Warthin tumor within the superficial lobe of the parotid gland: a suggested criterion for diagnosis.

The location of Warthin tumor (WT) in the parotid gland impacts the surgical approach and may be indicative of the elusive origin of this intriguing entity. Location in the deep versus superficial lobe of the gland is not directly addressed when defining WT characteristics. Our observation, of rare occurrence of deep lobe WT, if at all, led to the current investigation. The study design is cohort study. This is a retrospective chart review of all patients undergoing parotidectomy for WT in two tertiary academic referral centers: the Sheba Medical Center (SMC), Israel, and the Christiana Care (CC), Newark, Delaware, USA. 122 consecutive adult patients underwent parotidectomy for WT (72 from SMC and 50 from CC). Seventy percent were males, with a mean age of 60.6 years. Bilateral WT or multi-centric WT were found in 9.8 and 17.2% of the cases, respectively. In one case, the tumor was described as originating in the deep lobe. In all other cases, the tumor originated and was limited to the superficial lobe. 99.2% of WT originated in the superficial lobe, corresponding with the few reports directly addressing its location in the gland. The reason for the tumor to be limited almost uniformly to the superficial lobe is unknown, and could be related to the etiopathogenesis of this elusive entity. We suggest adding tumor location within the superficial lobe to the common characteristics of WT (male, smoking, and lower pole) that serve as "common criterion" while evaluating a parotid lesion.