Ultrastructural features of the adult laryngeal papilloma.

The ultrastructural features of nine laryngeal papillomas of the adult type were examined by transmission and scanning electron microscopy. The surface was covered by numerous microvilli varying in size and shape and often arranged in parallel cords. Although we did not find virus-like particles, the ultrastructural characteristics of the adult type of laryngeal papilloma did not differ from those previously found on the juvenile type. The two types may in nature be one and the same lesion, differing in behaviour because of the different environments.