Myoepithelial carcinoma of the breast treated with surgery and chemotherapy

Abstract

Myoepithelial carcinoma (malignant myoepithelioma) of the breast is a rare tumor, for which only a limited number of reports have been published. Most of the reports emphasized diagnosis and pathology but not biological behavior and treatment. We report a 61-year-old patient with breast myoepithelial carcinoma who developed locoregional and distant metastases and received many chemotherapy regimens. She presented with an elastic hard mass of the left breast. Breast conserving surgery was performed as part of both diagnosis and treatment. From the results of histological and immunohistochemical examinations, this case was considered to be a myoepithelial carcinoma. Fifteen months after the completion of adjuvant radiotherapy, distant metastasis of the left parasternal lymph node metastasis developed. She was treated by further excision and received a total of four regimens of chemotherapy including a combination of doxorubicin and cyclophosphamide. She received chemotherapy for 20 months after the diagnosis of metastasis.

Figure 1

(a) Microscopic examination of primary breast tumor showing invasive proliferation of spindle-shaped and small rhombus cells and showed alveolar formations in a part of the tumor (H&E, ×200). (b) Moderate nuclear pleomorphism, size differentiation, and mitotic figures were seen (H&E, ×400).

Figure 2

(a) Myoepithelial carcinoma revealed a diffuse cytoplasmic positivity for cytokeratin AE1/AE3 (immunohistochemical stain, ×200). (b) Cells showing calponin positivity (immunohistochemical stain, ×200). (c) Cells showing CK14 positivity (immunohistochemical stain, ×200).