Myoepithelial carcinoma with contralateral invasive micropapillary carcinoma of the breast

Adenomyoepithelioma (AME) is a rare benign tumor composed of myoepithelial cells (MECs) which are located beneath the epithelial cells of exocrine glands, especially in breast and salivary glands. These tumor cells show biphasic proliferation of epithelial and MECs. Malignant AME is characterized by distant metastasis, local recurrence, cytologic atypia, high mitotic activity and infiltrating tumor margins. A 51-year-old woman presented with an 8 months growth in the left breast. She underwent core-needle biopsy and consecutively mammotome assisted biopsy at a local clinic. After resection, she complained about re-growing remnant lesion and a newly developed solid mass in the right breast. Finally, the remnant mass in the left breast was diagnosed with myoepithelial carcinoma. Concurrently, contralateral breast mass was diagnosed with invasive micropapillary carcinoma. Herein we report an unusual case of synchronous myoepithelial carcinoma and invasive micropapillary carcinoma of the breast with a review of literatures.