A Case of Triple-negative Breast Cancer with Squamous Metaplasia in which a Pathologic Complete Response was Achieved with Neoadjuvant Chemotherapy

Abstract

A 57-year-old woman presented to a local clinic with pain and discomfort in her left breast. She was diagnosed with c-T4bN1MO stage IIIb locally advanced breast cancer and referred to our hospital for treatment. Needle biopsy cytology performed at our hospital revealed squamous metaplastic triple-negative breast cancer. A clinically objective tumor response was evident at the conclusion of four cycles of EC100 therapy and four cycles of docetaxel (75 mg/m²) as preoperative chemotherapy, and pectoral muscle-preserving mastectomy and axillary lymph node dissection were performed. On histopathological testing of the resected specimens, there were no residual cancer cells in either the tumor or the axillary lymph nodes. Many patients with this type of breast cancer are resistant to preoperative chemotherapy, and it is hoped that regimens with a high cure rate will be established in the near future with the aim of achieving a complete response.