Immunohistochemical study of basal cell adenoma in the parotid gland.

Basal cell adenoma of the parotid gland was studied with immunohistochemical methods. We observed cells in the tumor with positive reaction to polyclonal keratin, prekeratin, monoclonal PKK-1, polyclonal S-100 protein, monoclonal S-100 protein (alpha), secretory component, actin and laminin. However, no cells which stained positively with monoclonal KL-1, amylase, carcinoembryonic antigen, or epithelial membrane antigen were recognized. From these immunohistochemical results and our ultrastructural observations reported previously, we conclude that the cells constituting the basal cell adenoma are ductal, myoepithelial, and squamous cells but not secretory ones. It is also suggested that the origins of basal cell ademona as well as those of pleomorphic and clear cell adenoma are undifferentiated cells of intercalated duct.