What is the most common premalignant lesion in the oral cavity?

• A. Erythroplakia.
• B. Lichen planus.
• C. Leukoplakia.
• D. Geographic tongue.

Answer: (C)

Leukoplakia is the most common premalignant lesion in the oral cavity. It presents as a white patch or plaque that cannot be rubbed off and can’t be explained by another diagnosable condition. This condition is commonly linked to risk factors like tobacco, alcohol, or other irritants, and it may show dysplasia on microscopic exam, which means there’s a potential for progression toward squamous cell carcinoma if left unaddressed.

Erythroplakia, while it carries a higher risk of malignant transformation, is much less common than leukoplakia. Lichen planus can affect the oral mucosa and has some associated malignant potential, but it is not as prevalent as leukoplakia for premalignant changes. Geographic tongue is a benign mucosal variation with no premalignant significance. So the white, non-scrapable patch—leukoplakia—fits best as the most common premalignant oral lesion.