Malignant Adenomyoepithelioma of the Breast with Lung Metastases: Report of a Case

Adenomyoepithelioma of the breast is a rare lesion, and has a bicellular pattern of epithelial and myoepithelial cells which are regularly distributed in the tubular structures based on the histologic and ultrastructural features. It is thought to be a benign or a low-grade malignant disease. We herein describe a case of malignant adenomyoepithelioma of the breast with lung metastases in an 86-year-old woman. A primary massive tumor in the left breast grew rapidly within a short period of time. A simple mastectomy with sampling of the axillary lymph nodes was performed. The obtained lymph nodes did not include any metastatic lesions. Malignancy was evidenced by the presence of a high mitotic rate and severe nuclear atypia. Three months after the operation, radiology showed multiple lung metastases, and the patient died 2 weeks thereafter. Reviewing the literature, nine similar cases were reported, and the prognosis of malignant adenomyoepithelioma of the breast with distant metastases was very poor with the time of recurrence varying after initial treatments. Malignant adenomyoepithelioma should be followed up with careful screening for distant metastases.