Precancerous Lesions

White, red, or mixed white-red areas that are not easily wiped away, persist for more than 2 weeks, and are not definable as some other condition may be precancerous, that is, they tend to develop into cancer if left untreated. The same risk factors are involved in precancerous lesions as in cancerous growths, and precancerous lesions may become cancerous if not removed.

Leukoplakia is a flat white spot that may develop when the moist inner lining of the mouth (oral mucosa) is irritated for a long period. The injured spot appears white because it has a thickened layer of keratin--the same material that covers the outermost part of the skin and normally is less abundant in the lining of the mouth.

Erythroplakia is a reddened area that results when the lining of the mouth thins. The area appears red because the underlying capillaries are more visible. Erythroplakia is a much more ominous predictor of oral cancer than leukoplakia.