FNH肝局灶性结节性增生

Outline

FNHaccountsforapproximately8%ofallprimaryhepatictumorandisthesecondmostcommonbenignlivertumorafterhemangioma.

Thisbenigntumouroccursmostcommonlyinwomenaged20–50years,butmayoccurinbothmenandwomenatanyage,withmultiplelesionsbeingfoundin20percentofcases.FNH当前1页，总共25页。

Oralcontraceptive口服避孕药useisassociatedwithFNHbuttheresponsibilityoforalcontraceptivesintheoccurrenceofthelesionhasnotbeendemonstrated.当前2页，总共25页。ClinicalsymptomsFNHisusuallyanincidentalfindingatimagingandonlyone-thirdarediscoveredbecauseofclinicalsymptomssuchasmildepigastricpainordiscomfortandorpalpableabdominalmass.Bloodlivertestsarenormalinhalfofthecasesandshowonlyincreasedinserumgamma-glutamyl-transpeptidase血清r-谷氨酰转肽酶activityinmostoftheremnants.当前3页，总共25页。

well-circumscribedlobulatedmasswithcentralscar(arrow)andradiatingseptations.

Pathologicalappearance当前4页，总共25页。FNHisdefinedasanodulecomposedofbenign-appearinghepatocytesoccurringinaliverthatisotherwisehistologicallynormal.FNHisahyperplasticliverparenchyma（增生性肝实质）subdividedintonodulesbyfibrousseptathatmayformstellatescars（星状瘢痕）.Thelesionisusuallysolitary(80%)andmeasureslessthan5cmindiameter.Occasionally,FNHispedunculated(蒂).当前5页，总共25页。Photomicrographofhistopathologicspecimenshowsregionsofnodularhepatocellularproliferationseparatedbyradiatingbandsandsurroundingmyxomatousscar(arrows).当前6页，总共25页。Themarginissharp,oftenlobulatedandnocapsuleispresent.Hemorrhageandnecrosisarerare.Atmicroscopy,thecentralfibroticzoneisdenseconnectivetissue（致密结缔组织）whichcontainsnumerousabnormallythickwalledarteries.Markedproliferationofbiliarystructuressurroundedbyinflammatorycellsisobservedwithinandattheperiphery（边缘）ofthefibrousseptae.Kupffercellsarealsoseenwithinthelesion.当前7页，总共25页。FNHclassic(80%)non-classic(20%)

(a)telangiectaticFNH,

(b)withatypia,

(c)mixedhyperplasticandadenomatousFNH

当前8页，总共25页。Diagnosis（CT）Nonenhanced

CTscans

FNHisdemonstratedasafocalhypodenseorisodensemasscomparedwithnormalliver.Acentralhypodensescarisdepictedinonlyone-thirdofthecases.Calcificationswithinthecentralscarareveryrare

andobservedinonlyabout1%ofthecases.当前9页，总共25页。contrast-enhancedCTscanarterial

phaseThelesionenhancesrapidlyinmostcasesandthelesiontolivercontrastishigh.Lesioncontouriswelldemarcatedandmaybelobulated.Atthattime,thecentralscarishypodenseandappearsmoreevidentthanonunenhancedCTscans.当前10页，总共25页。

portalvenousphaselesionenhancementdecreasesandthelesionmaybeeitherisoorslightlyhyperdenserelativetonormalliver.Small-sizedFNHmaybebarelyvisible,whereaslarge-sizedFNHarevisualizedduetodeformityinthelivercontourordisplacementofadjacentvesselsordepictionofarelativelyhypoattenuatingcentralscar.当前11页，总共25页。

delayed

phase

FNHareisodenserelativetonormalliverandinmostcases,centralscarsappearisoorhyperattenuating.Acentralscarisobservedmoreofteninlargelesionsthaninsmalllesions.当前12页，总共25页。CT当前13页，总共25页。T1WIT2WI

Diagnosis（MRI）NonenhancedMRIscans

TypicalFNHsareisoorhypointenseonT1WIandisoorslightlyhyperintenseonT2WI.

ThecentralscarishypointenseonT1WI

andstronglyhyperintenseonT2WI.当前14页，总共25页。contrast-enhancedMRIscan

dramaticenhancementinthearterialphase,followedbyisointensityofthelesionduringtheportalvenousphase.Ondelayedphaseimaging,thecentralscarshowshighsignalintensity.

当前15页，总共25页。Atypicalforms当前16页，总共25页。scarsareseeninmorethan80%ofcases.However,radio-pathologicpapershavedemonstratedthatsomeFNHmayhavenoscarevenatpathologyespeciallyFNHmeasuringlessthan3cmindiameter。当前17页，总共25页。

Rarely,scarsremainhypodenseorisodenseondelayedscansorarehypointenseonT2-weightedimages.Thesefindingsmaybeobservedupto20%ofcases.

NearlyallFNHsarehypervascularatthearterialphaseoftheenhancement,butlesionenhancementmayvaryattheportalphaseorondelayedimages.Bothhypodensityorintensityofthemassondelayedphase,oronbothportalveinanddelayedphaseimagesaswellashyperdensity-intensityofthemassontheportalveinphaseoronbothportalveinanddelayedphasesmaybeseen.当前18页，总共25页。

AlthoughFNHisanon-encapsulatedlesion,capsulelikeenhancementmaybeobservedonportalveinandondelayedphasescansinabout25–36%ofthecases.Thepseudocapsule(假包膜)ishypointenseonT1andslightlyhyperintenseonT2.当前19页，总共25页。

Differentialdiagnosis肝囊肿Hepaticcyst

原发性肝癌primaryhepaticcarcinoma当前20页，总共25页。肝囊肿Hepaticcystnoncontrast-enhancedcontrast-enhancedCTnonenhancement当前21页，总共25页。肝囊肿Hepat