Adenomyoepithelioma With Myoepithelial Carcinoma of the Breast With Axillary Lymph Node Metastasis: Two Case Reports and Review of the Literature

Adenomyoepithelioma (AME) of the breast exhibits characteristic proliferation of the epithelial and myoepithelial cells. Most AMEs are benign, but the 2 inherent cell types can become malignant. The present study reports 2 cases of AME with myoepithelial carcinoma of the breast, one with axillary lymph node metastasis.A modified radical mastectomy was performed in a 67-year-old woman, because a sentinel lymph node biopsy revealed one metastatic lymph node composed of a myoepithelial carcinoma component. Despite receiving radiotherapy and chemotherapy, the patient died from lung and brain metastases 21 months later. In the second case, breast-conserving surgery with sentinel lymph node biopsy was performed in a 55-year-old woman. Following additional treatment with radiotherapy and chemotherapy, there were no signs of recurrence or metastasis.The tumors of the 2 patients were diagnosed as malignant, based on their high mitotic rate and severe nuclear atypia.Based on previously reported cases with distant metastases, the prognosis of myoepithelial carcinoma is poor. Myoepithelial carcinoma should be followed up with careful screening and treated aggressively.