Electronmicroscopy of the buccal proper lamina in leukoplakia.

The observations included the connective tissue laminae originating from samples of the buccal mucous membrane in leukoplakia. Following fixation and dehydration the materials were embedded in Epon 812, and the electronograms for the evaluation were obtained with the use of a Tesla BS 500 electron microscope. The macrophages were encountered close to the basal membrane in the proper lamina. The space between the basal cells and the macrophages was filled with the connective tissue matrix and numerous collagen fibres, as well as the fibroblast cells. Numerous mast cells, characterized by a specific activity, were noted. Additionally, the proper lamina contained few nerve fibres, usually nonmyelinated. The vascular bed was normal. The electronograms in leukoplakia revealed an active synthesis of the connective tissue matrix and collagen fibres. The marked activity of the mast cells was manifested by a high number of cells containing a relatively differentiated amount of granulation. This might be related to the chronic character of the disease. A significant activity of particular elements of the proper lamina, i.e. the cellular elements, collagen fibres and the connective tissue matrix appears to be characteristic of leukoplakia.