treatment. The patient has been treated for 5 years to date, and she is continuing to take oral 5-fluorouracil and is alive without any further disease progression.

Conclusions

We report a rare case of premenopausal invasive SPC with multiple metastases. Further study is needed to clarify the molecular characteristics and clinical behaviors of SPC and to explore the optimal treatment strategy.

Is it ductal carcinoma in situ with microinvasion or "Ductogenesis"? The role of myoepithelial cell markers

Mammary myoepithelial cells have been under-recognized for many years since they were considered less important in breast cancer tumorigenesis compared to luminal epithelial cells. However, in recent years with advances in genomics, cell biology, and research in breast cancer microenvironment, more emphasis has been placed on better understanding of the role that myoepithelial cells play in breast cancer progression. As the result, it has been recognized that the presence or absence of myoepithelial cells play a critical role in the assessment of tumor invasion in diagnostic breast pathology. In addition, advances in screening mammography and breast imaging has resulted in increased detection of ductal carcinoma in situ and consequently more diagnosis of ductal carcinoma in situ with microinvasion. In the present review, we discuss the characteristics of myoepithelial cells, their genomic markers and their role in the accurate diagnosis of ductal carcinoma in situ with microinvasion. We also share our experience with reporting of various morphologic features of ductal carcinoma in situ that may mimic microinvasion and introduce the term of ductogenesis.

A review of mucinous lesions of the breast

Mucinous lesions of the breast include a variety of benign and malignant epithelial processes that display intracytoplasmic or extracellular mucin, including mucocele-like lesions, mucinous carcinoma, solid papillary carcinoma, and other rare subtypes of mucin-producing carcinoma. The finding of free-floating or stromal mucin accumulations is a diagnostic challenge of which the significance depends on the clinical, radiologic, and pathologic context. This article emphasizes the differential diagnosis between benign and malignant mucin-producing lesions, with a brief consideration of potential mimics, such as biphasic and mesenchymal lesions with associated with mucinous, myxoid, or matrix material.

Solid papillary carcinoma of breast; a detailed clinicopathological study of 65 cases of an uncommon breast neoplasm with literature review

Solid papillary carcinoma (SPC) is an uncommon breast tumor whose prognosis depends on invasive component. We studied clinicopathological features of SPC by reviewing 65 cases. Invasive component was seen in 75.4% cases. Almost all tumors with grade III nuclei had invasive component. Mean patients' age of invasive tumors was significantly higher than that of non-invasive tumors (P = .036). All patients were alive and disease free except for a single patient who developed distant metastasis and died of disease. SPC have excellent clinical course. Careful search for invasive component is mandatory, especially in tumors with older patient's age and higher nuclear grade.

Challenges in management of male breast adenomioepithelioma with malignant behavior: Case report

RATIONALE

Male adenomyoepithelioma of the breast with malignant features is a rare tumor with only one previous case reported in the literature over 25 years ago.

PATIENT CONCERNS

We report the case of a 63-year-old man admitted to our Oncology Institute with a painless tumor mass of 6 cm in the left breast with no additional regional lymph nodes. Ultrasound revealed a complex cystic tumor mass of 60 mm in the left breast, with both anechoic (cystic) and echogenic (solid) components, with ill-defined margin.

DIAGNOSES

Extemporaneous assessment showed a solid (invasive) papillary intracystic carcinoma. Definitive pathology examination revealed the presence of a breast malignant adenomyoepithelioma.

INTERVENTIONS

Based on the extemporaneous assessment, wide tumor excision was performed. The tumor board decided to continue treatment with adjuvant anthracycline-based chemotherapy.

OUTCOMES

After 6 years of follow-up, the patient is cancer-free. No chronic side effects were noted.

LESSONS

Because this pathology is extremely rare, no guidelines are available for its therapeutic approach. All decisions regarding patient management should be made by a multi-disciplinary team and can only be based on clinical experience and the few cases reported in female patients.

Prognostic Factors, Treatment, and Outcomes in Early Stage, Invasive Papillary Breast Cancer: A SEER Investigation of Less Aggressive Treatment in a Favorable Histology

OBJECTIVES

Invasive papillary breast cancer (IPBCA) represents 0.5% of invasive BCA, and is thought to carry a favorable prognosis. This population-based study reports on prognostic factors, treatment, and outcomes of early-stage IPBCA to explore whether there is any evidence to support less aggressive treatment.

MATERIALS AND METHODS

IPBCA cases from 1990 to 2009 of the recent Surveillance, Epidemiology, and End Results were analyzed. Inclusion criteria included patients with stage T1-2, N0 IPBCA. Univariate and multivariate analyses were performed using the variables of treatment, stage, race, hormone receptor status, grade (G1-3), and age. Treatment modalities included lumpectomy alone (LA), lumpectomy with radiation treatment (LRT), and mastectomy alone (MA).

RESULTS

Among 10,485 patients, median follow-up was 56 months. Five and 10-year overall survival (OS) were 93.1% and 76.8%, respectively. Patients treated with LRT had superior mean OS 16.8 versus 14.9 years for MA (P=0.0004) and 14.2 years for LA (P=0.0003). Improved OS also correlated with lower histologic grade (P<0.0001), lower T-stage (P<0.0001), and younger age (P<0.0001). Black patients had the worst OS (12.7 y, P<0.0001).

CONCLUSIONS

LRT is associated with superior OS for early-stage invasive papillary BCA patients, when compared with LA or MA in this population-based study. The findings support the standard of care breast conservation approach for patients with invasive papillary BCA. Other prognostic factors associated with worse OS include increased age, higher T-stage, higher histologic grade, and black race.

CXCL1 Derived from Mammary Fibroblasts Promotes Progression of Mammary Lesions to Invasive Carcinoma through CXCR2 Dependent Mechanisms

With improved screening methods, the numbers of abnormal breast lesions diagnosed in women have been increasing over time. However, it remains unclear whether these breast lesions will develop into invasive cancers. To more effectively predict the outcome of breast lesions and determine a more appropriate course of treatment, it is important to understand the underlying mechanisms that regulate progression of non-invasive lesions to invasive breast cancers. A hallmark of invasive breast cancers is the accumulation of fibroblasts. Fibroblast proliferation and activation in the mammary gland is in part regulated by the Transforming Growth Factor beta1 pathway (TGF-β). In animal models, TGF-β suppression of CCL2 and CXCL1 chemokine expression is associated with metastatic progression of mammary carcinomas. Here, we show that transgenic overexpression of the Polyoma middle T viral antigen in the mouse mammary gland of C57BL/6 mice results in slow growing non-invasive lesions that progress to invasive carcinomas in a stage dependent manner. Invasive carcinomas are associated with accumulation of fibroblasts that show decreased TGF-β expression and high levels of CXCL1, but not CCL2. Using co-transplant models, we show that decreased TGF-β signaling in fibroblasts contribute to mammary carcinoma progression through enhancement of CXCL1/CXCR2 dependent mechanisms. Using cell culture models, we show that CXCL1 mediated mammary carcinoma cell invasion through NF-κB, AKT, Stat3 and p42/44MAPK dependent mechanisms. These studies provide novel mechanistic insight into the progression of pre-invasive lesions and identify new stromal biomarkers, with important prognostic implications.

Invasive Solid Papillary Carcinoma of the Nipple With Pagetoid Extension and Nodal Metastasis

We report a case of invasive solid papillary carcinoma (SPC) of the nipple with Pagetoid extension to the skin and lymph node metastasis. SPC is an uncommon primary breast cancer accounting for less than 1% of all breast cancers. Only 2 cases occurring in the nipple have been reported. However, both cases were without Pagetoid extension or lymph node metastasis. The presently reported tumor consisted of irregularly shaped solid cell nests with delicate fibrovascular cores. The tumor cells had round nuclei with low-grade atypia and eosinophilic cytoplasm. Neuroendocrine differentiation was confirmed by immunohistochemical positivity for CD56, synaptophysin, and chromogranin A. Immunohistochemistry also confirmed the absence of myoepithelial cells around the tumor cell nests. Therefore, a diagnosis of invasive SPC was made. Additionally, tumor cell deposits in the intramammary and axillary lymph nodes were identified, and these deposits had the same histological characteristics as the invasive SPC of the nipple. The invasiveness of SPC can be difficult to determine. However, the tumor cell nests in the current case exhibited a retraction artifact, which is known to be associated with invasive carcinoma and a poor prognosis, as well as morphological patterns that have been previously identified as characteristic of invasive SPC. Although SPC is widely recognized as having a favorable outcome, the existence of exceptionally aggressive cases occurring in the nipple must be recognized. Additional cases of invasive SPC of the nipple are needed to analyze the clinicopathological correlation.

Invasive papillary breast cancer with Paget's disease: first reported association and literature review

Invasive papillary carcinoma of the breast and Paget's disease are both rare entities. We report the first known case of invasive papillary carcinoma associated with Paget's disease in a woman who presented clinically with a nipple mass. While invasive papillary carcinoma has been reported to have an indolent course without need for overtreatment, our patient had unusual unfavourable histological features. Literature review of this rare subtype was performed.

An Update of Mucinous Lesions of the Breast

Mucinous lesions of the breast include a variety of benign and malignant epithelial processes that display intracytoplasmic or extracellular mucin, including mucocelelike lesions, mucinous carcinoma, solid papillary carcinoma, and other rare subtypes of mucin-producing carcinoma. The most important diagnostic challenge is the finding of free-floating or stromal mucin accumulations for which the significance depends on the clinical, radiologic, and pathologic context. This article emphasizes the differential diagnosis between mucocelelike lesions and mucinous carcinoma, with a brief consideration of potential mimics, such as biphasic and mesenchymal lesions with myxoid stroma ("stromal mucin") and foreign material.

Subclonal analysis in a lobular breast cancer with classical and solid growth pattern mimicking a solid-papillary carcinoma

Recently, a new variant of invasive lobular breast cancer (ILBC) with solid-papillary-like growth pattern has been described. We present a case of ILBC with solid-papillary-like growth pattern in the main tumour mass and classical invasive lobular growth pattern in adjacent satellite foci. The two tumour components were subjected to comprehensive molecular analyses. Both components were ER/PR-positive, HER2-negative, and showed a complete loss of E-cadherin and beta-catenin protein expression, as determined by immunohistochemistry. Gene expression profiling classified the main tumour and a satellite focus as luminal-B and luminal-A subtypes, respectively. Whole-genome copy number profiles were highly similar in both tumour components. Shared copy number alterations (CNAs) included gains of chromosome 1q21.1-q43 and losses of chromosome 16q11.2-q24.3, the locus of the CDH1/E-cadherin tumour suppressor gene. CNAs detected only in the main tumour included a gain of chromosome 20q12-q13.33 and a loss of chromosome 1p36.33-p34.3, which has recently been associated with the solid variant of ILBC. Next generation sequencing revealed an identical, truncating CDH1 mutation (p.G169fs*5) in both tumour components confirming a common clonal ancestry. In conclusion, we confirm the recently described variant of ILBC with solid-papillary-like growth pattern and provide evidence that it evolves from classical ILBC by subclonal evolution.

Nuclear DDX3 expression predicts poor outcome in colorectal and breast cancer

Purpose

DEAD box protein 3 (DDX3) is an RNA helicase with oncogenic properties that shuttles between the cytoplasm and nucleus. The majority of DDX3 is found in the cytoplasm, but a subset of tumors has distinct nuclear DDX3 localization of yet unknown biological significance. This study aimed to evaluate the significance of and mechanisms behind nuclear DDX3 expression in colorectal and breast cancer.

Methods

Expression of nuclear DDX3 and the nuclear exporter chromosome region maintenance 1 (CRM1) was evaluated by immunohistochemistry in 304 colorectal and 292 breast cancer patient samples. Correlations between the subcellular localization of DDX3 and CRM1 and the difference in overall survival between patients with and without nuclear DDX3 were studied. In addition, DDX3 mutants were created for in vitro evaluation of the mechanism behind nuclear retention of DDX3.

Results

DDX3 was present in the nucleus of 35% of colorectal and 48% of breast cancer patient samples and was particularly strong in the nucleolus. Nuclear DDX3 correlated with worse overall survival in both colorectal (hazard ratio [HR] 2.34, P<0.001) and breast cancer (HR 2.39, P=0.004) patients. Colorectal cancers with nuclear DDX3 expression more often had cytoplasmic expression of the nuclear exporter CRM1 (relative risk 1.67, P=0.04). In vitro analysis of DDX3 deletion mutants demonstrated that CRM1-mediated export was most dependent on the N-terminal nuclear export signal.

Conclusion

Overall, we conclude that nuclear DDX3 is partially CRM1-mediated and predicts worse survival in colorectal and breast cancer patients, putting it forward as a target for therapeutic intervention with DDX3 inhibitors under development in these cancer types.

The 21-gene recurrence score in special histologic subtypes of breast cancer with favorable prognosis

BACKGROUND/PURPOSE

The 21-gene recurrence score (RS) assay predicts the likelihood of distant recurrence and chemotherapy benefit in early-stage, estrogen receptor (ER)-positive, HER2-negative breast cancer. Data on the RS of special histologic subtypes of invasive breast carcinoma with favorable prognosis are limited.

METHODS

We reviewed our institutional database to identify patients with special histologic subtypes of breast cancer associated with favorable prognosis and available RS results. Our cohort consists of fifty-seven women: thirty-three patients with pure mucinous carcinoma (MC), ten with tubular carcinoma (TC), nine with encapsulated papillary carcinoma (EPC), and five with solid papillary carcinoma (SPC).

RESULTS

Most (44/57, 77.2%) carcinomas had low RS (≤17), and none had high RS (≥31). All EPCs had low RS, but other subtypes had RS 18-30. Higher RS was associated with lower progesterone receptor (PR) expression by immunohistochemistry and lower PR mRNA scores (P ≤ 0.007). No morphologic feature (tumor grade, biopsy site changes, cellular stroma, inflammatory cells) was associated with RS ≥ 18. At a median follow-up of 40 months, the distant recurrence-free survival was 100%. One patient with SPC developed locoregional recurrence at 22 months.

CONCLUSIONS

As the largest series to date, our study raises the question of whether the RS assay is necessary for breast cancers with favorable histology. Reflex testing of node-negative, ER+/HER2- breast cancers may be deferred for these special histologic subtypes, emphasizing the need for multidisciplinary discussions between breast pathologists and other members of the breast cancer team.

Neuroendocrine Tumors of the Breast

A small but increasingly recognized and studied subset of breast carcinomas are characterized by neuroendocrine (NE) differentiation. As with nearly all forms of breast neoplasia, NE tumors are characterized by considerable heterogeneity in microscopic appearance and clinical aggressiveness. About half of NE breast carcinomas recapitulate the histological spectrum typical of their counterparts in other organ systems, varying from "carcinoid-like" to small cell carcinoma, with most representing intermediate grade tumors. Despite NE morphology, these tumors have a high frequency of estrogen receptor expression. Clinical outcomes of women with NE breast carcinomas are reliably grade and stage dependent. Tumors associated with "solid papillary" differentiation comprise the remaining cases of NE breast neoplasia. Solid papillary carcinoma is an intrinsically low grade/favorable prognosis class of breast neoplasia that usually presents in post-menopausal age groups. About half of solid papillary carcinoma present as a distinctive pattern of ductal carcinoma in situ that may be difficult to recognize owing to its close resemblance to florid proliferative lesions. Invasive solid papillary carcinomas are characterized by a variety of histological patterns and often show mucinous differentiation. Future studies are necessary to better define the histogenesis, optimal classification, and improved directed therapies for NE breast neoplasia.

Papillary Lesions of the Breast: An Update

CONTEXT

-Papillary lesions of the breast, characterized by the presence of arborescent fibrovascular cores that support epithelial proliferation, constitute a heterogeneous group of neoplasms with overlapping clinical manifestation and histomorphologic features, but may have divergent biological behavior. These lesions are exclusively intraductal neoplasms, although an invasive carcinoma may rarely have a predominantly papillary architecture. Although recognition of a papillary architecture is typically not challenging, the histologic distinction of these entities is not always straightforward. Historically, different terminologies and variable criteria have been proposed for a given entity by various authorities. The difficulty in classifying these lesions has been further confounded by the scarcity of data and the heterogeneity across different studies with regard to the molecular genetic characteristics of this group of lesions.

OBJECTIVE

-To provide an overview focusing on the current concepts in the diagnosis and classification of papillary lesions of the breast incorporating recent molecular genetic advances.

DATA SOURCES

-Data were obtained from pertinent peer-reviewed English-language literature.

CONCLUSIONS

-The recent evolution of molecular techniques has enhanced our knowledge of the pathogenesis of papillary carcinomas of the breast. This, along with emerging outcome studies, has led to prognosis-based reclassification of some of these entities. Additional studies focusing on the molecular signatures are needed to identify potential decision tools to further stratify these lesions with respect to prognostic significance.

Neuroendocrine Differentiation in Breast Cancer: Clinicopathological Significance of Bcl-2 Positive Solid Papillary Carcinoma

Solid papillary carcinoma (SPC) is considered a rare malignant breast tumor. Maluf and Koerner first reported this disease entity as a special type of ductal carcinoma in situ with several characteristic histopathological features, including low-grade cellular atypia, intracellular or extracellular mucin deposition, and solid papillary growth pattern, as well as neuroendocrine differentiation. The present paper describes a case of SPC with bcl-2 expression, which is known as a marker for malignancy of neuroendocrine tumors. Interestingly, despite bcl-2 expression being a poor prognostic indicator of neuroendocrine tumors, the patient with this tumor has achieved long-term survival (approximately 6 years) at the time of writing this report. Because previous investigators reported that bcl-2 expression might play a role in the inhibition of the development of breast cancer, we suggest that bcl-2 expression might reflect a good prognosis in patients with SPC, rather than being a poor prognostic indicator, as it is in several types of neuroendocrine tumor. However, to confirm this hypothesis, further investigation is required.

Pathological criteria and practical issues in papillary lesions of the breast - a review

Papillary lesions of the breast include a broad spectrum of lesions, ranging from benign papilloma, papilloma with atypical ductal hyperplasia (ADH) or ductal carcinoma in situ (DCIS) to papillary carcinoma. The accurate diagnosis of mammary papillary lesions is a challenge for pathologists, owing to the overlapping features among these lesions. In this review, some of the diagnostic criteria of papillary lesions are discussed, with special emphasis on some key morphological features, namely fibrovascular cores, epithelial proliferation in a solid pattern, intraductal papilloma complicated by ADH or DCIS, and invasion and its mimics. The roles of immunohistochemistry, and the interpretation of myoepithelial cell markers, hormone receptors, and high molecular weight cytokeratin, are addressed. Finally, novel biomarkers and genetic aberrations in papillary lesions are summarized.

Papillary Lesions of the Breast: A Practical Approach to Diagnosis

Papillary lesions of the breast span the spectrum of benign, atypical, and malignant. Subclassification of these lesions may be diagnostically challenging, especially with limited sampling via core biopsy. This review outlines the features of papillary lesions of the breast and provides a practical approach to distinguishing diagnostically challenging lesions by using key morphologic features and, when helpful, immunohistochemical studies.

Diagnostic Pitfalls in Papillary Lesions of the Breast: Experience from a Single Tertiary Care Center

INTRODUCTION

Papillary neoplasms are a group of lesions that are characterized by presence of papillae supported by fibrovascular cores lined by epithelial cells with or without myoepithelial cell layer. These neoplasms may be benign, atypical or malignant.

AIMS

This study was conducted to analyse the clinicopathological characteristics of papillary lesions of the breast.

MATERIALS AND METHODS

A retrospective and prospective analysis of 34 cases of papillary lesions received over a period of 7 years from 2009 to 2015 was done. The patient's clinical details were collected from medical archives and the histopathological findings were reviewed. The lesions were classified into benign, atypical and malignant categories.

RESULTS

During the study period, there were 34 cases of papillary lesions of breast. The mean age was 58 years. The central quadrant was the most common location (66.6%). The most common presenting complaint was lump (76.5% cases). Papillary lesions presented more commonly as solitary lump (82.4%) rather than multifocal disease. Benign papillary lesions were more common than the atypical and malignant lesions. The most common papillary lesion accounting for 43% of the cases was intraductal papilloma. Malignant lesions accounted for 41.2% cases with intraductal papillary carcinoma and invasive papillary carcinoma constituting 14.7% cases each.

CONCLUSION

Diagnosis of papillary carcinoma is challenging and its classification includes different entities that have specific diagnostic criteria. Due to their heterozygosity in morphology with benign, atypical and malignant subtypes, morphological features such as type of fibrovascular core and continuity of myoepithelial layer along with immunohistochemical stains for myoepithelial cells should be considered for proper and accurate diagnosis.