[A Case of Squamous Cell Carcinoma of the Breast].

A 67-year-old woman presented with a 3 cm palpable mass in the lower lateral quadrant of her right breast. Mammography and ultrasonography showed a mass with an irregular border. Using fine needle aspiration biopsy and cytology, we detected malignant cells with keratosis, and made a diagnosis of squamous cell carcinoma(SCC). We performed total mastectomy with axillary lymph node dissection. Histologically, the tumor was identified as SCC with keratinization and a component of scirrhous adenocarcinoma; estrogen and progesterone receptor expression were not elevated. The tumor tested negative for HER2. The patient did not receive any adjuvant chemotherapy and is alive with no recurrence 13 years after surgery.