Oncocytomas of the submandibular gland. A series of 22 cases and a review of the literature.

BACKGROUND

Oncocytomas are benign salivary gland neoplasms that represent approximately 1.5% of all salivary gland tumors. Oncocytomas of the submandibular gland, however, are decidedly uncommon.

METHODS

Twenty-two cases of submandibular gland oncocytomas from the files of the Oral and Otolaryngic Tumor Registries of the Armed Forces Institute of Pathology were reviewed, and analysis of the histologic criteria, histochemical and immunohistochemical reactions, and ultrastructural and clinical follow-up data was performed.

RESULTS

The patients included 11 females and 11 males, age 21-88 years, with a mean age at presentation of 58.7 years. Clinically, the tumors were generally asymptomatic masses in the submandibular gland that increased in size over a period ranging from several weeks to 20 years and were occasionally associated with pain (n = 9). The tumors ranged in greatest dimension from 0.7 to 7 cm and were circumscribed to encapsulated. Histologically, the tumors were characterized by large epithelial cells with eosinophilic, granular cytoplasm. The cytoplasm stained positively with stains used to demonstrate mitochondria (phosphotungstic acid-hematoxylin, Novelli, Cresylecht violet V, and Kluver-Barrera Luxol fast blue stains). Immunohistochemical reactions demonstrated an epithelial origin (keratin and epithelial membrane antigen), whereas markers for myoepithelial derivation (S-100 protein, actin, and glial fibrillary acidic protein) were not identified. At the time this study was conducted, all patients with submandibular oncocytomas were either alive without evidence of disease or had died without evidence of recurrent disease, with surgical resection the only treatment.

CONCLUSIONS

Submandibular gland oncocytomas are rare, benign tumors. The tumor cells are filled with mitochondria, which are easily demonstrated by histochemical reactions. Complete surgical resection is adequate therapy.