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Lesions in the Posterior Oral Cavity and Oropharynx: variations of normal and when to investigate


June 1, 2015
by Anali Dadgostar, BSc (Hons), MD, FRCS(C) Otolaryngology - Head and Neck Surgery

Various mucosal abnormalities can be identified in the posterior oral cavity and oropharynx. It is not uncommon for individuals to identify lesions and bring it to the attention of their dentist. Often, they seek advice as the area causes discomfort, or simply because they are concerned for the potential of malignancy. This article reviews some of the more common pigmented, red, and white lesions, including normal anatomic variations and benign lesions, found in the posterior oral cavity and oropharynx. It further highlights the “red flags” of concerning clinical features, necessitating the need for biopsy and referral.

Oral mucosa is generally pink in colour. Highly keratinized, firm, stippled and pale masticatory mucosa covers the hard palate, dorsal surface of tongue, and gingiva. Thin, less keratinized and more pinkish non-masticatory mucosa covers the remaining intra-oral structures. A thorough examination of the posterior oral cavity and oropharynx should assess for change in colour and/or texture of the mucous membrane, inflammatory areas, erythema, hyperpigmentation, macules, papules, vesiculobullous lesions, white lesions, grayish white lesions, red lesions, induration, ulceration, swellings and growths.

Patients presenting with a lesion in the oral cavity should undergo a detailed medial and dental history and examination. The history should include the onset and duration of the lesion, change in size, history of trauma to the site, the presence of associated skin lesions, associated pain or bleeding, systemic signs and symptoms (e.g., fatigue, weight loss), use of over-the-counter and prescription medications, past medical history, and smoking and alcohol use. A thorough clinical head and neck, oral and dental examination should be performed with evaluation for cranial nerve function, palpable lymph nodes, masses and tenderness. Any lesions on the face, perioral skin and lips should be noted. The number, symmetry, distribution, size, shape and colour of the lesions should be assessed.

Pigmented Lesions
Pigmented lesions can typically be divided into generalized or localized pigmentations. Localized lesions are most commonly due to a benign vascular etiology, amalgam tattoos, and rarely malignant melanoma. Generalized lesions are typically physiologic/racial in origin, caused by smoking, and occasionally have a systemic cause (Table 1).

TABLE 1.

White Lesions
White mucosal lesions may result from thickening of one or several layers of the oral epithelium. They vary in size and depth, generally have an irregular outline, and may be solitary or multifocal. Common sites are the buccal mucosa, lateral border of the tongue, floor of the mouth, and hard palate. The term leukoplakia was previously used to describe all white lesions of the oral cavity, however, it is now used to describe white lesions of idiopathic origin. White lesions in the oral cavity can benign in nature, caused by trauma (e.g. cheek biting), infection (e.g. candidiasis), or mucocutaneous lesions (e.g. lichen planus). Biopsy is typically required to establish a diagnosis and rule out carcinoma.

FIGURE 1. This patient presented with a painless swelling of the soft palate/oropharynx. This does blanch and represents a varix.

FIGURE 2. This painless lesion has been present for many years and represents physiologic pigmentation.

Leukoplakia
Leukoplakia can arise at any site in the oral cavity, occurs most often on the buccal mucosa and least often on the soft palate and gingiva. These lesions are typically found in asymptomatic older males, and discovered on a routine dental examination. Biopsy of these lesions is essential for accurate diagnosis. Biopsy of oral leukoplakia will most often show hyperkeratosis, a purely reactive and harmless lesion. About 20 percent, however, will show dysplasia, a premalignant lesion, or cancer. The presence of severe epithelial dysplasia indicates a considerable risk of malignant development. The overall prevalence of malignant change is 3 to 33 percent over 10 years, but a proportion of such malignancies (about 15 percent) regress spontaneously. Thus, such leukoplakic growths must be excised completely and the region observed closely for recurrence.

Lichen Planus
Lichen planus can manifest as cutaneous or mucosal lesions. Mucosal lesions are common and typically present in middle age. The most common form, reticular lichen planus, is usually asymptomatic and clinically appears as lacy, white lines, and is most commonly found bilaterally in the buccal mucosa. In the less common, symptomatic erosive type, the same reticular pattern is seen but there are areas of erosion or ulceration. It typically affects the tongue or buccal mucosa bilaterally. Biopsy is usually necessary in this case to rule out dysplasia or carcinoma, as well as other potential diagnoses (e.g. Keratosis, lupus erythematosus, etc.), and lichenoid lesions (due to other factors and typically drug-induced). Patients with lichen planus require periodic reexamination, as there may be transformation to squamous cell carcinoma in a small number of cases. The incidence has been estimated at 0.5 percent to 2.8 percent.

Carcinoma
In excess of 90 percent of all oral cancers are due to squamous cell carcinoma. Early carcinoma may clinically appear as leukoplakia or erythroplasia. It may also appear as a mixture of erythroplasia and leukoplakia. Smoking and alcohol are risk factors, and the human papilloma virus (HPV) 16 and 18 have been found as a causative agent in the oropharynx. Soft palate, lateral and ventral tongue mucosa, and floor of the mouth are especially prone to develop squamous carcinoma. The tongue and floor of the mouth are the most common areas to be involved. All ulcerations present for more than two to three weeks, in which there is no apparent cause, should be biopsied to rule out carcinoma, especially in adults whose lesions are in high risk areas (Table 2).

TABLE 2.

Red Lesions
Typically, red lesions in the or
al cavity represent an inflammatory process, however, in a proportion, may represent malignancy. Red lesions can be divided into localized or generalized involvement of the oral cavity mucosa. Generalized lesions can be due to an underlying systemic condition (iron deficiency, polycythemia) or irritative/infectious causes (candidiasis, mucositis). Localized lesions can also be due to an underlying systemic cause, vascular lesions, and most notably, erythroplasia.

FIGURE 3. Leukoplakia of the soft palate.

FIGURE 4. This patient presented with significant odynophagia and painful oral lesions. Skin lesions were also noted. Biopsy revealed a diagnosis of bullous pemphigus.


Localized
Erythroplasia (erythroplakia) is an isolated, velvety red, but not ulcerated area on mucous membrane. There are usually no symptoms. It generally involves the floor of the mouth, the ventrum of the tongue, or the soft palate. The border may be sharp or blend into surrounding normal mucosa. It must constantly be kept in mind that early carcinoma frequently appears as an area of erythroplasia, as 75 to 90 percent of lesions prove to be carcinoma/carcinoma in situ or are severely dysplastic. The incidence of malignant change is 17 times higher in erythroplasia than in leukoplakia. This requires biopsy to rule out carcinoma.

Generalized Candidiasis
Candidiasis is a very common lesion of the oral cavity, resulting from an infection with the Candida species. Severity of infection varies from small, localized areas to generalized stomatitis. Risk factors for development of candidiasis include extremes of age, xerostomia, smokers, long-term antibiotic therapy, immunosuppression (HIV, corticosteroid use), and systemic chemotherapy or head and neck radiation. A speckled white-on-red appearance is common due to the uneven distribution of lesions. In contrast to most other white lesions, the white pseudo-membranes of Candidiasis often can be wiped off. When presenting as a red lesion, it is referred to as erythematous candidiasis. Red persistent lesions are especially noticeable on the palate (typically deture-induced) and tongue. Median rhomboid glossitis (central papillary atrophy) is a red depapillated rhomboidal area in the center of the dorsal tongue secondary to candidiasis (Table 3).

TABLE 3.

Miscellaneous Lesions
Various lesions or masses can commonly be found in the posterior oral cavity and oropharynx representing a variation of normal anatomy such as papillae of the tongue or lymphoid aggregates, foreign bodies, or benign lesions. Below are a few common etiologies.

FIGURE 5. Erythroplasia. Biopsy revealed invasive squamous cell carcinoma.

1. Normal Variations
a. Papillae of the tongue (foliate, circumvallate) — These papillae represent a component of the taste buds. Foliate papillae appear as an area of vertical folds and grooves located on the extreme posterolateral surface of the tongue. Circumvallate papillae appear at the most posterior aspect of the dorsal tongue.

b. Fordyce granules — Appear as flat to elevated yellow plaques just beneath the mucosal surface. The most common site is buccal mucosa although they may be found anywhere in oral mucosa. They are normal sebaceous glands and considering they are found in approximately 80 percent of the population.

c. Lymphoid aggregates — Appear as small, slightly elevated nodules that may be normal colored or have a slight yellow-orange hue. They may be found anywhere in the mucosa but are especially common at the oropharynx. This lymphoid rich area is known as Waldeyer’s ring.

d. Torus palatinus or mandibularis — Bony exostoses in the midline of the hard palate and on the lingual aspect of the mandible are referred to as torus palatinus and torus mandibularis respectively. Tori and other exostoses seldom cause symptoms. Because they extend above the level of surrounding normal mucosa, they can invite trauma.

FIGURE 6.  Asymptomatic lesion representing a squamous papilloma.                                                     
 

FIGURE 7. Typical torus palatinus.

FIGURE 8A.
  

 FIGURE 8B.

2. Various Benign Lesions
a. Tonsilloliths — Also known as tonsil stones, these are formed when trapped debris within crypts of the tonsils hardens or calcifies. This tends to happen most often in people who have chronic inflammation in their tonsils or repeated bouts of tonsillitis.

b. Squamous Papilloma — The most common benign epithelial neoplasm of oral mucosa. Squamous Papilloma, recognized by their small fingerlike projections, resulting in an exophytic lesion with a rough or cauliflowerlike verrucous surface. These lesions are thought to be induced by HPV 6 or 11.

c. Tonsillar cyst — Epithelial cysts of the tonsils are quite common. They are glistening, smooth white or yellowish sessile masses. Small cysts do not produce any symptoms. Larger cysts that cause a sensation of a “lump in the throat” may require removal.

3. Foreign Body

When to Further Investigate
In general, benign lesions are painless, symmetric, with regular borders and uniform in colour. In contrast, pain, bleeding, irregular borders, colour variation, and surface ulceration may suggest malignancy (Table 4).

TABLE 4.


Any concerning lesion that is persistent beyond two to three weeks, in which there is no apparent cause, should undergo biopsy to rule out carcinoma, particularly if the lesion is present in a high-risk location (soft palate, lateral and ventral tongue mucosa, and floor of the mouth) or in a high-risk population (smoker, age over 40, excess alcohol use). Other persistent lesions should be followed regularly and biopsied if any concerning features develop.OH


Dr. A. Dadgostar, MD, FRCSC, is an Otolaryngologist – Head and Neck Surgeon with a practice in Thunder Bay, Ontario. For further information, contact by email at dadgosta@tbh.net.

Oral Health welcomes this original article.

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