Table 2.

Modified WHO morphologic criteria of OED. In addition, verrucous morphology, budding rete processes, spontaneous apoptosis, ortho- or para-keratosis with abrupt lateral demarcation, subepithelial lymphocytic infiltrate and bulky suprabasal proliferation are increasingly accepted features of OED.

Architectural Changes	Cytological Changes
Irregular stratification	Abnormal variation in nuclear size
Loss of polarity of basal cells	Abnormal variation in nuclear shape
Bulbous rete ridges	Abnormal variation in cell size
Increased number of mitotic figures	Abnormal variation in cell shape
Premature keratinization in a single cell	Increased nuclear/cytoplasm ratio
Squamous eddies within rete ridges	Atypical mitotic figures
Loss of intracellular cohesion	Increased number and size of nucleoli
	Hyperchromasia