Sonographic and pathological features of metaplastic squamous cell carcinoma of the breast: a case series

Multimodal Imaging Features and Prognosis of Metaplastic Breast Carcinoma

RATIONALE AND OBJECTIVES

Metaplastic breast carcinoma (MBC) is an infrequent malignancy with an unfavorable prognosis, and there is a paucity of research on the multimodal imaging features of MBC. This study aimed to provide a comprehensive analysis of the multimodal imaging features, clinicopathological characteristics, and prognosis of MBC.

MATERIALS AND METHODS

A total of 36 patients with histologically confirmed MBC from 2012 to 2021 were included in the study. We analyzed the pre-treatment multimodal imaging features, including mammography, ultrasonography (US), and magnetic resonance imaging (MRI), as well as clinicopathology and prognosis of MBC. Follow-up data included local recurrence, distant metastasis, and overall survival (OS) rate.

RESULTS

MBC patients had a median age of 51 years at diagnosis. The most common histologic subtype was squamous cell carcinoma, with 86.1% of MBC being histological grade 3 and triple negative. The most common mammographic findings were irregular shape, non-calcification, and high density. The predominant US findings included irregular shape, parallel orientation, posterior acoustic enhancement, and hypoecho. On MRI, most masses exhibited irregular shape, spiculate margin, heterogeneous enhancement, Type II time intensity curve, and diffusion restriction on diffusion weighted images determined by apparent diffusion coefficient. According to breast imaging reporting and data system, mammography suggested malignancy in 50% of cases, US indicated a moderate to high suspicion of malignancy in 77.8% of cases, MRI revealed malignancy in all cases. At a median follow-up time of 48 months (range, 8-122 months) for 35 MBC patients, the local recurrence, distant metastasis, and OS rates were 11.4%, 28.6%, and 67.4%, respectively.

CONCLUSION

The benign features of MBC on mammography and US may cause misinterpretation. However, the inclusion of malignant features observed on MRI can improve diagnostic accuracy.

Primary squamous cell carcinoma of the breast: a case report

INTRODUCTION

Squamous cell carcinoma (SCC) of the breast is a rare variant of invasive breast cancer that has been classified as metaplastic carcinoma. When a tumor is composed of spindle cells, diagnosis is challenging.

CASE REPORT

A 42-year-old woman with a large mass in the right breast underwent modified radical mastectomy. A pathological examination revealed a tumor with central necrosis in it. The tumor had a sarcomatoid growth pattern and the cells were spindle-shaped with severe atypicality. Immunohistochemical staining showed that P63, P53, vimentin, and CKpan were positive, whereas estrogen receptor and C-erbB-2 were negative. Ki-67 proliferation index was as high as 90%. Therefore, a diagnosis of SCC of the right breast was made. The patient received eight cycles of postoperative chemotherapy with paclitaxel and carboplatin, followed by seven cycles of radiotherapy. During follow-up, the patient also had a left thyroid tumor, and postoperative pathology suggested microinvasive follicular carcinoma. Since breast surgery, the patient has remained disease-free for more than four years.

CONCLUSION

SCC of the breast with spindle cell and sarcomatoid features is rare. The diagnosis of such tumors requires exclusion of tumors with similar histological morphologies.

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.

Breast Metaplastic Carcinoma With Osteosarcomatous Differentiation: A Case Report and literature Review

Metaplastic breast carcinoma (MBCs) is a rare heterogeneous group of malignancies. Herein, we report a case of metaplastic breast carcinoma, which had 2 components. One of them was typical invasive ductal carcinoma (IDC), the other one was presenting as osteosarcoma with lots of immature trabeculae. The results of immunohistochemistry showed different presentations between them. The majority of MBCs show triple-negativity for ER, PR, and HER-2 and are thus associated with poor prognosis. Our report shows that, it is necessary to describe the proportion of the components and the presentations of immunohistochemistry in the diagnosis, which will be important to develop specific and effective therapies.