<prompt> All of the following lesions of the oral cavity are premalignant except-ErythroplakiaHyperplastic candidiasisSideropeniaAphthous ulcer  <response>: Ans. is d i.e., Aphthous ulcer Lesions with increased risk of malignancy Premalignant condition: - Leukoplakia, Erythroplakia, Speckled erythroplakia, chronic hyperplastic candidiasis. Conditions increasing risk: - Oral submucous fibrosis, syphilitic glossitis, sideropenic dysphagia Peterson Kelly syndrome. Risk is doubtful: - Oral lichen planus, DLE, Dyskeratosis congenita. Not premalignant:- Aphthous ulcers. 