Table 1.

Histopathologic features of oral epithelial dysplasia

	Proposed criteria	WHO criteria
Architectural features	Corrugated/verrucous/papillary morphology Hyperkeratosis and epithelial atrophy Bulky squamous proliferation, exophytic/endophytic growth Skip segments and demarcated hyperkeratosis Drop-shaped rete ridges	Irregular epithelial stratification Loss of polarity of basal cells Drop-shaped rete ridges Increased number of mitotic figures Abnormally superficial mitotic figures Premature keratinization of single cells Keratin pearls within rete ridges Loss of epithelial cell cohesion
Organizational features	Loss of upward maturation in the epithelium Dyscohesion Premature keratinization/dyskeratosis Keratin pearls within rete ridges Suprabasal mitotic figures
Cytologic features	Cellular/nuclear pleomorphism Basal cell hyperplasia Increased nuclear:cytoplasmic ratio Atypical mitotic figures Enlarged and multiple nucleoli Hyperchromasia and coarse chromatin Dyskeratosis and/or glassy cytoplasm	Abnormal variation in nuclear size Abnormal variation in nuclear shape Abnormal variation in cell size Abnormal variation in cell shape Increased nuclear:cytoplasmic ratio Atypical mitotic figures Increased number and size of nucleoli Hyperchromasia