[Oncocytic neoplasms of the parotid gland. Differential diagnosis, clinical course and review of the literature].

BACKGROUND AND OBJECTIVE

Oncocytic neoplasms of the salivary glands are rare.

PATIENTS/METHODS: We report on seven cases of oncocytic neoplasms of the parotid gland (one multifocal nodular oncocytic hyperplasia, five oncocytomas, and one oncocytic carcinoma).

RESULTS

While the history, clinical presentation, and histology of all oncocytic neoplasms showed no characteristic differences, intraoperatively the well-differentiated oncocytic carcinoma displayed an infiltrative, locally aggressive growth pattern. A local carcinoma recurring 7 years later corresponded to the primary tumor. There were no metastases. Immunohistochemistry revealed that all oncocytic neoplasms were positive for markers of cytokeratins (KI-1) and negative for markers of carcinoembryonal antigen (CEA), S-100 protein, and smooth muscle actin (SMA). In contrast to the benign neoplasms, the oncocytic carcinoma showed an increased rate of proliferating cells (MIB-1) and a strongly positive reaction with the antibody MA-903 against high molecular weight cytokeratins.

CONCLUSIONS

In a review of the literature, we could identify a group of locally aggressive, low-grade oncocytic carcinomas with a considerably better prognosis, similar to that of our case. The therapeutic significance of these findings is discussed.