外科学总论资料：肿瘤文稿

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Principlesofoncology

I.INTRODUCTION

Neoplasia(literallymeaning“newgrowth”)istheuncontrolledproliferationoftransformedcells.Thetermtumor,whichwasoriginallyusedtodescribetheswellingcausedbyinflammation,isnowusedinterchangeablywithneoplasm.

Tumorisanabnormalgrownoftissureresultingfromuncontrolled,progressivemultiplication

ofcells.Tumorsmaybebenignormalignant.Malignanttumorsusuallyarecalledcancer.As

Ahumandisease,cancerwasdescribedasearlyas1600B.CinancientEgyptianwritings.Hippocrates,theancientGreekphysician,recognizedthedifferencebetweenbenignandmalignantandnamedmalignanttumors`carcinos`.TheLatinwordofcancermeans`crab`.

Malignanttumorsconsistofundifferentiated,orunspecialized,cellsthatshowanatypicalcell

Structureanddonotfunctionlikethenormalcellsoftheorganfromwhichtheyderive.Malignanttumorsalsometastasizefromtneprimarysiteswheretheydeveloptootherdistant

sitesinbody.

Canceriscurrentlythesecond-leadingcauseofdeathindevelopedcountriesandamongthethreemostcommoncausesofdeathindevelopingcountries.Theothersarediabetesand

Cardio-celebralvasculardiseases.

Currenttheoryofcarcinogenesisconsidersthatcancerresultsfrommutationsofcertaingenesthatallowthecellstobegintheiruncontrolledgrowth.Traditionally,cancerhasbeentreatedbysurgery,chemotherapy,andradiationtherapy.Inrecentyears,withtheadvancesinbasicresearchandbiotechnology,

Biologicaltherapies,includingimmunotherapy,hormonaltherpyhavebeenaddedtothatlist.

Newdrugsandtechniquesareconstantlybeinginvestigatedanddeveloped,suchasantiangiogenicagents(e.g.,angiostatinandendstatin),geneticallyengineeredoncolyticviruses,

Andvaccineagents.Understandingtheprinciplesofmolecularoncologywillhelpcliniciansappropriatelyinterpretnewcontributionsandincorporatethemintopractice.

II.EPIDEMIOLOGY

Epidemiologicstudiesaimtomonitorcancerincidenceandmortalityofcertainpopulation.

Thediscoveryofassociationbetweentheincidenceandprevalenceofputativecausativefactorshelpustounderstandtheetiologyofcancer.

Incidenceisthenumberofnewcaseswithinaspecifiedtimeframeandisusuallyexpressedascasesper100,000peopleperyear.Prevalenceisthenumberofpatientswiththediseaseinthepopulation.Aperson'sriskofcontractingordyingofcancerisusuallyexpressedintermsoflifetimerisk(riskoverthecourseofalifetime)or,whendescribingtherelationshipofspecificriskfactorswithaparticularcancer,asrelativerisk(incomparisontothosewithorwithoutacertainexposureortrait).

GlobalBurdenofCancer

Worldwide,cancerisresponsibleforoneineightdeaths.By2020,70%ofallcancer-relateddeathswilloccurindevelopingcountries,wheresurvivalrates(20%-30%)arebarelyhalfthatofdevelopedcountries.[3]Indeed,80%to90%ofpeopleinwhomcancerisdiagnosedindevelopingcountriesareinitiallyfoundtohavelate-stage,terminalcancer.[3]Itcanthereforebeseenthatthevastmajorityofcancerdeathswilloccurinthecountriesleastequippedtohandletheburden.Ithasbeenestimatedthatmorethan11mollionpeoplearediagnesedwithcancereverydayworldwide.Lung,colorectalandgastriccancersareamongthefivemostcommoncancerintheworldforbothmenandwomen.Forwomen,themostcommoncancersarebreatandcervicalcancer.Thereareapproximately2millionnewcancercasesand1.5millionpeopledieofcancereveryyearinCnina.Theincidenceofcancerisvariablebygeography.Thisisdueinparttogeneticdifferences,parttodifferencesinenvironmentalanddietaryexposures.Inmanycases,thehigh

Incidenceofaspecificcancerinaparticularregionislinkedtoaspecificcausativeagent.Lungcanceristheleadingcancerworldwide.TheincidenceratesoflungcancerarehighinEasterEuropeandChinaformenandinNorthAmericanforwomen,whichmayreflectcigarettesmokingpattersof20-30yearsearlier.Theincidenceofgastriccancervariessignicantlyamongdifferentregionsoftheworld.Theage-adjustedincidenceishighestinJapanbutmuchlowerinNorthAmerica,easternandnorthernAfrica,andSoutheastAsia.GastriccancerisalsothemostcommonmalignancyintheruralareaofChina.ThedifferenceispresumedtobeduetodifferencesindietaryfactorsandintheincidenceofinfectionwithHelicobacterpylori,whichisknowntoplayamajorroleingastriccancerdevelopment.Theincidenceofcolonandrectalcancerishigherindevelopedcountriesthandevelopingcountries.TheincidenceofhepatocellularcarcinomaishighinpartsofAfricaandAsiaandpresumedtobeassociatedwiththefrequencyofhepatitisBinfectionintheseregions.

Comparisonofcancerincidenceratesiscriticaltoimprovingourunderstandingoftheetiologyofcancer.Analysisoftrendsincancerandmotalityallowsustomonitortheeffectsof

differentpreventiveandscreeningmeasures,aswellastheevolutionoftherapiesforspecific

cancers.

IV.CLASSIFICATION

Tumorsaregenerallyclassedintotwogroups.Benigntumorsarenoncancerous;malignanttumorsarecancerousandhencelifethreatening.

Benignandmalignantgrowthsdifferinseveralways.Malignantneoplasmsgrowrapidly;benignneoplasm,ontheotherhand,growslowslowlyandthenumberofcelldivisions(mitoses)isfarlessincomparisonwithmalignantneoplasms.Benignneoplasmsareencapsulatedandanddonotdomuchdamagetosurroundingtissue.Malignantgrowths,however,invasive(spreadingtosurroundingtissue.)Notonlydomalignantneoplasmsdestrysurroundingtissue,buttheyalsoinfiltratebloodandlymphvesselsfromwhichtheyspreadtootherareasofthebody.Thismigrationtootherareasofthebodyiscalledmetastasis.

Cancercellsshowahighdegreeofanaplasia(reversiontoamoreprimitiveform).Theseanaplasticcellsresembleprimitive,fetal-likecells.Theygrowrapidly(hyperplasia)anddonotdifferentiate—thatis,functionlikenormalcellsandjoinwithothercellstoformnormaltisssue.Themicroscopicevaluationoftumorcellsiscalledgrading.Gradingisconcernedwith

thedegreeofanaplasiaofthemalignantcells.GradeIcellsaremuchlikenormalcellsintheirdegreeofdifferentiation.Witheachsucceedinggrade,differenciationisreducedandanaplasiabecomesmoreprominent.

Alltumorsarenamedaccordingtothetypeoftissuefromwhichtheydevelop.Noncanceroustumorshavethesuffix–omaaddedtothetissuetype.Forexample,anadenomaisabenigntumororiginatingintheglandularepithelium.Thesuffixes–carcinomaand–sarcomaindicatemalignanttumors.Carcinomasarethemostcommonformofcancer.Theycanarisefrombothexternalandinternalepithelialtissue.Theyreadilyinfiltratesurroundingtissueandquicklymetastasize.Thewordadenocarcinomaindicatescanceroftheglandularepithlium.Sarcomasaremalignanttumorsdevelopingfrommesenchymaltissue（bone,fat,musle,blood,etc）,Lymphosacoma,forinstance,iscanceroflymphatictissue.Athirdtypeof

canceroustumorfromembryonalconnectivetissue,Wilms`tumor,whichoccursinchildren,forexample.Moreexample:

OriginBenignFormMalignantForm

SquamousepitheliumPapillomaSquamouscarcinoma

BloodvesselsHemangiomaHemangiosarcoma

SmoothmuscleLeiomyomaLeiomyosarcoma

StriatedmuscleRhabdomyomaRhabdomyosarcoma

BoneOsteomaOsteosarcoma

CartilageChondromaChondrosarcoma

V.ETIOLOGY

Theoriginofcancerisstillunderinvestigation.Currentlycancerispresumedasageneticdiseasethatarisesfromaccumulationofmutationswithincellsunderthestressofcarcinogen.

Environmentalcarcinogenincludeschemical,physicalandbiologicalagents.Thesecarcinogens

resultingeneticchangesofcells.However,carcinogenesisisamultiplestepprocessandalsoaffectedbymanyhostfactors,includinggeneticdispositionsandimmunologicalconditions.

ChemicalAgents(enviromentalfactorsandjobrelatedcarcinogen)

Alkylatingagent

Aromaticaminesandamides

Suchagentsasb-naphthylamine,producepapillomasandbladdercancerWorkersindye

andpesticideplantscaninhaleorabsorbthesesubstances.

Policyclicaromatichydrocarbons(PAH)

Besidesjob-relatedcarcinogens,Thehydrocarbonsproducedbyautomobilesandcigarettesmokecancauseoftheskin,bladder,respiratirytractandorgans.

Carcinogenicmycotoxin

Inorganicchemical,suchasarsenic,cadmium,andnickel

Chromiumandnickelproducecancerofthenasalcavity,sinus,andbronchusinworkersminingandrefiningthesesubstances.

Petroleumproducts,waxes,tars,andsimilaritemscauseskincancerinthoseworkingin

insuchindustriesasrefineriesandasphaltcompanies.

Coalderivativessuchascoaltar,pitch,andcreosote,produceskincancerandcancerof

thelarynxandbronchusincokeovenworkers,coaltardistillers,andthoseworkingin

certainareasofthelumberandchemicalindustries.

Foodadditives,suchasnitratesinbaconandothermeats,havebeenlinkedtogastrointestinalcancer.Chemicallikevinylchloridearewidelyusedinhomesandnowconsideredcarcinogenic.

Thehydrocarbonsproducedbyautomobilesandcigarettesmokecausecanceroftheskin,bladder,andrespiratorytractandorgans.

PhysicalAgents

UltravioletlightOverexposuretosunlightisthemostcommoncauseofskincancer.

Ionizingradiation

Radiationisapotentcarcinoge.Radiologistsandothersworkingnearradiationhaveahighincidenceofleukemiaandskinandbonecancer.

BiologicalFactors

Theviruscausesinfectiousmononucleosis,forexample,isalsothecauseofBurkitt`slymphoma,amalignanttumorofthejaw.Mycotoxinsproducedbymoldsarealsopotent

Carcinogens.Foodcontaminatedwithmoldhasbeenlinkedtolivercancer.

GeneticFactors(Heredity)

Adefinitepatterofinheritedcancershasnotbeenestablishedformostcancers;becausesomefamilieshaveahigherincidenceofcancerthanothers,however,thelikelihoodofinheritingapredipositiontocancerisincreased.Retinoblastoma,cancerofeyeoccurringin

Childhood,adenomasofthethyroidandparathyroids,andcolonicpolyposisareconsidered

inheritableneoplasm.

ImmunologicalFactors

Precancerousdisorders

Severalnonneoplasticdisordershavebeenlinkedtocancer.Theincreasedandextensivecellulargrowthcausedbythesedisordersmaypredisposethemtoformneoplasms.Some

examplesofprecancerousdisordersarelistedbelow.

PrecancerousDisorderCancer

LeukoplakiaSquamouscancerofthemouth

CirrhosisoftheliverHepaticcelladenocarcinoma

ChroniculcerativecolitisColonicadenocarcinoma

ChroniccervicitisSquamouscancerofthecervix

ChronicbalanitisSquamouscancerofthepenis

Paget`sdiseaseoftheboneOsteosarcoma

AplasticanemiaAcuteleukemia

Carcinogenesis

Carcinogenesisinhumansisamultistepprocess.Thecancercelldiffersfromitsnormal

Counterpartinthatofthederegulatedcelldivision,differentiationandapoptosis.Current

theorypresumethatasuccessionofgeneticchanges,eachconferringoneoranothertypeof

growthadvantage,leadstotheprogressiveconversionofnormalhumancellsintocancercells.Thesegeneticchangesresultinseveralessentialalterationsincellphysiologythtcollectivelydictatetomalignanttransformationandtumourprogression.

Cancercellsareself-sufficientingrowthsignal.Manyoftheknownoncogenesmimicnormal

growthsignalinginonewayoranother,suchasHer2/neuandras,stimulatingcancercell

proliferation.Cancercellsareinsensitivetoantigrowthsignals.

Itshouldbekeepinmindthatmalignanttransformationandtumorprogressionareexceedinglycomplexprocesses,andtheirgeneticandbiochemicaldeterminantsremainincompletelyunderstood.

CLINICALMANIFESTATION

Theclinicalpresentationofcancerdependentonthenatureofthespecifictumor,the

locationaswellastheprogressionofthedisease.Cancerusuallyappearsasanasymp-

tomaticlesiontoosmalltobeseenwithoutspecialexaminationsinearlystages.Withthe

Progressionofthedisease,somecommonsignsandsymptomsmayappears:

Localsymptoms

Thelocalsymptomsofneoplasmincludemass,pain,ulceration,hemorrhage,obstruction,invasionandmetastasis.Whentheneoplasmiseitheronornear

thesurfaceofthebody,itmaypresentsimplyasavisibleorpalpablemass.Forvisceral

neoplasm,themassmaynotbepalpable.Inthegastrointestinal,biliary,respiratory,and

urinaltracts,signsarefrequentlyrelatedtoobstruction.Examplesarevomiting,jaundice

,coughandurinaryretention.Theexpansilegrowthofcentralnervesystemneoplasmmaycausepain,paralysisor,sensoryloss.Whentumorinfiltratesorstimulatesnervesdue

toexpansilegrowth,necrosis,orinfection,painappears.Examplesarelumbosacralplexus

painincancerofthecervixandrectum,dorsalandlumbarspinepainincancerofthe

pancreas,andtheshoulderandarmpainandpalsywhencarcinomaofthelunginfiltrates

thebrachialplexus.Ulcerusuallydevelopedinskinandgastrointestinalcancerasaresult

ofrapidexpansilegrowth,insufficientbloodsupply,andsubsequentnecrosisorinfection.

Hemorrhageisrelativelycommoninmalignanttumors.Hematemesisandmelenamayindicatethelesionlocateintheupperalimentarytract,whereasrectalbleedingmaybethe

Signofloweralimentarytractneoplasm.However,acutegastrointestinalbleedingissomewhatunusual,butchronicoccultbloodlossiscommonandmanifestasirondeficiencyanemiaandheme-positivestool.Malignanttumorsinvadesurroundingtissue

andspreadthroughbloodorlu\ymphaticvessels.Lymphmetastasiscanresultinpalpable

enlargedregionalnodes.Themostfrequentsitesofmetastaticneoplasmsarethecervical

andsupraclavicularlymphnodes,lungs,liver,bonesandbrains.

Systemicsymptoms

Mostbenigntumoursandearlystagemalignanttumordonotpresentsystemicsyptoms.Withthedevelopmentofthedisease,nospecificsymptoms,suchasanemia,persistentfatigue,unintentionalweightlossandfever,maybepresented.Fatigueandweaknessmay

betheonlysymptomsincancerofthestomachorrightcolon,becausethetumourulcerationandbleedinghaveresultedinanemia.

Diagnosis

Earlydiagnosisandearlytreatmentcontributemostlytotheimprovedsurvivalofcancerpatientsinlastquartercentury.Carefulinquiryofilnesshistory,thoroughphysicalexaminationmayhelpphysicianstofindsignsofcancer.Thenavarietyoftestsareusedto

confirmoreliminateofthepresenceofdisease,monitorthediseaseprogress,andevaluatethe

effectivenessoftreatment.Diagnosticproceduresofcancermayincludeincludinglaboratory

test,imaging,endoscopicexaminationandbiopsy.Theearlierthediagnosis,themorepositive

theprognosis.

HistoryofIlness

Mostbenignandearlystagemalignancydonotpresentsystemicsymptoms.So,everyindividualshouldbeawareofthewarningsignsofcancer:

A.Unusualbleedingordischarge.Forexample,rectalcancerhaerrhoid

B.Alump.Withfever,notdisappear.

C.Asore(ulcer)thatdoesnotheal.Likeacrater

D.Achangeinbowelorbladderhabits.Urgencywithmucusorblood.

E.Acoughorhoarsenessthatpersists.

F.Difficultyinswallowingorindigestion.

G.Anychangeinawartormole.

H.Weightlossfornoapparentreason.

Differentkindsoftumorshavedifferentagedistribution.Forexample,leukemiausuallyoccursinchildren,sarcomaoftenoccursinadolescenceandcancerusuallyoccursinmiddle-

agedorelderlypatient.Benigntumorshavealongcourse,whereasmalignanttumourshave

shortcoure.Personalhistory,includinghabitofalcoholicdrinking,smokingorsomespecial

occupationscontactingcarcinogenicsubstancesmaybenoticed.Sometumorshavefamilyhistoryandarehereditary.

PhysicalExamination

Physicalexaminationincludesathoroughsearchoftheentireskinsurfaceforsquamouscellandbasalcarcinomas,indurativelesions,ulcers,suspiciousorirritatednevi,nodules,and

othersignsofmalignantdisease.Lymphnodesshouldbepalpatedforenlargement.Breastsshouldbecarefullyexamined.Rectalexaminationshouldincludeproctoscopicexaminationof

patientswhohavehemorrhoidsorrectalsymptoms.Indirectlaryngoscopyshouldbeperformedifpatientsishoarse,hasaneckmass,orissuspectedofhavinganintrathoracic

neoplasmorcancerofthethyroidgland.

3.LaboratoryEamination

Laboratoryeaminationshouldincludeacompletebloodcellcount,urinalysis,andexaminationofstoolforoccultblood.Othertestsshouldbeorderedwhereindicatedbysymptoms.Beforeoperatingonapatientforcureorpalliation,ametastaticwork-upshoulbe

done,directedbysymptomsandthemostlikelysiteofmetastases,todeterminewhetherthe

neoplasmisstilllocalized.Laboratorytestsinclude:

a)Serologicaltest

Serummarkersareunderactiveinvestigationastheymaybeusedasprognosticorpredictivemakerstoallowearlydiagnosisormonitorrecurrence.Unfortunately,manyofthe

tumormarkersproposedsofardohavehadsensitivitiesandspecificities.Tumormarkerscan

beelevatedinbenignconditions.Manytumorsarenotspecificforacertaintypeofcancerandcanbeelevatedwithmorethanonetypeoftumor.Inspiteofthesemanyclinicallimitation,severalserummarkersareinclinicaluse.Samplesare:

Prostate-specificantigen(PSA)ispotentiallythebestserummarkernowavaailable.PSAlevelsmaybeelevatedinthebloodofmenwithbenignconditionssuchasprostatitisandbenignprostatichyperplasia,aswellasinmenwithprostatecancer.PSAlevelshavebeenshowntobeusufulinmonitoringtheeffectivenessofprostatecancertreatmentandforrecurrenceaftertherapy.

Carcinoembryonicantigen{CEA}isaglycoproteinfoundintheembryonicendodermalepitheliumElevatedCEAlevelshavebeendetectedinpatientswithprimarycolorectalcancer

,aswellaspatientswithbreast,lungovarian,prostate,liver,orpancreaticcancer.CEAismostcommonlyusedforthemanagementofcolorectalcancer.

Alpha-fetoprotein(AFP)isaglycoproteinnormalproducedbyadevelopingfetus.Anelevatedlevelssuggeststhepresenceofeitherprimarylivercanceroragermcelltumorofthe

ovaryortesticle.BenignconditionsthatcancauseelevationsofAFPincludecirrhosis,hepatic

necrosis,acutehepatitis,chronicactivehepatitis,ataxia-telangiectasia,Wiskott-Aldrichsyndrome,andpregnancy.

b)Imaging

Techniquesthatmaybeusefulinlocalizingtumorlesionincludebariumexaminationsofthe

gastrointestinaltract;selectivearteriographyofmajorvesselssupplyinginternalorgans;radioisotopesandradiopaquedyethatconcentrateintheorganssuchastheliver,gallbladder,kidney,andlymphnodes;andultrasonographyandabdominalcomputerassistedtomography(CT),whichisrapidlybecomingthemostusefulinvestigativetechniqueforintra-

abdominaltumors.Sometimesmdyesareinjecttedintobloodvesselsorsubstancesareswallowedsothatanyobstruction(i.e.,atumor)tothepathsleftbythesesubstancesappearonthexray.

Theoperabilityofprimarytumorsisbestdeterminedbeforesurgerywithappropriateimagingstudiesthatcandefinetheextentoflocal-regionaldisease.Forexample,apreoperativethin-sectionCTscanisobtainedtodetermineresectabilityforpancreaticcancer,

whichisbasedontheabsenceofextrapancreaticdisease,theabsenceoftumorextensiontothesuperiormesentericarteryandceliacaxis,andapatentsuperiormesentericvein-portalveinconfluence.Diseaseinvolvingmultipledistantmetastasesisdeemedinoperablesinceitisusuallyotcurablewithsurgeryoftheprimarytumor.

c)EndoscopicExamination

Lesionsofesophagus,stomach,duodenum,colonandrectumcanbeexaminedbyendoscope.Tissuefromthelesionscanberemovedforpathologicalexamination.Thecolonoscopeallowsthephysiciantoseetheliningofcavitywall.Procedureslikeendoscopic

Retrogradecholangiopancreatography(ERCP)allowsthephysiciantodiagnoseandtreatproblemsinupperalimentarytractandpancreas.Laparoscopicexaminationisoftenrequired

toconfirmthediagnosisandobtainbiopsy.

d)Tumorbiopsy

Definitivediagnosisofsolidtumorsusuallyreliesonabiopsyofthelesion.Whenalesionis

nearthebodysurfaceorinvolvesoneoftheorificesofthebodythatcanbeexaminedwithappropriatevisualinstruments,suchasabronchoscope,colonoscope,orcystoscope.Asample

ofthelesioncanbeobtainedwithaneedleorwithanopenincisionalorexcisionalbiopsy.Deep-seatedlesionscanbelocalizedwithCTscanorultrasoundguidanceforbiops.

Inaneedlebiopsyaneeddleisinjectedintothesuspectedareaandatissuesampleisremovedformicroscopicevaluation.Afrozensectiontakenwhenalumpissurgicallyremoved.Athinportionofthetumorissliced,dyed,andquicklyfrozen.Next,itisexamined

Microscopicallybyapathologisttodeterminewhetheritisbenignormalignant.

e)Exfoliativecytology

Cellsarescrappedoffthebodysurfaceorinternalliningandexaminedmicroscopically

Fortumorcells.ThePapsmearisanexampleofexfoliation.

Theearlierthediagnosis,themorepositivetheprognosis.

Staging

VII.TREATMENT

Cancercanbetreatedwithsurgery,radiotheraoy,chemotherapyandbiologicalapproaches

suchasimmunotherapy.Amultimodality(multidisciplinary)approachwithsystemictherapyisnecessaryformosttypesofcancer.Itisimportantforsurgeonstoknownotonlyhowtoperformacanceroperationbutalsothealternativestosurgery.

Surgicaltreatment

Surgeryremainsaprimarytreatmentformosttypesofcancer.Thegoalofsurgicaltherapy

forcanceristoachieveoncologiccure.Acurativeoperationpresupposesthatthetumoris

confinedtotheorganoforigin,ortotheorganandthereginallymphnodebasin.Patientsin

whomtheprimarytumorisnotresectablwithnegativesurgicalmarginsareconsideredto

haveinoperabledisease.Onoccasion,primarytumaorsofpatientswithdistantmetastasis

areresectedinthesepatientsforpalliativereasons,suchasimprovingthequalityoflifeby

alleviatingpain,infection,orbleeding.Patientswithlimitedmetastasesfromaprimarytumoronoccasionareconsideredsurgicalcandidatesifthenaturalhistoryofisolateddistantmetastasesforthatcancertypeisfavorable,orthepotentialcomplicationsassociatedwith

leavingtheprimarytumorintactaresignificant.

Surgicalproceduresaredesignedtoremovetheprimaryneoplasmandthecontiguousroutes

ofspread(lymphaticsandregionallymphnodes),withthegoalofremovingeverycancercellservingasasourceofmetastasis,tocurethepatientortocontrolthediseaselocallyevenwhen

probabilityofcureislow.Advancesinsurgicaltechniques,anesthesia,andsupportivecare(

bloodtransfusions,antibiotics,andfluidandelectrolytemanagement)havepermittedthedevelopmentofmoreradicalandextensiveoperativeprocedures.Theseadvanceshaveresultedinsignificantimprovementsinthelocalcontrolratesforcertainhumanneoplasms.

Chemotherapy

Radiotherapy

Immunotherapy

TraditionalChinesedrugs

VIII.CUTANEOUSANDSUBCUTANEOUSTUMORS

Suffix–omameansswelling,tumor.

Lipoma

Lipomasarebenigntumorsderivedfromfattissueandcouldpresentassingleormultiple

softlesions.Theyarethemostcommonsubcutaneousneoplasm.Lipomascouldberound,

ovoid,orlobulatedwithdefinedborder.Theyoccurmostfrequentlyontheupperbackandshoulders.Singlelipomashouldberemoved.Multiplelipomasshouldbeignored,sometimes

subsideorselfconfinedspontaneously.

Fibromas

Fibromasconsistofwelldifferentiatedconnectivetissueandaresituatedinsubcutaneous

tissue.Theyaresmallandslowingrowth.Theskinoftheirsurfaceisnormal.Theyarefirm,smoothandmovable.Theirtreatmentissimpleexcision.Fibromasinthebreastusuallycombinewithglandtissueandformfibroadenomasandshouldbeexcised.

DermoidFibromasarefoundinabdominalwall.Theygrowinthemuscularlayerandaremorecommonlyinwomen.Theyaregenerallyconsideredtoberelatedtotheinjuryofabdominalmuscleduringlabor.DermoidFibromasalsooccurinskeletalmuscleinotherplaceandgrowwithinfiltrationandmaybecomesarcoma,thereforeshouldbeexcisedradically.

Neurofibromas

Neurofibromasusuallyarisefromnervetrunkinthearmpit,internalsideoftheelbow,

cheekandretroperitonealregion.Majorityofthemaresolitarywithsmoothsurfacewith

noadhesiontosurroundingtissue.Theyarediscretenodulesthatmaybelocallypainfulorradiatealongthedistrbutionofthenerve.Iftheneurofibromascomefromsympatheticnerve,ganglionandchain,theyareignoredduringoperation.Iftheycomefrombranchial

plexusorulnarnerve,nervetrunkshouldbepreservedduringoperation.

PachydermatoceleisatypeofpendantfibromaoftheskinandsubcutaneoustissuethatoccursinassociationwithvonRecklinghausen’sdisease.Thelesionsarepresentfrombirthbutmayincreasemarkedlyinsize.Theirtissueweightmaycausedistortionofregionalsofttissue,andunderlyingbonesmaybeenlargedbecauseoftheirvascularity.Theterm“pachydermatocele”comesfromthethick,corrugatedappearancemotunlikethatoftheskinofanelephant.Surgicalexcision,instagesifthetumorislarge,isadvised.Thetumormaybeextremelyvascularbecauseoflooseareolartissueandabundantlargevascularsinuses.Thesesinuseshavenocontractility,asdonormalbloodvessels,andcontrolofhemorrhagemaybedifficult.

Hemangiomas

Threetypesofhemangiomasaregenerallyrecognized,includingcapillaryhemangiomas,

cavernoushemangiomas,andwindinghemangiomas.Capillaryhemangiomasaresoft,compressiblepopularlesionswithsharpborderslocatedmostlymostlyontheshoulder,face,andscalp.Theycanbeexcisedorcryotherapybyliquidnitrogen.