Grading of oral epithelial dysplasia: Points to ponder

Over the years many grading systems have been put forward in an attempt to obtain objectivity in grading oral epithelial dysplasia (OED). However, despite these efforts variability remains unresolved. Our study aimed to evaluate the intra- and inter-observer variability in grading OED, using World Health Organization (WHO), Smith and Pindborg and Ljubljana grading systems and discuss the possible reasons for this variability if any.

Three oral pathologists graded 50 slides of OED independently twice at a time interval of 3 months. Variability was evaluated by multivariate kappa analysis.

Intra-observer reproducibility ranged from moderate to good in WHO system, fair to moderate in Smith and Pindborg system and moderate to poor in Ljubljana grading system. Inter-observer agreement was found to be fair in WHO, poor in Smith and Pindborg system and poor to fair in Ljubljana grading systems. Intra-observer reproducibility of the dysplastic features in WHO system was good for all except the loss of polarity and basilar hyperplasia for first observer and enlarged nucleoli for the third observer. Inter-observer agreement was good for increased number of mitosis and nuclear hyperchromatism. Intra-observer reproducibility and inter-observer agreement were found to be best in the WHO grading system though variability within this system still existed.

There is a need for an International body of pathologists to come to a consensus on a more definable grading system to resolve the issue of variability in grading dysplasia.