25: Potentially malignant disorders

Potentially malignant disorders

INTRODUCTION

Most mouth cancers are oral squamous cell carcinomas (OSCC) and appear to arise in apparently normal mucosa, in apparently otherwise healthy people but some are preceded by clinically obvious potentially malignant (sometimes termed premalignant) disorders (PMD) and OSCC is also increased in patients who:

PMD include (Table 25.1) mainly:

Table 25.1

Potentially malignant oral disorders

Disorder Aetiological factors Features
Actinic cheilitis (solar elastosis) Sunlight White plaque/erosions
Erythroplasia Tobacco/alcohol/betel Flat red plaque
Leukoplakia Homogeneous Tobacco/alcohol/betel, human papilloma virus White plaque
Leukoplakia Speckled (erythroleukoplakia) Tobacco/alcohol/betel, human papilloma virus Speckled plaque
Nodular/verrucous Tobacco/alcohol/betel, human papilloma virus Nodular white plaque
Proliferative verrucous leukoplakia Tobacco/alcohol White or speckled nodular plaque
Sublingual leukoplakia Tobacco/alcohol White plaque
Candidal leukoplakia Candida albicans White or speckled plaque
Syphilitic leukoplakia Syphilis White plaque
Lichen planus Idiopathic White plaque/erosions
Submucous fibrosis Areca nut/betel Immobile mucosa, white plaque
Palatal lesions in reverse smokers Tobacco White or speckled plaque
Immunocompromised patients Papilloma viruses
Candidosis
White or speckled plaques
Discoid lupus erythematosus Idiopathic White plaque/erosions
Dyskeratosis congenita Genetic White plaques
Epidermolysis bullosa Genetic Scarring
Fanconi anaemia Genetic White plaques
Periodontal disease
Paterson–Kelly syndrome (sideropenic dysphagia; Plummer–Vinson syndrome) Iron deficiency Postcricoid web
Xeroderma pigmentosum Genetic White plaque/erosions

image

image Actinic cheilitis (solar elastosis) (Ch. 26).

image Erythroplakia (erythroplasia – red patch; Fig. 25.1) (Ch. 27): defined by the World Health Organization (WHO) as ‘any lesion of the oral mucosa that presents as bright red velvety plaques which cannot be characterized clinically or pathologically as any other recognizable condition’. This is rare but has a very high malignant potential and many cases are already a carcinoma on microscopic examination.

image Leukoplakia (white patch; Figs 25.2–25.6) (Ch. 28): defined by the WHO as ‘clinical white patches that cannot be wiped off the mucosa and cannot be classified clinically or microscopically as another specific disease entity (such as lichen planus)’. Leukoplakia is, thus, a clinical diagnosis only and can only be made by exclusion. A workshop coordinated by the WHO Collaborating Centre for Oral Cancer and Precancer agreed that the term leukoplakia should be used to recognize ‘white plaques of questionable risk having excluded (other) known diseases or disorders that carry no increased risk for cancer’.

image Lichen planus/lichenoid lesions (Ch. 29): in many geographic areas these are the most common PMDs.

image Submucous fibrosis (Ch. 30).

image Palatal lesions in reverse smokers.

Apart from the conditions noted above, rare conditions that predispose to OSCC include:

There are also occasional associations of OSCC with:

Erythroplakia has a very high malignant potential. Leukoplakia can have a malignant potential – particularly high in the following types (Table 25.2):

Table 25.2

Malignant potential in the most important oral potentially malignant disorders

  Malignant potential
High (> 60%) Medium (< 30%) Low (< 10%)
Main entities Erythroplakia Leukoplakia (non-homogeneous)
Candidal leukoplakia
Leukoplakia (homogeneous)
Lichen planus/lichenoid lesions
Uncommon entities   Actinic cheilitis
Submucous fibrosis
Discoid lupus erythematosus
Rare entities Dyskeratosis congenita* Fanconi anaemia*  

image

*Malignant potential unclear but involves OSCC (mainly tongue) and other neoplasms, especially acute myeloid leukaemia.

AETIOLOGY AND PATHOGENESIS

Although genetics clearly predispose to PMD in some cases (such as in dyskeratosis congenita, Fanconi anaemia and xeroderma pigmentosum), lifestyle habits are often implicated, and most of these have psychotropic actions and are habit-forming or addictive. Those habits that are known to predispose to potential malignancy include:

Marijuana use, and oro-genital or oro-anal sex (via human papillomavirus (HPV) transmission) may also be implicated as discussed below and in Ch. 31.

Jan 9, 2015 | Posted by in Oral and Maxillofacial Pathology | Comments Off on 25: Potentially malignant disorders
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