Лейкоплакия: причины, виды, диагностика и риски озлокачествления.

The cause of leukoplakia is unknown. One specific type is common in HIV/AIDS. It is a precancerous lesion, a tissue alteration in which cancer is more likely to develop. The lesions from a yeast infection can typically be rubbed off while those of leukoplakia cannot. Treatment recommendations depend on features of the lesion. In potentially half of cases leukoplakia will shrink with stopping smoking; however, if smoking is continued up to 66% of cases will become more white and thick.

Leukoplakia could be classified as mucosal disease, and also as a premalignant condition. Although the white color in leukoplakia is a result of hyperkeratosis (or acanthosis), similarly appearing white lesions that are caused by reactive keratosis (smoker's keratosis or frictional keratoses e. g. morsicatio buccarum) are not considered to be leukoplakias. Leukoplakia may also occur in the larynx, possibly in association with gastro esophageal reflux disease. Oropharyngeal leukoplakia is linked to the development of esophageal squamous cell carcinoma, is usually well defined white patch of uniform, flat appearance and texture, although there may be superficial irregularities. "Verrucous leukoplakia" (or "verruciform leukoplakia") is a descriptive term used for thick, white, papillary lesions.<! There is a very high risk of dysplasia, transformation to squamous cell carcinoma with high mortality (PVL does not transform into verrucous carcinoma, which is a lesion with a good prognosis usually; the similarity of names does not reflect the common origin, but only the resemblance of their appearance).

Erythroleukoplakia (also termed speckled leukoplakia, erythroleukoplasia or leukoerythroplasia) is a non homogeneous lesion of mixed white (keratotic) and red (atrophic) color. Erythroplakia (erythroplasia) is an entirely red patch that cannot be attributed to any other cause. Erythroleukoplakia can therefore be considered a variant of either leukoplakia or erythroplakia since its appearance is midway between. although any part of the mouth may be affected. Erythroleukoplakia and erythroplakia have a higher risk of cancerous changes than homogeneous leukoplakia. However, some sources use this term to refer to leukoplakia lesions that become colonized secondarily by Candida species, thereby distinguishing it from hyperplastic candidiasis.

Oral hairy leukoplakia is a corrugated ("hairy") white lesion on the sides of the tongue caused by opportunistic infection with Epstein Barr virus on a systemic background of immunodeficiency, almost always human immunodeficiency virus (HIV) infection.

Leukoplakia of the esophagus is rare compared to oral leukoplakia.<!

In the context of lesions of the mucous membrane lining of the bladder, leukoplakia is a historic term for a visualized white patch which histologically represents keratinization in an area of squamous metaplasia.<!

Leukoplakia of the anal canal is rare. It may extend up to the anorectal junction. On digital examination it feels hard and granular, and at proctoscopy, it appears as white plaques which may be diffuse, circumferential, or circumscribed. The histologic appearance is similar to oral leukoplakia, with hyperkeratosis and acanthosis. It may be asymptomatic, with symptoms due to other lesions such as hemorrhoids or fissures. Progression to anal stenosis has been described. The malignant potential is seemingly low, and few cases of anal carcinoma have been reported associated with anal leukoplaka.

Tobacco smoking or chewing is the most common causative factor, Cigarette smoking may produce a diffuse leukoplakia of the buccal mucosa, lips, tongue and rarely the floor of mouth. This type of leukoplakia has been termed "sanguinaria associated keratosis" and more than 80% of people with leukoplakia in the vestibule of the mouth have used this substance. Upon stopping contact with the causative substance, the lesions may persist for many years. Although this type of leukoplakia may show dysplasia, the potential for malignant transformation is unknown. In vitro experimentation has demonstrated that HPV 16 is capable of inducing dysplastic changes in previously normal squamous epithelium. In another study, DNA damage, also measured by the comet assay, was found to be greater in oral leukoplakia and squamous cell carcinoma than in control subjects.

Leukoplakia is a diagnosis of exclusion, meaning that which lesions are included depends upon what diagnoses are currently considered acceptable. However, this definition is inconsistently applied in the medical literature, and some refer to any oral white patch as "leukoplakia". Severe dysplasia is synonymous with the term carcinoma in situ, denoting the presence of neoplastic cells which have not yet penetrated the basement membrane and invaded other tissues.

The term leukoplakia was coined in 1861 by Karl Freiherr von Rokitansky, who used it to refer to white lesions of the urinary tract. It is now thought that this white lesion on the tongue represented syphilitic glossitis, According to one source from 1961, leukoplakia can occur on multiple different mucous membranes of the body, including in the urinary tract, rectum, vagina, uterus, vulva, paranasal sinuses, gallbladder, esophagus, eardrums, and pharynx.