Leukoplakia

Leukoplakia - leukokeratosis, manifested as milky-white spots on the mucous membranes covered with multilayered flat epithelium (oral cavity, vagina, red lip rim), develops as a result of local irritant factors, as well as inflammatory phenomena. There are three clinical varieties of leukoplakia: flat, erectile and erosive-ulcerative.

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Flat leukoplakia

Flat leukoplakia is characterized by sharply outlined, different sizes and shapes of keratinized gray areas, usually without condensation, which do not rise above the surrounding mucous membrane, which are difficult to remove mechanically. At histological examination, acanthosis with parakeratosis is found in the lesions, and in the stroma - edema with the presence of merging perivascular polymorphic cell infiltrates.

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Veracious leukoplakia

Verruccus form of leukoplakia is a plaque, bumpy or warty foci of gray-white color, slightly dense, protruding above the surrounding mucosa, sometimes developing against a background of flat leukoplakia. Histologically, a pronounced hyperkeratosis without loosening of the horny layer is detected, the granular layer consists of 3-6 rows of cells with well-defined granularity, acanthosis with uneven epidermal outgrowths. The outgrowth of the thorny layer is thickened, in some groups of cells - intracellular edema. In the dermis - edema, vasodilation and perivascular lymphocytic infiltrates. On the mucous membrane of the cheeks, parakeratosis, sometimes hyperkeratosis, exocytosis and more pronounced infiltrates in the stroma are more often noted.

Erosive-ulcerative leukoplakia

The erosive-ulcerative form of leukoplakia is clinically characterized by the presence of single or multiple erosions of various sizes, usually occurring against the background of the cornified foci of flat leukoplakia. At a histological examination, an epithelial defect is found, along the edges of which acanthosis is found with an elongation of epithelial outgrowths, parakeratosis and exocytosis. In the stroma - pronounced inflammatory changes accompanied by hyperemia and edema, as well as the appearance of diffuse infiltrates from lymphocytes with an admixture of plasmocytes and tissue basophils.

A. Burkhardt and G. Seifert (1977) distinguish between benign, precancerous and cancerous forms of leukoplakia. In the benign form of leukoplakia, acanthosis, hyperkeratosis, and a clear basal membrane are found; there is no cellular atypia. Inflammatory phenomena are poorly expressed. Precancerous changes in the epithelium of the mucosa during leukoplakia go through three stages. In the first stage there is a discomplexation in the basal and suprabasal layers of the epidermis with insignificant cellular atypia. In the second stage, the distribution of foci of atypia is observed throughout the thickness of the epidermis with the phenomena of dyskeratosis and pronounced parakeratosis. In the third stage, the epithelium sharply thickens (acanthosis), cell polymorphism, dyskeratosis and parakeratosis with erosion spots are expressed. Accordingly, inflammatory phenomena are intensified, accompanied by dense infiltration of lymphocytes with an admixture of plasmocytes and numerous Roussel bodies.

Differentiating benign and precancerous leukoplakia is very difficult, because between them there are often transitional forms. Differential diagnosis must also be carried out with benign reactive epidermal hyperplasia, for example, in candida mucosa of the oral cavity.

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