A case of pilomatrixoma in the cheek in a 7-year-old girl Oral Science International

OralScienceInternational9 (2012) 26–28

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Oral Science International

j o u r n al hom ep a g e :w w w . e l s e v i e r . c o m / l o c a t e / o s i

Case report

A case of pilomatrixoma in the cheek in a 7-year-old girl

Koji Kashima

, Kaori Igawa, Koichi Takamori, Izumi Yoshioka, Sumio Sakoda

DepartmentofOralandMaxillofacialSurgery,FacultyofMedicine,UniversityofMiyazaki,Miyazaki,Japan

a r t i c l e i n f o

Articlehistory:

Received25October2010

Receivedinrevisedform8January2012 Accepted17January2012

Keywords:

Pilomatrixoma Calcifyingepithelioma Cheek

Ultrasonography

Magneticresonanceimaging

a b s t r a c t

Pilomatrixoma,alsoknownasacalcifyingepithelioma,isabenigntumororiginatingfromahairfollicle.

Wepresentacaseofpilomatrixomaina7-year-oldgirlcomplainingofswellinginthecheek.Clinical examinationdisclosedamass10mmindiameteranditwastotallyremoved.Themicroscopicexamina- tionshowedencapsulatedtumorsmainlycomposedofeosinophilicghostcellsandpartlywithbasophilic portionsinhyalinizedfibrousstromawithcalcification.Preoperativeultrasoundandmagneticresonance imaginggaveususefulinformationforcompletetumorexcisionthatthetumorexistedjustunderthe skinandtheriskoffacialpalsywouldberelativelylow.

© 2012 Japanese Stomatological Society. Published by Elsevier Ltd. All rights reserved.

1. Introduction

Pilomatrixoma,formerlyknownascalcifyingepithelioma,isa benigntumorarisingfromprotoepithelialcellsorhairmatrixcells, anditfrequentlyoccursinthesubcutaneoustissueoffaceandneck [1].Thislesionisusuallyreportedbydermatologistsandplastic surgeons,andnotcommonlyencounteredindentalpractice[2].In thisarticle,wepresentacaseofpilomatrixomainthecheekina 7-year-oldgirl.

2. Casereport

A7-year-oldgirlvisiteduscomplainingofswellingintheleft sideofthecheek.Shepresentedwitha1-monthhistoryofapain- less,bluishmass.Afterherfirstnoticingthetumor,ithadbeen growinggraduallyinsize.Herpasthistoryandfamilyhistorywere notcontributory.Clinicalexaminationdisclosedamass10mmin maximumdiameterinvolvingthecheek(Fig.1).Thetumorwas elastic,slightlyhard,bluish,tendertopalpationandnotfixedto theunderlyingtissues.Therewasnoregionallymphadenopathy andgeneralphysicalexaminationwasunremarkable.Neitherloss ofsensationnorsignsoffacialparalysiswereobservedinthecheek.

Althoughtherewerenosignsofodontogenicinfection,decayedand looseneddeciduousteethwerefoundinthemaxillaryfirstmolars onthebothsides.Apanoramicradiographshowedthattheroots

∗ Correspondingauthorat:DepartmentofOralandMaxillofacialSurgery,Faculty ofMedicine,UniversityofMiyazaki,5200Kihara,Kiyotake-cho,Miyazaki889-1692, Japan.Tel.:+81985853786;fax:+81985857190.

E-mailaddresses:kojikash@med.miyazaki-u.ac.jp, qq954eh9k@vega.ocn.ne.jp(K.Kashima).

wereabsorbing,whichwasabouttobereplacedbytheperma- nentsuccessionalteeth.Therewasnoradiopaqueconsolidationin theparotidandmassetericregion.Ultrasonographydemonstrated awell-defined,oval,heterogenoushypoechoicsubcutaneousmass withechogenic scattereddotsand Dopplerflow signaldidnot increasebothinthetumorandintheperipheralregion(Fig.2).

Magneticresonanceimaging(MRI)demonstratedawell-defined, 8mmin size,ovalmassinthesubcutaneoustissue oftheright cheek,withhomogenouslowT1-weightedsignalintensity,low-to- intermediateT2-weightedsignalintensity,withalackofcontinuity with the parotid gland and the masseter muscle (Fig. 3). The authorstentativelydiagnosedthemassasabenigntumorinthe leftcheek.Thelesionwasremovedwiththeoverlyingskinunder generalanesthesiawithprimaryclosureofthewoundintheusual manner.Grosslythetumorwaselasticslighthard,ovalmassmea- suring7mm×5mm×5mm,mottledwithwhite-yellowishcolor (Fig.4).Microscopically, the lesion wasencapsulated by fibro- connectivetissueinthesubcutaneoustissueandmainlycomposed ofeosinophilicghostcellswithcentralunstainedshadowinthesite ofthelostnucleus,andpartlywithbasophilicportionsinhyalinized fibrousstroma.Areasofcalcificationwerealsonoted,accompa- niedbymildchronicinflammatoryinfiltrationwithmultinucleated giantcells,fibroblasts,andangiogenesis(Fig.5).Afinaldiagnosis ofpilomatrixomainthecheekwasmade.Thepostoperativecourse wasuneventfulandtherewasnorecurrenceatfollow-up2years later.

3. Discussion

Apilomatrixomaisanodular,subepidermalbenigntumoraris- ingfromthehairmatrixanditisslightlymorecommoninfemales 1348-8643/$–seefrontmatter © 2012 Japanese Stomatological Society. Published by Elsevier Ltd. All rights reserved.

doi:10.1016/S1348-8643(12)00007-9

K.Kashimaetal./OralScienceInternational9 (2012) 26–28 27

Fig.1.Initialpresentationofthetumorshowingaslightlyhard,bluishnodule,ten- dertopalpationandnotfixedtotheunderlyingtissues.(Forinterpretationofthe referencestocolorinthisfigurelegend,thereaderisreferredtothewebversionof thearticle.)

Fig.2.Ultrasonographicappearancedemonstratingawell-defined,oval,heteroge- neoushypoechoicsubcutaneousmasswithechogenicscattereddots,andDoppler flowsignaldidnotincrease(arrow).

Fig.4.Macroscopicfindingsoftheexcisedtumorbeingelasticslighthard,oval massmeasuring7mm×5mm×5mm,mottledwithwhite-yellowishcolor.(For interpretationofthereferencestocolorinthisfigurelegend,thereaderisreferred tothewebversionofthearticle.)

andusuallyappearsinchildren,sothat60%ofcasesarereported inthefirsttwodecadesoflife[1,3].It occurspredominantly on theheadandneckwithover40%ofallcases,followedbyupper extremities[4].Ourcasewasa7-year-oldchildanditoccurredin thecheek.

Despiteitsfrequent occurrence,this lesionis notcommonly encountered in dental practice[2] and is misdiagnosed and/or missedinthedifferentialdiagnosis[1,4].Initially,thislesionwas calledcalcifyingepithelioma,becauseasebaceousglandoriginwas suspected.Later,thetermpilomatrixomawasgiven,indicatingthat thetrueoriginofthetumorishairmatrixcellsaswellasavoiding aconnotationofmalignancy[2].Theetiologyofthistumorisnot completelyunderstood,buttherearesuggestionsthatanactivating mutationinthe␤-cateningenemappedchromosome3p22–21.3 playsamajorroleinthetumorgenesis[5].

Althoughdiagnosisofpilomatrixomacanusuallybemadesolely onthebasis ofclinicalfeaturesbecauseofitssuperficialoccur- renceintheskin,theaccuracy isreportedly low,and a correct preoperativediagnosiswasmadefrom28.9%to49%ofthetime [6–8].Asfordiagnosticimaging,MRI findingsofpilomatrixoma arehomogenousintermediateT1-weightedsignalintensity,het- erogenoushighT2-weightedsignalintensity[9,10].Incomputed

Fig.3.Magneticresonanceimaging(MRI)demonstratingawell-defined,8mminsize,ovalmassinthesubcutaneoustissueoftherightparotid-massetericregion(left:

T1-weightsignalintensity,right:T2-weightedsignalintensity).

28 K.Kashimaetal./OralScienceInternational9 (2012) 26–28

Fig.5.Histopathologicfindingsinthespecimen(hematoxylin–eosinstain,left:4×,right:20×).Thetumorwasencapsulatedbyfibro-connectivetissueinthesubcutaneous tissueandmainlycomposedofeosinophilicghostcellsandpartlywithbasophilicportionsinhyalinizedfibrousstroma.Calcificationwasalsonoted,accompaniedwithmild chronicinflammatoryinfiltrationwithmultinucleatedgiantcells.

tomographic(CT)scan,itisdemonstratedasanoninfiltratingmass containingcalcificationslocatedwithinthesubcutaneoustissues [11].The ultrasound(US)findings demonstrated awell-defined natureofthelesions,internalcalcification,andaperipheralhypoe- choic rim or a complete echogenicmass with strongposterior acousticshadowing[12].Someauthors,however,insistedthatradi- ologicimaging isof littlediagnosticvalueforpilomatrixomato differentiateitfromothersubcutaneoustumorswithanycertainty [1,8].Inourcase,preoperativeUSandMRIgaveususefulinforma- tionthatthetumorexistedjustundertheskinaswellaswiththe lackofcontinuitywiththeparotidglandandthemassetermuscle, althoughwecouldnotdiagnosethelesionaspilomatrixomapre- operatively.However,ourechogenicpatternofasolidhypoechoic andavascularcomponentinformedusthatthemasswouldbea nodulepartiallycalcifiedwithinternalcalcareousformation.

Thecharacteristichistologicalappearanceofapilomatrixoma isnestsofsmallbasaloidcells thatundergokeratinization.And foreignbodyreaction,calcification,andossificationarecommon assecondary changes. Although differentialdiagnosisis varied, pilomatrixoma,firstofall,shouldbedifferentiatedfrombenign skinregionssuchasepidermalanddermoidcystsaswellasskin malignancies[8].Intheheadandneckregions,theseregionsoften presentasintraparotidorperiparotidtumorsandmaybeconfused withbenignmixedtumorsoftheparotid[8].Theotherdifferen- tialdiagnosisshouldincludevascularmalformation,branchialcyst, hemangioma,inflammatorylesion,calcinosiscuitis,andossifying hematomainourfields[3,13].

Once thediagnosis wasconfirmed, management consistsof radicalexcision.Yoshimura etal. recommendedthat thelesion shouldbeexcisedcompletely,togetherwiththeadherentskin[2].

Especiallyinthecheek,theprotectionoffacialnervefunctionis important.Inourcase,preoperativeultrasoundfindingsandMRI allowedususefulinformationthatthetumorexistedjustunderthe skinandtheriskoffacialpalsywouldberelativelylow.

4. Conclusion

Wepresentacaseofcalcifyingepitheliomaina7-year-oldgirl.

PreoperativeUSandMRIgaveususefulinformationforcomplete tumorexcision that thetumor existed just underthe skinand therisk of facialpalsy wouldbe relativelylow aswellas with thelack ofcontinuity withtheparotidgland andthe masseter muscle.

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