Rev. bras. ortop. vol.51 número3

rev bras ortop.2016;51(3):370–373

SOCIEDADE BRASILEIRA DE ORTOPEDIA E TRAUMATOLOGIA

w w w . r b o . o r g . b r

Case

report

Solid

variant

of

aneurysmal

bone

cist

on

the

distal

extremity

of

the

radius

in

a

child

夽

Adriano

Jander

Ferreira,

Sebastião

de

Almeida

Leitão,

Murilo

Antônio

Rocha,

Valdênia

das

Grac¸as

Nascimento

_,

_Giovanni

_Bessa

_Pereira

_Lima,

Antonio

Carlos

Oliveira

de

Meneses

UniversidadeFederaldoTriânguloMineiro,Uberaba,MG,Brazil

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Articlehistory: Received5April2015 Accepted28May2015 Availableonline30March2016

Keywords:

Aneurysmalbonecysts Bonetumor

Radiusfractures Child

a

b

s

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r

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c

t

Thesolidvariantofaneurismalbonecysts(ABC)isconsideredrare.Itoccurswithgreater frequencyinpediatricpatientsandinthetibia,femur,pelvisandhumerus.Wepresenta caseofametaphyseallyticlesiononthedistalextremityoftheradiusinachildwhose radiographwasrequestedafterlow-energytrauma.Thehypothesisofapathologicalbone fracturesecondarytoananeurysmalbonecystwassuggested.Afterbiopsy,thechild under-wentintralesionalexcisionwithoutbonegraftingandthehistopathologicalfindingswere compatiblewiththesolidvariantofaneurysmalbonecyst.

PublishedbyElsevierEditoraLtda.onbehalfofSociedadeBrasileiradeOrtopediae Traumatologia.ThisisanopenaccessarticleundertheCCBY-NC-NDlicense(http:// creativecommons.org/licenses/by-nc-nd/4.0/).

Variante

sólida

do

cisto

ósseo

aneurismático

na

extremidade

distal

do

rádio

em

uma

crianc¸a

Palavras-chave:

Cistosósseosaneurismáticos Neoplasiasósseas

Fraturasdorádio Crianc¸a

r

e

s

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o

Avariantesólidadocistoósseoaneurismático(COA)éconsideradalesãorara,ocorrecom maiorfrequêncianospacientespediátricose nosossos datíbia,fêmur,pelveeúmero. Apresentamosocasodeumalesãolíticametafisárianaextremidadedistaldorádiode umacrianc¸aemque,aoexameradiográficofeitodevidoaumtraumadebaixaenergia,foi aventadaahipótesedefraturaemumossopatológicosecundáriaaumcistoósseo aneuris-mático.Apósabiópsia,acrianc¸afoisubmetidaaressecc¸ãointralesionalseminterposic¸ão deenxertoeoexamehistopatológicofoicondizentecomavariantesólidadocistoósseo aneurismático.

PublicadoporElsevierEditoraLtda.emnomedeSociedadeBrasileiradeOrtopediae Traumatologia.Este ´eumartigoOpenAccesssobumalicenc¸aCCBY-NC-ND(http:// creativecommons.org/licenses/by-nc-nd/4.0/).

夽

StudycarriedoutattheServiceofOrthopedicsandTraumatology;HospitaldeClínicas;UniversidadeFederaldoTriânguloMineiro; Uberaba;MG;Brazil.

∗ _{Correspondingauthor.}

E-mail:vallfmtm@yahoo.com.br(V.d.G.Nascimento). http://dx.doi.org/10.1016/j.rboe.2016.03.002

rev bras ortop.2016;51(3):370–373

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Introduction

Theaneurysmalbonecyst (ABC)isanexpansile pseudotu-morlesionofunknownetiology,usuallyfoundinthetibia, femur,pelvisandhumerus.1_{ThesolidvariantoftheABCwas} describedin1983bySanerkinetal.2_{duetohistological} pre-dominanceofsolidmaterialintheaneurysmalbonecyst.It isconsideredrare,accountingfor3.4–7.5%ofallABCs, occur-ringmorecommonlyinpediatricpatients.3_{Painisthemost} commonsymptom,followedbymildedemathatcanprecede thedefinitivediagnosisinupto12months.3_{Radiographyand} CTscanimagesdiscloseanexpansileosteolyticlesion indis-tinguishablefromtheABC.4

Thesolidvariantofaneurysmalbonecystischaracterized byfibroblastproliferationwithoutanycellornuclear pleomor-phism,giantcellssimilartoosteoclastsrichareas,aneurysmal sinusoids,differentiatedosteoclastswithosteoidproduction and occasional foci of degenerated calcifying fibromyxoid tissue.2

Thedifferentialdiagnosesincludesimplebonecyst, repar-ativegiantcellgranuloma,hyperparathyroidismbrowntumor, giantcelltumorandmalignantprimarytumorssuchas chon-drosarcoma,osteosarcomaandEwing’ssarcoma.5

Inthisreportwepresentthecaseofapatientwiththesolid variantofaneurysmalbonecystdiagnosedafterfractureof thedistalextremityoftheradius, secondarytolow-energy trauma.

Clinical

case

Atwo-year-oldgirlwasbroughttotheemergencyroomwith wristpainfortwodaysafterfallingontheground,according tothefamily.Parentsdeniedepisodesoffever.

Physical examination showed pain on palpation of the distal right radius, edema, limitation in passive rotation andflexion–extensionmovementsofthewristduetopain, absenceofjointstiffnessandinflammatorysigns.

Plainanteroposteriorandlateralradiographsweretaken (Fig.1),anddisclosedthepresenceoflyticmetaphyseallesion, respectingthelimitsofthedistalradialphysis,predominantly homogeneous,withcorticalthinningassociatedwithdorsal andvolarcorticaldiscontinuityofthedistalextremityofthe radius.Aftertheinitialevaluation,aCTscanwasrequested (Fig. 2) and demonstrated more clearly the characteristics ofthelesion.Bonescintigraphyshowedamonostoticlesion withfocalincreaseduptake.Thereafter,itwassuggestedthe hypothesisofdistal radiusfracture ina pathologicalbone, probablyhavinganABCasprimarylesion,withdifferential diagnoses suchasunicameral bonecyst and telangiectatic osteosarcoma.

Thechildunderwent lesionbiopsythatshowedabsence of neoplasia, but without definitive diagnosis. We opted forsurgicaltreatmentwithintralesionalexcision(curettage) associatedwithadjuvantelectrocauterizationwithout inter-positionofbonegrafts and/orbonecement. Theharvested materialwassentforhistopathologyand,aftersurgicalwound closure,thechildwasimmobilizedwithantebrachiopalmar plastercastkeptforsixweeks.

Fig.1–Anteroposterior(a)andlateral(b)radiographic viewsshowingthelyticlesionindistalradialmetaphysis.

Histopathologyshowedsparsemultinucleatedgiantcells, intermingled with partially calcified trabecular immature bone; absence ofnecrosis, mitotic figures and aneurysmal spaces;andnoevidenceofsimplebonecyst.The histopatho-logicalaspectwassuspiciousofsolidaneurysmalbonecyst, despitetheabsenceofaneurysmalvascularspacesasseenon themicroscopeimages(Fig.3).

After eight weeks new radiographs were taken (Fig. 4). Onthefourthpostoperativemonth,newradiographsshowed reactive marginal sclerosis, distancing ofthe initial lesion fromthedistalradialphysisandcorticalthickening– mod-ificationsconsistentwithinactivelesion(Fig.5).

Discussion

Thesolidvariantofaneurysmalbonecystandreparativegiant cellgranulomawereprimarilydescribedincraniofacialbones andsmalltubularbonesofthehandandfoot.2_Theyare con-sideredreactiveandnon-neoplasiclesions,althoughtheycan leadtomisdiagnosisofgiantcelltumor,hyperparathyroidism browntumorandosteosarcoma(usuallyfibroblasticor low-gradevariant).6

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Fig.2–CTscanshowingtheexpansilelyticlesionandassociatedfractureintheaxialviews(aandb);andthemetaphyseal lesionlengthinthecoronalview(c).Intheaxialview(dande)withsofttissuewindow,attenuationofsofttissueswithin theintraosseouslesionthatmayrepresentasolidcomponentorthickfluidcontentcanbeobserved.

Althoughnotspecific, the detectionoffluid levelbyCT scanand/ormagneticresonanceimagingsuggeststhe diag-nosis of ABC.7 _{The presence of solid material inside the} intraosseouslesionwasidentifiedbytheauthorsbythe analy-sisoftheCTscansofttissuewindow,althoughthediagnostic

confirmationofthesolidvariantofaneurysmalbonecystwas achievedonlythroughthehistopathologicalanalysis,withthe followingpathologistdescription:‘histopathologicalaspectis suspiciousofsolidaneurysmalbonecyst,despitetheabsence of aneurysmalvascular spaces.Immature cancellous bone

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Fig.4–Anteroposterior(a)andlateralview(b)radiographs atsixpostoperativeweeksshowingfracturehealing.

Fig.5–Anteroposterior(a)andlateralview(b)radiographs fourpostoperativemonthsshowinginactivelesioninthe distalradialextremity.

withmyxoidinterstitialtissueischaracteristicofbone frac-turecallus’.

Recentreportsofthesolidvariantofaneurysmalbonecyst includethehamateboneasreportedbyMavrogenisetal.,8_the

cervicalspinebyKarampalisetal.3_{andthetibiabyTakechi} etal.9_{Consideringthescarcityofreportsintheliteratureon} thediagnosisofasolidvariantoftheABCinthedistalradius inachild,weconsideredrelevantreportingthiscase.

Treatment recommendations for ABC include curettage associated withbone grafting. Considering the high recur-rence rates these lesions have when treated with simple curettage only, many surgeons use adjuvant phenol or ethanol.

Inthepresentcase,consideringtheinitialhypothesisof aneurysmalbonecystandduetotheproximitytothedistal radialphysis,wechosetheintralesionalcurettageassociated with adjuvant electrocauterizationwithout graft interposi-tion.Satisfactoryevolutionwasobservedduringfollowup,as shownbythepresentimageswithmarginalsclerosis forma-tion,distancingofthelesionfromthedistalradialphysisand corticalthickening,consistentwithlesioninactivity.

Conflicts

of

interest

Theauthorsdeclarenoconflictsofinterest.

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