Abstract
Virus-like particles were found in nuclei of stratum corneum cells in one case of human lingual papilloma studied by electron microscopy. The size and structure of the particles resembled the papilloma viruses as described in the literature. Filaments with a characteristic structure and small irregularly-shaped particles were found in other nuclei where virus-like particles were absent. It is proposed that the filaments and the irregular particles represent stages in viral transformation.