Ultrastructure of sialadenoma papilliferum.

Sialadenoma papilliferum is a rare tumor of salivary gland origin and has been reported in the parotid and minor salivary glands of the oral cavity. This tumor is morphologically similar to the papillary syringoadenoma of the sweat gland. We report the clinical and morphologic features of five cases and review the literature. Ultrastructural examination of case 1 revealed the predominant cell type to be an oncocytic cell. These cells contained numerous mitochondria, exhibited parallel filaments within the cell cytoplasm, and were attached by desmosomes. The neoplastic cells appear to exhibit characteristic features of various cell types of the salivary gland duct apparatus.