[A clinicopathologic study on oncocytoma and oncocytic carcinoma of the salivary glands].

OBJECTIVE: To investigate the clinicopathologic features, differential diagnosis, treatment and prognosis of oncocytoma and oncocytic carcinoma of the salivary glands. METHODS: The clinicopathologic features were studied in 23 cases of oncocytomas and 15 cases of oncocytic carcinomas, and immunohistochemical staining as well as electron microscopy were performed. RESULTS: Most oncocytomas occurred in the parotid gland (95.6%) with no recurrence. The diagnosis was made based on histopathological features. Oncocytic carcinomas were high-grade tumors, mainly occurring in the parotid gland. The diagnosis was based not only on histopathology but also on ultrastructural findings, phosphotungstic acid hematoxylin (PTAH), and immunohistochemistry. Of the 14 cases with follow-up information, 7 cases recurred. Regional or distant metastases were found in 7 and 4 cases, respectively. CONCLUSION: Oncocytoma is a rare tumor with well prognosis, whereas oncocytic carcinoma of the salivary glands is a high-grade tumor, with frequent local recurrence, regional or distant metastasis, the diagnosis of which should be based on a combination of clinical and histopathological features. Immunohistochemistry for mitochondria is considered as a practical and helpful adjuvant for diagnosis.