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 less than 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 less than 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.