A critical evaluation of epithelial dysplasia in oral mucosal lesions using the Smith‐Pindborg method of standardization *

Abstract

Standardization is one of the greatest problems in assessing epithelial dysplasia, as is establishing the relative importance of different clinical and dysplastic features. In this study, 214 cases characterized historically by varying degrees of epithelial dysplasia, were analyzed for various clinical features: and representative sections were assessed histologically and graded according to the Smith-Pindborg standardized scoring system. Data were analyzed by computer Seven cases with scores of less than 10 were excluded as not dysplastic There were 85 cases (41%), with scores of 11–25 which were regarded as mild dysplasia; 60 (29%) with scores of 26–43 were regarded as moderate dysplasia; and 62 (30%) with scores of more than 45 which were reported as severe dysplasia. Peak frequency was in the 6th decade and the severe dysplasias were most frequent in the 8th decade The M:F was 2:1. Tongue (58 cases), lower lip (36), floor of mouth (32) and cheeks (26) were sites most commonly involved. Of 107 cases, 93 were described as homogeneous leukoplakia. 11 as speckled leukoplakia and 3 as crythroplakia. The distribution of mild, moderate and severe dysplasias did not differ significantly by ago. sex or race, Half of all cases involving floor of mouth and oropharynx were severely dysplastic, whereas most lesions occurring in check and alveolar mucosa/gingiva were mildly dysplastic; but differences were not significantly different. Severe grades of each dysplastic feature, as might be expected, occurred in lesions classified finally as ‘severe dysplasia’. Features which predominated in the severely dysplastic lesions were, in de-wending order, mitotic activity superficial to basal layer (98%); increased nucleo-cytoplasmic ratio (85%); increased mitotic activity (84%); pleomorphic cells and nuclei (79%); irregular epithelial stratification (75%); basal cell hyperplasia (73%); loss of polarity (72%); loss of intercellular adherence (71%) Other features, including bizarre mitoses (56%) occurred less frequently in the severe dysplasias. The use of a procedure of this kind is extremely valuable for purposes of standardization The question of whether the weighting of the different characteristics proposed by Smith and Pindborg is sufficiently accurate, or whether it is too subjective, should be tested Similarly, it is important to lest whether the histological criteria now used to assess the severity of dysplasia arc. in fact, those which arc of the greatest value in prognosing potential fur malignant change.