Myoepithelial Carcinoma: A Rare Neoplasm of the Breast.

BACKGROUND: Malignant myoepitheliomas of the breast are extremely rare. There has been a limited number of published reports of myoepithelial carcinomas originating from the breast. CASE REPORT: We describe a malignant myoepithelioma of the breast in a 56-year-old woman. Histological examination showed polygonal epithelioid cells and spindle cells with moderate to marked nuclear atypia. Immunohistochemistry showed reactivity in the spindle cells for smooth muscle actin, cytokeratin (AE1/AE3), and p63, indicating a myoepithelial cell lineage of tumor cells. The patient underwent radical surgical excision of the lesion and axillary lymph node dissection. She demonstrated no evidence of recurrence over an 11-month follow-up. CONCLUSIONS: We suggest myoepithelial carcinomas of the breast be managed with appropriate surgical clearance. A multidisciplinary approach is usually required.