11: Leukoplakia, Oral Dysplasia, and Squamous Cell Carcinoma

11 Leukoplakia, Oral Dysplasia, and Squamous Cell Carcinoma

Leukoplakia, Erythroplakia, and Dysplasia

The term oral dysplasia is synonymous with intraepithelial neoplasia as used when discussing the cervix. The equivalent terms squamous intraepithelial neoplasia and oral intraepithelial neoplasia have not to date been universally accepted. The diagnostic term epithelial atypia is sometimes used interchangeably with epithelial dysplasia and this causes confusion; reactive epithelial atypia should always be reported as such. Diagnosis of dysplasia when there is reactive epithelial atypia may account for why some so-called dysplastic lesions regress over time.

Leukoplakia is not any white plaque but rather a white plaque that does not conform clinically or histopathologically to any specific disease and cannot be attributed to reactive, frictional, or traumatic causes. As such, it is a clinical term only and is used when other specific histopathologic and clinical entities are excluded (especially frictional keratoses [see Chapter 10]). Leukoplakia is the most common precursor lesion before invasive cancer develops.

Clinical Features

Localized Leukoplakia

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FIGURE 11-2 Representation of the clinical and likely corresponding histopathologic findings in leukoplakia.

(Modified from Bouquot JE, Gnepp DR. Laryngeal precancer: a review of the literature, commentary, and comparison with oral leukoplakia. Head Neck. 1991;13:488-497.)

Etiopathogenesis and Histopathologic Features

Risk factors for localized leukoplakia (excluding the lip where lesions are usually related to actinic damage) are likely the same as for squamous cell carcinoma: cigarette smoking, excessive alcohol consumption, areca nut habit, history of cancer and cancer therapy, history of prolonged immunosuppression, family history of cancer, and age; risk factors for proliferative leukoplakia are less well-defined. Human papillomavirus (HPV) is associated with apoptotic dysplasias (see later). Mutations of genes on 3p, 9p, and 17 seen in squamous cell carcinomas have not been consistently found in oral dysplasia.

Architectural Evidence of Dysplasia

Features of dysplasia that occur in the absence of, or with minimal evidence of, cytologic dysplasia are often observed in clinical lesions of verrucous and proliferative leukoplakias (Table 11-1)

TABLE 11-1 Histopathologic Features of Dysplasia

Architectural features

Organizational features

Cytologic features (those noted on exfoliative cytology)

Cytologic Evidence of Dysplasia

Cytologic features are similar to those at other mucosal sites and are readily noted on exfoliative cytology (see Table 11-1); reactive epithelial atypia from inflammation may show the same features to a lesser degree.

Jan 12, 2015 | Posted by in Oral and Maxillofacial Pathology | Comments Off on 11: Leukoplakia, Oral Dysplasia, and Squamous Cell Carcinoma
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