Patterns of Keratinization in Oral Leukoplakia

LEUKOPLAKIA is the most commonly observed oral keratotic lesion. There are essentially two main types that can be differentiated microscopically. The majority of cases are characterized histologically by varying degrees of hyperkeratosis, parakeratosis, or a combination of both types of keratinization.¹,²This form of leukoplakia is referred to as the simple hyperkeratotic variety or benign leukoplakia.³In about 10% of the cases of oral leukoplakia, there is the additional histologic feature of dysplasia or atypia.⁴,⁵This variety of leukoplakia is referred to as the dysplastic, premalignant, or malignant form, and is comparable to the so called precancerous dermatoses, such as Bowen's disease. The benign form of oral leukoplakia represents a simple hyperkeratotic response to irritation. The dysplastic form of oral leukoplakia represents a premalignant lesion and may be regarded as a carcinoma in situ. The essential alteration from normal to malignant has already occurred and these lesions