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X-rayAppearanceandAdvancedImagingFindings
CalcificationsmaybeseenattheperipheryofthemassonplainX-ray.CTscanishelpfulin
determining any intraosseus extension. MRI findings in PS/MFH are intermediate signal
intensityonT1-weightedimagesandhigh-intensitysignalonT2-weightedimages.MRIhelps
definethesofttissuemass,marrowinvolvement,neurovascularstructures,andjointinvasion.
PS/MFHhasincreaseduptakeonbonescan,whichhelpsdemonstrateanymetastases.
DifferentialDiagnosis
The radiologic differential includes metastatic cancer, plasmacytoma, lymphoma, and
fibrosarcoma.
HistopathologyFindings
On gross examination,MFH is a lobulated, fleshy, gray-white mass. There may be yellow
areas of lipid or darker areas of hemorrhage. The mass may be all soft tissue or have
intraosseusextension.Themarginsofthetumorarenormallyill-definedanddestructive.Under
themicroscope,thereareplumpspindlecellsinastoriformpatterninfascicles.Apinwheel
patternisfoundespeciallyaroundvessels. Thetumorstainspositive forhistiocytic markers
CD68andlysozyme.Likeothersarcomas,PS/MFHisgradedfrom1to4,withahighergrade
having a worse prognosis. The classification and identification of PS continues to evolve.
Some pathologists believe that many of the tumors now classified as PS/MFH should be
reclassifiedwithamorespecificdiagnosissuchassynovialcellsarcomaorleiomyosarcoma,
basedoncarefulstudyofcellularmarkers.
TreatmentOptionsforThisTumor
TreatmentofPS/MFHdependsongrade,stage,andsite.Localtumorcontrolisalmostalways
accomplished with surgical resection with a wide margin. Radiation may be given
preoperativelyorpostoperatively.Preoperativechemotherapycansometimesreducethetumor
bulkandmayincreasethechancesofalimb-sparingprocedure.Selectivetranscatheterintraarterial chemotherapyhasbeenemployedtoreducesystemictoxicity. Localrecurrencesare
common.
OutcomesofTreatmentandPrognosis
TheprognosisofPS/MFHbecomesworseasthelesionislargeranddeeperinthesofttissue.
PS/MFHmetastasizestothelungs,lymphnodes,liver,andbone.
SynovialSarcoma
IntroductionandDefinition
SSisthemostcommonmalignantsofttissuesarcomainthefoot,accountingfor18%to22%of
allsuchtumors.Insomeseries,itisthesinglemostcommonsarcomaofanytypeinthedistal
lowerextremity. Thistumordeservesthefullattentionofeveryfootandankle specialistfor
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several reasons. Among these is the slow, painless growth pattern that mimics a benign
process, its peak incidence in young patients, and the serious consequences of delay in
diagnosis.
SSwasnamedin1934bySabrazesbasedonwhatappearedtobesynovialtissueonlight
microscopy.However,thenameismisleadingandbearsnorelationtotheoriginofthetumor.
Theinaccuratenamecontinuestoleadtomistakenassumptionsaboutthelocationandbehavior
of the tumor. Recent complementary DNA microarray-based studies found that the gene
expressionprofileofSSiscloselyrelatedtoneuralcrest–derivedmalignantperipheralnerve
sheathtumor.SSdisplaystwo distincttypesofchromosomal translocations t(X;18;p11;q11),
namedfusiontypeSYT-SSX1andSYT-SSX2.
IncidenceandDemographics
Most patients with SS are in their second through fifth decades, with the average age of
incidencearound28years, butSScanoccuratany age.SS mayoccur anywhereintheleg,
ankle,orfoot.
SymptomsandPresentation
Thistumorcanexhibitslow,painlessgrowth,andthereareseriousconsequencesduetothe
delayindiagnosis.Themostcommonlocationistheleg,ankle,orfoot.ThepresentationofSS
isvariableandmaymimicabenignprocesssuchasganglioncyst.Thelesionisusuallydeeply
seated,firm,andpainless,butsmallsubcentimeterlesionsarealsoseen.Thetumorisfirmto
examinationanddoesnottransilluminate.Metastasismayoccurtoregionallymphnodesand
theseshouldbeincluded inthephysical examination.Thepatient may haveamassthathas
beenpresentformonths,years,orevendecades,withslowgrowthandlittleornosymptoms.
Theremayhavebeenrecentrapidgrowthofalesionthathasbeenpresentforyearswithout
apparent change. Conversely, some SS may be very painful from the outset. The average
durationofsymptomsbeforediagnosisis21months.
X-rayAppearanceandAdvancedImagingFindings
Imagingstudiesarenotadequatetodistinguishthistumorfrombenignsofttissuemasses.Plain
radiographsarestillusefulandmayshowtheinvasivenessandthestippledcalcificationsome
SSshave. MRI findingsare“indeterminate”asdefinedpreviously,withintermediateor low
signalintensityonT1sequencesandhighsignalintensityonT2sequences.Axialimagingmay
revealthislesion’spotentialtoinvadeanddestroyadjacentbonesorsofttissues,butthetumor
mayappearwellcircumscribed.MostlesionspresentinstageII,whichindicatesithasspread
beyondthecompartmentoforigin.Imagingofregionallymphnodesshouldbeincludedinthe
MRIexamination.
DifferentialDiagnosis
Plantar fibroma can be surprisingly large and aggressive, and its appearance and location
overlapwithSS.Biopsyisrecommendedforallsofttissuetumorsgreaterthan2or3cminthe
footunlessthediagnosisisotherwiseestablishedwithcertainty.
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HistopathologyFindings
High-grade,monophasic,poorlydifferentiatedSSmayappeartobea“smallroundbluecell
tumor,” a group of tumors that includes Ewing/primitive neuroectodermal tumor (PNET),
rhabdomyosarcoma, lymphoma, and others. Final diagnosis requires immunohistochemical
staining analysis. However, immunohistochemical markers such as epithelial membrane
antigen (EMA) and cytokeratin that are considered to be the most specific for SS may be
absent.VimentinistypicallypositiveinSS.EMAandcytokeratinareusuallypositiveinSS.
S-100maybepositiveornegativeinSS.Onlightmicroscopy,SSmaybemonophasicfibrous
andbiphasic.Themonophasictypemayappeartobeamassofsmallroundbluecells,ormore
fibrouswithspindle-shapedcells.Thebiphasictypeisoffibrousareaswithcleftsorspaces
orareaswithepithelialcells.
TreatmentOptionsforThisTumor
Surgical resection with a wide margin remains the cornerstone of treatment. Both
chemotherapyandradiotherapyhavebeenshowntohaveapositiveeffectonsurvival.Inone
series,10of12patientswhohadsurgicaltreatmentforSSinthefootrequiredeitherabelowkneeoraChopartamputation.
OutcomesofTreatmentandPrognosis
OverallprognosisofSSis only fair.Approximately50% to60% ofpatientswillbefree of
diseaseat5years.Thereisaninversecorrelationbetweenprognosisandageatpresentation.
Distal lower extremity location may be a positive prognostic factor. Negative prognostic
factorsincludelargetumorsize,highhistologicgrade,andmetastasisatpresentation.
SpecialandUnusualFeatures
Recent data have shownthat SS displays two distinct typesofchromosomal translocations
t(X;18;p11;q11),namedfusiontypeSYT-SSX1and SYT-SSX2.Fusiontypeseemstohavea
significant impact on disease course and survival. Inone study, median and 5-year overall
survival fortheSYT-SSX1andSYT-SSX2groupswere6.1yearsand53%, and13.7years
and73%,respectively.
DiagnosticProcedure
Imagingstudiesarenotadequatetodistinguishthistumorfrombenignsofttissuemasses.Plain
radiographsare recommended and mayshow theinvasiveness ofthelesion or the stippled
calcification30% ofSSs have.MRIfindings are indeterminate as definedpreviously, with
intermediateorlowsignalintensityonT1sequencesandhighsignalintensityonT2sequences.
Axialimagingmayrevealthislesion’spotentialtoinvadeanddestroyadjacentbonesorsoft
tissues,butthetumormayappearwellcircumscribed.
ClearCellSarcoma
CCS,also knownas malignant melanoma of softparts, is anaggressive malignantsarcoma
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arisingfrommelanoblaststhatoccurintendons,aponeuroses,andsubcutaneoustissuesofthe
foot andankle. This tumoris oneofa group of rare malignancies associated with the gene
fusionproductEWSR1/ATF1orEWSR1/CREB1,whichincludesCCSofthesalivarygland,
CCS of the gastrointestinal tract, and others. More than 90% of CCS have a reciprocal
translocation t(12;22)(q13;q12). This rare tumor differs from malignant melanoma in both
histologyandnaturalhistory.
AlthoughCCSaccountsforonly1%ofsofttissuesarcomas, surgeonswhotreatthefoot
andankleshouldbefamiliarwithitspresentationandtreatmentduetothepredilectionofCCS
forthelowerextremity.Morethan90%ofcasesinsomeseriesinvolvethelowerextremity.
41
Unlikemostsarcomas,CCShasatendencytometastasizetolymphnodes.Latemetastasisto
locoregional nodesorlungmayoccurmonthsor years after treatment.Long-term follow-up
andsurveillanceformetastasisiswarranted.
CCSmayoccuratanyageincludingchildhood,butismostlikelytooccurinadults20to
40 years of age. The tumor does not contain melanin pigment. Typical presentation of this
tumorisofabenign, indolent appearing slow-growingsofttissuemassthatissuperficialor
adjacenttoatendonoranaponeurosis inthe ankle, theheel,orthe plantarfascia. Average
tumorsizeis4cm.
42
Treatmentdepends onearlyrecognition, comprehensive staging, andaggressive surgical
extirpationofthetumor.TheworkupshouldincludeCTscanofthechestandMRIoftheentire
limbandlocoregionallymphnodes.Themainstayoftreatmentisresectionwithawidemargin.
Multiagent chemotherapy has not been shown to have any impact on survival.43 Overall
disease-free survival at 5 years is approximately 68%.44 Tumor size appears to be a
prognosticfactor.Prognosiswasdismalincaseswheremetastasiswaspresent.
45
OtherMalignantSoftTissueTumorswithBenignClinical
Appearance
Twootheruncommonmalignantsofttissuetumorsalsohaveapredilectionforthefoot.Acral
myxoinflammatoryfibroblastic sarcoma46 andaggressive digital capillaryadenocarcinoma
47
are indolent,often painless tumors thatmaymimic a benign process. Because these lesions
maybemistakenforaskinconditionsuch asasebaceouscystorawart,itisrecommended
that allmasslesionsremovedfrom thefoot be submittedfor pathologicanalysis toavoid a
missed diagnosis in these potentially deadly tumors. Both these malignant tumors require
aggressive surgical removal with wide margins, which usually requires at least a partial
amputation.
46,48
SECTIONB:
BoneTumorsoftheFootandAnkle
Theterm“tumor”originatesfromtheLatintumere“toswell”anddenotesanytypeofmassor
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swelling of bone or soft tissue. Bone tumors can arise from several causes, including
hamartomas (an overgrowth of normal tissues), reactive or posttraumatic processes, and
inflammatorylesions,ortheymaybebenignormalignantneoplasms.Thefootiscomprisedof
numerous tightly confined and well-vascularized anatomic compartments that predispose to
localanddistantspreadofdisease.Theclinicianexaminingthepatientpresentingwithatumor
ofthefootoranklemustapproachtheprobleminaninformedandsystematicfashion.
Tumorsofthefootandanklerepresentauniquesubsetofallboneandsofttissuetumors,
showingvarianceintype,location,age,prognosis,andtreatmentfromtumorsintherestofthe
musculoskeletalsystem.Inlargeseriesoftumorsoftheentireskeleton,approximately3%to
4%ofallbonetumorsare locatedinthebonesofthefoot.Bonetumorsinthis locationare
morecommoninmalesbyasmallmargin.Mostarecartilaginousorcystic,withaminorityof
tumorsbeingosteoblastic.
Certaintumorsareoverrepresentedinthebonesofthefoot,likelybecauseoftheunique
structure and functional demands placed on the bones. For example, aneurysmal bone cyst
(ABC),atumorthatmaydevelopfollowinginjuryortrauma,ismorecommonthanexpectedin
thefoot.49Chondromyxoidfibroma(CMF)andchondroblastomaaregenerallyraretumors,but
forunknownreasonstheselesionsarerelativelycommoninthefoot.
Forbenignbonetumors,theoptimalmanagementstrategyinvolvesacarefulevaluationand
inmany cases a preliminarybiopsysothat the nature of the lesionis knownwithcertainty
beforethedefinitivesurgeryisperformed.Afterabenigntumorisfullycharacterized,surgical
removal is usually performed by curettage or marginal excision, according to the type and
locationofthetumor.
Malignant tumors require a completely different and more comprehensive management
strategy. Primary malignant tumors of mesenchymal origin are termed sarcomas. Although
sarcomasin thefootand ankle are rare, there is a significantlikelihoodthatfoot and ankle
surgeonswillencounteroneormoremalignantfootandankletumorsoverthecourseoftheir
practice. Treatment of bone sarcomas inthe foot and ankle requires a timely and complete
workup andstaging of thetumor,as well as attentionto avoidanceoferrors anddelays in
diagnosisandinitialmanagement.Surgeryforsarcomasusuallyinvolvesresectionwithawide
margin,andmayincludeadjuvantchemotherapyand/orradiotherapydependingontumortype.
Inthefootandankle,adequateresectionwithawidemarginmayrequirepartialorcomplete
amputationofthepart.
Limb salvage for lower extremity sarcomas is preferred to amputation when it can be
accomplishedwithoutcompromisingtheoncologicoutcomeofthesurgery.Ithasbeenshown
tobeequivalenttoamputationintermsoffunctionaloutcomeandoverallpatientsurvival.
50,51
Limbsalvagefollowingremovaloftumorsinthefootandankleiscomplicatedbytheloadson
the skeletal elements and the generally scant soft tissue coverage. These factors make the
salvageofaviable,durablefootwithusefulfunctionamajorchallengeinsomeinstances.The
goal of treatment in sarcomas is not necessarily preservation of the foot, but rather the
elimination of the tumor and prompt restoration of the patient’s quality of life, long-term
mobility,andfunction.
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PRESENTATIONANDINITIALASSESSMENT
Thepatientpresentingwithamassinthefootandankleshouldhaveacompletehistoryand
physical examination.Itis important to precisely determinethetimeof onset ofthepain as
wellastherateofprogressionandpreciselocation.Thiswillallowthecliniciantodetermine
whether the pain is actually coming from the tumor or from some nearby less worrisome
abnormality.
Tumorpain,althoughvariable,isusuallyagraduallyprogressivepain,welllocalized,that
growsmorepersistentovermanyweeksormonths.Inmanycases,thepatientwillascribethe
paintosomeminortraumaticevent.Theexaminingphysicianiscautionednottotaketheseredherringstoriesatfacevalue.Carefulquestioningmayrevealthatthepainclearlypredatedthe
event.
Forbonetumors,thephysicalexaminationcanprovideusefulinformationpertainingtothe
diagnosis of the lesion. The examiner should note the palpable size, local extent, and the
presenceanddimensionsofapalpablemassinthechart.Theexaminationshouldalsofocuson
thenearbystructuresofthefootorankletorevealpossiblepathologythatmaybecausingthe
painordisability.Anyangularorpositionaldeformityshouldbenoted.
Patientsbeyondthe ageof40are atincreased riskformetastaticcancerinthe footand
ankle,andthusadultsover40shouldbequestionedabouttheirpersonalhistoryofcancerand
cancerscreening.The statusofcancerscreeningexaminationssuchas the prostateexamand
prostate-specificantigenlevelinmen,mammographyinwomen,andlow-doseCTscansofthe
chestinhigh-risksmokersshouldbenoted.Riskfactorsforthefivemostcommontumorsthat
contributetobonemetastasis,whicharelung,breast,prostate,kidney,andthyroid,shouldbe
enumerated. These include immediate family members with lung or breast cancer; known
BRCA1andBRCA2genes;VonHippel–Lindaudisease;ahistoryofsmoking,radiationtothe
chest,orthyroid;exposuretoradonandtrichloroethylene;andobesity.
Sometumorsandtumorlikelesionsinthefootandanklepresentsimultaneouslyinmultiple
bones.Thisfindingimmediatelylimitsthedifferentialdiagnosistoasmallnumberofentities
(Table11-4).Combiningthisfindingwithotherinformationfromthehistory,images,andlabs,
theclinicianmaybeabletoeasilyconfirmthecorrectdiagnosiswithouttheneedforbiopsy.
Theclinicianshould carefullyinspectthe X-raysandimaging studies foradditionallesions.
ThemultiplelesionsthatpresentinthefootandankleareshowninTable11-4.
RecommendedImagingModalities
The initial screening examination of a bone tumor should always include two high-quality
orthogonalplain radiographs. MRI is indicated incases where a tumor is suspecteddueto
positive local or systemic symptoms,buttheinitialX-raysarenegative or wheretheX-ray
findingsdonotexplainthesymptoms.Nootherimagingmodalitiesareusefulorrecommended
in the initial evaluation of a suspected bone tumor. Ultrasound, CT, and PET/CT are not
recommendedaspartofascreeningevaluationforabonelesionofanytype.
52
Advanced imaging should not be ordered without careful consideration of the
appropriateness ofthe study. Some bonelesions canbedefinitivelydiagnosed basedon the
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Table11-4.
history and plain radiographs, for example, intraosseous lipoma in the calcaneus,
osteochondromaofthemetatarsal,andenchondromainthephalanges.Inthesecases,advanced
imagingisunnecessary,andmayincurasubstantialandavoidablecosttothepatientandtothe
health care system. Inappropriate imaging studies should be minimized. When advanced
imagingstudiesareordered,thesinglebeststudyshouldbeselected,ratherthanamultitudeof
studies.ThediagnosticvalueofanMRIscanwithandwithoutcontrastisgenerallysomewhat
superiortothevalueofaCTscanwithoutcontrastexceptintheevaluationofosteoidosteoma.
Therefore,inmostcases,thefirstadvancedimagingmodalityselectedshouldbeMRIscan.
TheindicationsfortheuseofCTscansinbonetumorsofthefootandankleincludeabone
lesionwithpossiblecorticaldisruptionorbonefragility,acalcificmatrixthatrequiresfurther
evaluation,asuspectedosteoidosteoma,orabonelesionwhere previousmetallicimplants
preclude theuse ofMRI.For thepurpose ofsurgical planning, CT scansare veryusefulin
evaluatingtheextentofbonyinvolvementinthetarsalbonesandhindfoot.CTimagingofbone
is complementaryand in somewayssuperior to MRI andis essential for the evaluationof
mechanicalintegrityandfracturerisk.
Appropriate criteria forthe useofMRI forbonetumorsof thefoot andankleincludea
destructivebonelesion,abiopsysuggestiveofsarcomaormalignancywithnopreviousMRI,
oraninterosseouslesionofsignificantsizeordocumentedgrowthwithuncertainetiology.The
diagnostic usefulness of MRI scans with and without contrast is somewhat higher than
noncontrastscans;therefore,MRIscansshouldbeperformedwithcontrastifpossible.Bone
scansareindicatedwhenthedifferentialdiagnosisorbiopsyishighlyconsistentorconclusive
formalignancy,metastaticdisease,ormultifocalsystemicdisease,andfortheevaluationofa
possiblestressfracture.IndicationsforPET/CTscansincludestagingofcancersinvolvingthe
breast, colon and rectum, esophagus, head and neck, lung, lymphoma, melanoma, and
sarcoma.
53
TumorsandTumorlikeLesionsThatPresentSimultaneouslyin
MultipleBones
Diagnosis X-rayAppearance
Typical
Presentation HelpfulStudies Frequency
Gout Multiplepunched-out
lesionsatmarginsof
joints
Older,male,
admittedfor
“cellulitisoffoot”
Serumuricacid
CTorMRIshowsmultiple
typicallesions
Common
PVNS Cystsinboneonboth
sidesoftheinvolved
joint
Youngerperson,
anklemost
common
MRIshowsthicksynoviumand
cysts,MRI“signalvoid”in
synoviumduetoironin
tissues
Infrequent
Synovial
chondromatosis
Multiplelobulesof
calcifiedcartilagein
joint
Youngtomiddle
ageadult,ankle
andmidfoot
MRIfindingsarediagnostic Uncommon
Metastatic
adenocarcinoma
Multipleadjacentbones
withaggressivelytic
lesions
Olderperson,
usuallyhas
knownhistoryof
carcinoma
Bonescanusuallywillshow
multiplebonelesions
Uncommon
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Multiplemyeloma Multiplesmallpunched-
outlesions
Age50–70 Serumproteinelectrophoresis Rareinthe
bonesof
thefoot
Multiplecartilaginous
exostoses
Multiplesessileor
pedunculated
exostosesinankleand
metatarsallesions
Youngadult X-raysarediagnostic Rare
Enchondromatosis
(Ollierdisease)
Multipleexpansilelucent
lesionsinmetatarsals
andphalanges
Youngadult SkeletalsurveyandX-raysof
handsconfirmdiagnosis
Rare
CT,computedtomography;MRI,magneticresonanceimaging;PVNS,pigmentedvillonodularsynovitis.
BENIGNBONETUMORS
GiantCellTumor
Introduction,Incidence,andDemographics
Giantcelltumoraccountsfor5%to9%ofallprimarybonytumors
54,55
:Itisthemostcommon
benignbonetumorinadultsaged25to40.Giantcelltumorisfoundmorecommonlyinwomen
thaninmen,and occursmostoftenduring the third decade.56This tumoris mostcommonly
found in the distal femur, proximal tibia, and distal radius, and is uncommon in the foot.
Approximately3%ofgiantcelltumorsaffectthebonesofthefoot.Giantcelltumorisoneof
themostcommonprimarybonelesionsinthedistalphalanx.Whetherthattumorarisesinthe
epiphysisordistalmetaphysisisamatterofcontroversy,butgiantcelltumorsonlyoccurafter
the epiphyseal plates have closed. A diagnosis of giant cell tumor in a patient with open
growthplatesshouldbequestioned.Giantcelltumorofboneisabenignlesionthatisusually
solitaryandlocallyaggressive(Fig.11-1).Itisbelievedbysometobepotentiallymalignant.
Inveryrareinstances,thislesionhasthepotentialformetastasistothelungs.Inthesecases,
thelunglesionsmaybehaveinanindolentfashionandevenrequirenotreatment.Theauthors
recommendachestCTscanforallpatientsnewlydiagnosedwithgiantcelltumor.
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FIGURE11-1.Giantcelltumorintheproximal1stmetatarsalofa36-year-oldfemale.Thetumorischaracteristically
alyticlesioninthemetaphysisextendingtothejointlevelbutpreservingthesubchondralbone.
SymptomsandPresentation
Mostpatientspresentwithslowlyprogressivepain,withorwithoutamass.Symptomsarise
whenthelesionbeginstodestroythecortexandirritatetheperiosteumorwhentheweakening
of the bone causes pain due to pathologic fracture. Some giant cell tumors present after a
pathologicfracture.
X-rayAppearanceandAdvancedImagingFindings
Thelesionoriginatesinthemetaphysealsegmentoftheboneadjacenttothephysealscar,and
expandsproximallyanddistallyintothediaphysisandepiphysis.Thetumorwillgrowuntilit
reachesthesubchondralsurfaceofthejoint,whichformsapartialbarrieragainstfurthertumor
extension.Theadjacentcortexmaybeexpanded,thin,ordestroyed,andthetumorcanextend
into the nearbysoft tissues. There maybe numerous septae or longitudinal striations inthe
involvedbone.Thezoneoftransitionisafewmillimeterswide,thereisnopermeation,and
thereisnomatrixmineralization.Thesetumorsoftenthinthecortex,andmayexpandintothe
softtissuessurroundingthebone,ortheymayexpandtheboneextensively,remainingwithinan
eggshell-thin rim of periosteal new bone. If the lesion has been present long enough, the
involvedbonecanbecomeexpandedtomanytimesitsoriginalvolume.CTscanwilldefine
the local extent of the tumor and help confirm the absence of matrix mineralization. MRI
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findings are nondiagnostic, although the lesions tend to be highlyheterogeneous ifthey are
largeenough.Theremaybecysticloculatedblood-filledinternalspaces.Bonescanfindings
arenonspecific.
HistopathologyFindings
Thegrossappearanceofthegiantcelltumorisfirmandhomogeneous,withfociofhemorrhage
ornecrosis.Microscopically,therearenumerousmultinucleatedgiantcells.Thestromalcells
arehomogeneousmononuclearcellswithround or ovoidshapes,largenuclei,andindistinct
nucleoli.Thenucleiofthestromalcellsareidenticaltothenucleiinthegiantcells,afeature
that distinguishesgiant cell tumors from other lesions that also containgiant cells. Another
featureofgiantcelltumoristhatthegiantcellsmaycontainverylargenumbersofnuclei,often
severalhundred.Insometumors,thegiantcellscanbeseentobeengulfingmorenucleifrom
thestroma.
DifferentialDiagnosis
OtheraggressivetumorsinthisagegroupandlocationincludeABC,sarcomasinbonesuchas
MFH,anddesmoplasticfibroma.
TreatmentOptionsandOutcomes
Treatmentofgiantcelltumorsisbyintralesionalexcisionby“extended”curettage.Curettage
aloneisassociatedwithahigh recurrencerate.Recurrencecanbe decreasedby“extended”
curettagethatinvolvestheapplicationofalocal adjuvanttreatmenttothe tumorcavityafter
mechanical curettage is complete. This treatment is designed to eliminate any viable tumor
cellsthatremaininthewallsofthetumorcavity after mechanicalcurettage.Availablelocal
adjuvanttreatmentchoicesincludechemicalcauteryusingphenol;multiplefreeze–thawcycles
usingliquidnitrogen;and/ortreatingthewallsofthecavitywithahigh-speedrotaryburr.All
ofthesehavebeenshowntodecreasetheriskoflocalrecurrence.Theauthor’spreferenceis
the high-speed burr, because of availability, ease, and precision of application. Local
recurrenceaftercurettagealonemaybeashighas50%.Recurrenceafterextendedcurettageis
10%.
57
The tumor cavity may be filled with polymethylmethacrylate cement (PMMA) or bone
graft,according to thesurgeon’spreference.Some believe thatPMMA lowers theriskof a
localrecurrenceduetothelargeamountofheatgivenoffduringhardening.Recurrencesare
normallytreated with asecondinterlesionalsurgery. Theuse ofbonegrafttofill the tumor
cavityinstead of PMMAmayallow for more favorable biomechanical loads onthe nearby
jointanddecreasetheriskoflatearthrosis.However,therecurrencerateishigherwhenbone
graftisusedinsteadofPMMA.58Theearlysignsoflocalrecurrencemaybemoredifficultto
detectincasestreatedwithbonegraft.
Lesions that are highly expansile and destructive or lesions that occur in “expendable”
bonessuchastheproximalfibulamaybeexcisedwithawidemargin.Multiplyrecurrentgiant
celltumorsarealsotreatedwithwideresection.Giantcelltumorsmayoccurinthesacrum,a
sitewherecompletesurgicalexcisionisverydifficult.Intralesionalremovalofasmuchofthe
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