Oral leukoplakia Oral leukoplasia Oral idiopathic white patch SNOMEDCT_US:414603003 UMLS:C0023532 SNOMEDCT_US:9187004 A thickened white patch on the oral mucosa that cannot be rubbed off. The definition of oral leukoplakia states that the lesion be characterized clinically or histologically as any other condition, and is not associated with any physical or chemical causative agent except tobacco. Leukoplakia is a precancerous lesion, i.e. a morphologically altered tissue in which cancer is more likely to occur than in its apparently normal counterpart. Oral idiopathic leukoplakia leukokeratosis UMLS:C1704317 HP:0002745 Oral white patch Oral idiopathic keratosis Oral leucoplakia Oral leukokeratosis Oral white plaque White lesion of the oral mucosa