The interpretation of leukoplakia in laryngeal pathology

Leukoplakia is only a descriptive clinical term designating a white patch or plaque of the mucosa and must be complemented by histology. On the other hand, keratosis is an exclusively histological term denoting pathological production and accumulation of keratin on the surface of the laryngeal epithelium. Leukoplakia is usually keratosis, but not always. Keratosis can mask various epithelial changes, from simple hyperplasia to invasive squamous carcinoma and is only the superficially visible manifestation of an underlying pathological process. Keratosis means total replacement of superficial epithelial cells by keratin filaments, and dissolution of the nuclei. When nuclei are retained in keratinized cells, the process is termed parakeratosis. Therefore, keratosis can be classified as a separate entity only when histopathological examination reveals superficial keratotic changes accompanying a normal squamous epithelium. To identify the presence of keratosis in various benign laryngeal entities divided according to severity of epithelial abnormalities, and to determine whether keratosis has any prognostic value, we performed a retrospective analysis on bioptic material on 4,291 tissue specimens over a period of 15 years. Our results suggest that keratosis must be considered as only one sign of the disorder within the complex of other pathological changes and not as a distinct pathological entity. For this very reason, keratinization of the epithelial surface was not included among significant parameters used for the grading of epithelial changes into the particular group according to Kambic-Lenart classification.