Breast metastasis of salivary duct carcinoma in a patient: a case report.

Salivary duct carcinoma (SDC) is a rare and highly aggressive cancer with a worse prognosis that has been demonstrated to exhibit invasive growth with early regional and distant metastasis. Breast metastasis of salivary duct carcinoma rarely occurs. Here, we reported a case of submandibular gland SDC metastasis to breast in a 64-year-old female patient who underwent a complete removal of a right submandibular gland and radical neck dissection in 2010 and undergo adjuvant radiotherapy and chemotherapy. Two years later, MRI identified mass in multiple regions, including bilateral cervical, bilateral breast, supraclavicular fossa, thyroid gland and the fourth thoracic vertebra. A fine-needle aspiration biopsy of the right breast was performed. SDC was confirmed by IHC analysis of the breast aspiration specimen.