White Lesions That Cannot Be Scraped Off

Question 1

Linea alba ***

Question 2

Leukoplakia ***

Answer 2

WHO definition: white plaque that is of questionable risk for oral cancer and only can be diagnosed once having excluded other known diseases. The term is strictly a clinical one and does not imply a specific histopathologic tissue alteration — represents a diagnosis of exclusion.

Question 3

Why are white lesions white?

Answer 3

The colour results from a thickened surface keratin layer; or a thickened spinous layer, which masks the normal vascularity [redness] of the underlying connective tissue.

Question 4

Leukoedema ***

Answer 4

Primarily in blacks; milky white alteration of buccal mucosa bilaterally; disappears when stretched

Question 5

White-coated tongue ***

Question 6

Lichen planus **

Answer 6

The strange name of the condition was provided by the British physician Erasmus Wilson, who first described it in 1869. Lichens are primitive plants composed of symbiotic algae and fungi. The term planus is Latin for flat. Wilson probably thought that the skin lesions looked similar enough to the lichens growing on rocks to merit this designation. Even though the term lichen planus suggests a flat, fungal condition, current evidence indicates that this is an immunologically mediated mucocutaneous disorder.

• Reticular
• Erosive
• Bullous — If the erosive component is severe, epithelial separation from the underlying connective tissue may occur. This results in the relatively rare presentation of bullous lichen planus.

The histopathologic features of lichen planus are characteristic but may not be specific, because other conditions, such as lichenoid drug reaction, lichenoid amalgam reaction, lichenoid foreign body gingivitis, oral graft-versus-host disease (GVHD), lupus erythematosus (LE), chronic ulcerative stomatitis, oral mucosal cinnamon reaction, and the incipient phase of proliferative verrucous leukoplakia may also show a similar histopathologic pattern. Varying degrees of orthokeratosis and parakeratosis may be present on the surface of the epithelium, depending on whether the biopsy specimen is taken from an erosive or reticular lesion.