CassiaGuimaraes

AlessandroFurlan

AmirBorhani

SpencerBehr

MitchellTublin

AntonioC.Westphalen

EMBRYOLOGY,ANATOMY,CONGENITALVARIANTSAND

AGE-RELATEDCHANGES

DISCLOSURES

CassiaGuimaraes:nodisclosures

AlessandroFurlan:bookcontract(Elsevier–Amirsys);Researchgrant(GeneralElectric)

AmirBorhani:bookcontract(Elsevier–Amirsys)

SpencerBehr:GEHealthcare-Grantandconsultant

MitchellTublin:bookcontract(Elsevier–Amirsys)

AntonioC.Westphalen:member,scienJficadvisoryboard(3DBiopsyLLC)

MULTIMODALITYIMAGINGOFTHEPROSTATEANDSEMINALVESICLES

•  Goals:

ü  Describetheembryology,anatomyandcongenitalvariantsoftheprostateandseminalvesicles

ü  Describeage-relatedanatomicalchangesseenoverJme,andunderstandtheirinfluenceonassessmentofprostatecancer

•  TargetAudience:

ü  Radiologyresidents,fellowandabdominalradiologists

EMBRYOLOGY,ANATOMY,CONGENITALVARIANTSAND

AGE-RELATEDCHANGES

Humanembryohastwopairsofgenitalducts:

•  Mesonephricducts(wolffian)

•  Paramesonephricducts(müllerian)

Malegenitaltractarisesfromthemesonephricduct.Therefore,anomaliesofseminalvesicles,vasdeferensandkidneysareoUenassociated.

Paramesonephricductinvolutesinmales.Mesonephric

duct

Paramesonephric duct

EMBRYOLOGY5thweek

EMBRYOLOGY5th–7thweeks

Mesonephric duct

Ureteric bud

5thweek

Theuretericbudarisesfromthe

mesonephricduct.

6th–7thweek

Kidneysascendandtheureterobtainsaseparateopeningintothebladder(arrow).

Ureter

Primitive kidney

6thweek

Theuretericbudblendswiththe

metanephricblastematobecometheprimiJvekidney.

Seminalvesicles(SV),vasadeferenJa(VD),ejaculatoryducts(ED),andepididymidesdevelopfromthemesonephricducts.

Urogenitalsinusarisesfromthecloacaandwilldevelopintothebladderandurethra.

Latertheprostateglandderivesfromtheurethra.

Mesonephric duct

Urogenital sinus

Primitive testis

Paramesonephric duct

EMBRYOLOGY6thweek

Mesonephric duct

Urogenital sinus

Primitive testis

Paramesonephric duct

Testis

Vas deferens

Seminal vesicle

Ejaculatory duct

Prostate utricle

EMBRYOLOGY8th–12thweeks

Separatebudsarisefromthedistalmesonephricducttoformtheseminalvesicles.

Paramesonephricductsinvolute,exceptfortheirdistalporJonwhichwouldcontributetoprostaJcutricle.

6weeks 8-12weeks

EMBRYOLOGY4thmonth

Seminal vesicle

Vas deferens

Ejaculatory duct

urethra

Prostate utricle

6weeks 8-12weeks 4months

Mesonephricductbecomesthevasdeferensandejaculatoryducts.

ProstaJcoutgrowthsareinducedbysurroundingmesenchymeandhormonaleffect.

Mesonephric duct

Urogenital sinus

Primitive testis

Paramesonephric duct

Testis

Vas deferens

Seminal vesicle

Ejaculatory duct

Prostate utricle

Prostate Gland

ANATOMYProstate

Zonalanatomy

Theglandisdividedin4regions

1)  Anteriorfibromuscularstroma(AFS):noglandularJssue

2)  TransiJonzone(TZ):surroundstheurethra,cranialtotheveromontanum,5%ofglandularJssue*

3)  Centralzone(CZ):surroundstheejaculatoryducts,20%ofglandularJssue*

4)  Peripheralzone(PZ):70-80%ofglandularJssue*

*inyoungadults

ANATOMYProstateMRImaging

AFS

TZ

PZ

•  AFS:locatedintheanterioraspectofmidandlowergland.DemonstrateslowsignalonT2Wimages

•  CZandTZarenotalwaysdisJnguishablebysignalintensityfromeachother.AppearsheterogeneouslyhyperintenseonT2Wimages

•  PZ:typicallyhomogeneouslyhyperintenseonT2Wimages

•  CapsulereferstoathinfibrousJssuesurroundingthegland,seenasalowT2signalrim

PZ

TZ

capsule

Base (B)

Midgland (M)

Apex (A)

ANATOMYProstateMRImaging

BMA

Bladder

UU

A

Produceandsecretetheseminalfluid.

Locatedatthebaseofprostate,posteriortothebladderanddistalureters(U).

Elongatedfluid-containingstructureswithseptanormallyhypointenseonT1WMRimagesandhyperintenseonT2WMRimages.

BA)PosteriorviewofmalepelvisshowstherelaJonshipbetweenSVs(arrows)andurogenitalorgansB)CoronalT2-weightedshowingthenormalappearanceofseminalvesicles(arrows).

ANATOMYSeminalVesicles

courtesyofAmirsys®

Symmetrictubularstructuresextendingfromtheepididymaltail,andrunningthroughtheinguinalcanal,thatjointheseminalvesicle.

VDusuallyhaslowsignalonbothT1WandT2W,althoughthedistalVDmayoccasionallybecysJcandT2hyperintense.

ThedistalporJonsoftheVDandSVareextraperitoneal.Thisenableitsinvolvementbydiseaseprocessesofadjacentorgans.

**

A)DiagramposteriorviewofmalepelvisshowstherelaJonshipbetweenVDsandtheurogenitalorgans.B)CoronalT2-weightedimageshowscysJcappearanceofdistalVD(arrows)beforeitjoinstheSV(*)toformED.

Prostate

VasDeferens

A

B

ANATOMYVasdeferens

courtesyofAmirsys®

A)AxialT2-weightedimageshowscourseoftheVDalongthelateralaspectofpelvis.(arrows).B)CoronalT2-weightedimagesshowingtheVDjoinstheSV(arrows).

Symmetrictubularstructuresextendingfromtheepididymaltail,andrunningthroughtheinguinalcanal,thatjointheseminalvesicle.

VDusuallyhaslowsignalonbothT1WandT2W,althoughthedistalVDmayoccasionallybecysJcandT2hyperintense.

ThedistalporJonsoftheVDandSVareextraperitoneal.Thisenableitsinvolvementbydiseaseprocessesofadjacentorgans.

A

ANATOMYVasdeferens

B

ANATOMYEjaculatoryducts

FormedbythejuncJonofSVsandthedistalporJonofVDs.

DrainintotheprostaJcurethraattheverumontanum.

Theductsareapproximately1-2cmlong.

SagiialT2-weightedMRimage(A)andsagiialillustraJon(B)showcourseofED(arrowheads)withintheprostategland.B

Ur

Ur

A

MRIonconsecuJveaxialT2-weightedimages(A–B).TherightVDandSVarenotseenintheposterioraspectofthebladder.TheleUSVispresent(arrows).

CONGENITALVARIANTSSeminalVesicleAgenesis

Associatedwith:

•  Ipsilateralagenesisofthevasdeferens

-  Insulttothemesonephricductduringembryogenesis

•  Ipsilateralrenalagenesis

-  Insultoccursbeforethe7thweeksofgestaJon(beforeureteralbudding)

•  CysJcfibrosis

-  BilateralSVandVDagenesis.Usuallywithnormalkidneys

A

B

CONGENITALVARIANTSSeminalVesicleAgenesis

Associatedwith:

•  Ipsilateralagenesisofthevasdeferens

-  Insulttothemesonephricductduringembryogenesis

•  Ipsilateralrenalagenesis

-  Insultoccursbeforethe7thweeksofgestaJon(beforeureteralbudding)

•  CysJcfibrosis

-  BilateralSVandVDagenesis.Usuallywithnormalkidneys

Axialnon-contrastCTimagesoftheupperabdomen(A)andpelvis(B)showagenesisoftheleUSV(B)associatedwithipsilateralrenalagenesis(A).

A

B

CONGENITALVARIANTSCongenitalseminalvesiclecysts

A)AxialT2WMRIimagesshowsasolitarySVcyst(*).B)CoronalT2WMRIthroughupperabdomen,inthesamepaJent,showsanemptyrightrenalfossa.

Isolatedorassociatewith:

•  Upperurinarytractanomalies

–  2/3ofthecasesareassociatedwithipsilateralrenalagenesis/dysplasia

•  AutosomaldominantpolycysJckidneydisease(ADPKD)

–  BilateralSVscystsinupto50%

MajorityofcystsaresmallandasymptomaJc;maybecomelargeandcauseurinary/GIsymptoms

A

B

CONGENITALVARIANTSCongenitalseminalvesiclecysts

Axialcontrast-enhancedCTimagesofthepelvis(A)andupperabdomen(B)showbilateralSVcysts(arrow)andmulJplekidneyandlivercystsassociatedwithADPKD(B).

Isolatedorassociatewith:

•  Upperurinarytractanomalies

–  2/3ofthecasesareassociatedwithipsilateralrenalagenesis/dysplasia

•  AutosomaldominantpolycysJckidneydisease(ADPKD)

–  BilateralSVscystsinupto50%

MajorityofcystsaresmallandasymptomaJc;maybecomelargeandcauseurinary/GIsymptoms

A

B

•  ProstaJcagenesis:frequentlyassociatedwith5a-reductasedeficiencyandtesJcularfeminizaJon

•  ProstaJchypoplasia:oUenseeninprunebellysyndrome,withdilatedprostaJcurethra

•  ProstaJcectopia:rare,locatedinthebladder,urethra,SV,epididymis,ortesJs

CONGENITALVARIANTSProstateagenesis,hypoplasiaorectopia

mullerianductcyst

CONGENITALVARIANTSProstateutricularcyst

Incompleteregressionofparamesonephricduct.

Pear-shapedmidlinecystnotextendingabovetheprostate.CommunicateswiththeprostaJcurethra.

AsymptomaJc,UTI,pain,post-voidinginconJnence,epididymiJs,andhematospermia.

MayexhibithighsignalintensityonT1WimagesduetoinfecJonorhemorrhage.

A)AxialandB)CoronalT2-weightedMRimagesshowingamidlineprostatecystcompaJblewithutricularcyst(arrows).

A

B

FocalincompleteregressionanddilataJonoftheparamesonephricduct.

Teardrop-shaped,midline,extendingabovetheprostate.Doesnotcommunicatewithposteriorurethra.

UsuallyasymptomaJc,butmaycauseurinaryretenJonandUTI.

MayexhibithighsignalintensityonT1WimagesduetoinfecJonorhemorrhage.

mullerianductcyst

CONGENITALVARIANTSProstatemülleriancyst

A)SagiialandB)CoronalT2-weightedMRimagesshowingamidlineprostatecystcompaJblewithmulleriancyst(arrows).Background=US

A

B

AGE-RELATEDCHANGES

AGE-RELATEDCHANGESBenignProstaticHyperplasia

Foundin8%ofmeninthe4thdecadeoflifeandin70%bythe7thdecade.

CausedbyproliferaJonofsmoothmuscleandepithelialcellsofthetransiJonalzoneinresponsetohormonalandinflammatoryfactors.

MRIfindingsincludeband-likeareas(arrowheads)andencapsulatednodules(*)inthetransiJonalzone,whichcanextrudeinto

theperipheralzone.

**

AGE-RELATEDCHANGESBenignProstaticHyperplasia

EnlargementofTZcondensesthesurroundingcentralzoneintoathinrim(pseudocapsule,usedasthesurgicalplaneofresecJon).

ProstateenlargementvariesinBPH;BPHnodulesandbandlikeareascanbefoundinmildlyenlargedglands.

Symptomsandtreatmentdependonsize,histologicalandmorphologicalcharacterisJcs.

AxialT2-weightedMRimagesA)Pseudocapsule-rimcorrespondaCZcondensed(arrow)andB)BPHfindingsinamildlyenlargedprostate.

A

B

Prostatenormalvolumeisapproximately:•  25cm3in30s

•  30–45cm3in70s

Theaverageincreaseisabout1.5-2%yearly.

BenignprostaJcenlargementisdefinedbyaprostateJssuevolumegreaterthan25cm3.

Age-relatedchangesinprostatesizeisvariable.WhileBPHresultsinprostatomegalyinmajorityofagingmen,inasmallproporJonofpeopleprostatevolumedecreasedwithaging.

AGE-RELATEDCHANGESProstateSize

Volume

Age

Age-relatedchanges

TZ

CZ

PZ

SVnormallymeasures3.0inlengthand1.5cmindiameter.Thesizereduceswithadvancingage.

AmyloidosisofSVsisaseniledisease,notaccompaniedbysystemicamyloidosisorclinicalsymptoms.Isthemostcommonformoflocalizedamyloidosis,withincidenceatautopsyof8%to16%inelderlymen.

FaiyreplacementofSVsisararedegeneraJveprocesswithunknownmechanism.

AGE-RELATEDCHANGESSeminalVesicles

A)Coronalnon-contrastCTshowsenlargementandfaiyreplacementofSVs(arrows).B)AxialT2WMRIinadifferentpaJentshowswallthickeningofSVs(arrows)insenngoflocalizedamyloidosis.

A

B

AGE-RELATEDCHANGESVasdeferens

A)Axialcontrast-enhancedCTofpelvisandandB)AxialT2-weightedMRIshowcalcifiedvasdeferens(arrows)intwodifferentpaJents.

CalcificaJonsofthevasdeferenshasbeendescribedinassociaJonwith:

•  Diabetes•  Hyperparathyroidism•  Genitourinarytuberculosis

MaycausemaleinferJlityandsymptomsfromtheurogenitaltract.

A

B

CONCLUSIONMultimodalityImagingoftheProstateandSeminalVesicle

•  Although uncommon, congenital abnormaliJes of the prostate andseminalvesiclesare increasinglyencounteredonprostateMRIandotherimagingmodaliJes.

•  Owing to the close embryologic relaJonship, these anomalies are oUenassociatedwithothersgenitourinaryabnormaliJes.

•  Familiaritywiththeembryology,congenitalanomalies,anatomy,andage-relatedchangesisimportant.ForpaJentswithsuspectedprostatecancer,these are essenJal for the opJmal interpretaJon of MRI and otherimagingmodaliJes.

1.  ShebelHM,FargHM,KolokythasO,El-DiastyT.Cystsofthelowermalegenitourinarytract:embryologicandanatomicconsideraJonsanddifferenJaldiagnosis.Radiographics2013;33:1125-43.

2.  KimB,KawashimaA,RyuJA,TakahashiN,HartmanRP,KingBF,Jr.Imagingoftheseminalvesicleandvasdeferens.Radiographics2009;29:1105-21.

3.  AroraSS,BreimanRS,WebbEM,WestphalenAC,YehBM,CoakleyFV.CTandMRIofcongenitalanomaliesoftheseminalvesicles.AJRAmJRoentgenol2007;189:130-5.

4.  KingBF,HaieryRR,LieberMM,WilliamsonB,Jr.,HartmanGW,BerquistTH.Seminalvesicleimaging.Radiographics1989;9:653-76.

5.  BoschJL,HopWC,NiemerAQ,BangmaCH,KirkelsWJ,SchroderFH.ParametersofprostatevolumeandshapeinacommunitybasedpopulaJonofmen55to74yearsold.JUrol1994;152:1501-5.

6.  RhodesT,GirmanCJ,JacobsenSJ,RobertsRO,GuessHA,LieberMM.Longitudinalprostategrowthratesduring5yearsinrandomlyselectedcommunitymen40to79yearsold.JUrol1999;161:1174-9.

7.  LoebS,KeiermannA,CarterHB,FerrucciL,MeierEJ,WalshPC.ProstatevolumechangesoverJme:resultsfromtheBalJmoreLongitudinalStudyofAging.JUrol2009;182:1458-62.

8.  SecafE,NuruddinRN,HricakH,McClureRD,DemasB.MRimagingoftheseminalvesicles.AJRAmJRoentgenol1991;156:989-94.

9.  StasinouT,BourdoumisA,OwegieP,KachrilasS,BuchholzN,MasoodJ.CalcificaJonofthevasdeferensandseminalvesicles:areview.CanJUrol2015;22:7594-8.

10.  CoyneJD,KealyWF.Seminalvesicleamyloidosis:morphological,histochemicalandimmunohistochemicalobservaJons.Histopathology1993;22:173-6.

IllustraJonsofembryologyandprostateanatomypropertyofA.C.Westphalen,MD.

REFERENCES

Authorcorrespondence:AntonioCarlos.Westphalen@ucsf.edu