Leukoplakia is a white patch or plaque-like oral precancerous lesion which has a tendency for malignant transformation. This condition affects the surfaces covered by the mucous membranes in the human body. It is more commonly seen in the mouth which is called Oral leukoplakia. It can also affect the gastrointestinal tract, urinary tract and the genitals.
The World Health Organization defines Leukoplakia as a whitish patch or plaque that cannot be characterized clinically or pathologically as any other disease and is not associated with any physical or chemical agent except the use of tobacco.
The Leukoplakic lesion cannot be scraped off. Although the chances of the transformation of Leukoplakia into cancer are very less, accurate diagnosis and treatment to prevent the risk of progression to carcinoma are mandatory.
Leukoplakia occurs more commonly in adults who are above 30 years of age. It is also more common in males than in females.
The most common sites of the appearance of this condition in humans are the buccal mucosa, sulcus area, lips, and gingiva. The floor of the mouth, palate and the tongue are less frequently involved.
Leukoplakia Causes: What Are the Risk Factors Involved?
There are numerous factors which can cause leukoplakia. Few of the important ones are as follows.
This is one of the main causative factors that induce lesion in humans. Use of tobacco, either by smoking, chewing or in the form of snuff /inhalation is closely related to the incidence of Leukoplakia.
In India, the most common form of tobacco use is in the form of paan chewing. Paan is a mixture of tobacco with areca nut, lime and betel leaf.
The leukoplakic lesions are most commonly seen in highly addicted paan chewers. In smokers, the chances of getting Leukoplakic disease also depends on the dosage of tobacco and the duration of use. It has also been observed that on cessation of smoking, the condition usually resolves either partially or completely.
Chronic alcoholics are another category of people who are known to suffer from Leukoplakic conditions. However, alcohol use alone is not known to cause this condition. When a person uses tobacco along with alcohol for many years, he or she may end up getting Leukoplakia due to the synergistic effect of alcohol with tobacco use.
Vitamin deficiencies like Vit A, Vit B12, and folic acid deficiencies have been associated with premalignant epithelial changes as seen in Leukoplakia.
Local irritating factors like the sharp edge of a broken tooth or a denture, sharp edge of a prosthetic clasp, etc, may irritate the oral mucosa causing ulcerations. This, when left untreated, may progress to leukoplakia.
Candida albicans, a yeast-like fungus which occurs in the normal flora of the mouth, is usually associated with leukoplakia. This condition is known as candidal leukoplakia and hyperplastic candidiasis. The epithelial changes with candidal leukoplakia are comparatively more than in leukoplakia.
Ultraviolet radiation is also a risk factor known to be associated with the condition. Sunlight ( with the UV rays in it) is a known causative agent of leukoplakia of vermillion border of the lower lip.
Leukoplakic lesions are also seen in patients suffering from syphilis.
Viruses such as Human papillomavirus and herpes virus have been associated with the lesion. Patients with HIV have been diagnosed with Hairy leukoplakia which is a benign form of the lesion.
The extract of the herb sanguinaria found in some toothpaste or mouthrinses is also known to cause leukoplakia in some people.
Types and Clinical Features of Leukoplakic Lesions
This is a low-grade reaction of the mucosa resulting in a greyish color lesion with a slight globular pattern and without a distinct border.
The lesions in this type are well defined white patches which are either fine, grainy, wrinkled or papillomatous in appearance. They have a low risk of malignant transformation.
These are of the following types.
The lesions are mixed white and red in which there are small white keratotic nodules spread over the reddish atrophic mucosa.
These lesions are often associated with pain or discomfort. They have a high risk of malignant transformation.
This is a form of leukoplakia where the causative factor is not known.
Proliferative verrucous leukoplakia
This is an aggressive form of idiopathic leukoplakia where the lesion has a high rate of malignant transformation.
This lesson is mainly seen in patients with HIV and Epstein Barr virus infection. The white lesion is found on the lateral surface of the tongue with corrugated projections. These are benign lesions.
Other Common Features
- These lesions can occur on any mucosal surface in the body.
- Usually, they are painless except in case of Non-homogenous leukoplakia
- Older the person more chances of getting the lesion.
- These lesions appear less frequently on the palate, tongue and the floor of the mouth. But if they appear on these sites, they have a higher chance of turning into a malignancy.
Histopathology of leukoplakic lesions
The leukoplakic lesion under the light microscope may show different types of cellular changes like epithelial hyperplasia and hyperkeratosis.
Epithelial dysplasia may be present or absent. However, the degree of epithelial dysplasia may range from mild to severe depending on the type of lesion.
A thorough clinical examination will be done and the past medical history will be recorded by the doctor.
The doctor may look for the following at this phase of medical investigation.
- Existence of an irritating local factor
- Habits like smoking, paan chewing, alcohol, etc.
- Screening for systemic factors
The definitive clinical diagnosis of leukoplakia can be done by the doctor only after ruling out other white lesions.
Taking a biopsy of the lesion is a standard rule to get the final confirmation of the type of leukoplakic lesion affecting the person. This is also necessary for formulating the treatment plan accordingly.
The treatment for Leukoplakia may involve the following.
- Surgical excision of the lesion can be done.
- Cryosurgery is useful in case of large lesions.
- Laser surgery using CO2 and Nd: YAG lasers are being used in recent times.
- Retinoids which are artificial analogs of vitamin A have been used for local application.
- The doctor will treat the local irritating factors if any.
- If in a person the leukoplakic lesions are a result of underlying systemic condition, the causes need to be treated first.
Prognosis and Follow Up
Once the surgical excision of the lesion has been done, regular follow up is compulsory because of the higher recurrence rate of Leukoplakia. Sometimes additional leukoplakic lesions may also develop.
People with tobacco and alcohol use may need to go for counseling to get help in stopping the habit.
Repeated follow-up visits and biopsies may be needed, more so when the complete elimination of irritants/causative agents are not likely to be achieved. In such patients, total removal may be a better idea.