Incidental Parotid Neoplasms: Pathology and Prevalence

To better characterize parotid masses incidentally identified on imaging.

Case series with chart review.

Academic medical center.

Medical records were reviewed for 771 patients who underwent parotidectomy at the University of Wisconsin from 1994 to 2013. Patients were stratified into 2 groups: those with tumors identified solely on imaging (parotid incidentalomas [PIs]) and those with palpable masses, pain, facial nerve dysfunction, or other reasons their mass was identified (nonincidentals [NIs]). A χ(2) test was employed to compare the prevalence of malignancy in PIs compared with NIs. Trend analysis was performed to determine the prevalence of PIs over the 20-year period.

Of the 771 patients, 67 (8.7%) had their mass discovered incidentally on imaging (PIs). There was a significant difference in the rate of malignancy in the NI (32.7%) compared with the PI group (6.0%) (P < .01). During the 1994 to 2003 time period, 4.0% of all parotoidectomies performed were for PIs, while during the second decade (2004-2013), this proportion increased to 10.2%. This represents a 155.0% increase in the percentage of parotidectomies carried out for PIs between these 2 periods.

In this study, the rate of malignancy in PIs was significantly lower than the rate of malignancy in patients with NIs. The occurrence of PIs has increased over time and now represents greater than 10.0% of all parotidectomies performed at the University of Wisconsin. This information is important to consider when consenting a patient for resection of a PI.