The ability to recognize and identify disease is one of the primary distinguishing characteristics of medical and dental professionals. All dental practitioners who treat patients regularly will evaluate oral and maxillofacial pathology with a certain frequency. Although the majority of the oral lesions that dentists encounter in their patients may be benign, it is not uncommon for more serious lesions to present themselves and first be noticed by the dental team. This chapter addresses common oral pathologic findings that should be familiar to dental practitioners maintaining patient oral health. Most of the entities presented in this chapter are associated with trauma or even self-inflicted injuries, while others may be infectious or neoplastic. Behavioral etiologies are also discussed. Awareness of the pathologic entities and consistent clinical examinations are critical for effective management as well as improved outcomes for all patients. The common oral conditions encountered regularly in patients are presented here by their name and definition along with applicable alternative names, clinical features, demographics, diagnoses, microscopic features, treatments, and prognoses. Suggested differential diagnoses are provided but are not intended as an exclusive list of all oral entities that should be considered. Each patient case should be assessed for a differential diagnosis that is the most fitting for his or her unique presentation.
Introduction
In this chapter, common oral conditions encountered regularly in practice are presented by their name and definition along with applicable alternative names, clinical features, demographics, diagnoses, microscopic features, treatments, and prognoses. Suggested differential diagnoses are provided but are not intended as an exclusive list of all oral entities that should be considered. Each patient case should be assessed for a differential diagnosis that is most fitting for his or her unique presentation.
Developing a Differential Diagnosis
When a lesion is identified upon a thorough head and neck exam, the process taken after identification is also important. The diagnosis and appropriate treatment of abnormal findings may be obvious after the thorough history and examination. Generally, there are various possible diagnoses, therefore a clinical differential diagnosis and plan of investigation needs to be developed.
Possible diagnoses should be recorded in the order of probability based on their prevalence and likelihood of causing the symptoms and signs. Even if only one diagnosis seems like the most appropriate, it is worth noting the next most likely possibility and any other causes that cannot be excluded. Formulating a differential diagnosis helps even experienced clinicians organize their thoughts. Precise diagnosis depends on histological findings.
Appropriate Medical Terminology
Appropriate medical terminology should always be used to describe clinical findings in the records because lay terminology can be misleading and nonspecific. High-quality digital photographs may also be printed and enclosed with the biopsy specimen or can be e-mailed separately to the pathologist. Photographs are helpful in demonstrating the clinical characteristics of the lesion. Box 5.1 lists several common physical descriptions that are useful in describing oral and maxillofacial pathologic entities.
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Bulla (pl. bullae): a blister; an elevated, circumscribed, fluid-containing lesion of skin or mucosa.
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Crusts (crusted): dried or clotted serum on the surface of the skin or mucosa.
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Dysplasia (dysplastic): any abnormal development of cellular size, shape, or organization in tissue.
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Hyperkeratosis: an overgrowth of the cornified layer of epithelium.
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Hyperplasia (hyperplastic): an increased number of normal cells.
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Hypertrophy (hypertrophic): an increase in size that is caused by an increase in the size of cells not in the number of cells.
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Keratosis (keratotic): An overgrowth and thickening of cornified (horned layer) epithelium.
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Leukoplakia: a slowly developing change in mucosa characterized by firmly attached, thickened, white patches.
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Macule: a circumscribed, nonelevated area of color change that is distinct from adjacent tissues.
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Malignant: anaplastic; a cancer that is potentially invasive and metastatic.
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Nodule: a large, elevated, circumscribed, solid, palpable mass of the skin or mucosa.
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Papule: a small, elevated, circumscribed, solid, palpable mass of the skin or mucosa.
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Pustule: a small, cloudy, elevated, circumscribed, pus-containing vesicle on the skin or mucosa.
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Scale: a thin, compressed, superficial flake of cornified (keratinized) epithelium.
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Stomatitis: any generalized inflammatory condition of the oral mucosa.
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Ulcer: a crater-like, circumscribed surface lesion resulting from necrosis of the epithelium.
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Vesicle: a small blister; a small, circumscribed elevation of skin or mucosa containing serous fluid.
Leukoplakia
Definition: White (leuko) patch (plakia)
Alternate names: White plaque, callus, frictional keratosis, dysplasia.
Clinical features: Leukoplakia (▶ Fig. 5.1) is not a histologic diagnosis. It is a clinical description defined by the World Health Organization (WHO) as a “white patch or plaque that cannot be wiped off nor characterized clinically or pathologically as any other disease.”
The oral mucosa can produce a tough protective protein called keratin which, when produced in excess, may appear as a white patch. This mucosal thickening is often part of the tissues’ normal protective response against rubbing, pressure, and other forms of local irritation. Other causes may include tobacco use, alcohol abuse, and sun exposure. Histologic diagnoses of biopsied leukoplakias range from hyperkeratosis to dysplasia and, at its worse, carcinoma. Overall, 5 to 25% of leukoplakias are dysplasia or carcinoma, but this likelihood also depends on the location of the lesion. Studies show an overall malignant transformation rate of 4 to 47%.
Demographics: Leukoplakias are the most common oral lesions, representing 23.7% of all oral lesions. Approximately 70% of cases occur in males and are usually seen in older adults over 40 years of age. Approximately 70% of oral leukoplakias are found on the lip vermilion, buccal mucosa, and gingiva. The tongue, lip vermillion, and floor of mouth are considered high-risk sites which account for more than 90% of leukoplakias that prove to be dysplastic or malignant.
Diagnosis: If trauma is the suspected cause of a white (leukoplakia) lesion, the clinician should remove the traumatic etiology and recheck the area in 2 weeks for resolution. If the white lesion is not resolved, then a biopsy is required to establish a definitive diagnosis. Sampling both white lesion and normal mucosa is most helpful in establishing a definitive diagnosis.
Microscopic features: Hyperparakeratotic stratified squamous surface epithelium showing a range of patterns from a regular pattern of maturation with scattered typical mitotic figures in the basal layer (hyperkeratosis) to invasive cords and islands of malignant epithelium within the lamina propria (squamous cell carcinoma). The underlying connective tissue is usually densely collagenized and can contain scattered chronic inflammatory cells.
Treatment: Remove the etiology (if trauma is suspected) and schedule frequent, regular clinical follow-up appointments. A biopsy of the white lesion may be required to confirm the diagnosis and rule out dysplasia and/or malignancy. In general, any dysplasia located in high-risk locations should be completely removed with long-term follow-up and rebiopsy in the event of recurrence. Squamous cell carcinomas (SCCa) are treated more aggressively depending on the stage of the disease.
Prognosis: Malignant transformation rates of oral leukoplakia range from 0.13 to 17.5%, while the rates of 5-year cumulative malignant transformation range from 1.2 to 14.5%. Some reports found a high incidence of malignant transformation in older patients.
Oral Candidiasis
Definition: An infection of the oral cavity caused by a fungal organism.
Alternate names: Thrush, oral mycosis, moniliasis.
Clinical features: The most common fungal organism present in the oral cavity is Candida albicans. This fungal organism is considered a normal component of the oral flora in approximately half of the population. As an opportunist, Candida populations will increase in number when the conditions are favorable, resulting in a shift to an infectious presentation. Candida infections can appear in various patterns, such as white plaques that scrape off (▶ Fig. 5.5) or red ulcerated areas (▶ Fig. 5.6).
Infections in the oral cavity can range from mild and superficial to severe and disseminated. The clinical presentation is a result of one or more key factors: the host immune status, the environment of the oral cavity, and the type of C. albicans present. Patients who wear complete dentures for extended periods of time (e.g., all day and night everyday) have an increased risk of developing candidal infections because the intaglio surface of the dentures provide mucosal coverage and promote a warm, moist environment that is suitable for candidal proliferation. Patients with systemic disorders, such as vitamin B deficiency or anemia, can also present with candidiasis often on the dorsum of the tongue (▶ Fig. 5.7) as a sequela to their underlying disorder.
Diagnosis: Diagnostic exam findings will help a clinician determine the probability of a fungal infection. A clinical finding of a white area that is easily scraped off—resulting in an underlying erythematous base—is highly probable for Candida infection. The most specific method for confirming the diagnosis of fungal infection is a cytologic smear or a biopsy of the affected tissue submitted for microscopic diagnosis.
Microscopic features: Microscopic analysis of either an exfoliative cytology sample or a biopsy tissue section will reveal candidal hyphae and yeast buds when stained appropriately. When stained with periodic acid–Schiff (PAS) or the Grocott-Gomori methenamine silver (GMS) stains, the candidal hyphae and yeasts are more easily identified. These stains highlight the fungal wall allowing for observable confirmation. The specimen will show numerous fungal organisms consistent with C. albicans.
Treatment: The first choice of treatment for oral candidiasis is a polyene agent, such as nystatin or clotrimazole troches. If the patient wears a denture, the denture should also be disinfected and treated in order to ensure complete treatment of the mucosa. This can be accomplished by cleaning the intaglio surface of the denture in 0.12% chlorhexidine solution. The most important aspect of treatment in edentulous patients is to improve denture hygiene. Instruct patients to remove the denture at night and clean/disinfect the prosthesis. The second line of treatment of a persistent infection is a triazole systemic agent such as fluconazole.
Prognosis: Oral candidiasis is typically a condition with no long-term consequences. It usually resolves with patient compliance resulting in improved denture hygiene and/or with proper use of the antifungal medication. In severely immunocompromised patients, the infection may present a more serious threat and persist intermittently for longer periods of time. If confirmed infection does not resolve, a patient should be referred to their primary care provider for a systemic medical work-up and management.
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Allergic contact stomatitis (▶ Fig. 5.8).
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Atrophic lichen planus (▶ Fig. 5.9).
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Morsicatio buccarum (▶ Fig. 5.10).
Irritation Fibroma
Definition: Exuberant scar tissue.
Alternate names: Focal fibrous hyperplasia, keloid.
Clinical features: Irritation fibroma occurs due to acute or repeated trauma to an oral site. The injured area will exhibit poor healing and possibly inflammation in the area of trauma. This may then result in a growth of tissue in response to the repeated trauma. Clinically, the fibroma will be a smooth surfaced, tissue-colored, dome-shaped nodule with a sessile (broad-based) attachment. These are most common on the buccal mucosa and the tongue. Patients often exhibit a parafunctional habit and have no symptoms related to the growth itself. In others, reactive lesions like pyogenic granuloma may fibrose over time into a fibroma. These lesions could demonstrate pigmentations from reactive melanosis or ulcerations if recently traumatized. They usually are smaller than 1 cm in diameter, but may grow to 3 to 4 cm in some patients (▶ Fig. 5.11). These lesions grow slowly, achieve full size within 6 months, and do not resolve on their own.
Demographics: While there is no gender predilection, fibromas typically occur in patients 40 to 60 years old; with a smaller, bimodal distribution in children as well. The lesions occur most commonly on the buccal mucosa, followed by the lip, lateral tongue, and the gingiva. Fibroma is the third most common lesion in adult patients.
Diagnosis: Clinical correlation will indicate that a lesion with this appearance and behavior is most often a fibroma. However, an excisional biopsy is indicated to remove the obvious lesion and confirm the diagnosis histologically.
Microscopic features: Sections will show an exophytic nodule surfaced by hyperparakeratotic, mildly atrophic, stratified squamous epithelium. The relatively avascular underlying connective tissue will contain bundles of dense collagen supporting spindled fibroblasts. Scattered chronic inflammatory cells will also be observed.
Treatment: The definitive treatment is conservative surgical excision and submission of tissue for histopathologic diagnosis.
Prognosis: The prognosis is excellent with excision and elimination of the traumatic etiology.
Squamous Papilloma
Definition: A benign epithelial proliferation that has papillary architecture.
Alternate names: Papilloma, oral wart.
Clinical features: These lesions are soft, painless epithelial protrusions that are most often pedunculated and exophytic (▶ Fig. 5.15).
Papillomas are induced by infection with the human papilloma virus (HPV). The HPV types that cause papillomas are typically those that do not incorporate into the host DNA and pose little risk of malignancy (most commonly HPV 6 and 11). The mode of transmission is through sexual contact—person to person—whereby the virus is inserted into traumatized, exposed epithelium. Clinically, the papilloma has numerous fingerlike surface projections that impart a “cauliflower” or wart-like appearance (▶ Fig. 5.16).
There is often a latency period of 3 to 12 months before the clinical presentation is observed.
Demographics: There is no gender predilection, with the typical age range consisting of 30 to 50 years. The most common locations are the tongue, lips, and soft palate. Approximately 1 out of 250 adults are infected with HPV and the papilloma accounts for 3% of all oral biopsies. This lesion, when in the genital region, can be transmitted from mother to child. This type of transmission accounts for approximately 7 to 8% of oral lesions in children.
Diagnosis: In order to diagnose this entity, a surgical excision with submission for microscopic diagnosis is required. DNA analysis can be obtained to ascertain the type of HPV infection present in the tissue.
Microscopic features: A pedunculated mass surfaced by parakeratotic, hyperplastic stratified squamous epithelium arranged in a frond-like configuration showing scattered typical mitotic figures in the parabasal layer. Koilocytes will be present in the spinous layer. The finger-like projections are supported by a thin, vascular, fibrous connective tissue core that also contains scattered chronic inflammatory cells.
Treatment: Surgical excision of the lesion to its base with close clinical follow-up is required. Confirmation of diagnosis predicates frequent surveillance for other papillomas or papillary growths orally and genitally. Preventative measures are in place to decrease the papilloma incidence with the development of vaccinations that target the most common low-risk HPV strains and two high-risk HPV strains.
Prognosis: The prognosis is good with complete removal and counseling regarding etiology in order to prevent further infections. Frequent oral evaluation is important, as high-risk HPV is also an etiologic factor in some oral cancers. Knowledge of previous infections is important to ascertain risk for a high-risk infection.
