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Oral mucosa leukoplakia

Oral leukoplakia (OLK) is a clinically common disease in the department of dentistry. It is manifested as white plaques that cannot be wiped off from the oral mucosa. It belongs to precancerous lesions and has the potential to transform into oral squamous cell carcinoma. The definition of the term "white spot" or term has been controversial for many years, and so far no consensus has been reached. In 1978, the WHO formulated a clearer definition of OLK for the first time, and revised the definition in 1983. The definition and diagnostic criteria of white spots are: OLK is a white plaque that occurs on the oral mucosa. It cannot be diagnosed clinically and histopathologically as other diseases. It should not include the tobacco-induced hyperkeratosis of the epiphysis and other local irritating factors. Simple hyperkeratosis, also pointed out that the disease is a precancerous lesion.

Overview of oral leukoplakia

Oral mucosa leukoplakia China s "Two Diseases" (oral leukoplakia and oral lichen planus) prevention and research collaboration group was modified in 1983 according to the definition of WHO: OLK is a white keratinized plaque that occurs on the oral mucosa and belongs to precancerous lesions, excluding smoking Simple hyperkeratosis that can be resolved after local stimulus is removed. The definition clarifies two points: clearly pointed out that OLK is a precancerous lesion; clearly excluded a large class of white keratosis caused by local physical and chemical factors.

At present, most scholars believe that OLK and oral benign hyperkeratosis (OHK) are two types of white lesions of oral mucosa with completely different properties. The former are precancerous lesions with varying degrees of epithelial hyperplasia; the latter are benign lesions with hyperkeratosis, but without epithelial hyperplasia, and have clear pathogenic factors such as smoking. After removing the cause, the damage can be reversed . The two should be strictly separated to facilitate the guidance of research and clinical work, while also alleviating the mental burden of most patients with keratosis albicans and increasing people's vigilance against OLK.

Pathogenesis of oral leukoplakia

The occurrence of oral leukoplakia is related to long-term stimulation of local factors and certain systemic factors.

1. Physical and chemical stimuli such as smoking

Epidemiological investigation shows that the incidence of white spots is proportional to the length of smoking history and the amount of smoking. The number of cigarettes smoked per day * the number of years of smoking is> 400, and the risk of white spots increases. In addition, there are differences in the types of cigarette products and the incidence of leukoplakia. The order from high to low is: dry tobacco> paper tobacco> hookah; domestic scholars can use cigarette smoke stimulation or direct application of tobacco extract and mucous membranes Animal models of white spot have confirmed that smoking is closely related to the onset of white spot.

Local physical and chemical stimuli such as drinking hard alcohol, eating hot or hot and sour foods, and chewing betel nuts are also related to the occurrence of white spots.

2. Candida infection

An epidemiological investigation showed that the detection rate of Candida albicans in oral leukoplakia was about 34%. Among them, Candida albicans and Candida tropicalis may be closely related to the occurrence of white spot. At the same time, it is certain that the white spot with Candida albicans infection-"white spot" is prone to malignant changes.

3. Systemic factors

Including trace elements (including manganese Mn, strontium Sr, calcium Ca), changes in microcirculation, susceptible genetic qualities, and lack of fat-soluble vitamins (vitamin A deficiency causes excessive keratinization of mucosal epithelium).

Clinical manifestations of oral leukoplakia

The local clinical manifestations of OLK damage are mainly white plaque lesions on one or more oral mucosa, which can occur anywhere on the oral mucosa, but the most common are buccal, tongue, and lip. Because the clinical manifestations of white spot disease vary widely, and the treatment and prognosis of various manifestations are not the same, in order to facilitate diagnosis, treatment and observation, it is necessary to carefully type or classify white spot disease.

For the classification of white spot disease, scholars at home and abroad have many different classification methods for many years. Banaczy classifies the local manifestations of OLK into three types: simple, verrucous, and ulcerous; Pinborg advocates that OLK can be divided into homogeneous and granular types, while domestic Li Huiyi divides OLK into plaque and granular Type, wrinkled paper and wart type 4.

Based on the comprehensive research results of the "Two Diseases" collaborative group in China, OLK is divided into the following 4 types:

1. Simple type (also known as homogeneous type) is a white patch with a slightly rough surface, wrinkled paper or grooved, asymptomatic or mild discomfort.

2. The wart-like type is milky white, thick and raised, the surface is uneven, thorn-like or fluff-like protrusions, rough, slightly hard, and may have discomfort.

3. Granular type On the hyperemic or red mucosa, there are white keratinized particles or nodules of various sizes above the mucosal surface, which can be accompanied by erosion and can cause irritation and pain.

4 The ulcerative type is on white plaques, with erosion or ulcers, often accompanied by spontaneous pain.

From the proportion of the above 4 types, the simple type accounts for the majority, followed by the wart type, while the granular and ulcer types are less, and the homogeneous, granular, and wart types may evolve. Into ulcer type.

White spot cancer of oral mucosa

Leukoplakia is a precancerous lesion with potential for malignancy. At present, white spot canceration has been confirmed, but the proportion is not too high. Therefore, it cannot be considered that white spots must be cancerous. According to research data reported by the WHO and China, the canceration rate of leukoplakia is mostly around 3% -5%.

What kind of leukoplakia should be paid close attention to clinically? What kind of leukoplakia is more dangerous? The following situations and problems are worthy of reference.

(A) clinical types

The tendency of white spot malignancy is closely related to the clinical type. Usually homogeneous type is not easy to malignant, wart-like type is easy to malignant, and granular and ulcer type have higher rates of malignant change. Pay special attention to watch out for its evil changes.

(Two) lesions

White spots can occur in any part of the oral mucosa, but there are three areas in the mouth: floor of the mouth-abdomen of tongue (including the narrow tongue margin); triangular area of buccal mucosa in the corner of the mouth; soft palate complex (including soft palate -Anterior pharynx column-posterior molar back pad) is the dangerous area of OLK, and it is a dangerous place that is prone to malignant changes. Therefore, we must be especially vigilant of white spots in these areas to prevent malignant changes.

(III) Smoking

Generally, those who smoke for a long time and smoke a large amount are more likely to develop white spot cancer.

(IV) Histopathology

Pathological examination showed epithelial dysplasia, and the white spots were more prone to canceration. Epithelial dysplasia is usually divided into mild, moderate, and severe three, with a higher rate of carcinogenesis in severe cases.

(5) Candida albicans infection

Many scholars have noticed the adverse effects of Candida albicans infection in the occurrence of white spot and cancer, and believe that when white spot combined with Candida albicans infection, there is a greater tendency to malignancy.

(6) White spots without obvious cause

It was clinically found that some white spots without obvious external causes were mainly related to internal factors. Such as immune factors, endocrine factors and so on. Relatively speaking, this kind of so-called sudden leukoplakia is more likely, so it is necessary to pay special attention to this kind of patients, especially for female patients with unknown causes, especially to prevent their occurrence.

(VII) Lesions

Patients with longer lesions, more severe symptoms, and irritating or spontaneous pain should also be given sufficient attention.

Differential diagnosis of oral leukoplakia

At present, the diagnosis of white spot disease is not very difficult. Based on the clinical manifestations and histopathological changes, a clear diagnosis can usually be made. However, due to the large number of white lesions that occur on the oral mucosa, white spots should be prepared. The differential diagnosis of the disease is still very necessary and meaningful. White spot disease should be distinguished from the following diseases.

(A) white edema

White edema (1eukoedema) is a developmental white lesion. Its clinical characteristics are that the lesions mostly occur on the cheek mucosa, which is thickened and whitish, translucent, soft and elastic. During the examination, if the mucosa of the lesion is compressed, the white color can be temporarily eliminated. The disease usually does not have any conscious symptoms. Histopathological manifestations are mainly thickened epithelium, but the surface layer is not keratinized, and the epithelial cells are

There is obvious intracellular edema. The disease does not require treatment.

(B) ectopic sebaceous glands

The disease, also known as Fordyce disease, is formed by the ectopic sebaceous glands on the oral mucosa. The clinical manifestations of the disease are many small yellow-white spots or small granular papules scattered on the mucosa, ranging from needle-like to miliary size. And lip mucosa. The disease has no symptoms, is not harmful to health, has no clinical significance, and requires no treatment.

White keratosis (1eukokaratosis) is a hyperkeratosis of the oral mucosa caused by obvious physical and chemical or mechanical factors. The clinical manifestations are white plaques on the mucosa, pale white, smooth surface, soft base, and mucosa. The elasticity is normal. After removing the pathogenic factors, the lesion will gradually reduce or heal. The main pathological manifestations are hyperkeratosis of the epithelial surface and thickening of the spinous layer, but there is no atypical hyperplasia of the epithelium. The disease is a benign lesion.

(D) white fold disease

White fold disease, also known as whitespongenevUS, is a familial hereditary disease. It is a milky white, wrinkled, thick plaque lesion that occurs on the oral mucosa and often has a family history. The disease can also occur in the mucosa of other parts, such as the esophagus, vagina, anus, and so on. Histopathological features are marked thickening of the epithelium, incomplete keratosis, edema in the epithelial cells, and vacuole degeneration, but the basal layer is intact. The disease is a degenerative change, has no tendency to malignant change, is not a precancerous lesion, and is asymptomatic without treatment.

(E) Candidiasis albicans

Oralcandidiasis mainly refers to chronic proliferative candidiasis. This is because when infected with Candida albicans, the fungus can penetrate the plasma membrane of the epithelial cells and enter the cells, causing the epithelial cells to proliferate and form white spot lesions. Its clinical characteristics are tight, firm white plaques that cannot be wiped away, clear boundaries, harder texture, and rough feel. There are often inflammatory reactions below and around the plaques, which mostly occur in the buccal mucosa. Mycelia can be found during clinical smear examinations. Biopsy can detect hyphae in the epithelium, and microabscesses are formed in the superficial epithelium. Antifungal treatment is usually effective.

(6) Oral Lichen Planus

Oral leukoplakia should be mainly distinguished from plaque-type lichen planus. Oral lichen planus (OLP) occurs mostly on the back of the tongue. It is similar to white spots. It is clinically manifested as a pearly white plaque connected by a uniform nipple. Usually there are no cracks or cracks on the surface. White streaks or hyperemic erosion, the streaks are mostly reticular or dendritic, and some patients may be accompanied by skin damage. The pathological manifestations of the disease are mainly liquefaction degeneration of the epithelial basal cells, dense zonal lymphocyte infiltration in the lamina propria, and the white spot does not have this disease characteristic in the tissue.

(VII) Submucosal fibrosis

Oral submucous fibrosis is a chronic progressive disease of unknown cause, which is mostly related to factors such as chewing betel nut. The disease is a precancerous lesion. Its clinical manifestations are pale white, cloud-like plaques in the oral mucosa, and fibrous cords can be touched under the mucous membranes, which are more common in the cheeks, with oral pain, burning sensation, taste disorders and dry mouth.

Due to the progressive aggravation of fibrosis in the later stage, it can lead to different degrees of dysfunction, such as closed teeth, difficulty in opening the mouth, and restricted tongue movement. The pathological changes are mainly epithelial atrophy, sometimes thickening, etc., often with atypical epithelial hyperplasia, collagen fibrosis or hyperplasia under the epithelium, and chronic inflammatory cell infiltration in the dermis.

(8) Cheek White Line

1ineaalbabuccalis refers to the gray-white linear bulge that appears in the cheek mucosa. It is a tissue reaction caused by the continuous stimulation of the cheek mucous membrane during chewing. It is common in adults. Its clinical characteristics are that the white line corresponds to the occlusal line. The outer line of the white line is smooth, soft and elastic. During the occlusal line, the linear bulge is located on the occlusal surface and extends backward from the mouth corner to the front of the mandibular ligament . The line is normal and usually has no symptoms and does not require treatment. Its histological characteristics are mainly epikeratosis.

In addition, white spots need to be distinguished from diseases such as map tongue and discoid lupus erythematosus.

Pathological changes of oral leukoplakia

White spot is a clinical diagnosis name. The definition by the WHO Collaborative Center for Oral Precancerous Lesions does not include histological implications. However, in the determination of treatment options and prognosis for white spot disease, pathological changes are indispensable. At present, the diagnosis of leukoplakia, especially the judgment of its malignant tendency, has been reported in the fields of histochemistry, histoimmunology, cell dynamics, ultrastructure, exfoliated cytology, and hematoporphyrin fluorescence. Stage, there is still a long way to go before practical application. Therefore, the most reliable and simplest method is to observe the pathological changes of tissue under light microscope.

The general pathological changes of white spots are excessive orthokeratosis of the epithelium. The granular layer is obvious, the spinous layer is thickened, and the epithelial spike is larger. Connective tissue is infiltrated with varying numbers of inflammatory cells. Verrucous leukoplakia is characterized by thickened epithelium, highly hyperkeratotic surfaces, and horny embolisms that make the surface thorn-shaped. The epithelium of ulcerative leukoplakia is damaged to form ulcers. But according to the degree of epithelial proliferation and disorder, the pathological changes of leukoplakia can be divided into two cases.

(1) Simple epithelial hyperplasia There are no abnormal epithelial cells during simple epithelial hyperplasia. The excessive cornering of the surface may be excessively positive cornering and / or excessively incomplete cornering. Infiltration of inflammatory cells in connective tissue. Generally, homogeneous leukoplakia mostly belongs to this pathological change. The pathological changes of white keratosis are pure hyperplasia, and the surface layer is mostly hyperkeratosis, which cannot be classified as a precancerous lesion.

(2) Epithelial hyperplasia If the histological changes of white spots have abnormal epithelial hyperplasia, there is a greater tendency for malignant transformation. According to the World Health Organization Collaborative Center for Oral Precancerous Lesions, there are 12 diagnostic criteria for abnormal epithelial hyperplasia: polar changes of basal cells; irregular epithelial layering and disorderly arrangement; proliferation of basal layer with multiple basal cells; Epithelial studs are drip-like; zygomatic nucleus increases, silk content increases, and sometimes there are abnormal silks; zygomatic nucleus-to-plasma ratio increases; dystrophic nucleus increases; dysfunction of nucleus dysfunction; increase of nucleus nucleus; polymorphism of nucleus cells , Heteromorphism; single cells or cell cluster keratinization in the sacrospinous layer; loss of intercellular adhesion. Two of the above changes were mild dysplasia, 2 to 4 were moderate dysplasia, and 5 or more were severe dysplasia.

Although WHO has made the above regulations, in fact, the extent of lesions and the frequency and degree of lesions in each case are not the same when reading the film. Coupled with the different subjective impressions and experiences of pathologists, it is difficult to evaluate the exact degree of epithelial hyperplasia. At the conference on precancerous lesions of oral mucosa held in Maim6, Sweden in 1983, Smith and Pindborg proposed a standard image method to modify the evaluation criteria. That is, the subjective evaluation of epithelial dysplasia is replaced by photography and computer calculations. In addition, Kramer proposed that a mathematical model be developed when evaluating the degree of epithelial hyperplasia. And not just to evaluate epithelial dysplasia, but also include clinical findings and all other test results. Although this can increase the accuracy of evaluating the malignant trend of a lesion, it still cannot completely eliminate the subjective difference in diagnosis. In recent years, research on quantitative pathology has been carried out. Using some new technologies, the morphological changes of tissues and cells and changes in certain substances such as DNA content are measured by images and photometric methods to obtain quantitative information. Comprehensive analysis can obtain an accurate diagnosis of cancerous conditions.

Oral mucosa leukoplakia treatment method

There are different opinions on the treatment methods and measures of oral white spot disease. However, in general, any type of white spot should be treated early and actively, and observed during treatment. As for the specific treatment method, it should depend on the specific situation of the patient.

The treatment of leukoplakia has the following aspects:

(1) Remove all pathogenic factors

Physicochemical or mechanical stimulation is one of the important reasons for inducing white spots in the oral cavity. Therefore, removing all the stimulating factors is the first and cannot be ignored method for treating white spots.

1. Abstain from all bad habits and hobbies, including abstaining from alcohol and tobacco, refraining from eating hot foods and eating less spicy foods, and correct unilateral chewing habits.

2. Sharpen the sharp edges of teeth, remove residual roots, residual crowns, dislocations and non-functional teeth, and also remove or modify bad restorations to eliminate local irritants.

3 Adjust the metal restoration that generates the current. It is generally believed that early replacement of the metal prosthesis that caused the current can reverse the lesion.

(B) local drug treatment

1. Vitamin A can be injected subcutaneously under local mucosa. Cob liver oil can also be used for topical rubbing or application to treat leukoplakia, which has a certain therapeutic effect.

2. Retinoic acid drugs have better efficacy and local safety in the treatment of leukoplakia, and should be treated at a low concentration, not too high, to reduce adverse reactions, generally from 0.05% to 0.2%. Usually this medicine is only suitable for the conservative treatment of homogeneous or part of wart-type leukoplakia, and is not suitable for the treatment of granular and ulcerative types.

3.5-Fluorouracil (5-FU) is usually applied topically with 5% ointment, twice a day. It has a certain effect, and the drug is discontinued when the lesion disappears.

4 Some white spots of antifungal drugs are closely related to Candida albicans infection. Therefore, for patients with white spot combined with Candida albicans infection, local treatment with antifungal drugs can often improve the efficacy. At present, nystatin, amphotericin, B tablets or clotrimazole are commonly used in mouth, and can also be used with 2% -4% sodium bicarbonate or 0.2% chlorhexidine solution.

5. In addition, certain therapeutic effects can also be obtained by using local treatment methods such as propolis film, blood circulation and blood stasis film, and iontophoresis drugs.

(Three) systemic drug treatment

1. Vitamin A plays an important role in regulating the normal development, growth and differentiation of epithelial tissue. Supplementation of Vitamin A can make hyperkeratosis subside. The usual dose is 25,000 U orally, 2-3 times a day, and the course of treatment is 1-2 months.

2. Retinoic acid drugs These drugs interfere with carcinogenesis, can prevent the occurrence of epithelial cancer, and can delay or stop or even reverse the precancerous cells into cancer cells. In addition, they also maintain the integrity of the structure and function of epithelial cells, and The formation of keratinization is suppressed. In clinical use, the initial dose should be small, 5mg each time, 2-3 times a day, after one week the dose can be gradually increased to 30-60mg daily, divided into 3 times, 1 to 2 months as a course of treatment, effective You can stop taking the medicine for one month before starting the second course of treatment. Pay attention to the occurrence of adverse reactions and contraindications during use. Because the drug has a lot of adverse reactions when taken orally, and there is a considerable recurrence rate after discontinuation, it is currently advocated for topical external use.

3 Other patients with anemia combined with anemia can be treated with vitamin B12. Lip and tongue damage can be treated with vitamin B supplementation. In addition, estrogen treatment is still available.

(D) surgical treatment

Surgical removal of leukoplakia has better curative effect. It is a commonly used and effective method for treating leukoplakia. Especially for those cases with atypical hyperplasia, it should be immediately removed as much as possible, and patients should be followed up for observation. Generally, surgical treatment can achieve good results only when it is combined with the removal of stimulus factors. The stimulus factors include external factors and intrinsic factors. Although surgical resection is effective, it is more complicated, the injury is large, and there is a certain recurrence rate, so it should be appropriately selected according to the condition.

(Fives). Cryotherapy

Cryotherapy is also one of the methods for treating white spots. This is mainly because the oral mucosa is superficial, relatively soft, with a moist surface and low tissue density, which is better for cryotherapy. This method often uses liquid nitrogen and has a certain effect, but it has the disadvantages of not being able to obtain specimens for pathological examination and slow wound healing of patients, and the problems of recurrence and canceration after treatment should also be considered.

(Six) radiation therapy

Radioactive isotope phosphate application is usually used for contact irradiation treatment, causing deep inflammation involving the entire epithelium of the disease. However, its use is still controversial as it may promote the malignant changes of white spots.

(VII) Chinese medicine and traditional Chinese medicine treatment

Chinese medicine believes that white spot is a local manifestation of a systemic disease. Its main etiology and pathogenesis are qi stagnation and blood stasis, sputum condensation and dampness, and weakness of the righteous qi. Humidification and so on.

In summary, the principles for the treatment of leukoplakia are summarized as follows:

1. Leukoplakia should be actively treated as early as possible, and the removal of all causative factors is the first and most important treatment method and the basis for successful treatment.

2. Conservative treatment of homogeneous leukoplakia can be used, but its malignant changes should also be guarded against, and biopsy should be done in time when there are suspicious cancerous manifestations in the clinic to understand the changes in the condition.

3. For granular and ulcerative leukoplakia, surgery should be performed immediately, and all lesions should be removed and biopsied; for verrucous leukoplakia and leukoplakia in three dangerous areas, which have not improved after 1-2 months of conservative treatment, surgical removal and Biopsy.

4 The white spots that have been surgically removed should be reviewed regularly after surgery; the cured white spots should be regularly reviewed because of the possibility of recurrence. According to the specific situation, review once every six months or so in order to detect problems early and actively treat them.