Epimyoepithelial' islands in lymphoepithelial lesions. An immunocytochemical study.

A panel of antibodies has been used in an immunoenzyme study in an attempt to characterize the cell types found in the 'epimyoepithelial' islands of lymphoepithelial lesions. Myoepithelial cells, which can be specifically stained with an anti-smooth muscle antibody were not found. The majority of cells stained with anti-prekeratin, suggesting a duct cell differentiation. A subpopulation of duct cells stainable with a monoclonal antikeratin (16a), previously described as occupying a basal location in normal salivary gland ducts, was clearly demonstrated. It is suggested that these cells may be important in the epithelial proliferation in these islands. The hyaline material within and surrounding the epithelial islands was positive for type IV collagen and therefore consists of basement membrane material.