D.R. Lecavalier, DDS, MSc J.H.P. Main, FRCD(C), PhD

Oral TumoursSUMMARYThe authors of this article review briefly theanatomy of the oral soft tissues anddescribe the more common benign andmalignant tumours of the mouth, givingemphasis to their clinical features. (Can FamPhysician 1988; 34:1377-1382.)

RESUMELes auteurs de cet article font une breve revue del'anatomie des tissus mous de la bouche et decriventles tumeurs benignes et malignes les plus frequentesde la cavite buccale, en insistant particulierementsur leurs caracteristiques cliniques.

benign oral tumours, malignant oral tumours,premalignant oral lesions

Dr. Lecavalier is SeniorResident, and Dr. Main isProfessor and Head of theDepartment of Oral Pathology inthe Faculty of Dentistry,University of Toronto. Requestsfor reprints to: Dr. J.H.P. Main,Department of Oral Pathology,Faculty of Dentistry, Universityof Toronto, 124 Edward St.,Toronto, Ont. M5G 1G6

LARGE NUMBER ofbenign andmalignant tumours may arise

in the mouth and jaws. The authors ofthis paper will discuss the clinical fea-tures of the more frequently seen neo-

plasms; they will also discuss some ofthe non-neoplastic tumours, because oftheir importance in differential diagno-sis. The discussion will be restricted tolesions in soft tissue, since intrabony le-sions require radiographic investiga-tions, which are not readily available inthe offices of most family physicians.Information on intrabony lesions isavailable in the books listed in "ForFurther Reading" at the end of this arti-cle.

Normal AnatomyThe diagnosis of intraoral abnor-

malities requires an understanding ofthe normal anatomical structures foundin the mouth, paying particular atten-tion to specific features.The oral cavity is lined with epithe-

lium supported by vascular connectivetissue. Those areas which overlie bone(hard palate, gingiva), as well as thedorsal aspect of the tongue, are

keratinized, whereas the rest ofthe oralcavity is normally covered by a non-

keratinizing epithelium. Many peoplealso display a line of keratinization on

the buccal mucosa which is parallel tothe line of closure of the teeth. Thiswhite line is referred to as the "lineaalba" and is the result of mild, chronicmasticatory trauma. Keratinized epi-thelia have a white-pink colour; non-

keratinized epithelia are pink-red.Most epithelia have a smooth surface,with the exception ofthe palate, with itsrugae and the gingiva, which fre-quently has a rough or stippled appear-ance. In some areas, most notably thebuccal mucosa and the lips, there are

collections of sebaceous glands. These

CAN. FAM. PHYSICIAN Vol. 34: JUNE 1988

glands appear as punctate yellow gran-

ules and are sometimes called "For-dyce's spots" or "granules". Areas ofpigmentation may also be seen withinthe oral cavity, predominantly in dark-skinned individuals. These areas oftenappear as patches of brown-black gin-giva, and are usually found in thewedge-shaped areas, the interdentalpapillae, between the teeth. The tonguemay display pigmentation along its lat-eral border

Both minor (accessory) salivaryglands and lymphoid tissue are normalconstituents of the oral submucosa. In-traoral salivary glands are between 450and 750 in number and can be found inthe lips, cheeks, hard and soft palates,uvula, floor of mouth, tongue,retromolar area, and peri-tonsillar re-

gions. I Any of these glands have thepotential to undergo a wide range ofpathological changes which can lead toa swelling. Lymphoid tissue is foundmainly within Waldeyer's ring, al-though lymphoid aggregates can some-

times be found elsewhere in the oralcavity. The lymphoid tissue that is a

normal component ofthe posterolateral

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border of the tongue, and that appearsas small, 2 mm to 3 mm nodules, is fre-quently misdiagnosed as an anomaly.The cervical chain of lymph nodes inthe neck provides lymphatic drainagefor the oral cavity, and as such, it isusually the first site of regional metas-tasis for intraoral malignancies.

Benign Mucosal LesionsFibroepithelial polyp

The fibroepithelial polyp (Figure 1)is the most common growth found inthe oral cavity. This lesion is not a neo-plasm; it is a reactive proliferation ofepithelial and connective tissue in re-sponse to chronic, low-grade irritation.It has no age or sex predilection. Thepolyp may be either sessile or peduncu-lated and has a smooth white or red sur-face which can become ulcerated. Theareas mostly commonly affected in-clude the buccal mucosa, gingiva,tongue, lips, and palate. Proliferationof fibro-epithelial tissue can also occuralong the borders of over-extendeddentures. In all occurrences, treatmentconsists of simple excision combinedwith elimination of the source of irrita-tion. The true neoplastic counterpart tothe fibroepithelial polyp is the fibroma;it is extremely rare in the oral cavity.

PapillomaOral squamous papillomas are

epithelial neoplasms that are pink orwhite in colour and have a papilliferousor cauliflower-like surface. They arefound most commonly in young adultsand have no sex predilection. Papil-

lomas are seen most often on thetongue, lips, and palate. Some of thesebenign tumours are induced by the hu-man papilloma virus. The clinical ap-pearance of the papilloma is frequentlyindistinguishable from the commonwart (verruca vulgaris) or from thegenital wart (condyloma acuminatum).Common warts occur most often on thelips; oral condylomas tend to be largerthan common warts and are multiple,often occurring on the lingual frenum.All of these lesions should be excisedand submitted for pathological evalu-ation.

Submucosal LesionsGranular cell tumours

This benign lesion was formerlycalled the granular cell myoblastoma.It presents as a painless, whitish-yellowsubmucosal swelling with normal over-lying epithelium. Most granular celltumours occur in the tongue, but on oc-casion, they can be found in the lips andfloor of the mouth. The histogenesis ofthe granular cell tumour remains unde-cided; research has suggested that stri-ated muscle, histocytes, fibroblasts,and neural tissue may all be possiblesources of the tumour. Young adultsare most frequently affected, but thetumour has no sex predilection. Thegranular cell tumour displays slowgrowth and is poorly demarcated.Hence treatment requires surgical exci-sion with moderate margins. A variant,the congenital epulis of the newborn,usually occurs on the anterior maxillaof infants. A rare malignant form isalso known.

NeurofibromaNeural tumours are very common in

the head and neck, and comprise overone-quarter of all peripheral-nervetumours. The neurofibroma is a tumourof nerve-sheath cells, either Schwanncells or perineural fibroblasts. Theselesions present as painless submucosalnodules and occur most often in thetongue. They may also be found in thelips, buccal mucosa, and alveolarridge.

Intrabony lesions, usually associatedwith the inferior alveolar nerve, havealso been described. Solitary neuro-fibromas are common among youngadults and show no sex predilection.They are removed by simple excisionand generally do not recur.The presence of multiple neuro-

fibromas is characteristic of neuro-fibromatosis. The lesions may be dis-crete and nodular or poorly demarcatedand pendulous. Patients are frequentlydiagnosed in their teenage years andmust be followed carefully becausethey carry a high (15%-20%) risk ofdeveloping malignant neural tumours.

SchwannomaThe schwannoma (or neurilem-

moma) is a benign tumour of Schwanncells (Figure 2). Like the neuro-fibroma, the schwannoma is a slow-growing, painless mass that can presentat any age. Schwannomas are two tofour times more common in womenthan in men. More than half of all in-traoral lesions occur in the tongue; theremainder are located throughout theoral cavity. This tumour is also found in

Figure 1Fibro-Epithelial Polyp on Buccal Mucosaof a 42-Year-Old Male

This condition was caused by chronic cheek biting andhad been enlarging slowly over a period of two years.

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Figure 2Schwannoma of the Tongue in a 53-Year-Old Male

This asymptomatic slow-growing lump must bebiopsied to establish the diagnosis.

CAN. FAM. PHYSICIAN Vol. 34: JUNE 1988

bone and in patients with neuro-fibromatosis. Solitary lesions requirelocal excision. Some lesions have acystic appearance.

Traumatic neuromaThe traumatic, or amputation,

neuroma is not a true neoplasm.Rather, it represents an abortive at-tempt by a peripheral nerve to regener-ate following section. This conditionoccurs most often when there is someimpediment between the proximal partofthe nerve and the distal nerve sheath.As might be expected, this lesion dis-plays neither age nor sex specificity. Incontrast to the benign neural tumoursdiscussed earlier, the traumatic neu-roma is usually tender or painful on pal-pation. Other possible symptoms in-clude paraesthesia and loss of sensa-tion. These submucosal nodules sel-dom exceed two cm in size and are mostcommon in the region of the mental fo-ramen. Other occurrences have beenreported in the alveolar ridges, in thelips, and on the tongue, following deeplacerations. The treatment is simple ex-cision.

ExostosesBony excresences or tori are com-

mon findings in the oral cavity. Theyare not true neoplasms of bone, but aredevelopmental phenomena. Theyrarely exceed one cm in diameter.The torus palatinus is the most com-

mon exostosis, occurring in 20%-25 %of the population. Women are affectedalmost twice as often as are men. Thistorus is found in the midline of the hardpalate and can assume a variety ofshapes. Most tori appear in the firstthree decades of life. The overlyingmucosa may appear blanched and canbecome ulcerated.

In general, mandibular tori are ob-served bilaterally on the lingual aspectsof the body of the mandible, above themylohyoid line. They may be single ormulti-lobulated and are usually locatednear the premolar teeth. From one percent to 12% of Caucasian patients canbe expected to have these tori; unlikethe palatal tori, this condition has nosex predisposition.

Multiple bony exostoses are occa-sionally found on the buccal aspects ofthe posterior maxilla and, less fre-quently, on the labial aspects of the an-terior regions of either jaw. These ex-ostoses appear as multiple nodular ex-cresences covered by mucosa, which

CAN. FAM. PHYSICIAN Vol. 34: JUNE 1988

may or may not be blanched. They aremore common in Black patients.

Tori do not usually require treatmentunless they become obtrusive, interferewith eating or speaking, or preventconstruction of a denture. If treatmentis necessary, the tori are removed sur-gically and rarely recur.

OsteomaTrue tumours ofbone are rare within

the oral cavity. Patients with osteomasare generally between the ages of 10and 50, and men are affected twice asoften as are women. Osteomas can befound in periosteal and endosteal sites,and, on occasion, in soft tissue (osseouschoristomas). They are generallyasymptomatic and therefore require notreatment.The presence of osteomas should al-

ways alert the clinician to the possibil-ity that the patient has Gardner's syn-drome. This autosomal-dominant con-dition is characterized by multiple os-teomas, soft-tissue tumours, andadenomatous polyposis ofthe colon andrectum. It is the latter finding which isofgreatest importance, since the polypsare premalignant.

LipomaIntraoral lipomas are rare, although

they are common in other parts of thebody. These sessile, or pedunculated,growths have a yellow hue and a soft,fluid consistency. In adults, they areusually found in the buccal mucosa,floor of the mouth, or tongue. Treat-ment consists of simple excision.

Pleomorphic adenomaApproximately 70% of benign

tumours of minor salivary glands arepleomorphic adenomas. They presentas slow-growing, painless lumps,found most often in the palate. They oc-cur in patients of all ages, and there is aslight predilection for women. Treat-ment consists of surgical excision witha margin of normal tissue because ofthe tendency of tumour nodules to lieoutside the capsule. Careful follow-upis advised, since this tumour has a slighttendency to recur.

HemangiomaHemangiomas are proliferations of

blood vessels. It is uncertain, however,whether this process is neoplastic or a

developmental anomaly. Kaban andMulliken2 believe that these lesionscan be satisfactorily divided into true

neoplasms and vascular malforma-tions. Oral hemangiomas present asdeep red or blue-red mucosal lesionsthat are flat or raised and, in general,are poorly circumscribed. The tongue,lips, buccal mucosa, and palate are themost frequently affected sites. Traumamay result in infection and ulceration.Most cases are evident within the firstyear of life, but they often go unnoticeduntil much later. Females are affectedtwice as often as are males. Some le-sions may undergo spontaneous involu-tion during the patient's first decade oflife, while others can continue to growconcomitantly with the patient. He-mangiomas have been treated by a vari-ety of methods including surgery,cryotherapy, radiotherapy, injection ofsclerosing agents, and embolization.

Multiple angiomatous lesions havebeen associated with two syndromes:hereditary hemorrhagic telangiecta-sia (Osler-Weber-Rendu disease)and encephalotrigeminal angiomatosis(Sturge-Weber disease). In the former,the telangiectatic or angiomatous areasare found widely disseminated over theskin and oral mucosa. The lips, gin-giva, buccal mucosa, and palate aremost commonly affected. These lesionsmay undergo spontaneous hemorrhagerequiring treatment for local hemos-tasis. Some cases can be life threaten-ing. In patients who have Sturge-Weber syndrome, the angiomatous ar-eas are unilateral and confined to all orpart ofthe distribution of the trigeminalnerve, both on the face and within themouth. These patients can also sufferfrom numerous neurological problemsthat result from the presence of lep-tomeningeal angiomas and calcifica-tions.

LymphangiomaApproximately 50% of lymphan-

giomas occur in the head and neck re-gions. Like the hemangioma, thepathogenesis of these lesions remainscontroversial: lymphangiomas alsomanifest within the first decade of life,but often go unnoticed and have no sexpredilection. In the oral cavity, they oc-cur most often in the tongue as well asin the palate, buccal mucosa, gingiva,and lips. Lympangiomas frequently ap-pear as nodular lesions and may imparta transparency to the overlyingmucosa. Irritation can result in intra-lesional hemorrhage, causing the lym-phangioma to be mistaken for a heman-gioma. Large lesions of the tongue pro-

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duce macroglossia. Treatment is bysurgical excision or cryotherapy.

Pigmented LesionsA wide range of lesions display pig-

mentation in the mouth. Many of theselesions reflect implantation ofamalgamor post-inflammatory hyperpigmenta-tion. Pigmented neoplasms in the oralcavity are uncommon, and their pres-ence deserves careful examination.Melanoma comprises a much higherpercentage ofthe pigmented tumours inthe oral cavity than it does on the skin,where freckles and moles are common-place.

Pigmented neviAll types of nevi found in the skin

may also occur in the oral cavity. Al-most 40% of oral lesions are found inthe palate, while a lower percentage isfound in the labial and buccal mucosae,gingiva and alveolar ridge, and the ver-milion border of the lip. Most cases be-

come evident in the third and fourthdecades of the patient's life, and thecondition has a predilection forwomen. Most nevi are of the in-tramucosal type. The blue nevus ac-counts for a much higher proportion ofnevi in the mouth (30%-35%)3 than itdoes in the skin. Nevi are most oftenraised, sessile lesions with brown orblue-black pigmentation. Some lesionsare macular and, in rare instances, pig-mentation is absent. Intraoral nevishould be excised for diagnostic pur-poses.

Malignant melanomaIntraoral melanoma accounts for

only a small percentage of all cases ofthe tumour. It is, however, more com-mon in Japanese and in Black popula-tions than in others. Most cases of ma-lignant melanoma occur in patients be-tween the ages of 40 and 70, and menare afflicted twice as often as arewomen. The areas most frequently in-

volved are the palate and maxillary gin-givae. In general, the lesions are nodu-lar with dark, irregular pigmentation,and they may ulcerate. Treatment con-sists of wide surgical excision (whenfeasible) combined with regionallymph-node dissection. The prognosisfor patients with intraoral melanoma ispoorer than that for patients with cuta-neous melanoma, which may reflectthe late stage at which many of thetumours are diagnosed.

PremalignantEpithelial LesionsThe epithelium in the oral cavity may

undergo a variety of dysplastic changesas a prelude to the development ofinva-sive cancer. The early detection ofsuchlesions is of paramount importance inreducing the risk ofdeveloping cancer.Leukoplakia

Leukoplakia is a clinical term used todenote a white patch or plaque "thatcannot be characterized clinically or

Figure 3Irregular Hyperkeratinisation in the BuccalMucosa of an 18-Year-Old FemaleI

This patient had an empty habit of chewing her cheek.No epithelial dysplasia was present on microscopicexamination, and the condition is essentially harmless.

Figure 4Diffuse and Irregular Hyperkeratinisation

with Erythematous Patches in an 88-Year-Old Manwith a History of Alcoholism

Marked dysplasia was present microscopically. Sincethis photograph was taken, the patient developed two

squamous cell carcinomas in the tongue, both ofwhich have been surgically excised. He remains at

high risk of developing further neoplasms.CAN. FAM. PHYSICIAN Vol. 34: JUNE 19881 380

pathologically as any other disease" . 4This definition precludes the presenceof epithelial dysplasia, since this condi-tion is identifiable only during micro-scopic assessment (Figures 3 and 4).Hyperkeratosis is a more appropriateclinical term to apply to such lesions.The etiology of hyperkeratosis is di-verse and can include chronic irrita-tion, tobacco smoking and chewing,and alcohol abuse. Some cases areidiopathic.

Hyperkeratosis is most often seen inmiddle-aged and elderly men. The epi-thelium is usually white, as a result ofincreased thickness of keratin, and itmay be flat, thickened, verruciform, ornodular in texture. Lesions may be sin-gle or multiple, large or small. Thepresence of red areas intermingled withwhite areas (speckled leukoplakia) hasmore serious implications. Whatevertheir appearance, these lesions must beexamined microscopically to assess thedegree of dysplasia present. Carefulfollow-up of patients with hyper-keratosis is mandatory, especially inthose patients in whom no obviousphysical irritation is present.

ErythroplakiaThe definition of erythroplakia is

analogous to that of leukoplakia, withtwo exceptions: the lesions appear asred, velvety patches, and epithelial at-rophy, instead of hyperkeratosis, oc-curs (Figure 5). Most erythroplakiasrepresent either severe dysplasia (in-cluding carcinoma in situ) or invasivecancer. Consequently, these lesions re-

quire immediate pathological assess-ment.

Malignant TumoursSquamous cell carcinoma

Squamous cell (epidermoid) carci-noma is the most common malignancyfound in the oral cavity. Most cases oc-cur on the lower lip, tongue, and in thefloor of the mouth (Figures 6 and 7).This cancer is most prevalent in malesover the age of40, but it has been foundin all age groups. The incidence ofsquamous cell carcinoma in the oralcavity has increased in younger popula-tions of late,5 as has the incidence oforal cancer in women, perhaps becauseof the greater social acceptability ofsmoking in recent years.A number of etiologic factors are

considered important in the genesis ofsquamous cell carcinoma. Smoking,alcohol abuse, and, especially, theircombination are considered to be themost significant etiologic factors for in-traoral cancer, while exposure to sun-light is most significant for lip cancer.The effect of other factors, such as nu-trition, chronic irritation, and viral in-fections, remains unknown.The clinical signs and symptoms of

squamous cell carcinoma vary accord-ing to the site and extent of the lesion.Chronic, non-healing ulcers are com-mon presenting features. These fre-quently have rolled borders and may beassociated with a region ofleukoplakia.The ulcer is usually indurated. Some le-sions are more exophytic and may pre-

sent as large, fungating masses. De-pending on the location, invasivesquamous cell carcinoma may interferewith swallowing or speech, cause teethto loosen, inhibit proper seating ofden-tures, or restrict mobility ofthe tongue.Swelling and increased salivation maybe associated with the condition. How-ever, few patients, even among thosewho have extensive lesions, complainof pain.The treatment and prognosis of

squamous cell carcinoma depends onthe site and staging of the tumour. Le-sions are usually treated by surgery, ra-diotherapy, or a combination of bothmodalities.

Verrucous carcinomaVerrucous carcinoma usually occurs

in elderly men and is associated, insome patients, with the long-standinguse of chewing tobacco. This epithelialcancer usually has thick, white areasthat have a warty or folded surface. Thetumour grows slowly and is only super-ficially invasive. It is most commonlyfound on the buccal mucosa and the al-veolar ridge or gingiva. Treatment isprimarily surgical, and because of theexophytic nature of the lesion, theprognosis is excellent. These patientsstill require careful follow-up, since10%-15 % of them are subsequently atrisk of developing invasive squamouscell carcinoma.

Mucoepidermoid tumourThe mucoepidermoid tumour is a

malignancy of salivary glands. Thisneoplasm occurs chiefly between the

Figure 5Erythroplakia in the Alveolar and Buccal Mucosaof a 58-Year-Old Male

Biopsy showed severe epithelial dysplasia (carcinomain situ).

Figure 6Early Keratinizing Squamous Cell Carcinoma of theLip in a 72-Year-Old Man Who Had Been a Farmer

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The lip also shows actinic cheilites with mild patchy hyper-keratosis at the skin/vermilion border and loss of elasticity.Lip carcinomas are usually well-differentiated and grow ata relatively slow rate.

CAN. FAM. PHYSICIAN Vol. 34: JUNE 1988 1381

third and fifth decades of life and has anequal sex distribution. The minor sali-vary glands in the mouth most often af-fected are those in the palate, buccalmucosa, tongue, and retromolar areas.Because of the histological features andthe tumour aggressiveness, this tumourhas been categorized as low- and high-grade malignancies. Low-grade lesionspresent as painless, slowly expandingsubmucosal swellings, whereas high-grade carcinomas grow at a muchfaster rate. Surgery remains the treat-ment of choice, and elective neck-nodedissection is often indicated for high-grade lesions. Radiotherapy has alsobeen a successful treatment modality.Prognosis for low-grade tumours is ex-cellent, for high-grade tumours, fair.Central mucoepidermoid carcinoma ofthe mandible has also been described.

Adenoid cystic carcinomaAdenoid cystic carcinoma is prob-

ably the most insidious of the salivarygland tumours. It usually occurs in pa-tients over the age of40, and both sexesare affected equally. The accessoryglands affected most often are those inthe palate and tongue (Figure 8). Thetumours are often painless submucosalmasses which may show surface ul-ceration. The adenoid cystic carcinomais a slow-growing, but relentless,tumour with a propensity for great ex-tension along nerves. It can cause ex-

tensive tissue destruction through di-rect extension, but only metastasizeslate in its course. Treatment involveswide surgical excision or wide fields ofradiation (or both). Because thistumour is known to recur many yearsafter initial treatment, considerablelong-term follow-up is required.

LymphomaNearly all lymphomas occurring in

the oral cavity are of the non-Hodgkin's type. Most intraoral cases ofextranodal non-Hodgkins's lymphomaare found within Waldeyer's ring, butsome are located on the palate and max-illary gingiva. These lesions occur pre-dominantly in elderly patients, wherethey begin as a swelling that can pro-gress to ulceration and then to the for-mation of extensive, necrotic masses.Some lesions develop within the jawbone and may cause pain and mobilityof teeth. Treatment is radiation or che-motherapy. The prognosis depends onthe histological type and stage of thetumour.

OverviewThis article has summarized the wide

range of neoplastic tumours that can oc-cur in the oral cavity. This informationmay prove useful to the family physi-cian in his or her daily practice. U

AcknowledgementThe authors wish to thank Dorothy

Tsang for secretarial assistance withthe manuscript.

References1. Barnes L, ed. Surgical pathology ofthehead and neck. Vol. 1 & 2. New York: MDakker Inc, 1985.2. Lucas RB. Pathology oftumours of theoral tissues. 4th ed. Edinburgh: ChurchillLivingstone, 1984.

3. Smith RM, Turner JE, Robbins ML. At-las of oral pathology. St. Louis: C.V.Mosby, 1981.4. Batsakis JG. Tumors of the head andneck: clinical and pathological considera-tions. 2nd ed. Baltimore: Williams andWilkins Co., 1979.5. Kaban LB, Mulliken JB. Vascularanomalies of the maxillofacial region. JOral Maxillofac Surg 1988; 44:203-13.

6. Buchner A, Hansen LS. Pigmented neviof the oral mucosa: a clinicopathologicstudy of 32 new cases and review of 75cases from the literature. Oral Surg OralMed Oral Pathol 1980; 49:55-82.7. WHO Collaborating Centre for OralPrecancerous Lesions. Definition ofleukoplakia and related lesions: an aid tostudies on oral precancer. Oral Surg OralMed Oral Pathol 1978; 46:518-39.8. Krolls SO, Hoffman S. Squamous cellcarcinoma of the oral soft tissues: a statisti-cal analysis of 14,253 cases by age, sex andrace of patients. J Am Dent Assoc 1976;92:571-4.

Figure 7Squamous Cell Carcinoma of the Tonguein a 68-Year-Old Male Presentingas a Typical Malignant Ulcer with Rolled Border

Carcinoma of the tongue occurs chiefly on the sidesit is rare on the dorsum.

Figure 8Adenoid Cystic Carcinoma Arising in thePalatal Salivary Glands in a 34-Year-Old Female

The lesion had been present for three months. This is themost common intraoral site for all salivary gland tumours.The speed of growth is usually the chief indicator of benig-nity or malignancy.

1382 CAN. FAM. PHYSICIAN Vol. 34: JUNE 1988