The surface structure of the human nasal mucosa. II. Metaplasia, dysplasia and carcinoma in nickel workers. A correlated study by scanning/transmission electron and light microscopy.

The results of recent histopathologic studies of the nasal mucosa in nickel workers show that, in addition to metaplastic changes, there are frequently dysplastic alterations which are probably preneoplastic lesions. Seen by scanning electron microscopy metaplasia appears monomorphic and no major qualitative differences exist between nickel workers and controls of the same age although it tends to be more pronounced in the former group. Dysplasia and carcinoma, on the other hand, are characterized by considerable polymorphism in surface features which make distinction from metaplasia simple. In both dysplasia and carcinoma four defined types of surface can be distinguished: globule- and tongue-like structures, pleomorphic microvilli and microridges. In addition, parts of individual cells and adjacent cells often show a considerable variation in surface pattern. The surface structures are dynamic features and changes in these are related to the degree of maturation, genetic and metabolic properties of epithelial cells.