Parotid Gland: An Unusual Site for Breast Cancer Metastasis—A Case Report and Review of Literature

Background: Breast cancer, which is the most common site-specific cancer in women, usually metastasizes to lung, liver, bone, and brain, although other sites can be involved less frequently. Parotid gland invasion by breast cancer, first reported in 1950, is extremely rare with very few reports worldwide. Case presentation: A 54-year-old woman with stage IIIA breast cancer presented with a right parotid mass and signs of facial nerve palsy 3 months after treatment completion, which was finally diagnosed as metastatic involvement of parotid gland. Conclusion: Breast cancer metastasis to parotid gland is extremely rare but can happen metachronously or synchronously even years after the primary disease. Therefore, this diagnosis should be kept in mind in any patient with a history of breast cancer presenting with a periauricular mass. Despite proposed treatments, including surgery, radiation, and chemotherapy, patients have a poor prognosis with a reported 5-year survival rate of 10%. However, palliative management should be recommended to all patients with parotid metastasis.