Histological characteristics of oral leukoplakia

Abstract

INTRODUCTION: Leukoplakia (LKP) is defined as a white patch or plaque on the mucosa of oral cavity, vulva, vagina etc., which cannot be removed and cannot be clinically or microscopically explained by presence of a disease. LKP is included in the group of lesions with malignant potential. MICROSCOPIC CHARACTERISTICS: Basic microscopic characteristics of oral LKP include hyperkeratosis of ortho- or parakeratotic type and acanthosis of the epithelium, with various degrees of chronic inflammatory infiltrates in lamina propria. Also, various degrees of epithelial dysplasia may occur. Some of the most important microscopic characteristics of dysplasia are: loss of polarity of basal cells, increased nuclear cytoplasmic ratio, irregular epithelial stratification, increased number of abnormal mitotic figures and their presence in the superficial epithelium, cellular and nuclear pleomorphism, keratinization of single cell groups. MALIGNANT POTENTIAL: LKP is the most common oral mucosal lesion (evident in 3% of adults). At the same time, up to 85% of all precancerous lesions are manifested as LKP. Overall malignant potential of LKP does not exceed 4%, but some authors found that even 16% LKP with some degree of dysplasia, have a potential to transform to carcinoma. MICROSCOPIC DIFFERENTIAL DIAGNOSIS: The most important differential diagnostic criteria are listed for lesions with similar microscopic appearance. CONCLUSION: Nowdays LKP is diagnosed more frequently than before, probable due to a better patients' education and dentists' caution, but not due to real increase in incidence.