The incidence of Warthin tumours and pleomorphic adenomas in the parotid gland over a 25‐year period

OBJECTIVES: Pleomorphic adenoma (PA) is reported to be the most common benign parotid tumour followed by Warthin tumour (WT), but the proportion of these two entities might have changed. DESIGN: Retrospective file analysis. SETTING: Tertiary referral head and neck centre. PARTICIPANTS: Patients who underwent a parotidectomy within a period of 25 years (1990-2014). MAIN OUTCOME MEASURES: Rate of occurrence of PA and WT as well as the development of the PA/WT ratio over the years. RESULTS: Overall, 1818 patients with WT (707, 38.9%) and PA (1111, 61.1%) were identified. There was a dominance of PA over WT in all years. An increase in percentage of WT, from 24% in 1990 to 48% in 2014, in comparison with PA was evident. CONCLUSIONS: In our single-institution hospital-based material of parotidectomies, the percentage of WT in comparison with PA has significantly increased over the last 25 years.