Fig.15.4A ).Inearlystages,thesecancersmayappearasraised,firm,pearlyplaquesorasirregular,roughened,orverrucousmucosalthickenings.Eitherpatternmaybesuperimposedonabackgroundofleukoplakiaorerythroplakia.Astheselesionsenlarge,theytypicallyformulceratedandprotrudingmassesthathaveirregularandinduratedorrolledborders.Histopathologicanalysishasshownthatsquamouscellcarcinomadevelopsfromdysplasticprecursorlesions.Histologicpatternsrangefromwell-differentiatedkeratinizingneoplasms(
Fig.15.4B )toanaplastic,sometimessarcomatoidtumors.However,thedegreeofhistologicdifferentiation,asdeterminedbytherelativedegreeofkeratinization,doesnotnecessarilycorrelatewithbiologicbehavior.Typically,oralsquamouscellcarcinomainfiltrateslocallybeforeitmetastasizes.Thecervicallymphnodesarethemostcommonsitesofregionalmetastasis;frequentsitesofdistantmetastasesincludethemediastinallymphnodes,lungs,andliver.
Fibromasandpyogenicgranulomasarecommonreactivelesionsoftheoralmucosa.
Leukoplakiaanderyhtroplakiaaremucosalplaquesthatmayundergomalignanttransformation.
Theriskformalignanttransformationisgreaterinerythroplakia(relativetoleukoplakia).
Amajorityoforalcavitycancersaresquamouscellcarcinomas.
Oralsquamouscellcarcinomasareclassicallylinkedtotobaccoandalcoholuse,buttheincidenceofHPV-associatedlesionsisrising.
There are three major salivary glands—parotid, submandibular, and sublingual—as well as innumerable minor salivary glands distributed throughout the oral mucosa. Inflammatory or neoplastic disease may develop within any of these.
Xerostomia is defined as a dry mouth resulting from a decrease in the production of saliva. Its incidence varies among populations but has been reported in more than 20% of individuals older than 70 years of age. It is a major feature of the autoimmune disorder Sjögren syndrome, in which it usually is accompanied by dry eyes (Chapter 5). A lack of salivary secretions is also a major complication of radiation therapy. However, xerostomia is most frequently observed as a side effect of many common classes of medications including anti-cholinergic, anti-depressant/ anti-psychotic, diuretic, anti-hypertensive, sedative, muscle relaxant, analgesic, and anti-histaminic agents. The oral cavity may reveal only dry mucosa and/or atrophy of the papillae of the tongue, with fissuring and ulcerations, or, in Sjögren syndrome, concomitant inflammatory enlargement of the salivary glands. Complications of xerostomia include increased rates of dental caries and candidiasis, as well as difficulty in swallowing and speaking.
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Inflammation of the salivary glands, referred to as sialadenitis, may be induced by trauma, viral or bacterial infection, or autoimmune disease. The most common form of viral sialadenitis is mumps, which may produce enlargement of all salivary glands but predominantly involves the parotids. Mumps produces interstitial inflammation marked by a mononuclear inflammatory infiltrate. While mumps in children is most often a self-limited benign condition, in adults it can cause pancreatitis or orchitis; the latter sometimes causes sterility.