Oncocytoma of the left parotid gland: a rare case report

Parotid oncocytoma is a rare benign epithelial salivary gland tumor with nonspecific clinical and radiological features, making preoperative diagnosis difficult. We report the case of a 69-year-old woman who presented with a painless, slowly enlarging mass in the left parotid region for 1 year. Preoperative ultrasonography and contrast-enhanced computed tomography demonstrated a left parotid mass, whereas fine-needle aspiration cytology suggested a benign lipomatous lesion. Because the mass had progressively enlarged, was firm on examination, and malignancy could not be completely excluded, the patient underwent left superficial parotidectomy with selective removal of intraoperatively detected left level II and periparotid lymph nodes. The tumor was located in the lower superficial lobe, inferior to the facial nerve branches, and the facial nerve and its branches were preserved. Histopathological examination of the resected parotid specimen confirmed benign oncocytoma, while all three lymph nodes showed reactive hyperplasia. The postoperative course was uneventful, and the patient was discharged without complications. This case illustrates the difficulty of establishing a specific preoperative diagnosis of parotid oncocytoma and the role of histopathological examination for definitive diagnosis. In this patient, superficial parotidectomy achieved complete removal with preservation of facial nerve function; however, treatment decisions should be individualized according to tumor characteristics, surgical history, and preoperative diagnostic uncertainty.