Ultrastructure Studies of Oral Mucosa. I. Comparison of Normal and Hyperkeratotic Human Buccal Epithelium

¹ School of Dentistry, University of California, San Francisco, California

Leukoplakia and adjacent clinically normal-appearing buccal mucosa were studied in ten human subjects in order to gain an insight into keratinization through fine structure.

The leukoplakia specimens differed from the normal ones by the following features: an interrupted and multiple basement lamina; an increased number of cell organelles; striated granules appearing in the high prickle layer; pronounced banding of the fibrils, which were assumed to be precursors or modified forms of keratin; keratohyalin granules, and a stratum corneum in which the cells were filled with an electron-dense fibrillar material (assumed to be keratin) and were separated by an irregular bulbous intercellular space that appeared to be filled with a mucinous material.

Further studies are necessary to relate the roles of various organelles to the synthesis of keratin under normal and pathologic conditions.