[Immunohistochemical study in pleomorphic adenomas of human parotid gland--with special reference to cytoskeletal filamentous proteins].

The purpose of this immunohistochemical study was to know the degree and direction of differentiation, the mechanism of mesenchymal appearance, and histogenesis in pleomorphic adenomas which were obtained from surgical removed specimens. All specimens were fixed in 10% neutral phosphoate buffered formalin, and embedded in paraffin. Sections were steined with the avidin-biotin peroxidase complex method for keratin, vimentin, desmin and S-100 protein, the peroxidase-antiperoxidase method for lysozyme, and the direct immunoperoxidase method for IgA and secretory component. Normal salivary glands were employed as controls. 1. Solid portion of pleomorphic adenomas were consisted of the focal hypline cells and scattered the duct cell-like cells. The hyaline cells were positive for vimentin and S-100 protein, and the duct cell-like cells were positive for keratin. But one case was found the bundles of spindle-shaped cells which was similar to myoepithelial cells were positive for actin and another case was consisted of the focal duct cell-like cells were observed. 2. In the tubular portion, the duct-like structures were classified into three types. One type was mono-layered structure, another type was double-layered structure and the other type is duct-like structure in the solid portion. Any inner layer of the duct-like structure were positive for keratin. 3. Double-layered duct-like structures were most common type. Among the double-layered structures, hyaline cells mostly made up the outer layered structures. At times, the spindleshaped cells of the outer layer were found. This structures were similar to intercalated portion of normal salivary glands. In one case, inner and outer layer was consisted of keratin positive cells, but outer layer was steined for keratin stronger than inner. This structure was similar to excretory duct of normal salivary glands. 4. IgA and sc were seen at inner cells and in luminal accumulation of the duct-like structures. 5. In the myxoid regions, stellate cells or spindle cells were positive for vimentin, S-100 protein and partial positive for desmin. In the chondroid regions, chondrocyte-like cells were positive for vimentin and S-100 protein. These results seemed to suggest that pleomorphic adenomas were composed of duct cell-like cells and hyaline cells. Duct cell-like cells consisted of the duct-like structure in order to transport secretion which was similar to the duct of normal salivary glands.(ABSTRACT TRUNCATED AT 250 WORDS)