ONCOCYTIC TUMORS OF MAJOR SALIVARY-GLANDS - A STUDY OF 68 CASES WITH FOLLOW-UP OF 44 PATIENTS

Oncocytic tumors rarely occur in major salivary glands and generally account for < 1% of all salivary tumors. Until now, a large series of these tumors with long-term follow-up has been lacking. We report on 68 cases of oncocytic major salivary gland tumors with clinical data on 44 patients. Eighty-four percent occurred in the parotid (male to female ratio of 1:1), and 11% arose in the submandibular gland (six males, one female). Additionally, 5% were incidentally found in salivary nests of the upper cervical lymph nodes. The mean age of all patients was 58 years. Unexpectedly, 20% of the patients had either radiotherapy to the face or upper torso or long-term occupational radiation exposure, 5-40 years prior to tumor discovery. Patients with previous radiation exposure had a mean age of 43 years at tumor discovery as compared with 63 years for all other patients (p < 0.01). Among 44 patients, there were four definite, documented cases of recurrences: two were multiple and bilateral. A minimum 7% incidence of bilateral disease was noted. An association exists among bilateral disease, tumor recurrence, and extensive clear cell change ("clear cell oncocytosis"). Only one case metastasized: an oncocytic adenocarcinoma of the submandibular gland. None of the oncocytomas studied (including three with perineural spread) metastasized after 0.5-38 years' follow-up (mean 12 years). The literature is reviewed with regard to cases of metastasizing malignant oncocytomas.