Leukoplakia

US government source image

Leukoplakia is also called keratosis.  This means that it is composed of keratinized tissue.  Keratin is a protein that is found in normal skin.  It is tough and leathery and not easily scraped off the underlying tissue as are Candida plaques, with which it is most often confused.  It forms in response to chronic irritating stimuli, like a callus found on the skin.  Keratosis is not generally found on the oral mucosa.  The irritating stimulus may come in many different forms. 

Ordinary, chronic mechanical abrasion can cause the mucosa to produce keratinized tissue.  It is commonly found on edentulous ridges (the "gums" where there are no teeth) in response to chewing constantly on them.    It is also produced in response to noxious stimuli such as constant exposure to irritating chemicals and tobacco smoke. 

When the leukoplakia is in response to constant exposure to noxious stimuli such as tobacco smoke, the presence of patches like the one above is considered pre-cancerous since squamous cell carcinoma often arises within them.  On the other hand, if the stimulus ceases before cancer arises within it, the leukoplakia will disappear over the course of a month or two.

US government source image

The image above shows a case of erythroplakia located on the oral mucosa just inside the corner of the lip.  Erythroplakia is a form of keratosis that appears red and is generally found in combination with, and most frequently embedded in a leukoplakic plaque.  It is also pre-cancerous, and is considered more likely to contain areas of dysplasia, which are areas where transformation to cancer is taking place.

Copyright 2006 Martin S. Spiller, D.M.D. courtesy of Dr. Ed Cataldo

The above image shows severe leukoplakia under the tongue.  Remember that this lesion is tough and leathery, and not easily scraped off.

Copyright 2006 Martin S. Spiller, D.M.D. courtesy of Dr. Ed Cataldo

The image above shows leukoplakia with embedded areas of erythroplakia.  In this case, the areas of erythroplakia show dysplastic activity under the microscope.  In other words, these areas are transforming into squamous cell carcinoma.  The whitish area extending to the right is on the soft palate, and has the appearance of nicotinic stomatitis, which does not generally transform into squamous cell cancer.  The "lump on the left is the tuberosity which shows considerable keratosis.  Beneath the tuberosity is the retromolar area which contains the most dysplastic tissue.  it is red and mottled.

Copyright 2006 Martin S. Spiller, D.M.D. courtesy of Dr. Ed Cataldo

This is leukoplakia associated with pipe smoking and eating hard foods on edentulous (toothless) ridges.  it builds in response to a combination of the stimulation of eating hard foods on the edentulous tissue, and the irritation of the tobacco smoke.