ImagingofSynovialSarcomawithRadiologic-PathologicCorrelation•Synovialsarcomaisthefourthmostcommonmalignantprimarysoft-tissueneoplasm.Theradiologicmanifestationsandspectrumofsynovialsarcomareflecttheunderlyingpathologicappearance.Wehavereviewed,illustrated,andcorrelatedtheclinical,pathologic,andradiologicfeaturesofsynovialsarcomaaswellasthetreatmentandprognosis.•Althoughtheradiographiccharacteristicsofsynovialsarcomaarenotpathognomonic,thefindingsofasoft-tissuemass,particularlyifcalcified,nearbutnotinajointinayoungpatient(15–40yearsofage)areverysuggestiveofthisdiagnosis.Cross-sectionalimagingfeaturesarevitalforstagingextentandforplanningsurgicalresection.•Theyalsofrequentlyrevealsuggestiveappearancesofmultilobulationandmarkedheterogeneity(creatingthetriplesign)withhemorrhage,fluidlevels,andsepta(creatingthebowlofgrapessign).Twofeaturesassociatedwithsynovialsarcomathatmayleadtoaninitialmistakendiagnosisofabenignindolentprocessareslowgrowth(averagetimetodiagnosis,2–4years)andsmallsize(<5cmatinitialpresentation);inaddition,theselesionsmaydemonstratewell-definedmarginsandhomogeneousappearanceoncross-sectionalimages.•Synovialsarcomaisanintermediate-tohigh-gradelesion,and,despiteinitialaggressivewidesurgicalresection,localrecurrenceandmetastaticdiseasearecommonandprognosisisguarded.Understandingandrecognizingthespectrumofradiologicappearancesandtheirpathologicbasesallowimprovedpatientassessmentandareimportantforoptimalclinicalmanagement.Synovialsarcomawithanintermuscularoriginadjacenttothehipofan18-year-oldmanwhonoticedanenlargingsoft-tissuemass.(a,b)AxialT1-weighted(a,)andT2-weighted(b)magneticresonance(MR)imagesshowalargejuxtaarticularheterogeneoussoft-tissuemass(M)withsignalintensityslightlyhigherthanthatofmusclewithT1weightingandintermediatesignalintensitywithT2weighting.Thelesioniscenteredbetweentherectus(arrow),tensorfascialata(T),andsartorius(S)muscles,whicharedisplaced.Asmallamountofintermuscularfatisseenposteriorly(arrowhead).(c)Photographoftheaxiallysectionedgrossspecimenrevealssimilarfeatureswithaseptated,multilobulatedsoft-tissuemass(*)arisingbetweentherectus(arrow),tenorfascialata(T),andsartorius(S)muscles.Synovialsarcomaoftheposteriorchestwallina31-year-oldmanwithanontender,progressivelyenlarging,soft-tissuemass.(a)Axialpostcontrastcomputedtomographic(CT)scanshowsalargeposteriorchestwallmasswithlowattenuationcentrally(*)resultingfromnecrosisandathicknodularwallperipherally(arrows).(b)Photographoftheaxiallysectionedgrossspecimenrevealssimilarfeatures,withnecrosis(N)centrallyandathicknodularwallofviabletumor(T)peripherally.•Synovialsarcomaadjacenttotheankleina37-year-oldwomanwithasoft-tissuemassnotedaftertraumaanddevelopmentofhematoma.(a)Angiogramshowsdensetumorstainingandneovascularity(arrowheads)ofthelargesoft-tissuemassadjacenttotheankle.Theposteriortibialarteryisdisplaced(arrows).(b)AxialT2-weighted(2000/80)MRimagerevealsmarkedheterogeneityandmultilobulation(bowlofgrapessign)withthetriplesign(areasofhigh[H],intermediate[I],andlow[L]signalintensity),fluidlevels(arrowheads)resultingfromhemorrhage,andcorticalerosion(arrows).(c)Photographofthesectionedgrossspecimenshowsthemultilobulatedhemorrhagicmorphology(*)correspondingtotheMRimagingappearance.
