SOCIEDADE BRASILEIRA DE ORTOPEDIA E TRAUMATOLOGIA
w w w . r b o . o r g . b r
Case Report
Lipoma arborescens of the elbow: a case with features of a high-grade tumor 夽
Wagner Santana Cerqueira, Rayssa Araruna Bezerra de Melo, Felipe D’Almeida Costa, Juliane Comunello, Almir Galvão Vieira Bitencourt
∗, Wu Tu Chung
A.C.CamargoCancerCenter,SãoPaulo,SP,Brazil
a r t i c l e i n f o
Articlehistory:
Received20December2016 Accepted3March2017 Availableonline19March2017
Keywords:
Lipoma Elbowjoint
Magneticresonanceimaging
a bs t r a c t
Lipomaarborescens(LA)isanuncommonnon-neoplasticdisorderthatmayaffectalmost anyjoint,mainlytheknee.LAisveryrareintheelbow,andthereareonlyafewcases reportedintheliterature.ThisstudyaimedtodescribeacaseofLAintheelbow,presenting withfeaturesofahigh-gradetumor.Theauthorsreportthecaseofa51-years-oldmalewho presentedtothisinstitutionwithpainandswellingontheleftelbow.Thepatienthada seven-yearhistoryofinvestigation,withinconclusivediagnosis.Magneticresonanceimag- ing(MRI)showedanexpansivemasswithlocalaggressiveness.Duetothesecharacteristics, itwasnotpossibletodiscardsofttissuesarcomaatthedifferentialdiagnosis.Afterbiopsy andamultidisciplinaryteammeeting,theauthorsoptedforsurgicalresection.Thefinal anatomopathologicalresultconfirmedthediagnosisofLA.Despitenotbeingatrueneo- plasm,LAcancausemanysymptomsandfunctionalimpairmentoftheaffectedjoint.Itis importanttokeepthisdiagnosisinmindwhenanyexpansivemasssurroundingajointis observed.
©2017SociedadeBrasileiradeOrtopediaeTraumatologia.PublishedbyElsevierEditora Ltda.ThisisanopenaccessarticleundertheCCBY-NC-NDlicense(http://
creativecommons.org/licenses/by-nc-nd/4.0/).
Lipomaarborescensdocotovelo:umcasocomcaracterísticasdetumor dealtograu
Palavras-chave:
Lipoma
Articulac¸ãodocotovelo
Imagemporressonânciamagnética
r e su m o
Olipomaarborescens(LA)éumadoenc¸anão-neoplásicaincomumquepodeafetarquase todasasarticulac¸ões,principalmenteojoelho.OLAémuitoraronocotoveloeháape- nasalgunscasosrelatadosnaliteratura.Oobjetivodesteestudoédescreverumcasode LAnocotovelo,apresentandocaracterísticasdetumordealtograu.Osautoresrelatam ocasode umhomemde 51anos deidade queseapresentouàinstituic¸ãocomdor e inchac¸onocotoveloesquerdo.Opacientetinhaseteanosdehistóriadeinvestigac¸ãocom
夽StudyconductedattheA.C.CamargoCancerCenter,SãoPaulo,SP,Brazil.
∗ Correspondingauthor.
E-mail:almirgvb@yahoo.com.br(A.G.Bitencourt).
https://doi.org/10.1016/j.rboe.2017.03.011
2255-4971/©2017SociedadeBrasileiradeOrtopediaeTraumatologia.PublishedbyElsevierEditoraLtda.Thisisanopenaccessarticle undertheCCBY-NC-NDlicense(http://creativecommons.org/licenses/by-nc-nd/4.0/).
diagnósticoinconclusivo.Ascaracterísticasdaressonânciamagnética(RM)mostraramuma massaexpansivacomagressividadelocal.Devidoaestascaracterísticas,nãofoipossível descartarsarcomadetecidomolenodiagnósticodiferencial.Apósabiópsiaeumareunião de equipe multidisciplinar, optou-se pela ressecc¸ão cirúrgica. Oresultado anatomopa- tológicofinalconfirmouodiagnósticodeLA.Mesmoquenãosejaumaneoplasiaverdadeira, oLApodecausarmuitossintomascomcomprometimentofuncionaldaarticulac¸ãoafetada.
Éimportanteteremmenteestediagnósticoquandoqualquermassaexpansivaemtorno deumaarticulac¸ãoforobservada.
©2017SociedadeBrasileiradeOrtopediaeTraumatologia.PublicadoporElsevier EditoraLtda.Este ´eumartigoOpenAccesssobumalicenc¸aCCBY-NC-ND(http://
creativecommons.org/licenses/by-nc-nd/4.0/).
Introduction
Lipomaarborescens(LA)isararenoninfectiousproliferative processofsynovialjoints,bursae andtendonsheaths. Itis characterizedbyahyperplasticproliferation ofmatureadi- posecells,givingrisetoavilloussynovialproliferation.The term“arborescens”isbecausethesefatcellssubstitutethe subsynoviallayersgivingthe“frond-like”or“tree-like”aspect ofthesynovium.TheexactetiologyofLAremainsunknown, butitislikelytobeanonspecificresponsetojointinjuryand synovialinflammation,ratherthananeoplasm.1,2
LAisusuallymonoarticular and occursmostfrequently intheknee,particularlyinthesuprapatellarrecess.Itrarely affects the elbow, with only a few cases reported in the literature.3–7Itshowsaslightlypredilectionformalesandcan occuratanyage,althoughitismorecommonafter40year old.4Itmayinvolveextraarticularsiteslikesynovialsheaths oftendon,bicipitoradialandsubdeltoidbursae.
TheaimofthisstudyistodescribeacaseofLAintheelbow, presentingwithfeaturesofahighgradetumor.
Case report
A51-years-oldmale withcomplaintsofswellingoftheleft elbowandforearmforalmostsevenyears.Herefersprogres- sivepainandmotordeficitofbiceps,digitalandwristflexors.
Hehadnopasthistoryoftraumaorjointproblems.Physical examinationrevealedswellingofproximalthirdofleftfore- armwithdiscreteedemaoflefthand.Palpationoftheswelling waspainful.
Standard radiographs were normal. MRI of left elbow showedexpansivesolid massintheantecubital fossa.The margins were partially defined, with fat proliferation in T1WI,highsignalintensityinT2WI/STIRandheterogeneous enhancementpostgadolinium(Fig.1).Itinvolvedthesupina- tor and pronator muscles and had close relationship with biceps tendon sheath, brachial vessels, and was close to medianandradialnerves.Itextendedtotheradialtuberosity showingcorticalirregularitiesandintramedullaryhighsignal intensity.
Alongthesesevenyearsheunderwenttwobiopsieswith inconclusiveresults. Thus, alarge coreneedle ultrasound- guidedpercutaneousbiopsywasperformed.Thehistological evaluationshowedabenignandmaturelipomatousprocess
fulfilling thesubsynovialconnectivetissue,focallylinedby synovialcells.Therewerescatteredfociofchronicinflamma- torycells,renderingthediagnosisofLipomaarborescens(Fig.2).
Becauseofthesediscordantfindings(localaggressiveness onMRIandbenignlesiononpathology)thecasewasdiscussed byamultidisciplinaryteamandsurgicalresectionwasdefined forclarifyingdiagnosis.
At surgery, the lesion presented as soft mass with ill- defined contours, fibrosis, and adhered to neuromuscular bundles(Fig.3).Toresectthetumor,itwasnecessarytoper- formradialandmediannervesneurolysisandligatureofsome brachialbranches,withnofunctionaldeficits.
Histologically,thespecimenshowedsynovialtissuewitha villousarchitecture.Thestromawasreplacedbymultiplenod- ulesofmatureadiposetissueandscatterednodularlymphoid aggregates andfibrosis.Thediagnosis ofLipomaarborescens wasconfirmed(Fig.4).
Discussion
LAhasalsobeencalledvillouslipomatousproliferationofthe synovialmembranetohighlightits non-neoplasticnature.7 There isnoreportofmalignantcells inthefat orsynovial tissueofpatientswithLA.
Thediagnosisischallenging,onceitcanmimicotherartic- ularmasses(i.e.noninfectioussynovialproliferativelesions, infectiousgranulomatousconditions,depositional jointdis- easesorarticularmassesofneoplasticandvascularorigin).
Synovialosteochondromatosis,pigmentedvillonodularsyn- ovitis (PVNS), rheumatoid arthritis, tuberculous arthritis and gouty arthropathy are the most common differential diagnoses.2
TherearefewreportsregardingtheimagingfeaturesofLA.
Sincetheimagescorrelatewiththehistopathology,MRIorCT canhelptoprovideaconclusivediagnosis.Thesynoviallin- ingofanaffectedjointorbursademonstratesmultiplevilli offatfeaturesonMRIandCT.Thesefattyvilliprotrudeinto theassociatedbursalorjointeffusion.7MRIisthemodality ofchoicefordiagnosisdemonstratingvilloustree-likearchi- tecturesynovialmass,hyperintenseonbothT1WIandT2WI, without significantenhancement.On MRI,achemical-shift artifactmaybeobservedattheinterfaceofthefattyvilliwith theadjacentfluid.
Inthepresentedcase,patient’slesionpresentedwithlocal aggressivenesssignssuchascorticaldestructionandapparent
Fig.1–Magneticresonanceimagingoftheelbowshowedanill-definedmassatthedistalportionofthebicipitaltendon associatedwithfatproliferationwithinthebicipitoradialbursaanderosionoftheradiotuberositywithsubtleedemaof bonemarrow.(A)AxialimageFSET1;(B)axialimageT2SPAIR;(C)axialT1postcontrast;(D)coronalimageT1;(E)coronal imagemT2SPAIR.
Fig.2–(A)Histologically,thebiopsyshowedwelldefinednodulesofmatureadiposetissueexpandingthesynovium;(B) thesurfaceofthenoduleswasvillousandcoveredbysynoviocytes.
A
1 2
3 5
4
6
5 4
B
Fig.3–Intraoperativeimagesbefore(A)andafter(B)tumordissection.1,radialnerve;2,brachialartery;3,supinator muscle;4,bicepsbrachiimuscletendon;5,tumor;6,tumorbedafterresection.
infiltrationoftheadjacentstructures,whichmadeitdifficult todifferentiatefrommalignancy.Asthepathologicevalua- tionofthesurgicalspecimenshowednomalignantcells,we suggest amechanical degenerative processto justifythese findings.
LAistypicallyobservedatthesynoviallining,howeverthe bursaadjacent toajointalsocanbeaffected.Asanexam- ple,involvementofthesubacromial-subdeltoidbursaofthe shoulderhasbeen reportedinassociationwithrotator cuff tearsandbursitis.8
DespiteosteoarthritisisnotacausefordevelopmentofLA, manystudiescorrelateLAwithearlyonsetofosteoarthritis ofthe affected joint.They suggest thatrepeated mechani- calinjurycauseeffusion andthickening ofthe proliferated synovium, which can lead to osteoarthritis. Depending on duration of symptoms, the degeneratives changes can be worse and, for this reason, some authors postulated
surgical treatment for every patient in order to avoid this complication.9
The treatment of LA depends on the clinical manifes- tations. It is an indolent condition and does not require aggressivetreatment.Thestandardtreatmentisanopenor arthroscopicinterventionwithsynovectomyandrecurrence is uncommon. Surgery usually provides adequate relief of pain and swelling.1 There are some reportsof local injec- tion of radionuclides called radiation synovectomy. Three radionuclidesmaybeused:Yttrium-90(Y-90silicate/citrate), Rhenium-186(Re-186sulfide),andErbium-169(Er-169citrate).
Y-90isoftentheradionuclideofchoiceandhasanoptimal penetrationinthesynovium.10
In conclusion, although LA is uncommon, it must be remembered in differential diagnosis of synovial masses, even if there are signal oflocal aggressiveness. MRI helps todifferentiateLAfromotherarticularlesions.Radiologists
Fig.4–(A)Themicroscopicexaminationofthesurgicalspecimenrevealedamultilobulatedlesioncomposedofadipose tissuenodulesmixedwithfocalfibrosisandchronicinflammation;(B)thesynoviocytesatthesurfaceofthenodules allowedtheidentificationofaproliferativesynoviallesionfulloftypicaladipocyteswithinthestroma,confirmingthe diagnosisofLipomaarborescens.
andorthopedicssurgeonsshouldbeawareofitsradiological featuresinordertorecognizethisconditionandavoidmisdi- agnosis.
Conflict of interest
Theauthorsdeclarenoconflictsofinterest.
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