Table 1.

Definition of diagnostic outcomes, including normal epithelium and the full spectrum of potentially malignant disorders.

Diagnosis	Histopathologic Criteria
Non-neoplastic/normal	Surface stratified squamous epithelium demonstrates normal thickness without hyperplasia or hyperkeratinization. The underlying lamina propria is devoid of chronic inflammatory cell infiltrate.
Benign lesions	Surface stratified squamous epithelium may reveal hyperkeratosis and hyperplasia, but without cellular atypia and disordered maturation (dysplasia). The underlying lamina propria may exhibit chronic inflammatory cell infiltrate: Chronic mucositis. This category may encompass a range of benign lesions including benign hyperkeratosis and lichen planus.
Dysplastic (mild)	Surface stratified squamous epithelium reveals cellular atypia and disordered maturation (dysplasia) limited to the basal and parabasal layers or verruciform epithelial hyperplasia and hyperkeratosis with mild degree of atypical architecture.
Dysplastic (moderate)	Surface stratified squamous epithelium reveals cellular atypia and disordered maturation (dysplasia) extending from the basal layer to the mid portion of the spinous layer or verruciform epithelial hyperplasia and hyperkeratosis with moderate degree of atypical architecture.
Dysplastic (severe)	Surface stratified squamous epithelium reveals cellular atypia and disordered maturation (dysplasia) extending from the basal layer to a level above the midpoint of the epithelium or verruciform epithelial hyperplasia and hyperkeratosis with severe degree of atypical architecture.
Dysplastic (carcinoma in situ)	Surface stratified squamous epithelium reveals cellular atypia and disordered maturation (dysplasia) involving the entire thickness of the epithelium.
Malignant	Islands and cords of malignant squamous epithelial cells arise from dysplastic surface epithelium and invade into the lamina propria.