ABSTRACT
Adenomyoepithelioma (AME) of the breast is an uncommon tumor characterized by its dual differentiation into luminal cells and myoepithelial cells. In most cases these tumors have a benign clinical course, but distant metastases have been reported. We present the case of a 51-year-old woman diagnosed with malignant AME. The patient underwent a right modified radical mastectomy, and pathological examination confirmed the diagnosis of malignant AME. Ten months after the operation, multiple hepatic, pleural, and abdominal wall metastases were detected. A number of palliative chemotherapeutic agents were tried, including anthracycline and taxanes. However, the disease continued to progress, and superior vena cava syndrome developed as a result of direct tumor invasion. The patient received salvage eribulin monotherapy. After two cycles of this treatment, her clinical symptoms were ameliorated, and a computed tomography scan showed a partial response. Eribulin chemotherapy was thus effective in treating malignant AME in this case.