Table 2.

World Health Organization architectural features for oral epithelial dysplasia

Architectural features
Group features	Specific features
Basal features	Irregular stratification
	Drop-shaped rete processes
	*Basal cell clustering/nesting
	Loss of polarity or disorganization of basal cells
	*Expanded proliferative compartment
Mitotic features	Mitoses high in epithelium
	Mitoses in maturing cells
Keratin features	Reduced keratinocyte cohesion
	Keratin pearls in rete processes
	Generalized premature keratinization
	*Altered keratin pattern for oral subsite
Structural features	*Verrucous or papillary architecture
	*Multifocal or skip lesions
	*Sharply defined margin to changes
	*Multiple different patterns of dysplasia
	*Extension of changes along minor gland ducts

*Denotes new additions to the criteria [10]