Warthin tumor. A new hypothesis concerning its development.

OBJECTIVE: Warthin tumor is the second most common benign parenchymal salivary neoplasm. The purpose of this study was to evaluate the histopathologic features of Warthin tumor to determine whether a developmental pattern could be identified. STUDY DESIGN: Seventy-nine Warthin tumors in 63 patients (62 male and 1 female; average age, 58.62 years) were examined. All cases were histopathologically classified and morphometrically analyzed with an Optomax system to measure the proportions of lymphoid tissue and cystic cavities. RESULTS: The predominantly epithelial type (21% of all cases) of Warthin tumor was associated with a mean patient age at diagnosis of 53 years, a mean evolution time of 2.8 months, an average size of 1 cm, and a mean lymphoid component of 10%. In the case of the classical type (61% of all cases), the mean patient age at diagnosis was 58 years, the mean evolution time 9 months, the average size 2.4 cm, and the mean lymphoid component 40%. For the predominantly lymphoid type (18% of all cases), these values were, respectively, 62 years, 11 months, 2.8 cm, and 74%. The mean size of the classical and lymphoid tumors (79% of the Warthin tumors) was significantly greater (p < 0.0001) than the mean size of the epithelial type (21% of the Warthin tumors). A positive correlation between tumor size and evolution time was found. CONCLUSION: Our results suggest that the Warthin tumor initially develops as an adenomatous epithelial proliferation followed by lymphocytic infiltration.