SMOKELESS TOBACCO KERATOSIS/TOBACCO POUCH KERTOSIS
Author: Sanketh DS, MDS
INTRODUCTION & ETIOLOGY
Tobacco pouch keratosis, as the name implies is a “white, keratotic” lesion whose clinical appearance is “pouch” like and occurs due to usage of “smokeless tobacco”. This habit of using smokeless tobacco, is prevalent among people in countries like United States, Sweden, India and other countries in South-East Asia. Smokeless tobacco in the western countries is used in the form of chewing tobacco, dry snuff or moist snuff. In India and other Asian countries, smokeless tobacco in addition to chewing may be combined with betel leaves, areca nut, lime and other spices.
Smokeless tobacco contains several carcinogens, the most important being N-Nitrosonornicotine(NNN) and there is causal relationship between smokeless tobacco and the oral mucosal changes it may induce. It may cause edema, inflammation and keratosis of the mucosa in contact. These changes may be caused by tobacco constituents, agents added for flavouring as well the high alkaline pH of smokeless tobacco – 8.2-9.3.
Although all forms of smokeless tobacco may induce this lesion, snuff/finely powdered tobacco is much more likely to cause tobacco pouch keratosis.
This lesion usually disappears 98% of the times on cessation of the habit and is generally not associated with oral cancer. However duration of the habit is very important as leukoplakia may develop with a prolonged habitual use of smokeless tobacco pouching for more than 2-3 years.
Although this lesion has not been classified by WHO as an “Oral Potentially Malignant Disorder” some pathologists consider this lesion to have a slightly increased risk of oral cancer.
Lesions develop in mucosal sites directly in contact with the smokeless form of tobacco. Lesion development is influenced by the duration of habit, type of smokeless tobacco and amount of tobacco consumed. The lesion starts of as an altered mucosa that is granular to wrinkled or fissured in appearance. It may look like “sand on a beach after an ebbing tide”. Subsequently it may develop a white keratotic component that may be wrinkled. The lesions are soft on palpation and resemble a “pouch”. These lesions are asymptomatic and are diagnosed during a routine oral examination. Advanced cases become leathery and may sometimes have an erythroplakic component with the white lesion. Tobacco pouch keratosis is most common in the mandibular- labial and posterior buccal vestibule, in relation to the anterior teeth and molars respectively. Additionally, the facial/buccal gingival surfaces of teeth in contact with tobacco may show recession. Dental caries in teeth in direct contact have also been reported probably because of the high sugar content in certain brands of smokeless tobacco. In Indian and South-East Asian population, the lesion may have a brownish-reddish black encrustation. This may be due to the additional components like betel-quid and other spices and could be wiped off with gauze.
Epithelium is hyperkeratotic and acanthotic with intra-cellular vacuolization and edema. Chevrons – pointed projections of parakeratin may be seen in the corneal layer. There may be a mild inflammatory infiltrate and an amorphous eosinophilic deposition may sometimes be noted in the subjacent connective tissue. Epithelial dysplasia is absent and if very rarely present is usually mild.
These lesions are fortunately not potentially malignant and most lesions regress on discontinuation of the habit, usually within 2 weeks. These lesions also have a distinct clinical appearance and biopsy is usually not needed, unless lesions appear atypical. A suspect tobacco pouch keratosis that persists for more than 2-4 weeks even after abstaining from the habit should be reconsidered as a true leukoplakia and a biopsy must be performed managed accordingly. Long-time exposure to smokeless tobacco, lasting decades may induce formation of squamous cell carcinoma or even verrucous carcinoma.
Shafer’s Textbook of Oral Pathology. Rajendran and Sivapathasundaram.6th Edition.
Oral and Maxillofacial Pathology.Neville,Damm,Allen,Chi. South Asian Edition.
Oral Pathology: Clinicopathologic correlations.Regezzi,Sciubba,Jorda.5th Edition.
OTHER (HACKDENTISTRY) PRACTICE/STUDY RESOURCES