Oncocytic neoplasms of the parotid gland. Differential diagnoses, clinicalcourse, and overview of the literature

Background and objective. Oncocytic neoplasms of the salivary glands are ra re. Patients/methods. We report on seven cases of oncocytic neoplasms of the pa rotid gland tone multifocal nodular oncocytic hyperplasia, five oncocytomas , and one oncocytic carcinoma). Results. While the history, clinical presentation, and histology of a II on cocytic neoplasms showed no characteristic differences, intraoperatively th e well-differentiated oncocytic carcinoma displayed an infiltrative, locall y aggressive growth pattern. A local carcinoma recurring 7 years later corr esponded to the primary tumor. There were no metastases. Immunohistochemist ry revealed that all oncocytic neoplasms were positive for markers of cytok eratins (KI-1) and negative for markers of carcinoembryonal antigen (CEA), S-100 protein, and smooth muscle actin (SMA). In contrast to the benign neo plasms, the oncocytic carcinoma showed an increased rate of proliferating c ells (MIB-1) and a strongly positive reaction with the antibody MA-903 agai nst high molecular weight cytokeratins. Conclusions. In a review of the literature, we could identify a group of lo cally aggressive, low-grade oncocytic carcinomas with a considerably better prognosis, similar to that of our case. The therapeutic significance of th ese findings is discussed.