ULTRASTRUCTURAL ANALYSIS OF THE ADJACENT EPITHELIUM OF ORAL SQUAMOUS-CELL CARCINOMA

Fifteen biopsies of the immediate adjacent epithelium of oral squamous cell carcinoma mere examined under light and electron microscopy. Lig ht microscopic examination of one micron thick sections revealed that the majority of lesions (67%) had hyperplastic or mildly dysplastic ep ithelium while the remaining (33%) had moderate to severe dysplasia. U ltrastructural observations showed that all these lesions had subcellu lar alterations similar to those seen in frank malignant oral tissue, particularly in the lower half of the epithelium. Important ultrastruc tural changes observed included bizarre nuclei of basal and lower spin al cells, enlarged and multiple nucleoli, presence of interchromatin a nd perichromatin granules, loss of desmosomes and marked spongiosis as well as disturbed cellular maturation sequences in the keratinocytes evidenced by abnormal and irregular distribution of maturation markers such as keratohyalin granules and tonofilaments. The present study th us shows the value of electron microscopy in the detection of malignan t changes in the adjacent epithelium of oral squamous cell carcinoma.