Clinical Medical & Case Reports

Open Journal of

ISSN2379-1040

Volume4(2018)Issue2

TandonA

OpenJClinMedCaseRep:Volume4(2018)

Extraneouskeratocysticodontgenictumor:AnunusualpresentationAnkitaTandon*;NarendraNathSingh

*AnkitaTandon

DepartmentofOralPathologyandMicrobiology,ITS‐CDSR,Muradnagar,Ghaziabad,UttarPradesh,

India

Phone:098‐9198‐7040;Email:drankitatandon7@gmail.com

Abstract

OdontogenicKeratocystisclassi�iedasadevelopmentalcystderivedfromtheenamelorganorfromthe

dental lamina. The 2005 WHO classi�ication uses the term ‘Keratocystic Odontogenic Tumor’.

Odontogenic Keratocysts manifests as radiolucencies that may appear anywhere in the maxilla or

mandibleincludingmandibularramus(extraneousvariant).ThetreatmentofOdontogenicKeratocystof

thejawremainscontroversialbuttheconservativetreatmentmodalitybasedonenucleationwithor

withoutdecompressionoffersaneffectiveoptionininaccessibleareaslikeramustherebyfacilitatinglow

patientmorbidityanduneventfulpostoperativeperiod.Wereportacaseof40yearoldmalepatient

whichpresentedwithswellingintheparotidarea.TheradiographicandCTevaluationrevealedanoval

radiolucentdefectinleftmandibularramuswithscleroticborders.Thecasewastreatedconservatively

andshowednorecurrenceoveratwoyearfollowup.

Keywords

odontogenickeratocyst;enucleation,mandibularramus

Introduction

The odontogenic keratocyst (OKC) is an epithelial developmental cyst. The first case was

presentedbyMIKULICZas"dermoidcyst"but ‘OdontogenicKeratocyst’wasintroducedbyPindborg

(1956)todesignateanyjawcystinwhichkeratinwasformedtoalargeextent[1,2].Thecystwastermed

"odontogenickeratocyst"byPhilipsen(1956)[3]andhasbeenoneofthemostcontroversialpathological

entitiesofthemaxillofacialregion.Duetoitsclinicopathologicalfeatures,therevisedclassificationof

HeadandNeckTumors(2005)byWHO,reclassifiedtheodontogenickeratocystasabenignintraosseous

neoplasm,recommendingthetermkeratocysticodontogenictumor(KCOT)[4].

Theodontogenickeratocyst(keratocysticodontogenictumour)isanaggressivecysticlesionmost

frequentlypresentinsecond,thirdandfourthdecadesoflifeattheposteriormandible[5];in(65%to

83%) [6]ofmalepatients [5].The frequencyofOKChasbeenreported tovary from3%to11%of

odontogeniccysts[6].

Fromaclinicalpointofview,OKCisoneofthemostaggressiveodontogeniccystsduetoitshigh

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recurrence rate, its fast growth, and its predisposition to invade adjacent tissues [3]. Malignant

transformation into squamous cell carcinoma, though rare, has been reported [4]. These striking

inconsistencies are thought to be related to different lengths of postoperative follow‐up periods,

operative techniques employed or inclusion of cases with nevoid basal cell carcinoma syndrome

(NBCCS)[4].

Thereisawidevarietyofsurgicalapproachesdependingonthesizeandextentofthepathology,

includingdecompression,curettage,marsupialization,enucleationorresection,withmorescrupulous

surgicalapproacheslinkingtoabetterprognosis[4].Thepresentcase,howeverhighlightsOdontogenic

keratocystpresentintheleftramusofmandibleandtreatedwithaconservativeapproach.

CasePresentation

A40yearoldmalepatientvisitedtheoutpatientdepartmentwithchiefcomplaintofenlargement

inleftmidfacialregionsincethreemonths.Theclinicalexamination,extraorally,revealedleftfacial

asymmetrywithswellinginparotidregionalsoextendingtowardstheinfraorbitalmargin(Figure1).

Theswellingrepresenteddiffusebordersandonlymildstretchingofskin.Thesurfacetemperatureofthe

swellingwasnotelevated.Intraorallytherewasadiffusesofttissueedemathatrepresentedinleftretro

molararea.Thehardtissueexaminationrevealedmissingteethinleftposteriormandibularsegment

andgeneralizedlossofattachmentofteeth.TheOrthopantomographrevealedanovalradiolucencyin

leftramusareawithwellde�inedscleroticbordersmeasuringroughly1.5cmingreatestdimensions(Fig

2).ThecoronalCTscanofmaxillahowever,revealedapearshapedradiolucentdefect in leftramus

measuring3x1.5cmindimensions(Figure3).Also,thedefectrevealedfocalradioopaquefoci.

Thebiopsywasthenplannedwithcompleteenucleationofthepathology.Thespecimenwas

submittedforhistopathologicalevaluationandthesectionsrevealedthepresenceofparakeratinized

strati�iedsquamousepitheliumoverlying�ibrocellularconnectivetissuestroma.Theparakeratinized

epitheliumappeared5‐6layeredwithfocalameloblastomatoidproliferationsofupto10‐15layersat

places.Wellde�inedpalisadedbasallayercontainingcolumnarcellswithintenselybasophilicnucleiand

increasedmitotic�iguresbothbasallyandsuprabasallywereevident.Thesuper�iciallayerappeared

corrugated.Theconnectivetissuestromarevealedsatellitecystsuspendedinedematousstromawith

collagen�ibresandplump�ibroblasts.Adiffuse in�iltrationofchronic in�lammatorycellsalongwith

endotheliumlinedbloodvesselsandextravasatedRBCswerealsorevealed(Figure4).

Basedontheclinical,radiographicandhistologicfeaturesadiagnosisof“extraneousodontogenic

keratocyst”wasmade.Thepatientwaskeptundersurvillliencetochecktherecurrences,ifany.

Discussion

Cystsaremorecommoninthejawsthaninanyotherbonebecauseoftheubiquitouspresenceof

epithelialrestsafterodontogenesis[7].Inthepast,odontogenickeratocysts(OKCs)wereconsideredto

initiatefromtheprimordium(organatitsearlierstageofdevelopment)ofatoothbeforemineralization

hadtakenplaceandhencecalledprimordialcysts.Astheyearspassed,thethoughtgainedgroundthat

remnantsofthedentallaminaplayedarole,particularlybecausemanyOKCsseemedtohaveanatypical

relationtoteethwhenpresentinginthedentatearea.Theirpresentationintheascendingramusofthe

mandiblewasexplainedbythehypothesisthatoffshootsofthedentallaminawereprobablyresponsible

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for the development of keratocysts in this region and for this reason the term ‘‘laminal cysts’’was

suggestedbyToller[8].Thedentallaminaarisesasaninvaginationofthebasallayeroftheepithelium

overlyingthefuturemandibularandmaxillaryalveolarprocessafterapproximately6weeksofgestation.

Thereafter,itloosensthisconnectionbydisintegration.Epithelialremnants,however,maypersistand

aremostlikelytobefoundinthegingivaoreventheperiodontium,becausewhentheteetheruptthey

passtheareawherethedentallaminawaslocated[8].

KCOTsaremoreoftenlocatedinthemandible,mainlyintheposteriorbody,theangleregionand

theascendingramus[9].Downwarddisplacementoftheinferioralveolarnervehasalsobeenreported [9]. Smallerodontogenickeratocystsusuallyappearas asymptomatic; larger cystsmaycausebony

expansion,andbeaccompaniedbypain[10].These lesionsaremorecommoninmalesthanfemales,

occuroverawideagerange,andaretypicallydiagnosedduringthe2nd,3rd,or4thdecade[10]asalso

seeninourcase.

Radiographically,odontogenickeratocystcanbeofdiversevarieties‐follicular,envelopmental,

replacemental,extraneousandcollateral[11].Main[2]suggestedthatthosecystswhichoccurinthe

ascending ramus away from the teeth are referred to as ‘extraneous’. The main radiographic

characteristicsofOKCareunilocularradiolucentarea,withscallopedborders,surroundedbya �ine

scleroticlineandwithlittleornoexpansionofcorticalbonessimulatingthe�indingsofourcase.The

liningistypicalandthecysticcavityalwayscontains�luidorsemi�luidmaterialthatmayabsorbX‐raysto

differingdegrees.Theluminalcontentcanhavedifferentconsistenciesdescribedasa‘‘straw‐colored

�luid’’;‘‘thickpuslike’’material;oracaseous,thick,cheesy,milkwhitemass.Thevaryingconsistencies

replicatevariousdensitiesofkeratinaciousdebris[12].Theefforttoaspiratethecysticcontentsinour

casecouldnotrevealanysuchmaterial.

OKC,eventhoughtheygrowmainlythroughcancellousbone,haveacapsuleandanepithelial

lining.Thus,thecontentde�initelygeneratesahigherhydrostaticpressuredistributedalongtheentire

surfaceduetowalldialysis.SinceOKCgrowthisslow,thepressurewouldbesuf�icienttoprovokea

reaction of adjacent bone, with deposition of bone matrix and minerals (sclerotic border). In the

panoramictechnique,theincidenceoftheX‐raybeamsisnotalwaysparalleltoawallofthelesionbutat

times isoblique,blurring thebordersand impairing clarity.A combinationof these factorsmaybe

responsible for the presence of a radiopaque halo in a segment and its absence in another, thus

preventingthedistinctionofthelesions[13].

CTprovides additional informationabout the contentsof the lesion.Thehighattenuation is

thoughttobetheresultofahighproteinconcentrationinthecondensedkeratin�illingthelumen.Other

possibilitiescouldincludehemorrhageorcalci�ication.Ifthehighattenuationrepresentedcalci�ication

rather than simply a high protein content, the differential diagnosis would include a Gorlin cyst

(calcifying odontogenic cyst), Pindborg tumor (calcifying odontogenic tumor), and adenomatoid

odontogenictumor.HighattenuationonCTscansalsocouldhavebeencausedbyblood.Ahemorrhagic

bonecyst(simplebonecyst),vascularlesionormalformationcanalsobeconsideredinthedifferential

diagnosis. However,with a vascular lesion, a change in attenuation should occurwhen a contrast‐

enhancedCTscaniscomparedwithanonenhancedCTscan[12].Theselesionsareoftendif�icultto

evaluateonthebasisoftheirradiographicfeaturesalone.The�inaldiagnosismustbedonebasedon

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macroscopic andmicroscopic examinationbecause several other lesions (including ameloblastoma,

adenomatoidodontogenictumor,calci�iyingodontogeniccyst,etc.)showsimilarradiographic�indings

[7]. Other differential diagnosis may include ameloblastoma, simple bone cyst and arteriovenous

malformations[9].

Recent genetic and molecular research has lead to important breakthroughs as to the

physiopathologyofKCOTs.Someproliferationmarkers(PCNA,p53andKi‐67)arealreadyknowntobe

correlatedwiththispathology.Othermarkersknowntoberapidlyinducedinresponsetogrowthfactors,

tumorpromoters,cytokines,bacterialendotoxins,oncogenes,hormonesandshearstress,suchasCOX‐2,

mayalsoshedsomelightoverthebiologicalmechanismsinvolvedinthedevelopmentofthisaggressive

neoplasmofthe jaws[9].PTCH(“patched”),atumoursuppressorgeneinvolvedinbothNBCCSand

sporadicKCOTs,occursonchromosome9q22.3‐q31.Normally,PTCHformsareceptorcomplexwiththe

oncogeneSMO(“smoothened”)fortheSHH(“sonichedgehog”)ligand.PTCHbindingtoSMOinhibits

growth‐signaltransduction.SHHbindingtoPTCHreleasesthisinhibition.IfnormalfunctioningofPTCH

islost,theproliferation‐stimulatingeffectsofSMOarepermittedtopredominate[11].

According to Main (WHO, 2005), KCOTs have following pathognomonic histopathological

features:

–Wellde�ined,oftenpalisaded,basallayerofcolumnarorcuboidalcells.

–Intensebasophilicnucleiofthecolumnarbasalcellsorientedawayfromthebasementmembrane.

–Parakeratoticlayerswithanoftencorrugatedsurface.

–Mitotic�iguresfrequentlypresentinthesuprabasallayers[9]

Keratinizationcanoccurintheliningofmanydifferenttypesofdentalcysts,butthereisaspeci�ic

typeinwhichthekeratinispredominantlyoftheparakeratinizingvariety[13].

TheclinicallyaggressivebehaviorofOKCisaresultofthepropertiesoftheliningepithelialcells

and the connective tissue capsule. Raised osmolality of cystic �luid also plays an important role in

expansilegrowth,whileanalternativeviewtothisisthat,themuralproliferationscontributestothe

enlargementoftheselesions.Thislatterviewissupportedbyauthorswhobelievedthatthemultilocular

outline exhibited by OKC suggested a multicentric pattern of cyst growth brought about by the

proliferationoflocalgroupofepithelialcellsagainstasemisolidcysticcontent.Theaggressivebehavior

ofOKCwasfurtherattributedtotheinfoldingoftheepithelialliningintothecapsulewhichsuggested

thatthiswastheresultoftheactiveepithelialproliferation[1].Throughprojectionsdescribedas“glove

�ingers”andthroughtheproductionofosteolyticenzymes,OKCsgrowthroughmedullaryspaces,rarely

deformingcorticalplates[12].

In1984,Ahlforsandotherssuggestedthat“iftheOKCwererecognizedasatrue,benigncystic

epithelialneoplasm,thequestionofmodi�iedtreatmentscheduleswouldberaised”[11].Thethinfriable

epitheliallining,partialsurgicalaccess,skillandunderstandingofthesurgeon,corticalperforation,and

thedesiretopreserveadjacentvitalstructuresmayleadtoincompleteremovaloftheOKC[9].Thereisa

wide variety of surgical approaches depending on the size and extent of the lesions, including

decompression, curettage, marsupialization, enucleation or resection [4]. Among the adjunctive

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therapies thathavebeenproposed,useofCarnoy’ssolution,peripheralosteotomy,cryotherapyand

electrocauteryarethemostcommonones[9].Carnoy’ssolution,whichhasameanbonepenetration

depthof1.54mmafter5minutes,isconsideredenoughtoeliminateanyepithelialislandswhichare

boundtobelocatedrathersuper�iciallyinthedefect[9].Similartreatmentmodalitywasexecutedinour

caseandthepatientshowednorecurrenceoveratwoyearfollowupperiod.Also,themainadvantageof

theconservativetreatmentisthepreservationofbonestructureandthisprovestobelesstraumaticfor

thepatient,eliminatingmedicationandhospitalizationexpenses,andinmostcases,avoidtheneedof

extensivereconstructions[14].

ThemostimportantfeatureoftheOKCisitsunusuallyhighrecurrenceratethatrangesfrom5%to

62.5%[15].Brannonstatedthattherecurrencerateofkeratocyst,whichwastreatedwithenucleation

alone,was12%[15].Woolgaretal.listed3differenthypothesesthatmightexplainthehighrecurrence

rateinKCOT:

(a)Incompleteremovaloftheoriginalcystlining.

(b)GrowthofanewKCOTfromsmallsatellitecystsorodontogenicepithelialrestsleftbehindbythe

surgicaltreatment.

(c)DevelopmentofanunrelatedKCOTinanadjacentregionofthejawsthatisinterpretedasarecurrence

[9].

Mostrecurrencesarethoughttopresentwithinthe �irst5–7years,althoughrecurrenceshavebeen

reportedtooccur9ormoreyearsafterthe initial treatment.Gosauetal.reportedthatrecurrences

occurredmoreofteninlargerlesionsthaninsmallerones,althoughKuroyanagietal.hasreportedthat

sizedidnothaveanyin�luenceintherecurrenceratesportrayedintheirstudy.Nakamuraetal. and

Myoungetal.foundthatOKCsintheangle‐ramusregionofthemandiblehadahighertendencytorecur

thanthoseinthemandibularbody.Theyexplainedthisdifferencebecauseofthedif�icultyinremoving

OKCsfromtheramus[7].

Figure1:Extraoralphotographrevealingleftfacial

asymmetrywithswellinginparotidregion

Figure 2: Orthopantomograph showing an oval

radiolucencywithwellde�inedscleroticborders in

leftmandibularramus

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Figure 2: Orthopantomograph showing an oval

radiolucencywithwellde�inedscleroticbordersin

leftmandibularramus

Figure 4: Photomicrograph showing cystic lining

withpathognomonic features (Trinocular research

microscope (Kyowa), Digital camera (Sony cyber‐

shot;7.2megapixels,CarlZeisslens,H&Estain,400

X)

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13.FerreiraJuniorO,DamanteJH,LaurisJR.Simplebonecystversusodontogenickeratocyst:differentialdiagnosis

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ManuscriptInformation:Received:September21,2017;Accepted:January17,2018;Published:January31,2018

*1 2AuthorsInformation:AnkitaTandon ,NarendraNathSingh

1DepartmentofOralPathologyandMicrobiology,ITS‐CDSR,Muradnagar,India2DepartmentofOralPathologyandMicrobiology,KothiwalDentalCollege&ResearchCentre,India

Citation:TandonA,NathSinghN.Extraneouskeratocysticodontgenictumor:Anunusualpresentation.OpenJClinMedCase

Rep.2018;1367.

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