ULTRASTRUCTURAL VARIATIONS AND ASSESSMENT OF MALIGNANT TRANSFORMATIONRISK IN ORAL LEUKOPLAKIA

Oral cancer is the most common malignancy in India, having a well defi ned precancerous state, leukoplakia. Various follow-up studies have sh own that only 4 to 18% of oral leukoplakia lesions subsequently progre ss into invasive malignancy over a period of time. This study evaluate s the potential of electron microscopy in the early detection of malig nant changes in leukoplakia. The study revealed that of the 25 leukopl akia lesions examined, 7 showed changes akin to malignancy. Predominan t ultrastructural alterations observed were reduplication and disconti nuity of the basal lamina, basal cells with pleomorphic and bizarre nu clei containing perichromatin and interchromatin granules, prominent i ntercellular spaces and poorly formed desmosomes. Since none of these changes were evident under light microscopy the study demonstrates the value of electron microscopy in evaluating oral carcinogenesis. A lon g term follow-up of such patients is needed to understand the prognost ic implications of these ultrastructural variation and how they can be used as a base line for better light microscopic evaluation.