EXPRESSION OF INVOLUCRIN IN HUMAN SALIVARY GLAND LESIONS AND TUMORS

An immunohistochemical study was undertaken to determine the localization of involucrin in human salivary gland lesions and tumors. Normal glandular tissues and those with obstructive sialadenitis were negative for involucrin staining. In pleomorphic adenomas, the luminal surface of tubular, ductal, duct-like, and cystic structures was positive for involucrin, and some cells lining the cavities of these structures were also positive. In the outer layer of the duct-like structure, spindle-like cells having long anastomosing processes were negative. Squamously metaplastic cells and cells with ongoing keratinization strongly indicated the presence of involucrin. In Warthin's tumor specimens, cells strongly positive for involucrin were found, though rarely, scattered around the eosinophilic tumor epithelium. Immunohistochemically detected involucrin may be a specific marker for detecting squamous metaplasia or keratinizing change in the epithelia of salivary gland tumors.