Answer:
Leukoplakia is characterized by white patches which may occur on the vermilion border of the lips and the vulva as well as the oral mucosa. No definitive etiology is known, but it is thought to be caused by external noxious agents such as tobacco, poorly fitting dentures, or decaying teeth or internal intrinsic disease such as atrophic glossitis of syphilis. A disturbance in keratinization results in whitish patches which are often flat but may become verrucous, suggesting malignant transformation. Most lesions are benign with histopathology of hyperkeratosis. Reported rates of malignant transformation to squamous cell carcinoma range from 6 to 15%. These lesions may regress upon removal of the irritants if identifiable. Localized patches can be selectively destroyed with cautery or curettage. Indurated or verrucous patches, however, should be biopsied or excised. If excision is not feasible, leukoplakia should be closely followed.
Erythoplakia (also called erythroplasia) is a clinical diagnosis of a flat or slightly raised red, velvety, or slightly granular lesion without a known precipitating cause. There are three clinical variations: homogeneous erythroplakia, erythroplakia interspersed with patches of leukoplakia, and granular or speckled erythroplakia. It is associated with a greater likelihood (4 to 7 times) of malignant transformation compared to leukoplakia. Surgical excision is recommended.