dysplasia diagnosis

Aims: Histological diagnostic criteria are used for the assessment of the degree of dysplasia and hence the risk of cancer progression for premalignant lesions. Clonal changes in the form of hyperorthokeratosis and hyperchromasia that are sharply demarcated from adjacent areas are not currently part of the criterion for dysplasia diagnosis. The objective of this study was to determine whether such clonal change should be regarded as a diagnostic feature for dysplasia. The following histological conditions were used to define such change: (1) hyperorthokeratosis; (2) hyperchromatism but no other features of dysplasia; (3) sharp margin demarcation from adjacent area by both the hyperorthokeratosis and hyperchromasia (clonal change), and (4) no prominent rete ridges, marked acanthosis or heavy inflammation. Lesions fitting these criteria were termed orthokeratotic lesions with no dysplasia. Methods: Patients from a population-based longitudinal study with more than 10 years of follow up were analyzed. Of the 214 patients with primary oral premalignant lesions, 194 had mild or moderate dysplasia (dysplasia group) and 20 fit the criteria for orthokeratotic lesions without dysplasia (orthokeratotic with no dysplasia group). The two groups were compared for their cancer risks using clinical (site and toluidine blue), histological (nuclear phenotype score), and molecular criteria (loss of heterozygosity) and by outcome (progression). Results and conclusions: The lesions from orthokeratotic with no dysplasia group showed a similar cancer risk (clinical, histological and molecular risk) and time to progression as the dysplastic lesions. We recommend that the clonal change should be included as a criterion for dysplasia diagnosis