Skin lesions from sun exposure: a treatment guide.

Leukoplakia is a clinical term that may histologically represent actinic changes or frank squamous cell carcinoma. Because the nature of dysplasia may differ in various portions of the involved lip, adequate histologic examination is mandatory. Histologic characteristics of squamous cell carcinoma include loss of cell organization and orientation, loss of intercellular bridges, presence of nuclear atypia and mitotic figures, and premature cell keratinization.