Usefulness of fine-needle aspiration in parotid diagnostics

Abstract

Fine needle aspiration (FNA) is a safe diagnostic technique that is widely employed for lesions of the head and neck. Among head and neck sites, the parotid gland is unique in the number, diversity, and peculiarity of its pathological processes. This complexity has prompted a great deal of discussion regarding the application of FNA to parotid masses, primarily focusing on the reliability of FNA as a diagnostic tool in guiding patient management. This review presents an analysis of the usefulness of FNA in differential diagnosis of parotid pathologies. Recent studies have confirmed a wide range of accuracy rates for FNA evaluation of parotid masses, varying from 79% to 97%. These data cannot be uniformly anticipated across all diagnostic scenarios. FNA is notoriously unreliable in recognising the malignant nature of parotid carcinoma providing its precise classification and establishing its grade. A few malignant neoplasms are particularly prone to diagnostic error: acinic cell carcinoma is frequently interpreted as benign, and low-grade lymphomas are often discounted as inflammatory processes. FNA cytology is useful in avoiding surgery (inflammatory lesions) or limiting surgical procedures (benign tumours). For planning the extent of surgery of malignant parotid tumours, the histological subtype and/or grade should be determined; therefore, a histological diagnosis by frozen section analysis is required. Moreover, reliance on FNA findings at the expense of clinical, radiographic, and intraoperative findings is unwarranted. Regardless of whether FNA is used routinely or selectively in patients with parotid masses, the findings should contribute to, and not replace, the overall diagnostic impression.