Metaplastic breast carcinoma: a retrospective study of 26 cases

Abstract

Metaplastic breast carcinoma is a rare invasive breast cancer. Metaplastic breast carcinoma is mainly characterized by an epithelial or mesenchymal cell population mixed with adenocarcinoma. We collected 26 cases of metaplastic breast carcinoma in the First Affiliated Hospital of Bengbu Medical College from 2008 to 2014. Tumor size, tumor grade, vascular invasion, ER/PR status, histologic classification, and HER2/neu status were assessed for all cases and the literature was reviewed. Clinicopathologic characteristics of patients diagnosed with metaplastic breast carcinomas and its key points of differential diagnosis were discussed. All patients were female, with the median age of 50 years. The mean tumor size was 3.2 cm. 4 subtypes of metaplastic breast carcinomas were documented. Fibromatosis-like metaplastic carcinomas are typically characterized by wavy, intertwined, gentle spindle cells. When the tumor components are almost squamous cell carcinoma components and the primary squamous cell carcinoma of other organs and tissues are excluded, we can diagnose breast squamous cell carcinoma. In spindle cell carcinoma, atypical spindle cells are arranged in many ways and are usually accompanied by inflammatory cell infiltrate. Cancer with interstitial differentiation has mixed malignant epithelial and mesenchymal differentiation, and the mesenchymal components are diverse. Most tumors are triple negative. At present, surgical resection combined with chemotherapy or radiation therapy is the most effective and acceptable method for treating metaplastic breast carcinoma.

Keywords: Metaplastic breast carcinoma; immunohistochemistry; pathology.

Figure 1

Molybdenum target results of metaplastic breast cancer. A. Molybdenum target displays the mass is located in the outer posterior quadrant of the left breast, with irregular shape and lobulated shape. B. Molybdenum target displays the mass is located in the outer upper quadrant of the left breast, with irregular shape and burr shape, and tortuous blood vessels can be seen around. C. Molybdenum target displays the mass is located in the right upper quadrant of the breast, irregular shape, lobulated, burr-like, with rough and uneven calcification. D. Molybdenum target displays the mass is located in the right upper quadrant of the breast, and irregular in shape, with multiple small line-like and branch-like calcifications.

Figure 2

Microscopic manifestations of various metaplastic breast cancers. A. Fibromatosis-like metaplastic carcinoma (magnification, ×100). B. Squamous cell carcinoma (magnification, ×100). C. Squamous cell carcinoma (magnification, ×200). D. Spindle cell carcinoma (magnification, ×100). E. Spindle cell carcinoma (magnification, ×200). F. Cancer with osseous differentiation (magnification, ×200).

Figure 3

Immunohistochemical markers of metaplastic breast cancer. A. Immunohistochemical staining shows that broad-spectrum cytokeratin was positive in the neoplastic cells (magnification, ×200). B. Immunohistochemical staining shows that vimentin was positive in the neoplastic cells (magnification, ×200). C. Immunohistochemical staining shows that p63 was positive in the neoplastic cells (magnification, ×200). The brown-yellow staining indicated by the arrow is positive.