Salivary Gland Oncocytomas. A Systematic Review

Oncocytoma is a primary benign epithelial neoplasm comprising less than 2% of salivary tumors with a low recurrence rate.

A systematic review of documented case reports and case series of oncocytomas is presented. Searches from different databases were performed to identify articles from 1956 to 2024. The variables included were gender, age, symptoms, duration time before diagnosis, type of gland, histological features, special or immunohistochemical evaluation, treatment, follow-up, recurrence, and relation with a medical condition or syndrome.

Of the 147 cases reported, 53.1% affected females, and 46.9% were in males. The average age was 58.7 years, and the mean size was 2.3 cm. The most common clinical presentation was swelling (92.6%) and 66.7% were asymptomatic. The parotid was the most commonly affected gland with 66% of cases, the submandibular gland with 23.3%, and the minor salivary glands with Phosphotungstic acid-hematoxylin (PTAH) was the most common special stain used in 36.7%, followed by a combination with Periodic acid-Schiff (PAS) with and without diastase in 26.6%. Excisional biopsy was the most common treatment in 38.1% followed by superficial parotidectomy in 32.7%. Follow-up was 34.7 months on average. Bilateral oncocytomas were found in 4.8% with a 6 to 1 female-male proportion. Recurrence was found in 2.7% and association with Birt-Hogg-Dube (BHD) syndrome was 8.2%.

Salivary oncocytoma is a rare epithelial neoplasm with nonspecific clinical presentations. Diagnosis can be suspected on cytology and confirmed by histologic examination. The lesion has an indolent clinical course and most of the reported cases did not recur. There seems to be an association between bilateral oncocytomas and females and a low but interesting association with BHD. Overall, this review serves to better highlight the features of this rare benign neoplasm.