Rev. bras. ortop. vol.49 número2

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rev bras ortop.2014;49(2):206–209

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Case

Report

Patellar

osteochondroma:

case

report

夽,夽夽

Frederico

Barra

de

Moraes

∗

_,

_Mariana

_Christino

_de

_Melo,

_Allan

_Vieira

_Rocha,

Mauro

Rodrigues

dos

Santos

FaculdadedeMedicina,UniversidadeFederaldeGoiás,Goiânia,GO,Brazil

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Articlehistory:

Received24April2013 Accepted13May2013 Availableonline22March2014

Keywords:

Boneneoplasms Patella

Osteochondroma

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Theaimwastoreportonararecaseofpatellarosteochondroma.A60-year-oldman pre-sentedatumoronhisleftpatellathathaddevelopedovera10-yearperiod,whichisarare occurrence,consideringthepatient’sageandthesiteatwhichthetumorappeared.The clinicalconditioncomprisedmildpainandthepresenceofamass,withoutlimitationof flexion–extensionoranyneurovasculardeficit.Thetumordimensionswere8cm longitudi-nally×6cmtransversally×3cmanteroposteriorly.Itwashardenedandwasadheringtothe

patellarboneplane.Onradiographsandtomographicscans,weobservedareasofgreater densitycorrespondingtoboneandotherlessdenseareasthatcouldcorrespondto slow-growingcartilage,withirregularitiesonthepatellofemoraljointsurface.Simpleresection ofthetumorwasperformed,andtheanatomopathologicalexaminationconfirmedthatit wasapatellarosteochondroma.Osteochondroma,orosteocartilaginousexostosis,includes alargeproportionofthebenignbonetumors.Itresultsfromcellalterationsthattrigger unregulatedproductionofspongybone.Itisbasicallytreatedbymeansofsurgicalremoval ofthetumormass.Thisisnotessential,butisrecommendedinordertoavoidlesionscaused bycontiguityandtheriskofmalignanttransformation.

Osteocondroma

patelar:

relato

de

caso

Palavras-chave:

Neoplasiasósseas Patela

Osteocondroma

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Relatodeumcasorarodeosteocondromapatelar.Homemde60anosapresentoutumor napatelaesquerda quetemse desenvolvidopor 10 anos,fatoraro,considerando-se a idadedo pacientee olocalde surgimento dotumor.Dor levee a presenc¸a da massa compunhamoquadroclínico,semlimitac¸ãodaflexoextensão oudéficitneurovascular. Otumorapresentava8cmlongitudinal×6cmtransversal×3cmanteroposterior,

endure-cido,aderidoaoplanoósseopatelar.Nasradiografiasetomografiasobservamosáreasmais densascorrespondentesdeossoeoutrasmenosdensas,quepodemcorresponderà carti-lagem,decrescimentolento,eirregularidadesnasuperfíciearticularpatelofemoral.Foifeita ressecc¸ãosimplesdotumoreoanatomopatológicoconfirmouosteocondromadapatela.

夽_Please_cite_this_article_as:_de_Moraes_FB,_de_Melo_MC,_Debieux_P,_Rocha_AV,_dos_Santos_MR._{Osteocondroma}_patelar:_relato_de_caso._Rev

BrasOrtop.2014;49:206–209.

夽夽_Work_performed_in_the_Department_of_Orthopedics_and_{Traumatology,}_Faculdade_de_Medicina,_Universidade_Federal_de_Goiás,_Goiânia,

GO,Brazil.

∗ _{Corresponding}_author_.

E-mail:[email protected](F.B.deMoraes).

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rev bras ortop.2014;49(2):206–209

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Osteocondroma,ouexostoseosteocartilaginosa,abrangeumagrandepartedostumores ósseosbenignos.Eleresultadealteraçõescelularesquedesencadeiamaprodução desregu-ladadeossoesponjoso.Seutratamentoéfeitobasicamentepelaretiradacirúrgicadamassa tumoral.Nãoéessencial,masrecomendadaparaevitarlesõesporcontiguidadeeriscode malignização.

Introduction

Osteochondroma is the commonest benign tumor and accountsfor10%ofallbonetumorsand30%ofbenigntumors. Thisosteocartilaginousexostosistendstobedetectedduring childhoodand adolescenceand isless frequentinadults.1

Itresults from modification tothe growth directionofthe growthplate,whichstartstoproducehistologically disorga-nized spongybone coveredbyacartilaginous coating and, atitsbase,bytheadjacentperiosteum.Thethicknessofthe cartilaginouscoatingisrelatedtothemalignityofthetumor, especiallyinadults.

Thediagnosisofosteochondromaispredominantly radio-graphic,butitmaybediscoveredincidentallyduringpalpation ofamassinthe region affected,whichcauses pain.2 _This

painoriginatesfromdirecttraumatothetumor,orfromthe inflammatoryprocesstriggeredbythelesion.Inthecaseof osteochondromas located in the scapular belt, pelvic belt, spineorlimbroots,ordinaryradiographsmaynotshowthe cartilaginouscoating.Axialcomputedtomographyisneeded inordertodelimititsrealextent.Tumorsinthepatellaare veryrare.3–5_The_objective_of_the_present_study_was_to_report

onararecaseofpatellarosteochondroma.

Case

report

Thepatientwasa60-year-oldman.Hereportedthataround 10 years earlier,he had noted a slow and painless tumor formation in his left knee, laterally on the patella. On physicalexamination,ahardenedtumormeasuring8cm lon-gitudinally×6cmtransversally×3cmanteroposteriorlywas

observed,adheringtothepatellarboneplane,withoutother phlogistic signs. It moved together with the patella when flexion–extensionkneemovementsweremade.Therewasno neurovasculardeficitandtherangeofmotionofthekneewas notimpaired(Fig.1).

Inthe radiological evaluation, tumor formationof bone densityinthelowercenterofthepatellaoftheleftkneewas shown.Onradiographs,weobserveddenserareas correspond-ingtoboneandother,lessdenseareasthatmightcorrespond tocartilage(Fig.2).

Tomographyshowedaprimarytumoratthelowercenterof thepatella,withosteocartilaginouscharacteristicsandslow grow,andwithirregularitiesinthepatellofemoraljoint sur-face,whichsuggestedthattherewasarthrosisinthisregion (Fig.3).

Thediagnostichypothesisofpatellarosteochondromawas made,and surgical resectionwas indicatedbecause ofthe tumorgrowth.Duringtheoperation,weobservedthatthere

wasabonelesionsurroundedbyacartilaginouscoating,and simpleresectionofthetumorwasperformed(Fig.4).From anatomopathologicalexamination,thediagnosisofpatellar osteochondromawithoutsignsofmalignanttransformation wasconfirmed.Overthecourseofthefollow-up,thepatient didnotpresentanysignsofrecurrenceforfiveyears.

Discussion

Osteochondromas occur in adolescents and in bones that presentendochondralossification.Themainlocationisthe kneeregion,inthedistalmetaphysisofthefemurand prox-imalmetaphysisofthetibia;thisisfollowedbylocationsin theproximalregionofthehumerusandtheproximalfemur. Thelesionsarelocatedinthemetaphysealregionofthebone andtendtogrowinthedirectionofthediaphysis,while mov-ingawayfromtheepiphysis.6_The_case_reported_here_is_very

unusual, fortwomainreasons:the patient’s age, 60years, which was much greater than what tends tobe observed; andthelocationfromwhichthetumororiginated,thepatella, whichisalsoveryunusual.

Osteochondromasofthekneedevelopslowlyoveraperiod ofseveralyears,generally10–20years,buttherehavebeen some reportsoftumorsthat evolvedin notmorethan six months.7_Some_symptoms_in_the_knee_may_arise_as_a

conse-quenceofpatellartumors,suchastendinitis,jointlocking, limitation of flexion–extension, degenerative arthritis and, rarely,evenneurovascularcompression.8–11 _Our_patient

pre-sentedmildsymptomsofpain,butwhatinconveniencedhim mostwasthegrowthofthetumor.However,healsopresented degenerativearthritisonexamination,whichmayhavebeen afrequentoccurrencebecauseofhisolderage.

Ithasbeenshownthattheexostosisiscoveredbyathin layerofperichondriumthatadherestothecartilageand con-tinueswiththe periosteumoftheadjacent bone.Itcanbe sessileorpedunculate.Thecartilaginouscoatingtendstovary from1to3mminthickness.Theyoungerthepatientis,the thickerthecoatingis.Theinterioroftheexostosisformedby normalspongybone,whichiscontinuouswiththeadjacent metaphyseal bone.Apouch may formover the osteochon-dromaandgenerallyresultsfromtheinflammatoryprocess, whichoccursthroughirritationoftheadjacentmusclesand tendons. The pouch may containfluid and fibrous bodies, sometimescalcified.Microscopicexaminationrevealsnormal endochondral ossification; foci ofproliferativecartilage are foundinthedeeplayers.Theremaybefibroticbonemarrow, impregnatedwithdetritusfromcalcifiedcartilage.Thebone marrowfrominsidetheexostosisispredominantlyfatty.1,2,12

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Fig.1–Clinicalappearanceoftheleftkneeinanteriorview(A)andlateralview(B),showingtumorformationmeasuring 8cmlongitudinally×6cmtransversally×3cmanteroposteriorly,withhardenedconsistency,adheringtothepatella,which

didnotlimitthepatient’sflexion–extension(C).

Fig.2–Radiographsinanteroposteriorview(A)andlateralview(B),showingbonetumorformationinthelowercenterof thepatellaoftheleftknee.

Fig.3–Transversetomographicslicesthroughtheleftknee,showingtumorformationoriginatingprimarilyfromthe patella,atitslowercenter(A),whichextendedinferiorlytocreateabulgeintheskinandthesubcutaneoustissuelaterally (B).

epiphysisandthelesionstabilizes.However,growthofthese formationsaftermaturationoftheskeletonis,inmostcases, anearlysign ofmalignanttransformation.Generally, there isalowdegreeofmalignity,withagoodprognosisandlow risk of metastasis, with a good prognosis and low risk of

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Fig.4–Intraoperativeappearanceofthetumorresection(A);macroscopically,theresectionshowedanosteocartilaginous tumor(B).

Therewereno signsofmalignanttransformationofthe tumorinourpatient,suchaspainonpalpationorthepresence ofphlogisticsigns.Thedurationof10yearsthatthetumor tookto reach the size presentedwas alsoindicative ofits benignnature.Ifithadbeenmalignant,thegrowthwouldhave occurredoverashorterperiod,thusmakingitimpossiblefor theskintoadaptandcausingtypicalsignsofinflammation.

When the lesions are multiple,they represent an auto-somal dominant hereditary disease, in which the rate of malignanttransformationismorethan10%ofthecases.The incidencerangesfrom0.9to1.4%per100,000inhabitantsand thedistributionisgenerallysymmetrical.Theconditionleads toindividualsofshortstature(40%ofthecases)withvalgus deformityatthelevelsofthekneeandankleand asymme-tryofthepelvicandscapularbelts.Inthesecases,malignant transformationhasslowgrowthandappearsafterthesecond decadeoflife.1,2,11

Surgerytoresectthetumorisnotessentialinallcases.Its mainindicationsare whenthe exostosisisinterferingwith thegrowth ofthe extremity,which leadstofunctional and mechanicalalterations;inthepresenceofmalignant transfor-mation,whichischaracterizedbyathickcoatingofmorethan 2cminadults;andinthepresenceofboneerosion,vascular compressionand/ornervecompressionwithsymptomsand jointlockingpromotedbytheosteochondroma.Therelative indicationsareestheticcomplications,whichoftengiverise topostoperativeskinscarringthatisworsethantheesthetic deformityitself;andpain,whichmayoccurbecauseof bursi-tisorafterfracturing,dependingonthepatient’ssymptoms. Incasesofpatellar tumors,totalorpartialpatellectomyor onlywideresectionofthetumorcanbeperformed,inorderto improvethesymptoms.Thechoicebetweenthesedependson thetumorlocation,whetherthetumorispedunculate,tumor volumeandskinconditions.13,14

Conflicts

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Theauthorsdeclarenoconflictsofinterest.

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1.JaffeHL.Tumorsandtumorousconditionsofthebonesand

joints.Philadephia:LeaandFebiger;1958.p.558–67.

2.AlvesMPT,DiasLH,CamposMM.Osteocondromada

extremidadeproximaldaulna:relatodecaso.RevBrasOrtop.

1999;34(7):85–9.

3.SadykhovAG.Osteochondromaofthepatella.Ortop

TraumatolProtez.1962;23:77–8.

4.UdvarhelviL.Acaseofosteochondromaofthepatella.Magy

TraumatolOrthopHelyreallitoSeb.1972;15(1):23–7.

5.SarmientoA,ElkinsRW.Giantintra-articular

osteochondromaoftheknee.JBoneJointSurgAm.

1975;57(4):560–1.

6.MaurerHJ.Symmetricalosteocartilaginousexostoses

(osteochondroma)ofthepatella.FortschrGebRontgenstr

Nuklearmed.1963;98:771–2.

7.MilgramJW,JastyM.Casereport238:para-articular

osteochondromaoftheknee.SkeletalRadiol.

1983;10(2):121–5.

8.OzturanKE,YucelI,CakiciH,GuvenM,GurelK,DervisogluS.

Patellartendinopathycausedby

extraskeletalosteochondromainthelateralinfrapatellar

regionoftheknee:acasereport.CasesJ.2009;2:9341.

9.TurhanE,DoralMN,AtayAO,DemirelM.Agiant

extrasynovialosteochondromaintheinfrapatellarfatpad:

endstageHoffa’sdisease.ArchOrthopTraumaSurg.

2008;128(5):515–9.

10.SeveroA,CalieronLG,KuhnA.Compressãodonervofibular

comumporosteocondroma:relatodecaso.RevBrasOrtop.

2001;36(9):50–4.

11.TornquistFA,LeopardoCC,SegalaTC,HamidAJ.Vascular

complicationofosteochondroma:casereport.JVascBras.

2007;6(1):92–6.

12.DeMaioF,BisicchiaS,PotenzaV,CateriniR,FarsettiP.Giant

intra-articularextrasynovialosteochondromaoftheknee:a

reportoftwocases.OpenOrthopJ.2011;5:368–71.

13.LouisR,PouyeI,ContyRC,QuenumC,OuimingaRM.

Voluminousosteochondromaofthekneecap.Patellectomy.

BullSocMedAfrNoireLangFr.1968;13(3):722–9.

14.ReithJD,BauerTW,JoyceMJ.Para-articularosteochondroma

oftheknee:reportof2casesandreviewoftheliterature.Clin