Immunohistochemical study of the epithelial and stromal components of Warthin's tumor

Warthin's tumor is a benign monomorphic adenoma with unclear origin with the highest incidence in the sixth and seventh decades. The analysis of tumor markers involved in the pathogenesis of Warthin's tumor can improve the patients' prognosis. This study included 29 cases of Warthin's tumor, which were histopathologically and immunohistochemically examined for different compartments of tumors. For immunohistochemical study, we used as specific markers for epithelial compartment CD117, CEA and AMA, respectively S100 and D2-40 for the stromal compartment. The evaluation of immunoreactions was performed by semiquantitative analysis. The analysis of the CEA, CD117 and AAM immunoexpression allowed observing various patterns of immunostaining for tumor double-layered epithelia, which has the tendency of being similar to that in the normal ductal epithelia. S100 protein positivity similar to Langerhans cells suggests that delayed hypersensitivity can be involved in tumor development. The presence of D2-40 expression in majority of tumor subcapsular vessels, similar to lymph nodes structure, confirms the hypothesis that Warthin's tumor has its origin in regional lymph nodes.