Pathology of malignant and premalignant oral epithelial lesions.

Oral mucous membranes and the surrounding structures are largely composed of stratified squamous epithelium that is supported by a fibrous connective tissue lamina propria and a submucosa of fibroadipose tissue. Minor salivary glands, nerves, and capillaries course abundantly throughout the supporting collagen and fibro-fatty submucosa. Premalignant and malignant lesions arise most frequently from epithelium, and these epithelial lesions ultimately account for 95% of all cancers of the oral cavity. Malignant neoplasia of bone, cartilage, salivary glands, and connective tissue and those of lymphoproliferative derivatives are far less common occurrences in the oral cavity. Malignant neoplasms can and do arise from the tooth germ apparatus, but neoplasms of odontogenic elements are rare and are not included in this discussion.