Malignant Oncocytoma of the Parotid Gland: Report of a Case and Review of Literature

We reported a case of malignant oncocytoma arising from the right parotid gland through neck metastasis. In 1992, the patient was treated by surgical removal of a lymph-node mass, diagnosed as malignant unclassified tumor. In 1995, a right parotid gland tumor and right neck lymph-node masses occurred. We suspected the patient of having a malignant tumor of the right parotid gland through neck metastasis, especially recurrence of the previous clear-cell carcinoma. In July 1995, a right-side total parotidectomy and a neck dissection were carried out. A definite diagnosis was based on histological findings of the resected tumor as malignant oncocytoma: large eosinophilic granular cells were detected, and electron-microscopically, cytoplasms of tumor cells were rich in mitochondria with no encapsulation, perineural and intravascular invasion, and metastases to the cervical lymph nodes. Additional therapy such as chemotherapy and irradiation were not applied. To date, he has had no evidence of disease for 6 years.