Many dermatologic conditions, inflammatory, immunologic, infectious, or neoplastic, can also occur in the oral mucosa, with essentially similar clinicopathologic features. Occasionally, the mouth is the sole manifestation of a dermatologic condition as in the case with lichen planus and mucous membrane pemphigoid. There are also common conditions that are unique to the oral mucosa, such as recurrent aphthous stomatitis (canker sores) and geographic tongue. In this chapter, the reader will be introduced to the clinical characteristics, differential diagnosis, and management of common oral conditions.
Anatomy of the Oral Cavity
With the exception of the posterior one-third of the tongue, which is of endodermal origin, the epithelium that lines the oral mucosa derives mostly from ectoderm. In contrast to the skin, the oral epithelium exhibits different patterns of keratinization. For example:
The masticatory mucosa (hard palate, gingiva, and alveolar mucosa) has keratinized or parakeratinized (retained nuclei in the stratum corneum) squamous epithelium.
The tongue has parakeratinized, nonkeratinized, and specialized epithelia (papillae).
The buccal mucosa and vestibule have nonkeratinized stratified or parakeratinized squamous epithelia, respectively.
The supporting connective tissue is of ectomesenchymal origin. Adnexal elements are not present in the connective tissue of the oral mucosa, with the exception of sebaceous glands, known as Fordyce granules/spots (Figure 38-1), which are present in 70% to 90% of individuals. However, the mouth has 800 to 1000 lobules of minor salivary glands, with the exception of the gingiva and the anterior aspect of the hard palate.
Intraoral sebaceous glands (Fordyce granules). Small yellow papules on the vestibule and buccal mucosa.
Categories of Oral Diseases
Clinically, oral lesions can be (1) ulcerated, (2) vesiculobullous, (3) maculopapular, (4) exophytic, papillary, or fungating, (5) nodular or polypoid, and (6) pigmented. Special attention should be given to lesions that are white (leukoplakic), or red (erythroplakic) patches or a mixture of the two (erythroleukoplakic) and lesions that are gray, black, or brown, as these lesions may be malignant or premalignant.
Oral ulcers have various etiologies, which include trauma, immunologic diseases, infections (bacterial, deep fungal, or viral), and neoplasms (squamous cell carcinoma, lymphoma, malignant salivary gland tumors, etc). They are generally painful, except for squamous cell carcinoma, which may be asymptomatic, when it presents as an ulcer.
Traumatic ulcers are usually the result of physical injury (eg, accidental biting during mastication, contact with sharp or broken cusps of teeth, and sharp food), and less often, thermal or chemical burn (eg, chemicals used during dental or surgical procedures, aspirin, alcohol, peroxide, and other acidic substances). Rarely, electrical injury can occur, especially in very young children who accidentally chew on an ...