Cytological and histological keratinization studies in leukoplakias of the mouth.

A correlative histocytological study for keratinization was done in 446 cases of oral leukoplakia. Cytologically, keratinization could be correctly identified in 91% of leukoplakias exhibiting orthokeratosis, 73% of leukoplakias exhibiting parakeratosis, and 78% of cases showing both types of keratinization. Cytologically, orthokeratosis was present in 83% of individuals with homogeneous leukoplakia and in 69% with ulcerated leukoplakia, while parakeratosis was present in 7% of homogeneous leukoplakias and in 19% of ulcerated leukoplakias. A higher frequency of dysplasia was observed in smears and their corresponding histological sections for those cases which had revealed only parakeratosis in the cytological examination and for both orthokeratosis and parakeratosis as compared to those showing only orthokeratosis. It is suggested that the cytological method is a reliable method for studying oral keratinization and is of value to the clinician in identifying the type of leukoplakias which may need to be biopsied for further surveillance.