Rev. Bras. Reumatol. vol.55 número3

r e v b r a s r e u m a t o l . 2015;55(3):313–316

w w w . r e u m a t o l o g i a . c o m . b r

REVISTA

BRASILEIRA

DE

REUMATOLOGIA

Case

report

Achilles

tendon

xanthoma

imaging

on

ultrasound

and

magnetic

resonance

imaging

Eloy

de

Ávila

Fernandes

_,

_Eduardo

_Henrique

_Sena

_Santos

,

Tatiana

Cardoso

de

Mello

Tucunduva

_,

_Antonio

_J.L.

_Ferrari

_,

Artur

da

Rocha

Correa

Fernandes

a_{DepartmentofImagingDiagnosis,UniversidadeFederaldeSãoPaulo,SãoPaulo,SP,Brazil}

b_{DepartmentoofMedicine,UniversidadeFederaldeSãoPaulo,SãoPaulo,SP,Brazil}

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Articlehistory:

Received24September2013 Accepted11December2013 Availableonline13May2015

Keywords:

Xanthoma Achillestendon Ultrasound

Magneticresonanceimaging

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b

s

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TheAchillestendonxanthomaisararediseaseandhasahighassociationwithprimary hyperlipidemia.Anearlydiagnosisisessentialtostarttreatmentandchangethedisease course.Imagingexamscanenhancediagnosis.Thisstudyreportsthecaseofa60-year-old manhavingpainlessnodulesonhiselbowsandAchillestendonswithouttypicalgoutcrisis, followedinthemicrocrystallinediseaseclinicofUnifespfordiagnosticworkup.Laboratory testsobtainedshoweddyslipidemia.Theultrasound(US)showedadiffuseAchilles ten-donthickeningwithhypoechoicareas.Magneticresonanceimaging(MRI)showedadiffuse tendonthickeningwithintermediatesignalareas,andareticulatepatternwithin.Imaging studiesshowedrelevantaspectstodiagnoseaxanthoma,thushelpinginthedifferential diagnosis.

©2014ElsevierEditoraLtda.Allrightsreserved.

Aspectos

de

imagem

do

xantoma

do

tendão

calcâneo

na

ultrassonografia

e

ressonância

magnética

Palavras-chave:

Xantoma Tendãocalcâneo Ultrassonografia Ressonânciamagnética

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e

s

u

m

o

Oxantomanotendãocalcâneoéumadoenc¸araraetemumaaltaassociac¸ãocom hiper-lipidemiaprimária.Odiagnósticoprecoceéfundamentalparaoiníciodotratamentoe paraalterarocursodadoenc¸a.Osexamesdeimagempodemauxiliarnessediagnóstico. Esteestudorelataocasodeumhomemde60anosapresentandonódulosindoloresnos cotovelosetendõescalcâneos,semcrisestípicasdegota,acompanhadonoambulatório de doenc¸asmicrocristalinas daUnifespparaesclarecimentodiagnóstico.Ostestes lab-oratoriaissolicitadosapresentavamdislipidemia.Ultrassom(US)mostrouespessamento difusodostendõescalcâneoscomáreashipoecoicas.Ressonânciamagnética(RM)mostrou

∗ _{Correspondingauthor.}

E-mail:eduardosena1@yahoo.com.br(E.H.S.Santos). http://dx.doi.org/10.1016/j.rbre.2013.12.003

314

espessamentodifusodostendões,comáreasdesinalintermediárioepadrãoreticuladono interior.Osexamesdeimagemmostraramaspectosrelevantesnodiagnósticodexantoma, auxiliandonodiagnósticodiferencial.

©2014ElsevierEditoraLtda.Todososdireitosreservados.

Introduction

Xanthomasarenonneoplasticlesionscharacterizedbyalocal concentration of lipid-laden macrophages, giant cells, and otherinflammatorycells inresponsetocholesterol deposi-tionintissues.Theyarerelativelycommon,withmostofthem occurringontheskin,especiallyontheeyelids.1_Thelesions

are most frequently seen on tendons and synovium and theyusuallyinvolvetheextensortendonsofthehands,both Achilles tendons, and patellar ligaments.1,2 _{They typically}

occuratthethirddecadewithafemale4:3ratiopredominance overmales.2

TheAchillestendonxanthoma isarare disease3 _{and is}

highlyassociatedwiththeprimaryhyperlipidemia.Theearly diagnosisisessentialsothatthetreatmentisstartedandit canchangethediseasecoursebeforethedevelopmentofan advancedcoronarydisease.

Imagingdiagnosismightbeearlierthanclinicaldiagnosis, thusitisclinicallyimportanttorecognizeimaging character-istics,especiallyultrasoundandmagneticresonanceaspects ofxanthomas.

Case

report

A male patient aged 60 with pain nodules on the elbows and Achilles tendons with no typicalgout crisis has been followed in the microcrystalline disease clinic, Depart-ment ofRheumatology, Universidade Federalde São Paulo (Unifesp). A suspected chronic tophaceous gout with an atypical presentationwasconsideredbecause ofthe nodu-lations. Laboratory tests obtained were as follows: total serumcholesterol(268mg/dL)andcholesterolfractions(HDL: 43mg/dL; LDL: 192mg/dL), triglycerides (166mg/dL) and uric acid (5.6mg/dL). He underwent ankle ultrasound (US) and magnetic resonance imaging (MRI) in the diagnostic workup.

TheUS(Fig.1)showedadiffusethickeningoftheAchilles tendonswithhypoechoicareasandothersmallhyperechoic confluences.MRI(Fig.2)showedadiffusethickeningof ten-donswithintermediatesignalareasandareticularpattern within.

Thepatientunderwentaresectionbiopsyofelbowlesions.

Discussion

TheAchilles tendon xanthoma is a rare condition of con-cern to orthopedic surgeons when planning surgeries for cosmetic deformities. The numbers of lesions, cholesterol levels,age,andgenderarecorrelated.4_{Itisimportantin}

Inter-nalMedicineand inDermatologybecause ofalinkwith a

specificchangeinthelipid metabolism,thefamilial hyper-cholesterolemia. Thefamilial hypercholesterolemia has an autosomaldominantinheritanceandischaracterizedbyan elevated LDL-cholesterol, tendonxanthomas, and coronary disease. Although xanthomas have been described in the absenceoffamilialhypercholesterolemia,thiscanbethefirst diseasemanifestation.5

Despite thexanthoma isusuallyknown asasofttissue lesion,itcanrarelybefoundinbone.6_{Thevariabilityofcell}

compositionleadstoadiscussiononwhethertheseskeletal systemlesionsaretrulytumorsornot.Histologicalfindings similartoxanthomascanbeseeninneoplasticand nonneo-plastic bone lesions.Xanthomatous changes may occur in lesionssuchasfibrousdysplasia,giant-celltumor, aneurys-maticbonecyst,nonossifyingfibroma,fibrouscorticaldefect, benignandmalignantfibroushistiocytoma,Erdheim-Chester disease,xanthogranulomatousosteomyelitis,andrenal car-cinoma metastasis. Xanthomas, therefore, can develop a conditionunrelatedtohyperlipidemia.7

Clinical manifestations of Achilles tendon xanthomas depend on the lesion sizes. The smaller lesions are often asymptomatic.Thelargerlesionsareclinicallyapparentand manifestascosmeticallydisfiguringmasseswhichcanimpair ambulationandcauselocalpainorirritatingskinsymptoms.7

Radiography,US,and MRIcanbeusedpreviouslytothe emergence of clinical manifestations. On X-rays, tendon xanthomas areshowneitherasanabnormaltendon thick-eningor softtissuenoncalcifiedmasseswithanonspecific appearance.7,8

US and MRI are effective techniques in assessing and detectingAchillestendonxanthomas.RMtendonxanthoma imagingmaypresent morphologicalorsignalchanges.The ventralmarginoftheAchillestendonisnormallyflator con-cave,butitmayhaveaconvexappearanceinaxialimaging whenaxanthomaispresent.7

MRIcharacteristicsoftendonsaffectedbyxanthomasshow eitheradiffusereticulatepattern9_{orfocalareaswithahigh}

signalonT1andT2,withthislatteraspectoccurringwhen triglycerides are predominantly deposited.5 _{In the current}

case,adiffusereticulatepatternwasobserved.Thispattern maybeexplainedbythepatient’slipidprofile–predominantly LDLfractiondyslipidemiaandtriglyceridelevelscloseto nor-malrange.

Althoughsmallareas withhigh signal,especiallyonT2, canbefoundintendonxanthomas,theyarepredominantly characterizedbyatendonenlargementonMRIwhichis indis-tinguishable from thatseen in tendondiseases with other etiologies,thuslimitingtheclinicaluseofMRIintendon xan-thomaworkup.5

rev bras reumatol.2015;55(3):313–316

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Figure1–1a)Achillestendonultrasoundextendedinthelongitudinalplane(P=proximal;D=distal)and1b)cross-sectional plane(D=right;E=left)showingmarkeddiffuseandconcentricthickeningoftheAchillestendon(arrowheadsmarkthe tendonexternalmargins)predominatinginmiddle-anddistalsectionswithadiffuseheterogeneity,withconfluent hypoechoicareas(openarrows)andthinhyperechoicfociwithinthetendonbeingobserved,whichcausealossofthe fibrillarpatternoftendons.Arrowsdelineatecalcaneuscorticalbone,(*)demonstratesKagerfatpadand(sc)isthe subcutaneoustissue.Nohyperechoicmassesareseeninthetendondespitetheextensorinvolvementofthetendon.

a fibrillar pattern. The histological correlation shows that fibrillarechoesarisefromtheinterfacebetweenendotendon septa.10_{Achillestendonxanthomashavebeendescribed as}

hypoechoicnoduleswithinthetendonorhavingadiffusely heterogeneouspattern.9

Inthecurrentcase,theUSstudywascrucialto differenti-atetheintratendinousxanthomafrompyrophosphatecrystal deposition,gout,andtendondisease.

The different tendon impairment patterns by tophi in chronictophusgouton aultrasoundstudy includesodium monourato crystal deposits, translatedashyperechoic dot-tedfociorintratendongoutytophi,whichareheterogeneous hyperechoicnodulationswithbrightdotssometimeshaving calcifications within. Ill-defined nodules, multiple grouped nodules and the presence of an anechoic halo are also described as characteristics oftophi.11 _{Thetophus can be}

locatedinvolvingthetendonhavingnorelationshipwiththe tendon,atthetendoninsertion,compressingitorwithinthe tendon,12_{thusbeingeasilydetectedonultrasound.}

AsanextendeddiffuseimpairmentoftheAchillestendon wasobservedinthecurrentcaseandnogroupedtophiwere observedashyperechoicovoidmasseswithinthetendonor calcifiedareas,thediagnosisoftophusinAchillestendonswas ruledoutbytheultrasound.

In calcium pyrophosphate disease, crystal depositionin tendons is typically linear and extended, thus an acous-ticshadowmightbegenerated.13 _{Thisappearancewasnot}

observedinthestudyeither.Thediffusethickeningpattern associatedwithhyperechoicareasobservedinAchilles ten-donssupportedtheultrasounddiagnosisofxanthoma.14

Anearly diagnosis ofxanthoma isessential sothat the treatment can be initiated and the disease course can be

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modifiedpriortothedevelopmentofanadvancedcoronary disease. Imaging studies showed relevant aspects in xan-thomadiagnosis,thusaidinginthedifferentialdiagnosis.The USwasshowntobemorehelpfulandspecifictocharacterize thiscondition.

Conflicts

of

interest

Theauthorsdeclarenoconflictsofinterest.

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