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PreferredBiopsyTechniqueforThisTumor
Tru-cutneedle,open.
HistopathologyFindings
Grossly,thetumormaybeyellowortanfattymaterial,softorsemiliquid,withagrittytexture.
Squeezingthetissuewillcauseoildropletstobeproduced.Theremaybeoilyliquidwithin
thetumorcavity.Thetumoriscomprisedofmaturefatcellsandvaryingamountsoffibrousand
vasculartissue.
Basedonalargecaseseries,lipomaofbonehasbeendividedintothreestages,according
to the histopathology findings, which also correspond with the radiologic findings. Stage I
lesionsareradiolucentwithfinetrabecularbone.StageIIlesionshavepartialfatnecrosisand
some fat calcification. Stage III lesions have a reactive ossified rim and more central
calcificationand ossification.Stage III lesions show more extensive necrosis on histologic
examination.Itisnotclearwhetherthisstagingsystemhasanyvaluefordiagnosis,treatment,
orprognosis.
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TreatmentOptionsforThisTumor
Themerepresenceofalipomainthecalcaneusdoesnotmandatetreatmentforthetumororfor
possible pathologic fracture. Many patients can be treated with observation and follow-up
only.Becausethelesioncanbediagnosedwithcertaintybasedonimagingstudies,biopsyis
notalwaysnecessary.Curettageandbonegraftingshouldbereservedforlarge,worrisome,or
symptomatic lesions, or lesions where there has been documented radiographic change, or
definite increase insymptomatology. Lesions in weight-bearing bonesthat require treatment
may require additional bone stabilization procedures, such as internal fixation or
intramedullary rodding. This lesion is notexpected to recur following curettage. However,
curettage does not alwaysresultincompleterelief ofsymptomsrelatedto thetumor. Inthe
calcaneus, theauthor’s preferred treatment iscurettage andpacking of the bonedefect with
corticocancellousallograftchips.
PreferredMarginforThisTumor
Intralesional.
PRIMARYMALIGNANTBONETUMORS
Introduction
Chondrosarcoma,Ewingsarcoma,andosteosarcomaarethemostcommonbonesarcomasin
thefootandankle.Epithelioidhemangioma(epithelioidhemangioendothelioma),alow-grade
vascular tumor that is intermediate between benign hemangioma and highly malignant
angiosarcoma,alsoseemstohaveapredilectionforthefootbones.Theproportionoftumors
inreportedseriesoffootandankletumorsthatexhibitmalignantbehaviorvariesfrom5%to
45%.Malignanciesappeartocomprisealargerproportionoftumorsinthefootandanklethan
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elsewhere in the body. However, patient survival is significantly better in distal lower
extremity tumors than for sarcomas in other musculoskeletal sites. A larger than usual
proportion of the osteosarcomas in the foot are low-grade tumors. Taken together, the
metatarsals are the most common location of malignant tumors in the foot, whereas the
calcaneusisthemostcommonsingleboneaffected.
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Bone and soft tissue sarcomas are thought to arise from alterations in the structure or
expressionofthecellularDNA.Afewarecausedbyexposuretoradiationorbyanunderlying
geneticabnormalitysuchastheRB-1geneinhereditaryretinoblastoma,orthep53geneinLi–
Fraumenisyndrome.Aminorityofsarcomashaveasimplekaryotypeandcarrydefinedgenetic
alterationsortranslocations,whereasmosthave acomplexkaryotype andshowavarietyof
suchalterations.Sarcomaswithdefinedtranslocationsmayexpressanoncogenicfusiongene,
suchasSS,CCS,dermatofibrosarcomaprotuberans,andmyxoidliposarcoma.Thesesarcomas
arerelativelyfrequentinthefoot.Thepresenceofspecificfusionproteinsinthesemalignant
tumorsrepresentsapathwayforfuturetargetedtreatments.
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Thediscoveryofapotentiallymalignanttumorinthe footandankle canoverwhelmthe
patient and thefamilywith fear and worry. The behavior ofthe clinicianatthe time ofthe
initialdiscoveryofthetumorhas a strong impacton thepatient’s psychologicalwell-being.
Thebestwaytomanageanxietyisthroughdirectedaction.Theclinicianshouldsteerthefocus
awayfromworryandspeculationandinsteadlayoutacoursetowardanaccuratediagnosis,a
comprehensivetreatmentplan,andaprospectforrecovery.Minimizationoftheproblem,false
assurances, and uninformed conjecture should be avoided, as these contributetodiagnostic
delay.Thesurgeonshould promptlyseek assistance from the radiologist,thepathologist,an
orthopedic tumorspecialist,andother colleagues.Itisimportanttodocument any adviceor
recommendations received from other physicians in the patient’s chart. The information
gatheredshould besharedfullywiththepatientand thepatient’sfamily,andpresentedinan
understandable and emotionally sensitive way. Even when presenting very bad news, the
surgeonshouldalwaysleaveroomforhope.
Themainstayoftreatmentofsarcomainthefootandankleisbysurgicalresectionwitha
widemargin.Adjuvantchemotherapyandradiationtherapyaregivenforosteosarcoma,Ewing
sarcoma,andother high-grade sarcomas on a case-by-case basis. The goals of thesurgery
includeanenblocexcisionoftheentiretumorwithanuncontaminatedmarginof5to10mmof
normaltissuesurroundingallaspectsofthemass.Optimally,thereisnospillingorexposureof
anypartoftheactualtumor.Atruewidemarginrequiresthatnopartofthetumor,itscapsule,
or the reactive zone around the tumor is ever seen in the surgical field. All parts of the
dissectiontakeplacethroughuninvolved,nonreactivenormaltissues,andthesenormaltissues
completely envelop all parts of the excised specimen. Many foot and ankle surgeons are
unpreparedforthe degreeofcollateral damagetothefootthatisrequiredtoachieve a true
widemarginaroundasarcoma.Asaresult,surgeonswhoinfrequentlytreatsarcomamaybe
morelikelytofailtoachieveanoptimalmargin.
Chondrosarcoma
IntroductionandDefinition
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Chondrosarcomaisamalignanttumorthatproducescartilagematrix.Primarychondrosarcoma
is very uncommon, arises centrally in the bone, and is found in children. Secondary
chondrosarcomaarisesfrombenigncartilagetumorssuchasosteochondromaorenchondroma.
Chondrosarcomas can also be classified as intramedullary, which generally arise from
enchondromas,andsurfacewhicharisefromosteochondromas(Fig.11-6).
IncidenceandDemographics
Chondrosarcoma most commonly affects adults aged 30 to 70 years, with the peak age of
incidencebeingsometimearound40to60years.Chondrosarcomahasamaletofemaleratio
of 1.5:1. It is most common in the femur, humerus, ribs, and on the surface of the pelvis.
Patients with Ollier disease (multiple enchondromatosis) or Maffucci syndrome (multiple
enchondromasandhemangiomas)areatmuchhigherriskofchondrosarcomathanthenormal
populationandoftenpresentinthethirdandfourthdecade.
Chondrosarcomaisrelativelyrareinthebonesofthefoot,withthislocationaccountingfor
approximately2%ofallsuchtumors.Thetumorsmaybeprimaryordevelopasasecondary
malignancyinanenchondromaorosteochondroma.Becauseenchondromaoccursfrequentlyin
thefoot,itisessentialtoproperlydifferentiatebetweenbenignandmalignantcartilagetumors.
Benign enchondromas in the small bones of the foot may have X-ray features that are
suggestiveofchondrosarcomainlargerbones.
SymptomsandPresentation
The presentation ofchondrosarcoma depends onthe grade ofthe tumor.A high-grade, fastgrowingtumorcanpresentwithexcruciatingpain.Alow-grade,moreindolenttumorismore
likely to present in an older patient complaining of hip pain and swelling. Pelvic tumors
presentwithurinaryfrequencyorobstructionormaymasqueradeas“groinmusclepulls.”
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FIGURE11-6.APandlateralradiographsshowingamesenchymalchondrosarcomaofthetalus.Locationinthe
hindfootisasignofpotentialmalignancy.
X-rayAppearanceandAdvancedImagingFindings
Onplainradiographs,chondrosarcomaisafusiform,lucentdefectinbonewithscallopingof
theinnercortexandminimalperiostealreaction.Extensionofthelesionintothesofttissuemay
bepresentaswellaspunctateorstippledcalcificationofthecartilagematrix.CTishelpfulin
defining the integrity of the cortex and distribution of calcification. MRI is invaluable in
surgical planning asitdemonstratesthe intraosseusandsofttissueinvolvementofthetumor.
MRI is also helpful in evaluating possible malignant degeneration of osteochondromas by
allowingaccuratemeasurementsofthecartilagecap,whichshouldbelessthan2cmthick.
Inthefoot,theradiographicappearanceofchondrosarcomamayoverlapconsiderablywith
thatofenchondroma.Bothtypesoftumorsarelyticandmayexpand,damage,andweakenthe
bonesignificantly.Matrixmineralization,intheformofringsandarcs, occursinabouttwothirds of both benign and malignant lesions. The presence of scalloping, expansion, and
corticaldestructionisnotareliablewaytodiscriminatebenignfrommalignantlesionsinthe
foot.In a recentstudy, sizegreater than5 cmandlocationinthehindfootwerefoundtobe
associatedwithpotentialformalignancy.
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DifferentialDiagnosis
Osteosarcoma,benigncartilagelesions.
PreferredBiopsyTechniqueforThisTumor
Incisional.
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HistopathologyFindings
Ongrossexamination,chondrosarcomaisagrayish-white,lobulatedmass.Itmayhavefocal
calcification, mucoid I degeneration, or necrosis. Histologically, chondrosarcoma is
differentiated from benign cartilage growths by enlarged plump nuclei, multiple cells per
lacunae, binucleated cells, and hyperchromic nuclear pleomorphism. Chondrosarcoma is
graded from 1(low)to3(high).Low-gradechondrosarcomaisverycloseinappearanceto
enchondromas and osteochondromas and has occasional binucleated cells. High-grade
chondrosarcomas have increased cellularity, atypia, and mitoses. There is an inverse
relationship between histologic grade and prognosis, with higher grades having a worse
prognosisandearlymetastases.
TreatmentOptionsforThisTumor
Treatment of chondrosarcoma is wide surgical excision. There is a very limited role for
chemotherapy or radiation. Biopsies must be planned with future tumor excision in mind.
Patientswithadequatelyresectedlow-gradechondrosarcomashaveanexcellentsurvivalrate.
Thesurvivalofpatientswithhigh-gradetumorsdependsonthelocation,size,andstageofthe
tumor.
PreferredMarginforThisTumor
Wide.
Treatment
Treatmentofhigh-gradechondrosarcomaisbysurgicalresectionwithawidemargin.
Innovativelimbsalvageprocedures, such as replacement of the entire calcaneus with a
freshosteoarticularallograft,havebeenreported.Maximumrestorationofmobilityinatimely
fashionandwithminimal complicationsisthe goalofsurgery. Ifconservationofadurable,
minimallypainfulplantigradefootisimpossibletoachievewithoutcompromisingthesurgical
margin,amputationshouldbeconsidered.
Chemotherapyandradiationtherapyareusedincaseswheresurgicalcontrolisinadequate
orimpossible.Chemotherapyisgivenforhigh-gradechondrosarcomainsomecancercenters
whereexperimentalprotocolsarebeinginvestigated.
OutcomesofTreatmentandPrognosis
Survival of chondrosarcoma is difficulttoprecisely definebecause of the large number of
subtypes,varyinghistologicgradesofthetumor,andawidevarietyoftreatmentsthataregiven
dependingontumorextentthanlocation.Recentdatafromarelativelyhomogeneousgroupof
patients with primary central chondrosarcoma who presented with localized disease are
available.74 Overall survival at 5 years was 72% and at 10 years was 69%. Event-free
survivalat5and10yearswas57%and53%,respectively.
Oneofthemoststrikingfindingsinthedataconcernsthedevelopmentoflocalrecurrence
anddistantmetastasis.Theauthorsfoundthatbothlocalrecurrenceanddistantmetastasislead
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toasignificantdecreaseinoverallsurvivalregardlessoftumorgradeandlocalization.Inthis
groupof patients, long-term survival was onlypossible if therecurrenceor metastasis was
completelyresectedwithwidemargins.
Factors associated with improved overall survival for chondrosarcoma located in the
extremityincludedlow-gradetumors,ageunder 40years, andtumorsizelessthan100 cm3.
Factorsthatdidnotaffectlong-termsurvival includedmale sex,AJCCstage,and qualityof
surgicalmargins.However,multipleotherstudieshaveshownthatinadequatesurgicalmargins
areassociatedwithpoorprognosis.
SpecialandUnusualFeatures
Therearethreeadditionaltypesofchondrosarcoma.Mesenchymalchondrosarcomaisarare
variantwithabimorphichistologicpictureoflow-gradecartilaginouscellsandhypercellular
small, uniform, and undifferentiated cells that resemble Ewing sarcoma. Mesenchymal
chondrosarcoma has a predilection for the spine, ribs, and jaw and presents in the third
decade.Itismorecommoninfemales andcangrowexceptionallylarge.Itisverylikelyto
metastasizetolungs,lymphnodes,andotherbones.Clearcellchondrosarcomaisamalignant
cartilagetumorthatmaybetheadultvariantofchondroblastoma.Itisarare,low-gradetumor
withanimprovedprognosisoverotherchondrosarcomas.Likechondroblastoma,itisfoundin
theepiphysisofthefemurandhumerus.Histologically,softtissueinvasionisrare.Clearcell
chondrosarcoma has clear cells with vacuolated cytoplasm. The cartilage matrix has
significantlycalcifiedtrabeculaeandgiantcells.Dedifferentiatedchondrosarcomaisthemost
malignant form of chondrosarcoma. This tumor is a mix oflow-grade chondrosarcoma and
high-gradespindlecellsarcomawherethespindlecellsarenolongeridentifiableashavinga
cartilage origin. The dedifferentiated portion of the lesion may have histologic features of
MFH, osteosarcoma,orundifferentiatedsarcoma.This biphasic qualityis evidenton X-ray,
with areas ofendosteal scalloping andcortical thickening contrasting withareasofcortical
destructionandsofttissueinvasion.Dedifferentiatedchondrosarcomahasa5-yearsurvivalof
10%.
Osteosarcoma
IntroductionandDefinition
Osteosarcoma(osteogenicsarcoma)isthemostcommonprimarysarcomaofbone.Initsmost
common form, it is an aggressive sarcoma that occurs in teenagers and young adults.
Osteosarcomaismorecommoninmalesthaninfemales.Currenttreatmentresultsinexcellent
chances for survival for patients with manageable tumors who do not have metastasis.
Althoughpatientsexperiencelingering negativeeffectsfollowingtreatment,thesearereadily
acceptedduetotheaggressiveandpotentiallydeadlynatureofthetumor.Osteosarcomaisnot
causedbyinjury,fluoride,vaccines,orexposuretochemicals.Theexactcauseisunknown.In
mostcases,anabnormalityinthechromosomalDNA(thegenes) ofaprimitive bonecellor
bone precursor cell can be detected. Current research is focused on the role of the Notch
signaling pathway, which controls many crucial aspects of cell proliferation, migration,
invasiveness,andangiogenesis,aswellastheabilityofcancercellstobreakawayfromthe
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originaltumorandmetastasizetodistantsiteswithinthebody.
IncidenceandDemographics
Approximately 1,000 new cases of osteosarcoma occur in the United States each year,
includingabout600inchildren.About85%ofosteosarcomacasesare ofthe“conventional
intramedullary” type, and the other 15% consists of several other subtypes, including
telangiectatic, low-grade intramedullary, and small cell, as well as the surface subtypes
parosteal, periosteal, and high-grade surface osteosarcoma. Osteosarcoma canoccur atany
age.Themostcommonsiteisthedistalfemurandproximaltibia.Osteosarcomacanoccurin
anyboneofthefoot.
SymptomsandPresentation
Themostcommonpresentationispainandeventuallyamass,whichoccursnearajoint.The
painmayinitiallyaccompanyactivity,graduallybecomesmoreconstant,andmaybesevereat
night.Patientsotherwisemayhavefewornosymptoms.Initially,thepainmaybeintermittent
andrelatedtoaminorinjuryorexerciseactivity, andthustheproblemismisdiagnosedasa
commonsprainorstrain.
X-rayAppearanceandAdvancedImagingFindings
Themostcommonformofosteogenicsarcomaisconventionalosteosarcoma,whichaccounts
for 75% to 85% of all osteosarcomas. On radiographs, conventional osteosarcoma occurs
predominatelyinthemetaphysis,andappearsasamixedscleroticandlytic lesion,thatmay
permeatetheboneandthenearbycortex,causingasofttissuemassandaperiostealreaction.
Boneformationwithinthetumorischaracteristicofosteosarcomaandisusuallyvisibleonthe
X-rays. Radiographs will initially reveal a subtle mixed lysis and sclerosis, followed by
increasingsclerosis,permeation,destruction,andexpansionintotheadjacentsofttissueswith
boneformationinthesofttissuemass.
LaboratoryFindings
Laboratorytestsdonotaidinthediagnosis,butalinkbetweenalkalinephosphataselevelsin
thebloodandprognosisofthediseasehasbeenestablished.
PreferredBiopsyTechniqueforThisTumor
Biopsymustbecarefullyplannedsothatsubsequentdefinitivesurgicalremovalofthetumoris
not compromised. Most authors strongly recommend that the biopsy be performed by the
surgeon who will be doing the final tumor resection. An increased rate of avoidable
amputationshasbeenattributedtoerrorsinbiopsytechnique.Insomecenters,tru-cutneedle
biopsy is used, but a well-planned and meticulously executed open biopsy remains the
mainstayofdiagnosisinosteosarcoma.
DifferentialDiagnosis
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The differential diagnosis should include infection, lymphoma, chondrosarcoma, Ewing
sarcoma,andpleomorphicundifferentiatedsarcoma(previouslytermedMFH).
TreatmentOptionsforThisTumor
Beforetreatment can be planned,a complete oncologic stagingworkup must be completed.
Thisincludesassessmentofanypotentialformetastasistothechest,tonearbybonesortherest
of the extremity, or to other areas as indicated. Most patients have CT scans of the chest,
whole-bodybonescan,andMRIoftheextremityincludingthelesion.Additionalscanssuchas
PETscanmayhavearoleinthestagingworkup.
For most types of osteosarcoma, treatment is multimodal. Neoadjuvant multiagent
chemotherapyis givenprior tosurgery.Surgical resectionwith a widemarginfollows. The
majorityofpatientscanhavelimb-sparingsurgeryratherthanamputation.Inthefootandankle,
thetumorisremovedandthefootisreconstructedwithafusion,anallograft,oracombination
ofthese.Followingsurgery,postoperativechemotherapyisusuallygiven,andmaybemodified
dependingontheresponseofthetumortothepreoperativechemotherapy.Radiationisusually
notused.Low-gradeosteosarcomaistreatedbysurgeryonly.
PreferredMarginforThisTumor
Wide.
OutcomesofTreatmentandPrognosis
The prognosis of osteogenic sarcoma depends very largely on the extent of the tumor.
Localized, nonmetastatic tumors in relatively accessible sites such as the knee, hip, and
shouldergenerallyhaveaverygoodtoexcellentprognosis.Verylargetumorsand tumorsin
difficultsitessuchasthepelvisandspinehavealessfavorableprognosisduetothedifficulty
withcompletelyremovingthetumorbysurgicaltechniques.Onceclinicallyevidentmetastasis
occurs,theprognosisissubstantiallydiminished.Tumorsthatpresentwithmetastasisalready
present or tumors where metastasis is discovered after the initial treatment have a poor
prognosis.Surgicalremovalofmetastasiscoupledwithchemotherapymayleadtoimproved
survival.
SpecialandUnusualFeatures
Itisestimatedthat80%ofpatientswithosteosarcomahavemetastasisatpresentation,although
only15%ofthese are clinicallyapparent.Themostcommonsiteofmetastasisisthe lungs.
Systemicchemotherapyisgiventoallpatients.Followingtreatmentofosteosarcoma,patients
continue to experience lingering effects. The functional capacity and quality of life are
impaired to an extent that depends on theextent of the tumor and the success ofthe limbsparing surgery. Lingering effects and toxic effects of the chemotherapy require ongoing
observationandsometimestreatment.
EwingSarcoma
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IntroductionandDefinition
Ewingsarcomaisahighlymalignantsmall,round, bluecell tumorthatoccurs mainlyinthe
seconddecadeoflife.Ewingsarcoma,alongwithPNET,comprisestheEwingsarcomafamily
of tumors. The tumor commonly stains for CD99 and has translocations of the EWS gene
EWSR1-FLI1.Ewingsarcomaisfoundinthelowerextremitymorethantheupperextremity,
butanybonemaybeaffected.Themostcommonsitesarethemetaphysisanddiaphysisofthe
femurfollowedbythetibiaandhumerus.
IncidenceandDemographics
Ewingsarcomaismostcommoninthefirstandseconddecadebutmayaffectpersonsfromage
2 to80.This tumor preferentiallyaffectswhitesmorethanblacksandAsians.The ratio of
males to females is 3:2. Ewing sarcoma is relatively rare in the bones of the foot. The
calcaneusisthemostcommonlyinvolvedsite,butthistumormayalsopresentinanyboneor
asamassinthesofttissues.
SymptomsandPresentation
TheclinicalpresentationofEwingsarcomaincludespainandswellingofweeks’ormonths’
duration.Erythemaandwarmthofthelocalareaaresometimesseen.Osteomyelitisisoftenthe
initial diagnosis based on intermittent fevers, leukocytosis, anemia, and an increased
erythrocytesedimentationrate(ESR).PatientswithEwingsarcomainthefootfrequentlysuffer
delaysindiagnosis.Themeanageatpresentationforlesionsinthefootis17years,andthe
averagedurationofsymptomsis14months.Patientswithforefoottumorshadanaverageof7
monthsofsymptomspriortodiagnosis,whereaspatientswithhindfoottumorshadanaverage
of 22 months of symptoms prior to diagnosis. In many cases, patients are treated for
osteomyelitis before the correct diagnosis is made. The lesion presents with pain, which
initially will follow some minor sporting activity or injury. The patient appears entirely
healthyotherthanthefootandanklesymptoms.Poorprognosticsignsincludeincreasedage,
increasedESR,andleukocytosisatpresentation.
X-rayAppearanceandAdvancedImagingFinding
Radiologically, Ewing sarcoma is often associated with a lamellated or “onion skin”
periosteal reaction. This appearance is caused by splitting and thickening of the cortex by
tumorcells.Thelesionisusuallylyticandcentral.Endostealscallopingisoftenpresent.The
“onion skin” appearance is often followed with a “moth-eaten” or mottled appearance and
extensionintosoft tissue.Bone marrow infiltrationis notobviousonplain X-ray. Although
Ewingsarcomaisusuallylytic,itmaypresentasascleroticlesionwithboneexpansion.
CTis helpful in defining bone destruction.MRIis essential toelucidate the soft tissue
involvement; T1-weighted imagesthe tumor has low intensitycompared to the normal high
intensity of bone marrow. On T2-weighted images the tumor is hyper intense compared to
muscle. Ewing sarcoma has increased uptakeon bone scan.A completeradiologic workup
should consistofplainradiographsofthepart,CTscanandMRIscanoftheprimarytumor,
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whole-bodybonescan,andCTscanofthechest.
Inthefootandankle,theinitialradiographswillshowveryminor,unimpressivechanges,
with focal lysis andpermeation oftheinvolved bone.Ifthediagnosisis delayed,extensive
permeation,bonydestruction,anda softtissuemasswilldevelop. Thecharacteristic“onion
scanning”orlamellarperiostealreactionisnotusuallyseenbecauseoftheanatomyofthefoot.
DifferentialDiagnosis
Infection,neuroblastomametastasis,lymphoma,leukemia,osteosarcoma.
PreferredBiopsyTechniqueforThisTumor
Open biopsy is recommended for bone lesions. Core or trucut is adequate for soft tissue
lesionsifthepathologisthassignificantexperiencewithsarcomas.
HistopathologyFindings
Grossly,thetumorisgraytowhiteincolorandpoorlydemarcated.Theconsistencyissoftand
gray and sometimes semiliquid, especially after breaking through the cortex. Areas of
hemorrhage andnecrosis are common. Thedestructionis often greater ongross appearance
thanwas visibleonradiographs.Underthe microscope, Ewingsarcomaconsistsofdensely
packeduniformsmallcellsinsheets.Thecellshavescantcytoplasmwithoutdistinctborders.
Thecellsaretwotothreetimesasbigaslymphocytesandhaveasingleovalorroundnucleus
without prominent nucleoli. The tumor spreads through Haversian canals, which cause the
appearanceofpermeative margins onX-ray.Glycogen is presentwithin the cells, causinga
positivereactiontoperiodicacid-Schiffstain.MostEwingsarcomasarepositivewithHBA71 or 0-13 stain, which is an antibody to the protein product of myc 2. The microscopic
differential includes lymphoma and metastatic neuroblastoma, which must be excluded by
reticulin stain and urine vanillylmandelic acid and homovanillic acid, respectively.
Rhabdomyosarcomaisruledoutifthespecimenstainsnegativelywithdesmin,myoglobin,and
actinstains.Aneuraloriginis supportedbyelectronmicroscopefindingsofpseudorosettes.
This is further supported by the common finding inEwing sarcoma and PNETs of choline
acetyltransferaseandthetranslocationt(11:22)(q24;ql2).ItisthoughtthatEwingsarcomawith
itsfeworganellesisthepoorlydifferentiatedendofthespectrumofPNET.Neuroepithelioma
is an example of well-differentiated PNET and has neurosecretory granules and neuritic
processes.
TreatmentOptionsforThisTumor
Treatment for Ewing sarcoma includes surgery, radiation, and multidrug chemotherapy.
Radiation or chemotherapy with vincristine, dactinomycin, and cyclophosphamide is used
preoperatively.Adjuvantchemotherapyfollowssurgeryanddecreasesrecurrences.Thetumor
canmetastasizetothelungs andlymph nodes.Poor prognosticsigns includeincreased age,
increasedESR,andleukocytosisatpresentation.
Ewingsarcomathatoccursintheforefoothasanoverallsurvivalof70%,whereasEwing
sarcomain the hindfoothas anoverall survival ofonly33%.The survival of patients with
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