Warthin's tumor as a hamartomatous dysplastic lesion: a histochemical and immunohistochemical study.

The etiology of Warthin's tumor was sought by histochemical and immunohistochemical methods using 7 surgically extirpated samples and normal salivary glands as a control for the epithelial component. All the samples exhibited a variety of amyloid deposition in the interfollicular area of the lymphoid component. The interfollicular lymphoid cells were both T-cells and cells of B-cell lineage with an almost 1 to 2 population ratio. Most antigen-positive B-cells were plasma cells that exhibited polyclonality of immunoglobulin. B-cells were also present in the lymphoid mantles and a few were found in the germinal centres. The epithelial component exhibited mucinous and proteinaceous fluid in the lumen and varied immunohistological reactions; being particularly positive to carcinoembryonic antigen, S-100 protein, and B-cell antigen; quite similar to that of normal salivary duct cells. The results suggest that Warthin's tumor may not be a hamartomatous neoplasm at all but a hamartomatous dysplastic lesion.