Immunohistochemical demonstration of S-100 protein in salivary gland neoplasms.

A peroxidase-antiperoxidase technique for S-100 protein has been applied to 68 salivary glands. These included 17 pleomorphic adenomas, seven adenoid cystic carcinomas, 23 adenolymphomas and a number of other neoplasms. In addition, five specimens of myoepithelial sialadenitis ('benign lymphoepithelial lesion') and five normal parotid glands were included. Consistent results were obtained, myoepithelial cells and cells in myxoid and chondroid areas in pleomorphic adenomas staining intensely. In adenoid cystic carcinoma, on the other hand, there was no staining. The adenolymphomas possessed intensely S-100 protein-positive cells in the interfollicular lymphoid areas; these were probably interdigitating reticulum cells. In addition, branching structures, probably corresponding to Langerhans' cells, were observed in the epithelium of adenolymphomas.