Nodular oncocytic hyperplasia: Can cytomorphology allow for the preoperative diagnosis of a nonneoplastic salivary disease?

BACKGROUND: Nodular oncocytic hyperplasia (oncocytosis) of the salivary glands is a benign process that does not inherently require surgical excision. However, cytologic findings in fine-needle aspiration (FNA) of oncocytosis cases have not been well characterized previously, limiting preoperative identification. METHODS: All available cases of oncocytosis with corresponding FNA specimens were identified from the pathology archives of 3 academic institutions. Clinical, cytologic, and histologic findings were tabulated for all cases. RESULTS: Twelve cases of oncocytosis were identified from 11 patients, including 11 parotid FNA specimens and 1 submandibular FNA specimen. On the original diagnoses, 6 specimens were classified as benign, 4 as atypical, and 2 as nondiagnostic. Oncocytosis was listed in the differential diagnosis in only 1 case. Among diagnostic aspirates, 8 demonstrated low cellularity and 2 demonstrated moderate cellularity. All 10 cases demonstrated oncocytic cells in small to medium groups, with single cells in just 1 case. Spindled and squamous morphology were each noted in 3 cases. Four cases demonstrated cystic change and 1 showed background mucin without goblet cells. No necrosis or mitoses were observed. CONCLUSIONS: Although oncocytosis demonstrates some overlap with Warthin tumor and oncocytoma, it lacks the diagnostic findings specific to oncocytic salivary gland malignancies such as salivary duct carcinoma, acinic cell carcinoma, mammary analog secretory carcinoma, and mucoepidermoid carcinoma. Despite current limitations in the understanding of oncocytic salivary gland lesions, the presence of a paucicellular specimen comprised of small groups of oncocytic cells should raise the possibility of oncocytosis in the differential diagnosis and can favor it in elderly patients with multiple salivary nodules. Cancer Cytopathol 2017;125:627-34.