Pleomorphic adenoma of the salivary gland. With special reference to histochemical and electron microscopic studies and biochemical analysis of glycosaminoglycans in vivo and in vitro.

Pleomorphic adenoma of the salivary gland is classified into two types based on the morphology of the cells and biochemical analysis of glycosaminoglycans. Type 1: the tumors consisted mainly of spindle cells, producing a large amount of mucinous material, and contained not only chondroitin 4- and 6-sulfate and hyaluronic acid but also heparan sulfate. When the tumors of this type were dissociated and cultivated, spindle cells proliferated vigorously as mulitlayer and secreted mucinous substance into the intercellular space. The cells looked like non-epithelial cells in a conventional culture bottle, but showed an epithelial-like arrangement when they were cultivated in sponge matrix or inoculated subcutaneously into mice. Fine fibres stained with orceine or resorcin-fuchsin were observed in the intercellular material both in resected tissue and in culture. Type 2: the tumors consisted mainly of ductal cells, having no mucinous area, and contained little heparan sulfate. When the tumors were cultivated, the growth of epithelial-like polygonal cells was observed in monotonous pattern, producing scanty intercellular substance, and proliferating, as monolayer, much less rapidly than the cells of Type 1.