Nasopharyngeal carcinoma metastasis to the breast.

Breast metastases from extra-mammary neoplasms are rare, accounting for less than 2% of breast cancer cases. A 43-year-old female patient presented with a mass in her left breast and swelling in her left axillary region. A histopathological examination of the mass showed enlarged polygonal tumor cells with scant to moderate, eosinophilic to amphophilic cytoplasm and enlarged, hyperchromatic and pleomorphic nuclei with irregular nuclear membranes. An immunohistochemistry (IHC) examination was positive for pan cytokeratin and negative for CK7, CK20, S-100, LCA, HMB45, CD 20, desmin, myogenin, GCFDP-15, transcription factor-1, villin, estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2. As she was a known case of nasopharyngeal carcinoma, and based on the histopathology ndings and IHC profile, the patient was diagnosed with breast metastasis from NPC. The patient was deceased 3 months after refusing the recommended medical intervention.