What is "leukoplakia"

n. (context medicine English) patch of keratosis on the mucous membranes of the oral cavity and in other areas, associated with smoking.

Leukoplakia (also termed leucoplakia, leukokeratosis, leukoplasia, idiopathic leukoplakia, idiopathic keratosis, or idiopathic white patch), normally refers to a condition where areas of keratosis appear as firmly attached white patches on the mucous membranes of the oral cavity, although the term is sometimes used for white patches of other gastrointestinal tract mucosal sites, or mucosal surfaces of the urinary tract and genitals.

Leukoplakia in the mouth (oral leukoplakia), is defined as "a predominantly white lesion of the oral mucosa that cannot be characterized as any other definable lesion". However, this definition is inconsistently applied, and some refer to any oral white patch as "leukoplakia". Leukoplakia is a descriptive clinical term that is only correctly used once all other possible causes have been ruled out (a diagnosis of exclusion). As such, leukoplakia is not a specific disease entity, and the clinical and histologic appearance are variable, i.e. the term has no specific histologic implications. Leukoplakia may be confused with other common causes of white patches in the mouth, such as oral candidiasis or lichen planus. The lesions of leukoplakia cannot be rubbed off, as would be the case in pseudomembraneous candidiasis (oral thrush).

Oral leukoplakia more commonly occurs in those who smoke, but often the cause is unknown (hence the name idiopathic leukoplakia). Chewing tobacco is also associated with this type of lesion. Leukoplakia is a premalignant lesion, i.e. "a morphologically altered tissue in which cancer is more likely to occur than in its apparently normal counterpart". The chance of transformation into oral squamous cell carcinoma (OSCC, a type of oral cancer) varies from almost 0% to about 20%, and this may occur over 1 – 30 years. The vast majority of oral leukoplakias will not turn malignant, however some subtypes hold greater risk than others. No interventions have been proven to reduce the risk of cancer developing in an area of leukoplakia, but people are generally advised to stop smoking and limit alcohol consumption to reduce their risk. Sometimes the white patch will shrink and eventually disappear after stopping smoking, but this may take up to a year. In many cases, areas of leukoplakia will slowly expand, become more white and thicken if smoking is not stopped. Management usually involves regular review of the lesion to detect any possible malignant change early, and thereby significantly improve the prognosis, which normally is relatively poor for OSCC.