Imaging Findings of Metaplastic Carcinoma of the Breast with Pathologic Correlation

Special Types of Breast Cancer: Clinical Behavior and Radiological Appearance

Breast cancer is a complex disease that includes entities with different characteristics, behaviors, and responses to treatment. Breast cancers are categorized into subgroups based on histological type and grade, and these subgroups affect clinical presentation and oncological outcomes. The subgroup of "special types" encompasses all those breast cancers with insufficient features to belong to the subgroup "invasive ductal carcinoma not otherwise specified". These cancers account for around 25% of all cases, some of them having a relatively good prognosis despite high histological grade. The purpose of this paper is to review and illustrate the radiological appearance of each special type, highlighting insights and pitfalls to guide breast radiologists in their routine work.

Carcinosarcoma of breast - A chimera among breast neoplasms

Malignant phyllodes, along with ductal carcinoma, is known as metaplastic cancer of the breast. This tumor is additionally known as breast carcinosarcoma. Malignant phyllodes in conjunction with ductal carcinoma is a rare finding in routine clinical practice. We describe the case report of a 47-year-old female patient who arrived with a large right breast mass. A core biopsy was performed, and histopathological examination indicated that the tumor was a malignant phyllodes tumor. A positron emission tomography (PET) scan revealed hyper-metabolic and hypo-metabolic tumors with perilesional stranding and satellite nodularity. There were a few metastatic right axillary nodes visible. There was no indication of distant metastases. Due to the presence of both components, a modified radical mastectomy surgery with axillary dissection was undertaken for this patient. Histopathological analysis of paraffin sections revealed ductal carcinoma in situ (DCIS) comedo-epithelial component and spindle-shaped cells with hyper-chromatic oval nuclei and scanty cytoplasm.

Sonographic and clinicopathologic features of metaplastic breast carcinoma and infiltrating ductal carcinoma: a comparative single-center cohort study

Background

The rarity of metaplastic breast carcinoma (MBC) has resulted in limited sonographic data. Given the inferior prognosis of MBC compared to invasive ductal carcinoma (IDC), accurate preoperative differentiation between the two is imperative for effective treatment planning and prognostic prediction. The objective of this study was to assess the diagnostic accuracy of MBC and differentiate it from IDC by analyzing sonographic and clinicopathologic features.

Methods

In this retrospective cohort study, 197 women comprising 200 IDC lesions were enrolled between January 2012 and December 2021 and 20 women comprising 20 pure MBC lesions were enrolled between January 2019 and December 2019. A comparison was made between the sonographic and clinicopathologic characteristics of MBC and IDC.

Results

The results indicated that patients with MBC had a higher proportion of tumor grade 3 (95.0% vs. 32.5%; P<0.001), high Ki-67 expression (100.0% vs. 75.0%; P<0.001), and the triple-negative subtype (90.0% vs. 13.0%; P<0.001) as compared to those with IDC. On ultrasound (US) findings, MBC lesions tended to have a larger size (≥5 cm: 45.0% vs. 1.5%; P<0.001), regular shape (45.0% vs. 1.5%, P<0.001), circumscribed margin (40.0% vs. 0.5%, P<0.001), a complex cystic and solid echo pattern (50.0% vs. 3.5%; P<0.001), and posterior acoustic enhancement (95.0% vs. 14.5%; P<0.001). Additionally, MBC was more likely to be misinterpreted as a benign lesion by sonographers than was IDC (30.0% vs. 4.5%; P<0.001). Multilayer perceptron analysis revealed posterior acoustic enhancement, circumscribed margins, and size as distinguishing factors between these two tumor types. The estimated rates of local recurrence, distant metastasis, and 5-year overall survival in 19 cases with MBC were found to be 10.5%, 31.6%, and 65.0%, respectively.

Conclusions

MBC typically presents as a large breast mass with more benign US features in older women, findings which may facilitate its accurate diagnosis and differentiation from other breast masses.

Discrepancy between Tumor Size Assessed by Full-Field Digital Mammography or Ultrasonography (cT) and Pathology (pT) in a Multicenter Series of Breast Metaplastic Carcinoma Patients

Metaplastic breast cancer (BC-Mp) presents diagnostic and therapeutic complexities, with scant literature available. Correct assessment of tumor size by ultrasound (US) and full-field digital mammography (FFDM) is crucial for treatment planning.

METHODS

A retrospective cohort study was conducted on databases encompassing records of BC patients (2012-2022) at the National Research Institutes of Oncology (Warsaw, Gliwice and Krakow Branches). Inclusion criteria comprised confirmed diagnosis in postsurgical pathology reports with tumor size details (pT) and availability of tumor size from preoperative US and/or FFDM. Patients subjected to neoadjuvant systemic treatment were excluded. Demographics and clinicopathological data were gathered.

RESULTS

Forty-five females were included. A total of 86.7% were triple-negative. The median age was 66 years (range: 33-89). The median pT was 41.63 mm (6-130), and eight patients were N-positive. Median tumor size assessed by US and FFDM was 31.81 mm (9-100) and 34.14 mm (0-120), respectively. Neither technique demonstrated superiority (p > 0.05), but they both underestimated the tumor size (p = 0.002 for US and p = 0.018 for FFDM). Smaller tumors (pT1-2) were statistically more accurately assessed by any technique (p < 0.001). Only pT correlated with overall survival.

CONCLUSION

The risk of underestimation in tumor size assessment with US and FFDM has to be taken into consideration while planning surgical procedures for BC-Mp.

Metaplastic carcinoma with osteosarcomatous differentiation in the breast: Case report

Metaplastic breast carcinoma is rare and may present as a highly aggressive subtype of breast cancer. In this case report of metastatic metaplastic breast carcinoma with osteosarcomatous differentiation in a female patient previously treated for invasive ductal carcinoma, we describe the new presentation of a palpable mass with associated calcifications on imaging near the site of prior partial mastectomy. This article will detail the clinical presentation, imaging findings, histopathology, and clinical course following treatment of our case. Knowledge of the clinical and imaging presentation of this rare subtype, which can present with benign features on mammography and ultrasound, can facilitate timely diagnosis as treatment paradigms evolve.

Metaplastic breast carcinoma with osseous differentiation: A report of a rare case and literature review

Metaplastic matrix-producing breast carcinoma is a type of metaplastic breast carcinoma (MBC), which is a rare malignancy, accounting for 0.2-1% of breast carcinomas. A 52-year-old female visited a hospital because of a palpable painless mass in the right breast and was diagnosed with Breast Imaging Reporting and Data System (BI-RADS) category 4A via ultrasound (US) with a suspected positive lymph node at the right axillary region. Excision of the breast mass was performed and histopathologically confirmed that it was MBC with osseous differentiation. No distant metastasis was revealed before a modified radical mastectomy; however, metastasis to a lymph node of the right axillary region was observed (1/22). She received six cycles of TEC scheme chemotherapy (docetaxel, epirubicin, and cyclophosphamide, 21 days) and 5 weeks of radiotherapy (48 Gy/25 f/5 days a week), but without any follow-up examinations since radiotherapy. Twenty-four months after surgery, distant metastases to lungs and liver were confirmed and died 3 months later. This case provides valuable information for clinicians on MBC and suggests that further examination or biopsy should be performed to US BI-RADS 4A masses before surgery. In addition, regular postoperative follow-up plays important roles in detecting metastases early and improving prognosis.

Metaplastic breast cancer: an all-round multidisciplinary consensus

Metaplastic breast cancer (MpBC) is a rare and aggressive histologic subtype of breast cancer (BC) characterized by the presence of at least two cellular types, commonly epithelial and mesenchymal components. Despite growing evidence that MpBC is a unique entity, it has long been treated as a variant of nonspecial type (NST) BC. MpBC typically shows the phenotype of triple-negative breast cancer (TNBC), but compared to NST-TNBC, it is a relatively chemorefractory tumor associated with worse outcomes. Therefore, there is an urgent need to develop management guidelines specifically for MpBC to improve the prognosis of patients with early MpBC. This expert consensus aims to guide diagnosis and standardize clinical management of early MpBC among treating physicians. We provide guidance on the challenging radiological and pathological diagnosis of MpBC. Evidence on the involvement of genetic predisposition in the development of MpBC is also explored. We emphasize the importance of a multidisciplinary approach for the treatment of patients with early MpBC. The optimal surgery and radiotherapy approach is presented, as well as the opportunity offered by novel therapeutic approaches to increase treatment response in this chemoresistant subtype. Appropriate management of patients with MpBC is critical to reduce the high risk of local and distant recurrence that characterizes this disease.

Metaplastic breast carcinoma: Analysis of clinical and pathologic features, a five-year study

Background

Metaplastic carcinoma breast (MCB) is a rare tumor comprising of both glandular and non-glandular patterns with epithelial and or mesenchymal components. Due to their varied clinicomorphological features, diagnosis has been challenging.

Aim

To study the clinicopathological and histomorphology of cases of metaplastic carcinoma breast diagnosed in a tertiary care hospital along with literature review.

Materials and Methods

This is a retrospective study including data of 11 patients who were diagnosed with MCB either on trucut or mastectomy specimens conducted between January 2014 and December 2018.

Results

The study includes 11 patients, out of which 10 were diagnosed on mastectomy while one on trucut specimen. All the patients were women with the mean age of presentation being 43.8 years. The most common presentation was palpable breast lump with mean tumor size of 7.3 cm in greatest dimension. Skin involvement was seen in 36.3% of cases. While eight cases (72.7%) were classified as epithelial, three (27.2%) were classified as mixed. Amongst epithelial variety, in eight cases, squamous component was seen along with infiltrating ductal carcinoma (IDC) while one was pure squamous type. In mixed variety, one case showed spindled areas along with squamous areas and areas of IDC. Other two showed focal sarcomatous and cartilaginous areas in one and angiosarcomatous, bone and cartilage formation admixed with areas of IDC in other case.

Conclusion

MCB are rare breast tumors with aggressive course and are characterized by their large size and rapid growth rate. Recently, there has been an upsurge in the cases of MCB due to increase in recognition of this entity. It has to be distinguished from other tumors by the pathologists so as to guide proper treatment.

Case report and literature review on a large MBC with ulceration

RATIONALE

Metaplastic breast cancer (MBC) is a rare tumor of the breast, and skin ulceration of breast tumors is a difficult clinical problem that reduces the patient's quality of life.

PATIENT CONCERNS

There are currently no Standard Treatment Guidelines for MBC at present, and the treatment for the skin ulceration of breast tumors is limited in clinics.

DIAGNOSIS

Here, we report the case of a patient with a large MBC and skin ulceration, accompanied by exudation and odor.

INTERVENTION

The combined treatment of albumin paclitaxel and carrelizumab (anti-PD-1 immunotherapy) was effective in reducing the tumor, but it increased the severity of the skin ulceration. After taking traditional Chinese medicine, the skin ulceration healed completely. Then the patient underwent a mastectomy and radiotherapy.

OUTCOMES

The patient has a high quality of life and was in good condition after the comprehensive treatment.

LESSONS

This suggests that traditional Chinese medicine may have a good auxiliary therapeutic effect on the skin ulceration of MBC.

Multimodality imaging and histopathology of metaplastic breast cancer

Metaplastic breast cancer (MBC) is a rare subtype of invasive breast cancer characterized by mixed epithelial and mesenchymal differentiation. Commonly seen subtypes include squamous cell carcinoma, spindle cell carcinoma, and metaplastic carcinoma with heterologous mesenchymal differentiation. MBC tends to have a more aggressive clinical presentation, higher metastatic potential, higher rates of local recurrence, and a worse prognosis compared with invasive breast carcinoma of no special type. Most MBCs are triple-negative breast cancers, which explains their resistance to most systemic therapies. Therefore, accurately diagnosing MBC early is crucial for deciding the treatment strategy and predicting the prognosis. In this pictorial essay, the imaging findings of MBC in different modalities and the histopathologic features of its subtypes are reviewed.

Metaplastic breast carcinoma: an overview of the radio-pathologic features in retrospective cohort tertiary hospital

Background

Metaplastic breast carcinoma (MBC) is a rare type of breast carcinoma. It accounts for 0.2–1% of all invasive breast carcinoma. The aim of this study is to investigate the radiological features of this tumor and correlate them with the pathological findings.

Results

Of the 22 patients with pathology-proven metaplastic cancers, 18 patients  (81.82%) presented with a palpable mass. The majority of the mammogram findings were masses with irregular shapes (n = 12, 63.16%) and indistinct margins (n = 11, 57.89%). Similarly, the majority of the ultrasound studies showed masses with irregular shapes (n = 16, 72.73%) and indistinct margins (n = 8, 36.36%). Most of the echopatterns were complex or with heterogeneous textures, each presented in eight cases (36.36%). More than half of the cases had a posterior acoustic enhancement (n = 12, 54.55%). Most of the cases tested negative for estrogen receptors, progesterone receptors and HER2 protein, and they were high-grade tumors with a high proliferative index (Ki-67%) of > 15%.

Conclusion

MBC is a rare and distinct aggressive breast cancer with no definite characteristic imaging compared to other breast cancer. It shows a mass with irregular shape and indistinct margins in both mammogram and ultrasound. Additionally, it reveals posterior acoustic enhancement and rarely contains microcalcifications. The correlation with the pathological findings is crucial for the diagnosis and subsequent appropriate treatment.

Imaging Findings of Metaplastic Breast Carcinoma with Chondroid Differentiation: A Case Reports

Metaplastic carcinoma of the breast is a heterogeneous group of neoplasms with mixed epithelial and mesenchymal differentiation. Metaplastic carcinoma of the breast is a rare and aggressive malignancy, with high recurrence and metastasis. Metaplastic carcinoma with chondroid differentiation is an uncommon subtype that tends to have a relatively good prognosis than that of other subtypes. We report the imaging features of three cases of pathologically proven metaplastic carcinoma with chondroid differentiation as follows: a high-density mass with amorphous or coarse heterogeneous calcifications on mammography; a microlobulated or partially indistinct, complex cystic, and solid mass on sonography; and a relatively circumscribed or partially indistinct, irregular mass with heterogeneous T2 high-signal intensity and heterogeneous or rim enhancement with initial fast enhance ment and delayed washout on MRI.

Differences of Clinicopathological Features between Metaplastic Breast Carcinoma and Nonspecific Invasive Breast Carcinoma and Prognostic Profile of Metaplastic Breast Carcinoma

Introduction

Metaplastic breast carcinoma is a rare special type of breast cancer, which has distinguished clinical characteristics. We aimed to evaluate the clinicopathological features of metaplastic breast carcinoma compared with nonspecific invasive breast carcinoma and study the prognosis of metaplastic breast carcinoma.

Methods

We reviewed metaplastic breast carcinoma cases (n = 37) from January 2000 to December 2021 and nonspecific invasive breast carcinoma cases (n = 433) from January 2019 to December 2020 extracted from our institution retrospectively. The following variables were recorded, including the patients' general information, complications, T stage, expression of estrogen receptor, progesterone receptor, human epidermal growth factor receptor 2, Ki-67, molecular subtyping, lymph node status, skin or chest wall involvement, vessel carcinoma embolus, therapy modality (surgical treatments, chemotherapy, and radiotherapy), and survival.

Results

Patients with metaplastic breast carcinoma had more advanced disease than patients with nonspecific invasive breast carcinoma (T stage: P=0.0011). A greater proportion of metaplastic breast carcinoma presented with triple-negative breast cancer than nonspecific invasive breast carcinoma (79.41% vs. 12.47%, P ≤ 0.001). Our study showed that the skin or chest wall invasion was more frequent in metaplastic breast carcinoma patients (11.76% vs. 1.62%, P=0.005). The 5-year survival rate for metaplastic breast carcinoma patients was 57.66% (95% CI: 0.3195∼0.7667). No local recurrence was observed while distant metastasis occurred in 33.33% of patients with metaplastic breast carcinoma. Death due to disease occurred in 24.24% of patients with metaplastic breast carcinoma.

Conclusion

The majority of metaplastic breast carcinoma patients had more advanced disease and triple-negative disease than nonspecific invasive breast carcinoma patients. Also, metaplastic breast carcinoma patients had frequent skin or chest wall invasion and a high rate of distant metastasis and mortality.

A huge metaplastic breast carcinoma with chest wall invasion and pulmonary metastasis: a rare case report

Metaplastic breast carcinoma (MBC) is a diverse group of invasive breast carcinoma, in which the neoplastic epithelium differentiates toward squamous cells or mesenchymal looking elements, including but not restricted to spindle, osseous and chondroid cells. MBC was formally considered a distinct pathological pattern by WHO classification of breast tumors in 2000. We report the case of a 49-year-old Syrian female who presented to our hospital due to a painful huge mass in her right breast. Radiographic and clinical findings were highly indicative of breast carcinoma. Therefore, a core needle biopsy was performed, and surprisingly, microscopic examination suggested the diagnosis of soft tissue sarcoma, whereas immune stains confirmed the diagnosis of metaplastic carcinoma. We aim to introduce a challenging case that clarifies the rarity of this tumor, and the methods we used in diagnosing, examining and treating this malignancy.

A Comparative Assessment of MR BI-RADS 4 Breast Lesions With Kaiser Score and Apparent Diffusion Coefficient Value

Objectives

To investigate the diagnostic performance of the Kaiser score and apparent diffusion coefficient (ADC) to differentiate Breast Imaging Reporting and Data System (BI-RADS) Category 4 lesions at dynamic contrast-enhanced (DCE) MRI.

Methods

This was a single-institution retrospective study of patients who underwent breast MRI from March 2020 to June 2021. All image data were acquired with a 3-T MRI system. Kaiser score of each lesion was assigned by an experienced breast radiologist. Kaiser score+ was determined by combining ADC and Kaiser score. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic performance of Kaiser score+, Kaiser score, and ADC. The area under the curve (AUC) values were calculated and compared by using the Delong test. The differences in sensitivity and specificity between different indicators were determined by the McNemar test.

Results

The study involved 243 women (mean age, 43.1 years; age range, 18-67 years) with 268 MR BI-RADS 4 lesions. Overall diagnostic performance for Kaiser score (AUC, 0.902) was significantly higher than for ADC (AUC, 0.81; p = 0.004). There were no significant differences in AUCs between Kaiser score and Kaiser score+ (p = 0.134). The Kaiser score was superior to ADC in avoiding unnecessary biopsies (p < 0.001). Compared with the Kaiser score alone, the specificity of Kaiser score+ increased by 7.82%, however, at the price of a lower sensitivity.

Conclusion

For MR BI-RADS category 4 breast lesions, the Kaiser score was superior to ADC mapping regarding the potential to avoid unnecessary biopsies. However, the combination of both indicators did not significantly contribute to breast cancer diagnosis of this subgroup.

Spindle Cell Metaplastic Breast Carcinoma

INTRODUCTION

Metaplastic breast carcinoma is an uncommon malignancy that constitutes < 5% of all breast cancers. There are 5 subtypes which are spindle cell, squamous cell, carcinosarcoma, matrix-producing and metaplastic with osteoclastic giant cells. Spindle cell carcinoma represents approximately <0.3% of invasive breast carcinomas. It is typically a triple-negative cancer with distinct pathological characteristics, but relatively a non-conclusive imaging findings.

CASE REPORT

An elderly lady presented with an enlarging painful left breast lump for 1 year. Palpable left breast lump noted on clinical examination. Mammography demonstrated a high density, oval lesion with a partially indistinct margin. Corresponding ultrasound showed a large irregular heterogeneous lesion with solid-cystic areas. Histopathology showed atypical spindle-shaped cells which stained positive for cytokeratins and negative for hormone and human epidermal growth factor receptors, which favours spindle cell metaplastic carcinoma. Left mastectomy and axillary dissection were performed, and the final diagnosis was consistent with metaplastic spindle cell carcinoma.

CONCLUSION

Spindle cell carcinoma of the breast is a rare aggressive histological type of carcinoma which may present with benign features on imaging. Tissue diagnosis is essential for prompt diagnosis with multidisciplinary team discussion to guide management and improve patient's outcome.

Clinicopathologic Characteristics and Outcome Descriptors of Metaplastic Breast Carcinoma

CONTEXT.—

Metaplastic breast carcinoma is an aggressive form of breast cancer that accounts for 0.5% to 3% of all breast cancers.

OBJECTIVE.—

To study the clinicopathologic characteristics and outcomes of this rare disease.

DESIGN.—

Retrospective study of patients with a diagnosis of metaplastic breast carcinoma between 2000 and 2019. Hematoxylin-eosin-stained slides were reviewed and additional clinical data were obtained from electronic medical records. Univariable and multivariable Cox proportional hazard regression analyses were used to determine associations between overall survival and several clinicopathologic variables.

RESULTS.—

Of the 125 patients with metaplastic breast carcinoma identified, only patients with high-grade disease (N = 115) were included in the data analysis. A total of 38 participants (33%) were white, 66 (57%) were African American, and 11 (10%) belonged to other ethnicities. The median age at diagnosis was 57 years. The median tumor size was 3 cm. Heterologous histology was seen in 30% of cases. Multivariable analyses showed that patients with a larger tumor size had worse overall survival (hazard ratio [HR], 1.25; 95% CI, 1.10-1.44; P < .001). Distant metastatic disease was also associated with worse overall survival on multivariable analysis (HR, 10.27; 95% CI, 2.03-55.54; P = .005). In addition to treatment with either partial or complete mastectomies, 84 patients (73%) received chemotherapy. Multivariable analyses showed that chemotherapy had no effect on overall survival (HR, 0.53; 95% CI, 0.09-6.05; P = .55).

CONCLUSIONS.—

A larger tumor size and distant metastatic disease are associated with worse overall survival in patients with metaplastic breast carcinoma. Additional studies are needed to further characterize our findings.

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.

A Retrospective Study of the Imaging and Pathological Features of Metaplastic Breast Carcinoma and Review of the Literature

Background

Metaplastic breast cancer (MBC) is a rare type of breast cancer, characterized histologically by the presence of two or more malignant cell types (epithelial and mesenchymal). This retrospective study aimed to review the imaging and histological features of MBC, with a review of the literature.

Material/Methods

Nineteen patients with MBC (age range, 28–75 years; mean, 55 years) underwent review of their clinical records, histopathology, immunohistochemistry, and imaging findings, which included mammography, sonography, and magnetic resonance imaging (MRI) with T2-weighted imaging (T2WI), diffusion-weighted imaging (DWI), and diffusion restriction determined by the apparent diffusion coefficient (ADC) and a time-intensity curve (TIC) for signal intensity.

Results

The mammographic features of MBC were oval shaped (54.5%), with indistinct margin (45.5%), and high tumor density (72.7%), and on sonography, they were oval shaped (57.1%), with hypo-echogenic areas (85.8%). On MRI, MBC showed moderate hyper-intensity with a high signal intensity in the center of the tumor on T2WI (100%), an indistinct margin (75.0%), and rim enhancement (58.3%). Using a TIC, the early phase showed rapid enhancement, and the delay phase showed a signal plateau (91.7%). DWI showed diffusion restriction in all cases determined by the ADC. Immunohistochemistry showed negative expression of estrogen receptor (ER) (91.0%), progesterone receptor (PR) (81%), and HER2 (erbB-2) (80.0%).

Conclusions

Imaging features of MBC on mammography and ultrasound were benign. The use of T2WI MRI showed characteristic features of signal intensity using TIC curve and ADC analysis, which may support biopsy and histological analysis for definitive diagnosis.