Monarch Disease Ontology term MONDO_0004844 (oral mucosa leukoplakia) is a white patch or plaque on the oral mucosa that cannot be characterized clinically or pathologically as any other disease. The diagnosis of leukoplakia is one of exclusion; other conditions such as candidiasis, lichen planus, leukoedema, etc., must be ruled out before a diagnosis of leukoplakia can be made. Leukoplakia may be a premalignant condition. Also known as: leukokeratosis of oral mucosa, leukoplakia of oral mucosa, leukoplakia of the oral mucosa, oral keratoses, oral keratosis, oral leukoplakia.