Bilateral Warthin's tumor: report of case and review of Japanese literature.

A case of Warthin's tumor with bilateral and multiple involvement is described, along with a review of 104 cases reported in the Japanese literature. The tumor comprised 3.5% to 6.7% of all tumors in the parotid gland, which was affected in 96.2% of our cases. Bilateral or multiple involvement was observed in 17 cases. The incidence was approximately four times higher in males than in females, and 91.4% of the cases occurred between the fifth and eight decades of life, with a mean of 57.2 years. Onset of the initial symptoms had been disregarded for a few months to five years in 80% of the patients. All the tumors were treated surgically and diagnosed histologically as Warthin's tumor of a benign type with the exception of two cases.