Metaplastic carcinoma of the breast

Poor response to neoadjuvant chemotherapy in metaplastic breast carcinoma

Metaplastic breast carcinoma (MpBC) is a rare special histologic subtype of breast carcinoma characterized by the presence of squamous and/or mesenchymal differentiation. Most MpBCs are of triple-negative phenotype and neoadjuvant chemotherapy (NAC) is frequently utilized in patients with MpBC. The aim of this study was to evaluate response to NAC in a retrospective cohort of MpBCs. We identified 44 patients with MpBC treated with NAC at our center between 2002 and 2018. Median age was 48 years, 86% were clinical stage II-III, and 36% were clinically node-positive. Most (80%) MpBCs were triple-negative or low (1-10%) hormonal receptor positive and HER2 negative on pre-NAC biopsy. While on NAC, 49% showed no clinical response or clinico-radiological progression. Matrix-producing subtype was associated with clinico-radiological response (p = 0.0036). Post NAC, two patients initially ineligible for breast-conserving surgery (BCS) were downstaged to be eligible for BCS, whereas three patients potentially eligible for BCS before treatment became ineligible due to disease progression. Only one (2%) patient had a pathologic complete response (pCR). Among the 16 patients presenting with biopsy-proven clinical node-positive disease, 3 (19%) had nodal pCR. Axillary lymph node dissection was avoided in 3 (19%) patients who had successful axillary downstaging. Residual cancer burden (RCB) was assessed in 22 patients and was significantly associated with disease-free survival and overall survival. We observed a poor response or even disease progression on NAC among patients with MpBC, suggesting that NAC should be reserved for patients with inoperable MpBC.

MRI Virtual Biopsy of T2 Hyperintense Breast Lesions

A wide variety of benign and malignant breast processes may generate hyperintense signal at T2-weighted magnetic resonance imaging (MRI). MRI has been traditionally used in the pre-treatment planning of breast cancer, in assessing treatment response and detecting recurrence. In this comprehensive review, we describe and illustrate the MRI features of a few common and uncommon T2 hyperintense breast lesions, with an emphasis on MRI features that help to characterize lesions based on morphological features, specific appearances on T1-and T2-weighted imaging, and enhancement characteristics on the dynamic post-contrast phase that are either diagnostic or aid in narrowing the differential diagnosis.

Radiologic Findings of a Rare Subtype of Invasive Breast Cancer with Poor Prognosis: Metaplastic Carcinoma of the Breast

BACKGROUND AND OBJECTIVES

The purpose of this study was to evaluate the mammographic, sonographic and MRI findings of metaplastic breast carcinoma.

METHODS

In this retrospective review study, we analyzed the medical files of 9600 patients who were treated for invasive breast cancers. Clinical information, histopathologic and radiologic findings of 65 patients were included in this study. All existing radiologic images and medical reports were reviewed retrospectively. Thirty-three patients had MG, 58 patients had US and 7 patients had MRI imaging results.

RESULTS

Mammographically, the most frequent presentations of MPBC were round shape, microlobulated margin and high density masses. Calcifications with or without masses were not a frequent finding. The most common sonographic findings were round shape, partially indistinct angular margin, hypoechoic and heterogeneous echo patterns and no posterior feature masses. All lesions were presented as masses rather than non-mass enhancements on magnetic resonance imaging. Features of masses had more malignant feature on MRI than other modalities in all 7 patients.

CONCLUSION

Metaplastic breast carcinoma is one of the rarest poorly differentiated invasive breast carcinomas. Interestingly, these aggressive tumors demonstrate benign or moderately malign features on imaging methods. This appearance of MPBC can cause it to be misdiagnosed as a benign breast lesion especially in young women. MPBC should be kept in mind in the differential diagnosis of large palpable breast masses. Therefore, follow-up at short intervals and/or multimodality imaging studies which include breast MRI are important for the diagnosis of MPBC.

When Something Seems Amiss: Radiology-Pathology Correlation of Metaplastic Breast Cancer

Metaplastic breast cancer is difficult to diagnose, resistant to conventional treatment, and biologically aggressive. A suspicious timeline and discordance between imaging findings and histopathologic tissue diagnosis should trigger additional workup. New, large lesions or rapidly growing lesions with complex echogenicity on ultrasound warrant correlation with image-guided biopsy for a definitive diagnosis. Lesions that appear aggressive on imaging, with negative biopsy findings, may represent false negatives due to sampling bias from intratumoral heterogeneity. In such cases, it may be advisable to obtain an excisional biopsy. These tumors are known to progress even with neoadjuvant chemotherapy. Immunotherapy, however, may be effective even for metastatic disease. A multidisciplinary approach and a high index of suspicion may, therefore, confer survival benefits in circumstances where the imaging phenotype does not fit with the timeline or pathologic diagnosis. This report describes five cases of metaplastic breast cancer diagnosed at our institution to highlight the importance of a timely and accurate diagnosis of this rare but aggressive breast malignancy.

Response to Dabrafenib and Trametinib of a Patient with Metaplastic Breast Carcinoma Harboring a BRAF V600E Mutation

Background

Metaplastic breast carcinomas are rare and carry poor prognoses. They are also more aggressive than other breast cancers and are known for their resistance to chemotherapy. Prolonged treatment with dabrafenib and trametinib is a therapy for malignant melanoma that improves the progression-free survival and overall survival. Such molecular-targeted therapies are also being developed for cancers with BRAF mutation, a driver of malignant melanoma. Case Presentation. A 57-year-old woman with metaplastic breast cancer and chemotherapy-refractory massive pleural effusion. After contained anthracycline regimen failure, her breast cancer progressed to an advanced stage. We ordered next-generation sequencing- (NGS-) based tumor molecular profiling from core needle biopsy of the breast. The NGS report indicated the presence of a BRAF V600E mutation. After initiation of dabrafenib and trametinib, her symptom and the pleural effusion were decreased. The first assessment of CT scans showed a decreased pleural effusion and shrunken subcutaneous lesions. Approximately 2 weeks later, a new lesion appeared. She died from 12 weeks after initiation of dabrafenib and trametinib treatment.

Conclusion

To the best of our knowledge, this is the first report of BRAF mutation breast cancer treated with dabrafenib and trametinib and it heralds the possibility of targeted therapy for rare breast cancers.

Combination of PI3K and MEK inhibitors yields durable remission in PDX models of PIK3CA-mutated metaplastic breast cancers

Background

Metaplastic breast cancer (MBC) is a rare form of breast cancer characterized by an aggressive clinical presentation, with a poor response to standard chemotherapy. MBCs are typically triple-negative breast cancers (TNBCs), frequently with alterations to genes of the PI3K-AKT-mTOR and RTK-MAPK signaling pathways. The objective of this study was to determine the response to PI3K and MAPK pathway inhibitors in patient-derived xenografts (PDXs) of MBCs with targetable alterations.

Methods

We compared survival between triple-negative MBCs and other histological subtypes, in a clinical cohort of 323 TNBC patients. PDX models were established from primary breast tumors classified as MBC. PI3K-AKT-mTOR and RTK-MAPK pathway alterations were detected by targeted next-generation sequencing (NGS) and analyses of copy number alterations. Activation of the PI3K-AKT-mTOR and RTK-MAPK signaling pathways was analyzed with reverse-phase protein arrays (RPPA). PDXs carrying an activating mutation of PIK3CA and genomic changes to the RTK-MAPK signaling pathways were treated with a combination consisting of a PI3K inhibitor and a MEK inhibitor.

Results

In our clinical cohort, the patients with MBC had a worse prognosis than those with other histological subtypes. We established nine metaplastic TNBC PDXs. Three had a pathogenic mutation of PIK3CA and additional alterations to genes associated with RTK-MAPK signaling. The MBC PDXs expressed typical EMT and stem cell genes and were of the mesenchymal or mesenchymal stem-like TNBC subtypes. On histological analysis, MBC PDXs presented squamous or chondroid differentiation. RPPA analysis showed activation of the PI3K-AKT-mTOR and RTK-MAPK signaling pathways. In vivo, the combination of PI3K and MAPK inhibitors displayed marked antitumor activity in PDXs carrying genomic alterations of PIK3CA, AKT1, BRAF, and FGFR4.

Conclusion

The treatment of metaplastic breast cancer PDXs by activation of the PI3K-AKT-mTOR and RTK-MAPK pathways at the genomic and protein levels with a combination of PI3K and MEK inhibitors resulted in tumor regression in mutated models and may therefore be of interest for therapeutic purposes.

Comparative Effectiveness of an mTOR-Based Systemic Therapy Regimen in Advanced, Metaplastic and Nonmetaplastic Triple-Negative Breast Cancer

BACKGROUND

Triple-negative breast cancer (TNBC) is a heterogeneous disease with subtypes having different "targetable" molecular aberrations. Metaplastic breast cancers (MpBCs) are typically TNBCs and commonly have alterations in the PI3K/Akt/mTOR pathway. We previously reported efficacy for an mTOR-based chemotherapy regimen in MpBC. To determine if tumor subtype influences prognosis, we compared treatment outcomes of patients with MpBC with those of patients with nonmetaplastic TNBC receiving an mTOR-based systemic therapy regimen.

PATIENTS AND METHODS

Patients with advanced MpBC and nonmetaplastic TNBC were treated at our institution from April 16, 2009, through November 4, 2014, using mTOR inhibition (temsirolimus or everolimus) with liposomal doxorubicin and bevacizumab (DAT/DAE). Median progression-free survival (PFS) and overall survival (OS) were estimated by the Kaplan-Meier method. Cox regression analyses were used to evaluate associations between tumor histology and outcomes. Multivariable models were adjusted for all covariates.

RESULTS

Fourteen patients with nonmetaplastic TNBC and 59 patients with advanced MpBC were treated with DAT/DAE. MpBC patients were older (p = .002) and less likely to have a history of bevacizumab use (p = .023). Median PFS for the nonmetaplastic TNBC and MpBC patients was 2.5 months and 4.8 months, respectively. This difference in PFS was statistically significant on univariable (p = .006) but not multivariable analysis (p = .087). Median OS for the nonmetaplastic TNBC and MpBC patients was 3.7 months and 10.0 months, respectively (p = .0003). MpBC remained significantly associated with improved OS on multivariable analysis (p < .0001).

CONCLUSION

In our study, DAT/DAE appeared to be more effective in MpBC compared with nonmetaplastic TNBC. These data support patient selection for targeted therapy in TNBC.

IMPLICATIONS FOR PRACTICE

Metaplastic breast cancers (MpBCs) represent <1% of all breast cancers, demonstrate mesenchymal differentiation, and are typically resistant to chemotherapy. Patients with advanced MpBC treated with an mTOR-based systemic therapy regimen had better long-term outcomes compared with patients with nonmetaplastic triple-negative breast cancer treated with the same regimen, suggesting that metaplastic histology may predict benefit from agents targeting the PI3K/Akt/mTOR pathway.

Expression of GHRH-R, a Potentially Targetable Biomarker, in Triple-negative Breast Cancer

PURPOSE

Growth hormone-releasing hormone (GHRH) has been shown to modify the growth behavior of many cancers, including breast. GHRH is produced by tumor cells, acts in an autocrine/paracrine manner, and requires the presence of GHRH receptor (GHRH-R) on the tumor cells to exert its effects. GHRH activity can be effectively blocked by synthetic antagonists of its receptor and hence, the expression of GHRH-R by tumor cells could serve as a predictor of response to GHRH-R antagonist therapy. In this study, we investigated the expression of GHRH-R in triple-negative breast cancers (TNBC). As TNBCs are morphologically and immunophenotypically heterogenous, the staining results were also correlated with the histologic subtypes of these tumors.

MATERIALS AND METHODS

On the basis of histomorphology and immunophenotype, 134 cases of primary TNBCs were further subdivided into medullary, metaplastic, apocrine, and invasive ductal carcinomas of no special type (IDC-NST). Immunohistochemistry for GHRH-R was performed on paraffin sections and the staining results were assessed semiquantitatively as negative, low expression, moderate, and high expression.

RESULTS

Of the 134 TNBCs, 85 were classified as IDC-NST, 25 as metaplastic, 16 as medullary, and 8 as apocrine carcinoma. Overall, positive reaction for GHRH-R was seen in 77 (57%) of tumors including 66 (77.6%) of IDC-NST. All medullary carcinomas were negative for GHRH-R and, with the exception of 1 case with low expression, none of the metaplastic carcinomas expressed GHRH-R (P<0.005).

CONCLUSIONS

A considerable number of TNBCs are positive for GHRH-R as a predictor of potential response to anti-GHRH-R treatment. This expression however, varies considerably between histologic subtypes of triple-negative breast cancers. Although most medullary and metaplastic carcinomas do not express GHRH-R, three fourths of the IDC-NST show a positive reaction. Testing for GHRH-R expression is therefore advisable if anti-GHRH-R therapy is being considered.

Clinicopathological characteristics and prognosis of metaplastic carcinoma of the breast

Metaplastic carcinoma of the breast (MBC) is a rare and heterogeneous type of neoplasm. Knowledge about its clinical characteristics, prognostic significance and optimal treatment modalities is fragmentary and controversial. The present retrospective study aimed to investigate the prognostic value of the clinicopathological features and different therapeutic strategies in MBC. For this purpose, the medical records of 69 MBC patients subjected to surgical resection for MBC at the Tianjin Medical University Cancer Institute and Hospital (Tianjin, China) were reviewed. A total of 69 MBC cases were followed up for 9–139 months. The 5-year disease-free survival (DFS) rate was 52.2% and the overall survival (OS) rate was 60.2%. Survival analysis revealed that large tumor size and lymph node (LN) metastases were correlated with shortened 5-year DFS and OS rates. In addition, chemotherapy significantly improved the prognosis of patients with LN metastasis, while radiation therapy (RT) significantly improved the 5-year OS and DFS rates of MBC patients with tumors ≥5 cm or with >4 metastatic LNs. In conclusion, MBC is a clinically aggressive subtype of breast cancer associated with a large tumor size. Chemotherapy may be recommended for certain subtypes of MBC with LN positivity, and RT may be a component of multimodality therapy for some MBC patients.

IMP3 contributes to poor prognosis of patients with metaplastic breast carcinoma: A clinicopathological study

Metaplastic breast carcinoma (MBC) is a rare type of tumor with heterogenous histological patterns. We investigated the immunohistochemical expression of IMP3, an oncofetal protein, in 31 MBC patients in association with histological subtypes and clinical outcomes. The cohort consisted of spindle cell carcinoma (SPC) (n=11), squamous cell carcinoma (SCC) (n=14), matrix-producing carcinoma (MPC) (n=4), carcinoma with osteocartilaginous elements (COC) (n=1), and low grade adenosquamous cell carcinoma (ASC) (n=1). IMP3 expression was identified in 7 cases of SPC (64%) and 6 patients of all the other subtypes (p=0.051). In comparison between IMP3 high (n=13) and low (n=18) groups, a large-sized tumor (≥4.0cm) was identified in 9 IMP3 high patients, and 14 IMP3 low patients had a small-sized tumor (p=0.01). High Ki67 positivity was detected in all of the IMP3 high patients and in 7 of the IMP3 low patients (p=0.002). During the follow-up period, 9 IMP3 high patients died, whereas 15 of the 18 IMP3 low patients remained alive (p=0.004). A univariate analysis revealed that IMP3 expression and tumor size were significantly associated with poor clinical outcomes (p=0.03 and <0.001, respectively). The IMP3 high group was likely to be associated with reduced overall survival compared to the IMP3 low group (p=0.06). These findings indicate that IMP3 may contribute to the aggressive behavior of MBC, and that this expression could potentially be a prognostic marker of MBC.

Role of RPL39 in Metaplastic Breast Cancer

Background: Metaplastic breast cancer is one of the most therapeutically challenging forms of breast cancer because of its highly heterogeneous and chemoresistant nature. We have previously demonstrated that ribosomal protein L39 (RPL39) and its gain-of-function mutation A14V have oncogenic activity in triple-negative breast cancer and this activity may be mediated through inducible nitric oxide synthase (iNOS). The function of RPL39 and A14V in other breast cancer subtypes is currently unknown. The objective of this study was to determine the role and mechanism of action of RPL39 in metaplastic breast cancer.

Methods: Both competitive allele-specific and droplet digital polymerase chain reaction were used to determine the RPL39 A14V mutation rate in metaplastic breast cancer patient samples. The impact of RPL39 and iNOS expression on patient overall survival was estimated using the Kaplan-Meier method. Co-immunoprecipitation and immunoblot analyses were used for mechanistic evaluation of RPL39.

Results: The RPL39 A14V mutation rate was 97.5% (39/40 tumor samples). High RPL39 (hazard ratio = 0.71, 95% confidence interval = 0.55 to 0.91, P = .006) and iNOS expression (P = .003) were associated with reduced patient overall survival. iNOS inhibition with the pan-NOS inhibitor N^G-methyl-L-arginine acetate decreased in vitro proliferation and migration, in vivo tumor growth in both BCM-4664 and BCM-3807 patient-derived xenograft models (P = .04 and P = .02, respectively), and in vitro and in vivo chemoresistance. Mechanistically, RPL39 mediated its cancer-promoting actions through iNOS signaling, which was driven by the RNA editing enzyme adenosine deaminase acting on RNA 1.

Conclusion: NOS inhibitors and RNA editing modulators may offer novel treatment options for metaplastic breast cancer.

Intracystic Primary Squamous Cell Carcinoma of the Breast: A Challenging Diagnosis

We report a case of a 36-year-old woman that presented with a painful mass in the outer quadrants of the left breast that had grown rapidly. Physical examination revealed a well circumscribed elastic mass and breast ultrasound showed a cyst measuring 26 mm with vegetation growing on the inner wall. Microscopic evaluation, after fine needle aspiration cytology (FNAC), suggested benign lesion. Tumorectomy was performed and the final diagnosis was a pure squamous cell carcinoma (SCC) of the breast. A simple mastectomy with sentinel node biopsy was performed. The histological study of the specimen revealed residual SCC and the sentinel lymph node was negative. The patient received 6 cycles of adjuvant chemotherapy and adjuvant radiotherapy. Four years later, the patient is free of disease.

Metaplastic Breast Cancer: Molecular Typing and Identification of Potential Targeted Therapies at a Single Institution

INTRODUCTION

Metaplastic breast carcinoma (MBC) is a rare and aggressive histologic subtype of breast cancer comprising approximately 0.5% to 5.0% of all invasive breast cancers with a poor prognosis and limited therapeutic options.

PATIENTS AND METHODS

We investigated MBC at our institution to evaluate outcomes and investigate the molecular profile of our cohort to determine the presence of mutations for which there are targeted therapies.

RESULTS

We found our cohort to consist mainly of the matrix-producing variant (72%) with 48% having the stereotypical estrogen receptor-negative/progesterone receptor-negative/human epidermal growth factor receptor-2-negative phenotype. While the overall survival of our cohort was an average of 1679 days (4.6 years), we had a surprising number of patients with second primaries (40%) and distant metastases (40%), yet few recurrences (12%). Molecular analysis of the tumors indicated that one gene mutation, CSFIR, was significantly associated with outcome (P = .021); however, the cohort was defined by frequent mutations in ERBB4 (36%), PIK3CA (48%), and FLT3 (60%), for which there are now targeted therapies.

CONCLUSION

While surgery is the appropriate first step in the management of this aggressive malignancy, the collection of data pertaining to the use of targeted agents, although anecdotal, may provide clues to better treatment for these patients.

Aggressive Metaplastic Carcinoma of the Breast with Osteoclastic Giant Cells

Metaplastic carcinoma of the breast is an uncommon type of malignancy that is aggressive but can mimic other benign breast neoplastic processes on imaging. We present a case of a young female patient who presented with a rapidly progressing metaplastic carcinoma with osteoclastic giant cells subtype. There have been only very rare published reports of this pathologic subtype of metaplastic carcinoma containing osteoclastic giant cells.

Metaplastic breast cancer: clinical overview and molecular aberrations for potential targeted therapy

Metaplastic breast cancer is a rare subtype of invasive mammary carcinoma, with an aggressive behavior and usually poor outcome. Responses to systemic chemotherapy are suboptimal compared to patients with standard invasive ductal carcinoma. Limited data are available in regards to best treatment modalities, including chemotherapy. This review gives an overview of metaplastic breast cancer and its clinical and pathologic characteristics, in addition to treatment strategies, clinical trials, and future directions.

Triple-negative Breast Carcinoma: Morphologic and Molecular Subtypes

Breast carcinoma is a heterogenous disease. Carcinomas lacking expression of estrogen, progesterone, and HER2/neu receptors by immunohistochemistry and Her2 amplification are designated as triple negative. This group of carcinomas comprises approximately 10% to 20% of all breast carcinomas and is characterized by an aggressive nature with shorter rates of disease-free and overall survival. This aggressive behavior is further compounded by the lack of available targeted therapies. Patients receive cytoxic chemotherapy regimens. Although tumors are initially sensitive to this therapy, drugs are toxic and ineffective in maintaining long-term response thereby providing limited benefit. Much effort is being spent on this group of cancers for the identification of appropriate molecular targets, an effort that is proving challenging due to the presence of marked heterogeneity, both at the morphologic and molecular levels. An understanding of the advances in this field is crucial for developing targeted therapies and tailored patient management protocols. This report summarizes the pathologic subtypes of breast cancer that are commonly of a triple-negative immunophenotype and recent molecular advances in this field.

Genomic profiling of advanced-stage, metaplastic breast carcinoma by next-generation sequencing reveals frequent, targetable genomic abnormalities and potential new treatment options

CONTEXT

Metastatic metaplastic breast carcinoma (MPBC) is an uncommon, but aggressive, tumor resistant to conventional chemotherapy.

OBJECTIVE

To learn whether next-generation sequencing could identify potential targets of therapy for patients with relapsed and metastatic MPBC.

DESIGN

Hybridization capture of 3769 exons from 236 cancer-related genes and 47 introns of 19 genes commonly rearranged in cancer was applied to a minimum of 50 ng of DNA extracted from 20 MPBC formalin-fixed, paraffin-embedded specimens and sequenced to high uniform coverage.

RESULTS

The 20 patients with MPBC had a median age of 62 years (range, 42-86 years). There were 9 squamous (45%), 9 chondroid (45%), and 2 spindle cell (10%) MPBCs, all of which were high grade. Ninety-three genomic alterations were identified, (range, 1-11) with 19 of the 20 cases (95%) harboring an alteration that could potentially lead to a targeted treatment option. The most-common alterations were in TP53 (n = 69; 75%), PIK3CA (n = 37; 40%), MYC (n = 28; 30%), MLL2 (n = 28; 30%), PTEN (n = 23; 25%), CDKN2A/B (n = 19; 20%), CCND3 (n = 14; 15%), CCNE1 (n = 9; 10%), EGFR (n = 9; 10%), and KDM6A (n = 9; 10%); AKT3, CCND1, CCND2, CDK4, FBXW7, FGFR1, HRAS, NF1, PIK3R1, and SRC were each altered in a single case. All 16 MPBCs (100%) that were negative for ERBB2 (HER2) overexpression by immunohistochemistry and/or ERBB2 (HER2) amplification by fluorescence in situ hybridization were also uniformly (100%) negative for ERBB2 amplification by next-generation sequencing-based copy-number assessment.

CONCLUSIONS

Our results indicate that genomic profiling using next-generation sequencing can identify clinically meaningful alterations that have the potential to guide targeted treatment decisions in most patients with metastatic MPBC.

Survival outcomes of metaplastic breast cancer patients: results from a US population-based analysis

BACKGROUND

Metaplastic breast cancer (MBC) is a rare histologic subtype needing further characterization. The aim of our study was to compare MBC to infiltrating ductal carcinoma (IDC) of the breast and to identify demographic, clinicopathologic, treatment, and survival differences.

METHODS

MBC and IDC patients were identified using the Surveillance, Epidemiology, and End Results (SEER) public-use data set. Disease-specific survival (DSS) differences were compared using the Kaplan-Meier method and log-rank tests. Univariate and multivariate Cox proportional hazard models were used to assess factors prognostic for DSS. To control for hormone receptor status, a subsequent planned analysis was completed for receptor-negative MBC and IDC. Lastly, a matched case-control analysis was conducted to minimize potential bias due to baseline demographic, clinical, and pathologic differences.

RESULTS

The SEER data set included 1,011 MBC and 253,818 IDC patients diagnosed from 2001 to 2010. MBC patients had larger, higher grade tumors, had less frequent axillary nodal involvement, and were more likely to be treated with mastectomy. Five-year DSS rates were significantly worse for patients with MBC than for IDC patients (78 vs. 93 %, p < 0.0001) and for patients with receptor-negative MBC than receptor-negative IDC (77 vs. 85 %, p < 0.0001). The findings were confirmed on matched analysis. Prognostic factors identified on multivariate analyses included age, MBC histology, tumor grade, T stage, and axillary lymph node involvement.

CONCLUSIONS

MBC patients have shorter DSS than IDC patients. Improved clinical and biological understanding of MBC may result in more effective therapy and better cancer outcomes.

How our practice of histopathology, especially tumour pathology has changed in the last two decades: reflections from a major referral center in Pakistan

Continued advances in the field of histo-pathology (and cyto-pathology) over the past two decades have resulted in dramatic changes in the manner in which these disciplines are now practiced. This is especially true in the setting of a large university hospital where the role of pathologists as clinicians (diagnosticians), undergraduate and postgraduate educators, and researchers has evolved considerably. The world around us has changed significantly during this period bringing about a considerable change in our lifestyles and the way we live. This is the world of the internet and the world-wide web, the world of Google and Wikipedia, of Youtube and Facebook where anyone can obtain any information one desires at the push of a button. The practice of histo (and cyto) pathology has also evolved in line with these changes. For those practicing this discipline in a poor, developing country these changes have been breathtaking. This is an attempt to document these changes as experienced by histo (and cyto) pathologists practicing in the biggest center for Histopathology in Pakistan, a developing country in South Asia with a large (180 million) and ever growing population. The Section of Histopathology, Department of Pathology and Microbiology at the Aga Khan University Hospital (AKUH) in Karachi, Pakistan's largest city has since its inception in the mid-1980s transformed the way histopathology is practiced in Pakistan by incorporating modern methods and rescuing histopathology in Pakistan from the primitive and outdated groove in which it was stuck for decades. It set histopathology in Pakistan firmly on the path of modernity and change which are essential for better patient management and care through accurate and complete diagnosis and more recently prognostic and predictive information as well.

Metaplastic carcinoma of the breast with chondroid differentiation (matrix-producing carcinoma): study of the diagnostic cost-effectiveness of fine-needle aspiration biopsy and needle core biopsy

Metaplastic carcinoma with chondroid differentiation (MMPC) is a subtype of breast metaplastic carcinoma with mesenchymal differentiation. Although fine-needle aspiration (FNAB) and core-needle biopsy (CNB) are commonly used for the diagnosis of breast cancer, not enough studies proving the diagnostic cost-effectiveness of these techniques for the identification of MMPC have been published so far. The aim of this study was to investigate the concordance between the presurgical diagnosis using FNAB/CNB and the definitive diagnosis in the surgical specimen in pure MMPC. A case of MMPC is also reported.

STUDY DESIGN

All cases of MMPC diagnosed in our institution from 1995 to 2011 were reviewed. The presence of chondroid differentiation in cytological studies or biopsies and the proportion of chondroid matrix in the surgical specimen were evaluated.

RESULTS

A total of 13 cases of pure MMPC were collected. The diagnosis was suspected in 25% of FNABs and was rendered in 40% of CNBs.

CONCLUSIONS

The chondroid component in MMPC is hard to identify by FNAB and CNB. The random distribution and proportion of the chondroid differentiation in the tumour and the expertise in performing the technique and in identifying the chondroid component may play an important role in the diagnosis of MMPC using these techniques.

Metaplastic breast cancer: histologic characteristics, prognostic factors and systemic treatment strategies

Metaplastic breast cancer (MBC) is a rare subtype of invasive breast cancer that tends to have an aggressive clinical presentation as well as a variety of distinct histologic designations. Few systemic treatment options are available for MBC, as it has consistently shown a suboptimal response to standard chemotherapy regimens. These characteristics result in a worse overall prognosis for patients with MBC compared to those with standard invasive breast cancer. Due to its rarity, data focusing on MBC is limited. This review will discuss the clinical presentation, breast imaging findings, histologic and molecular characteristics of MBC as well as potential future research directions.

Molecular alterations in metaplastic breast carcinoma

Metaplastic carcinoma of the breast is a rare and heterogeneous subtype of breast carcinoma with a generally poor outcome, and few therapeutic options once disease recurs or progresses. Metaplastic carcinomas of the breast are usually of a larger size at diagnosis, with less frequent nodal metastasis compared with invasive ductal carcinoma no special type, and lack hormone and HER2 receptor expression. Recent research has revealed some potentially actionable genetic changes in a subset of these rare tumours. However, ongoing efforts to further characterise the genetic basis and the molecular alterations underlying the distinctive morphological and clinical characteristics of these tumours are needed in order to identify new targets for treatment. This review will describe the theories of pathogenesis of metaplastic breast carcinoma, and highlight genetic changes and potential therapeutic targets in this generally poor prognosis malignancy.

Management of unusual histological types of breast cancer

There is increased understanding of the heterogeneity of breast tumors, with greater emphasis now being placed on histological and molecular profiles and, in particular, their implications for prognosis and therapy. This review addresses breast cancers of unusual histological subtype with an approximate incidence ≤1%. Given the rarity of these tumors, the literature contains primarily case reports, small series, and population-based studies. Data are heterogeneous and almost entirely retrospective, frequently gathered over long time periods, in the context of changing pathological techniques and reporting. In addition, our understanding of the disease biology and therapeutic context has also evolved significantly over this time. There is often limited information about the specific therapies used and the rationale for choosing such an approach. Meaningful comparisons of treatment modalities are not feasible and it is not possible to define management guidelines. Instead, this review correlates the available information to give an impression of how each subgroup behaves-of the favored surgical technique, responses to therapy, and prognosis-as well as the emerging molecular data, highlighting new research areas for potential target in clinical trials. Each tumor subtype described represents a small but real cohort of patients with breast cancer, and although inferences may be made from this review, we are mindful of the paucity of data. The management of each patient must be considered in the context of their unique clinical presentation and correlated with the evidence-based principles that apply to more common breast cancer histologies.

Review of metaplastic carcinoma of the breast: imaging findings and pathologic features

Metaplastic carcinoma (MPC), an uncommon but often aggressive breast cancer, can be challenging to differentiate from other types of breast cancer and even benign lesions based on the imaging appearance. It has a variable pathology classification system. These types of tumors are generally rapidly growing palpable masses. MPCs on imaging can present with imaging features similar to invasive ductal carcinoma and probably even benign lesions. The purpose of this article is to review MPC of the breast including the pathology subtypes, imaging features, and imaging pathology correlations. By understanding the clinical picture, pathology, and overlap in imaging characteristics of MPC with invasive ductal carcinoma and probably benign lesions can assist in diagnosing these difficult malignancies.

Triple negative mixed metaplastic breast carcinoma with squamous and spindle cells in an 84-year-old woman: a rare entity with unclear management strategy and poor prognosis

Metaplastic carcinoma of the breast, a rare neoplasm, usually presents at an advanced stage, metastasises to distant sites more frequently, has higher Ki-67 expression and is more often triple negative compared with other invasive breast cancers. Here, the authors discuss a case of an 84-year-old woman with triple negative mixed metaplastic breast carcinoma treated with radical modified mastectomy, axillary lymph node dissection and radiation therapy. Because of the rarity of the disease, the pathogenesis and the management remain controversial, thus contributing to overall poor prognosis.

Metaplastic Carcinoma of the Breast With Dominant Squamous and Sebaceous Differentiation in the Primary Tumor and Osteochondroid Metaplasia in a Distant Metastasis

Metaplastic breast carcinoma is an uncommon tumor that develops from conventional ductal mammary carcinoma, usually consisting of squamous and/or spindle cell components and/or mesenchymal elements. Although several morphological subtypes of metaplastic breast carcinoma are known, sebaceous metaplasia has not yet been described in this context. The authors report a case of an 84-year-old woman with a huge, ulcerated primary tumor in her left breast that had already been present for 10 years. Pulmonary and bone metastases and a tumor nodule in the contralateral breast were also detected at the time of admission. Left simple mastectomy was performed. Histological examination of the tumor revealed metaplastic carcinoma consisting of ductal carcinoma, which immunohistochemically exhibited a triple-negative immunoprofile, along with dominant areas of squamous and sebaceous differentiation. Adjuvant chemotherapy was subsequently given with partial regression of the systemic metastases. Seven months after surgery and diagnosis, a new, rapidly growing, large soft tissue metastatic tumor appeared in the intramuscular compartment of the patient’s right thigh, which was removed and histologically examined. Morphologically this metastatic tumor showed ductal adenocarcinoma along with areas of sebaceous differentiation and, in addition, osteochondroid metaplasia. Immunohistochemically, unlike the primary, this tumor expressed HER-2. The case is presented because of its rarity, and sebaceous differentiation is also proposed as a novel type of metaplasia in this context, expanding the spectrum of the histological patterns of metaplastic breast carcinoma. The literature concerning breast sebaceous lesions is reviewed, and the hypothetical biological mechanisms responsible for the tumor pathogenesis in this case are discussed.