A Case of Parotid Nodular Oncocytic Hyperplasia Diagnosed Preoperatively by Core Needle Biopsy

Nodular oncocytic hyperplasia (NOH) is classified as a non-neoplastic epithelial lesion in the 2017 World Health Organization (WHO) classification of salivary gland tumors. It is rare, accounting for less than 1% of all salivary gland tumors. The patient, a 63-year-old woman, presented with a slowly increasing swelling of the right cheek. Imaging showed multiple nodular lesions bilaterally in the parotid glands. We performed fine needle aspiration cytology (FNAC), which was inconclusive. Core needle biopsy (CNB) was performed and the findings were consistent with the diagnosis of NOH. As the lesions were benign, we offered the patient several options for managing the condition, including careful follow-up. Due to cosmetic concerns, however, she requested a right parotid tumor resection. The tumor occupied most of the right parotid gland, and the surgery was akin to superficial parotidectomy. A small residual tumor in the right accessory parotid grand and the lesions on the left side are now under observation. We compared the age, sex, presentation, the results of FNAC, and management of 14 cases of NOH reported in the literature, including the present case. In most cases, surgical treatment was undertaken because of the difficulty in preoperative diagnosis of NOH by cytology. There are no previous other reports of the use of CNB for diagnosis, which appears to be useful for preoparative diagnosis of NOH.