Diagnosing and treating dermatologic lesions of the mouth and gums is challenging for most clinicians because of the wide variety of disease processes that can present with similar appearing lesions and the fact that most clinicians receive inadequate training in mouth diseases. In a study of oral lesions in elderly patients, for example, almost all physicians surveyed felt that it was important to examine older patients' mouths, but less than one-fifth stated that they routinely performed such examinations . Almost four-fifths did not correctly diagnose a clinical picture of an early squamous cell carcinoma.
One of the keys to improving accuracy in diagnosing oral lesions is forming an appropriate differential diagnosis. This review will discuss the presentation and treatment of the most common oral lesions, including tumors, infections, autoimmune and connective tissues diseases, aphthous ulcers, and other miscellaneous oral lesions.
TUMORS (AND LESIONS THAT MIMIC)
Squamous cell carcinoma — Cancer of the oral cavity is associated with ulcers or masses that do not heal and with dental changes or poorly fitting dentures. Tongue and lip cancers present as exophytic or ulcerative lesions often associated with pain. Up to two-thirds of patients with primary tongue lesions have nodal disease; the incidence is substantially lower in patients with hard palate and lip cancers.
Persistent papules, plaques, erosions, or ulcers in the mouth should be biopsied to rule out squamous cell carcinoma, particularly in patients with appropriate risk factors (picture 1A-C). It has been estimated that the use of tobacco and alcohol account for up to 80 percent of cases of squamous cell carcinoma of the head and neck . The combined effect of alcohol and smoking is multiplicative with the risk of developing head and neck cancer being as much as 200 times greater for heavy smokers and drinkers. A subset of oropharyngeal squamous cell carcinoma is associated with human papillomavirus (HPV) infection, particularly with high-risk type 16 (HPV-16). Oral infection with HPV-16 confers an approximately 50-fold increase in risk for HPV-positive oropharyngeal squamous cell carcinoma . (See "Epidemiology and risk factors for head and neck cancer" and "Human papillomavirus associated head and neck cancer".)
Leukoplakia — Oral leukoplakia is a precancerous lesion that presents as white patches or plaques of the oral mucosa (picture 2A-C). It represents hyperplasia of the squamous epithelium, which is believed to be an early step in the transformation of clonally independent premalignant lesions from hyperplasia, to dysplasia, to carcinoma in situ, to invasive malignant lesions (see "Head and neck squamous cell carcinogenesis: Molecular and genetic alterations"). Leukoplakia is also seen in purely inflammatory conditions not associated with malignancy. An association exists between leukoplakia and human papillomavirus (HPV) .