.

1. grading schemes for
oral epithelial dysplasia.

2. Hyperplasia
Hyperplasia describes increased cell numbers.
This may be in the spinous layer leading to
hyperplasia of acanthosis in the basal⁄parabasal
cell layers, termed basal cell hyperplasia.
The architecture shows regular stratification and
there is no cellular atypia.

3. Dysplasia
• the term dysplasia applies
when ;
When architectural disturbance
is accompanied by cytological
atypia
(variations in the size and shape
of the keratinocytes)

4. The oral
intraepithelial
neoplasia
(OIN)
system uses terminology to emphasize that all
levels of dysplasia are actually different levels of
true neoplasia, prior to invasion.
It does not consider simple epithelial hyperplasia
to be part of the dysplasia process, since it can be
seen in so many other disorders of the mucosa.

5. These features could be broadly categorized a:
1- changes to the architecture of the epithelium
2-those that manifest as cellular atypia.
Conventionally
dysplasia is divided into grades of:
mild, moderate and severe.

7. Grades of
dysplasia
Mild dysplasia
In general, architectural disturbance limited to
the lower third of the epithelium, accompanied
by minimal cytological atypia.
defines the minimum criteria of dysplasia.

8. Mild

9. Moderate
Architectural disturbance extending into the middle
third of the epithelium is the initial criterion for
recognizing this category.
Consideration is then given to the degree of cytological
atypia.
The presence of marked atypia may indicate that a lesion
should be categorized as severe dysplasia despite not
extending into the upper third of the epithelium.
Alternatively, lesions with mildly atypical features
extending into the middle third of the epithelium may
merit being graded as mild dysplasia.

10. Moderate

11. Severe
Recognition of severe dysplasia starts with
greater than two-thirds of the epithelium
showing architectural disturbance with associated
cytological atypia.
However,
Architectural disturbance extending into the
middle third of the epithelium with sufficient
cytological atypia is upgraded from moderate to
severe dysplasia.

12. Severe

13. To sum up

14. References
• Bouquot, J. E., Speight, P. M. and Farthing, P. M. (2006) ‘Epithelial dysplasia of the oral mucosa -
Diagnostic problems and prognostic features’, Current Diagnostic Pathology, 12(1), pp. 11–21. doi:
10.1016/j.cdip.2005.10.008.
• Fleskens, S. and Slootweg, P. (2009) ‘Grading systems in head and neck dysplasia: their prognostic
value, weaknesses and utility.’, Head & neck oncology, 1, p. 11. doi: 10.1186/1758-3284-1-11.
• Kujan, O. et al. (2006) ‘Evaluation of a new binary system of grading oral epithelial dysplasia for
prediction of malignant transformation’, Oral Oncology, 42(10), pp. 987–993. doi:
10.1016/j.oraloncology.2005.12.014.
• Pitiyage, G. et al. (2009) ‘Molecular markers in oral epithelial dysplasia: Review’, Journal of Oral
Pathology and Medicine, 38(10), pp. 737–752. doi: 10.1111/j.1600-0714.2009.00804.x.
• Warnakulasuriya, S. (2001) ‘Histological grading of oral epithelial dysplasia: revisited’, The Journal
of Pathology, 194(3), pp. 294–297. doi: 10.1002/1096-9896(200107)194:3<294::AID-
PATH911>3.0.CO;2-Q.
• Warnakulasuriya, S. et al. (2008) ‘Oral epithelial dysplasia classification systems: Predictive value,
utility, weaknesses and scope for improvement’, Journal of Oral Pathology and Medicine, 37(3),
pp. 127–133. doi: 10.1111/j.1600-0714.2007.00584.x.