Magnetic resonance imaging of solid urethral and peri-urethral lesions

Transcription

1 Insights Imging (2013) 4: DOI /s PICTORIAL REVIEW Mgnetic resonnce imging of solid urethrl nd peri-urethrl lesions Andrew Del Gizo & Alvin C. Silv & Dor M. Lm-Himlin & Brin C. Allen & John Leyendecker & Akir Kwshim Received: 26 Mrch 2013 /Revised: 25 April 2013 /Accepted: 29 April 2013 /Pulished online: 19 My 2013 # The Author(s) This rticle is pulished with open ccess t Springerlink.com Astrct Solid urethrl nd peri-urethrl lesions re rre nd encompss enign nd mlignnt etiologies. A dignosis without imging is often chllenging secondry to non-specific clinicl symptoms nd overlpping findings t the time of physicl exmintion. Mgnetic resonnce (MR) imging my e helpful in confirming dignosis while providing ntomicl detil nd delineting disese extent. This rticle reviews the norml MR ntomy of the mle nd femle urethr, the MR ppernce of solid primry nd secondry urethrl lesions, nd the MR ppernce of solid urethrl lesion mimics. Teching points MRI is n importnt imging technique in the evlution of the spectrum of solid urethrl lesions. With excellent soft tissue resolution, MR is ccurte in stging primry urethrl crcinom. Disruption of the zonl ntomy of the femle urethrl wll indictes peri-urethrl extension. Be wre of enign urethrl lesions, prticulrly those tht my mimic solid urethrl msses. Keywords Urethr. Crcinom. Mgnetic resonnce. Solid lesions This rticle is sed on Exhiit LL-URE2534 t the RSNA 2011 Annul Meeting, where it received the Certificte of Merit wrd A. Del Gizo (*) : B. C. Allen : J. Leyendecker Deprtment of Rdiology, Wke Forest University, Medicl Center Blvd., Winston-Slem, NC 27157, USA e-mil: delgiz@wfumc.edu A. Del Gizo : A. C. Silv Deprtment of Rdiology, Myo Clinic, Scottsdle, AZ, USA D. M. Lm-Himlin Deprtment of Pthology, Myo Clinic, Scottsdle, AZ, USA A. Kwshim Deprtment of Rdiology, Myo Clinic, Rochester, MN, USA Introduction Solid disorders of the urethr nd peri-urethrl tissue re rre, nd include rod spectrum of innocuous nd ggressive processes. To correctly differentite these conditions without imging is chllenging due to non-specific nd overlpping clinicl signs nd symptoms. Furthermore, physicl exmintion often fils to distinguish the process origin s urethrl from disorders of djcent orgns, nd is unle to ccurtely delinete etween the types of primry urethrl msses [1, 2]. Mgnetic resonnce (MR) llows for high resolution multiplnr imging of the urethr. Advncements in phsed-rry pelvic nd endovginl coils hve led to improved evlution of urethrl nd peri-urethrl disorders [1, 3]. Trditionl imging techniques, such s voiding cystourethrogrphy nd retrogrde doulelloon positive-pressure urethrogrphy, re helpful, ut re invsive nd unle to chrcterise extrluminl spred or peri-urethrl conditions [1, 4]. Therefore, incorrect dignosis nd delyed tretment often occurs when relying on these modlities [1, 3]. High-resolution trnsvginl, trnsperinel nd trnsurethrl ultrsound hve een touted s relile techniques for the dignosis nd chrcteristion of urethrl normlities. While contriutory when performed y n experienced sonogrpher, the exmintion cn e lengthy nd is opertor dependent [5]. Furthermore, while ultrsonogrphy is n importnt tool in the evlution of cystic urethrl nd peri-urethrl lesions, the contrst resolution nd ntomicl detil provided y MR imging for solid lesions is unsurpssed. MR imging cn provide criticl informtion in the mngement nd preopertive plnning of solid urethrl nd peri-urethrl conditions. The im of this rticle is to review the norml MR ntomy of the mle nd femle urethr, s well s the MR fetures of enign nd mlignnt solid primry nd secondry urethrl lesions. In ddition, the MR ppernce of solid urethrl lesion mimics will e discussed.

2 462 Insights Imging (2013) 4: Norml MR ntomy of the mle urethr The mle urethr verges cm in length, nd consists of nterior nd posterior portions. The posterior urethr is sudivided into the prosttic nd memrnous segments [6]. T2-weighted mgnetic resonnce imging (MRI) llows for visulistion of the urethrl course s it trnsverses the prostte nd urogenitl diphrgm respectively [7] (Fig. 1). The nterior portion is locted in the corpus spongiosum nd my e sudivided into penile nd ulous segments. The ulous urethr extends from the inferior mrgin of the urogenitl diphrgm to the penoscrotl junction. The penile segment then continues to the externl metus. The norml nterior urethrl lumen my e difficult to delinete without ctheter in plce. While there is inter-institutionl vriility, the stndrd imging protocol emphsises T2-weighted nd gdoliniumenhnced T1-weighted sequences (Tle 1). At our institution, for lesions in the nterior urethr, the ptient is positioned supine, with folded towel etween the ptient s legs to elevte the scrotum nd penis. With the penis in the ntomicl position nd loosely secured in position ginst the midline lower domen, surfce coil is plced over the penis [8, 9]. For posterior lesions, or when otining pelvic imges to look for inguinl or oturtor lymphdenopthy, phsedrry pelvic or ody coil is used [8, 9]. While dependent on lesion loction, dynmic contrst enhnced imges re most often otined in the sgittl plne. Norml MR ntomy of the femle urethr The femle urethr verges 3-4 cm in length nd extends from the ldder neck to the vestiule, forming the externl metus etween the li minor (Fig. 1). T2-weighted MRI llows for demrction of the concentric zonl ntomy in ech of the three orthogonl plnes, displyed s lternting hyper- nd hypo-intense rings. Centrlly, intrluminl fluid (when present) is hyperintense. The surrounding mucos is hypointense. The Tle 1 Imging protocols for the mle nd femle urethr Sequence TR (ms) TE (ms) Flip ngle FOV Mtrix Slice thickness (mm)/ spcing Fig. 1 Norml ntomy. Sgittl T2-weighted imge lelling the prosttic, memrnous nd ulous segments of the norml mle urethr. Norml ntomy. Illustrtion of the norml femle urethr in xil cross-section. c Norml ntomy. Axil T2-weighted imge of norml femle urethr. Note the hypointense signl of the mucos nd outer musculr lyer, nd hyperintense sumucos Axil T2 TSE FS 5, /1 Axil high-resolution 4, /1 T2, no FS Sgittl high-resolution 4, /1 T2, no FS Coronl highresolution T2, no FS 4, /1 Dynmic VIBE /1 pre- nd postgdolinium sgittl (mle) Axil (femle) Axil VIBE post gdolinium /6

3 Insights Imging (2013) 4: %: 90% SCC 60%: 80% TCC sumucos, consisting of smooth muscle contiguous with the ldder neck, is hyperintense. The outermost lyer, composed of circulr strited muscle, is hypointense [6, 7] (Fig.1c). MR imging of the femle urethr is typiclly performed with pelvic phsed-rry coil. For higher resolution imging, endovginl or endorectl coils re occsionlly requested to delinete detiled ntomy for surgicl plnning. Stndrd protocols emphsise xil, coronl nd sgittl fst spin-echo T2-weighted sequences, nd xil 2D ft-suppressed spoiled grdient-echo T1-weighted sequences efore nd fter intrvenous contrst dministrtion. In contrst to mles, the dynmic phse imges re most often performed in the xil plne for femles. Mlignnt primry tumours of the mle urethr 30%: 90% TCC Fig. 2 Illustrtion of the mle urethr in the sgittl plne highlighting the percentge of urethrl crcinom y loction (1st percentge) nd the most common histologicl sutype in tht loction (2nd percentge). TCC trnsitionl cell crcinom, SCC squmous cell crcinom Mlignnt urethrl lesions in mles tend to present fter 50 yers of ge s plple mss in the perineum or long the length of the penile urethr. Other potentil presenttions include: ostructive voiding symptoms, urethrl stricture or leeding, serosnguinous dischrge, perinel pin, urethrl fistul, or peri-urethrl scess [6]. Urethrl tumours my e ctegorised ccording to loction nd histology. In mles, 60 % rise in the ulomemrnous portion. Of these, 80 % re trnsitionl cell crcinom (TCC), 10 % re squmous cell crcinom (SCC) nd 10 % re denocrcinom. Thirty percent rise in the prosttic urethr, of which 90 % nd 10 % re TCC nd SCC, respectively. The remining 10 % rise in the penile urethr, of which 90 % re SCCnd10%reTCC[6, 10] (Fig.2). MRI is useful in demonstrting tumour loction nd size, s well s for locl stging [6, 11 14] (Tle 2). Reltive to the norml corporl tissue, tumour will e hypointense t T1-weighted imging (T1WI), hypointense t T2-weighted imging (T2WI), nd progressively enhnce t T1WI following intrvenous gdolinium-sed contrst dministrtion (T1WI + C). As the corpor tend to e very vsculr, mss my pper to e reltively hypoenhncing. In generl, stge I disese is not detectle on MRI. However, MRI redily depicts stge II tumour s invsion of the corpus spongiosum, prostte, or peri-urethrl muscle (Fig. 3). The tumour is upstged to stge III with the presence of corpus cveronsum invsion or extension eyond the prosttic cpsule (Fig. 3 nd c). In ddition to direct extension, urethrl lesions cn metstsise to regionl lymph nodes. An nterior tumour spreds vi inguinl lymph nodes nd occsionlly into the externl ilic chin lymph nodes (Fig. 4). Posterior urethrl tumours most commonly spred first to the deep pelvic lymph nodes, hrouring much worse prognosis when present. Accurte preopertive stging of urethrl crcinom is criticl, s tumours spring the corpus spongiosum nd corpor cvernos my qulify for conservtive surgicl pproch. In contrst, dvnced lesions often require totl penectomy with cretion of perinel urethrostomy when Tle 2 Stging mlignnt tumours of the mle nd femle urethr Stge Gender Depth of invsion Key points Stge 0 nd I Either Non-invsive (in situ) or confined to the suepithelil Not detectle on MRI connective tissue Stge II Mle Invsion of the corpus spongiosum, prostte, or peri-urethrl muscle If present, most ptients will not qulify for conservtive surgicl mngement Femle Invsion of the peri-urethrl muscle Loss of the norml T2WI trget-zonl ntomy Stge III Mle Invsion of the corpus cvernosum nd ldder neck or extension eyond the prosttic cpsule Also includes metstsis in single lymph node less thn 2 cm (in gretest dimension), regrdless of depth of invsion Femle Invsion of the nterior vgin or ldder neck Stge IV Either Invsion of other djcent orgns Also includes distnt metstsis, metsttsis in single node greter thn 2 cm (in lrgest dimension), or metstsis in multiple nodes, regrdless of depth of invsion

4 464 Insights Imging (2013) 4: Fig. 3 Mlignnt mle tumour: stge II ulr urethrl squmous cell crcinom. The ptient presented with plple non-tender mss. Sgittl T2-weighted imge demonstrtes ulr urethrl mss invding the corpus spongiosum (rrows). Mlignnt mle tumour: stge III penile urethrl squmous cell crcinom. In different ptient, sgittl T2- weighted imge demonstrtes lrge penile urethrl mss involving the corpus sponsiosum (rrows) nd foclly invding the tunic lugine nd corpor cvernos (lock rrow). c Mlignnt mle tumour: penile urethrl squmous cell crcinom. Retrogrde urethrogrm of the sme ptient s demonstrtes irregulr nrrowing of the penile urethr secondry to the mss (rrows). The full extent of the mss nd the corpor cvernos invsion is not pprecited y this modlity involving the nterior urethr nd nterior exentertion with rdicl cystoprosttourethrectomy nd urinry diversion when involving the posterior urethr [15, 16]. Mlignnt primry tumours of the femle urethr While rre in oth genders, urethrl mlignncies re more common in femles, with femle-to-mle rtio of 4 to 1 [6, 17]. As with mles, the presenting popultion tends to e greter thn 50 yers old. Potentil ssocited symptoms include: urethrl leeding, urinry frequency, ostructive symptoms, plple urethrl mss or indurtion. Femle urethrl mlignncies re clssified s nterior, where tumour is isolted to the distl third of the urethr, or entire, where the proximl two-thirds of the urethr +/ the nterior segment re involved (Fig. 5). There is no distinction in tretment etween tumours involving the entire urethr nd those isolted to the proximl two-thirds. The nterior sutype ccounts for pproximtely 45 % of urethrl tumours, nd tend to e less extensive nd low grde [7]. Histologicl sutypes re 60 % SCC, 20 % TCC, 10 % denocrcinom, 8 % undifferentited tumour nd srcom, nd 2 % melnom [6]. MRI cn ply n importnt role in locl stging (Tle 2). Tumours of squmous cell or trnsitionl cell origin will e reltively hypointense on T1WI nd hypointense to intermedite intensity t T2WI nd demonstrte heterogeneous enhncement. In contrst, denocrcinom tends to e reltively T2 hyperintense, with vrile enhncement [5]. As with urethrl tumours in mles, MRI hs limited utility in depicting stge I disese. However, the trget-like ppernce of the norml urethr on xil T2-weighted imges will e disrupted in stge II lesions [6, 18]. With stge III nd IV disese, differentition of primry urethrl lesions from those of the vulv or vgin my e difficult (Fig. 6). Benign urethrl lesions Solid enign urethrl lesions re very rre. The more commonly encountered include: leiomyoms, hemngioms c nd firoepithelil polyps [6, 7, 12, 19, 20]. While MR imging chrcteristics of enign lesions overlp with those of mlignnt tumours, there re imging chrcteristics which my ssist in the dignosis. Urethrl leiomyoms originte from smooth muscle fires of the urethr. They tend to present in reproductive ge femles s difficulty in micturition nd urinry

5 Insights Imging (2013) 4: Fig. 4 Mlignnt mle tumour: urethrl squmous cell crcinom with lymph node metstses. Axil T1-weighted imge fter intrvenous gdolinium-sed contrst dministrtion demonstrtes heterogeneously enhncing ulomemrnous squmous cell crcinom (rrows). Mlignnt mle tumour: urethrl squmous cell crcinom with lymph node metstses. Axil T1-weighted imge fter intrvenous gdolinium-sed contrst dministrtion through the pelvis in the sme ptient demonstrtes necrotic left inguinl lymphdenopthy (rrows). The presence of multiple (>1) regionl lymph node metstses upstges to stge IV Fig. 5 Mlignnt femle tumour: entire urethrl squmous cell crcinom. Axil T2-weighted imge demonstrtes n infiltrtive mss replcing the norml concentric ppernce of the femle urethr (rrows). Mlignnt femle tumour: entire urethrl squmous cell crcinom. Sgittl T2-weighted imge shows the mss involving the entire urethr (rrows), extending into the ldder (top rrow) trct infections, dyspreuni, nd/or hemturi [19, 20]. At MRI, urethrl leiomyoms tend to e well demrcted, nd follow signl chrcteristics of non-degenerted uterine leiomyom; low to intermedite signl intensity on T1WI, low to intermedite signl intensity on T2WI nd firly homogeneous enhncement (Fig. 7). Hemngioms of the urethr re elieved to rise from emryonic remnnts of ngiolstic cells tht filed to develop into norml lood vessels [21]. Urethrl hemngioms occur much more commonly in mles, with hemturi nd/or hemtospermi eing the presenting symptoms [22, 23]. At MRI, high T2WI signl similr to the chrcteristic ppernce of heptic hemngiom hs een reported [21]. Ultimtely, cystourethroscopy nd iopsy re required for dignosis [21 23]. Firoepithelil polyps of the urethr present more commonlyinchildren[24]. When presenting in dulthood, the clinicl, rdiogrphic nd endoscopic findings will most often e tht of n ostructing mss t the ldder neck nd prosttic urethr [24 26]. MRI cn demonstrte the typicl polypoid shpe, with stlk connected to the ldder neck. The tumour contins undnt strom; therefore, homogeneous enhncement fter intrvenous gdolinium dministrtion is chrcteristic [27]. Secondry tumours to the urethr Secondry tumours involving the urethr most commonly occur y direct invsion or contiguous spred from

6 466 Insights Imging (2013) 4: c Fig. 6 Mlignnt femle tumour: invsive squmous cell crcinom. Axil T2-weighted imge demonstrtes disruption of the trget sign y mss (lock rrow), which extends posteriorly to invde the nterior wll of the vgin (rrows). Mlignnt femle tumour: invsive squmous cell crcinom. Histologicl specimen shows infiltrting islnds of mlignnt cells (purple) throughout the imge, representing squmous cell crcinom of the urethr. The rrow points to one of these islnds. (Hemtoxylin nd eosin, originl mgnifiction 40 ) djcent orgns. This includes primry tumours originting in the prostte, rectum, spermtic cord, penis, vgin (Fig. 8), vulv or ldder. Primry TCC of the urinry ldder hs een reported to involve the proximl urethr in 2 13 % of women t the time of dignosis [1, 3]. Bldder TCC my lso spred to the nterior urethr y seeding during urethrl instrumenttion or t cystectomy, nd will e difficult to differentite from metchronous urethrl TCC oth cliniclly nd rdiogrphiclly. This hs een descried t urethrogrphy s multiple smll mucosl nodules [6, 12]. A similr ppernce cn e demonstrted t MRI, with multiple smll enhncing mucosl nodules (Fig. 9). Hemtogenous metstses to the corpus spongiosum re occsionlly seen with melnom, prostte, ldder, colon, testiculr nd renl primries [6, 12] (Fig. 10). Erosion into the urethr will then produce urethrl irregulrities. Fig. 7 Benign lesions: urethrl leiomyom. Axil T2-weighted imge shows n exophytic, well demrcted mss rising from the urethr nteriorly (rrows). Benign lesions: urethrl leiomyom. Axil T1weighted imge fter intrvenous gdolinium-sed contrst dministrtion demonstrtes homogeneous enhncement of the mss (rrows). c Benign lesions: urethrl leiomyom. Histologicl specimen shows chrcteristic intersecting fscicles of smooth muscle throughout the imge in this enign stroml tumour. The rrows point to one of these fscicle nds. (Hemtoxylin nd eosin, originl mgnifiction 100 ) Urethrl tumour mimics Complex cystic peri-urethrl lesions my mimic solid mss on imging. Exmples include inflmed/infected urethrl diverticul nd urethrl ulking gents. An uncomplicted urethrl diverticulum will e high signl on T2WI nd demonstrte little, if ny, enhncement (Fig. 11). In

7 Insights Imging (2013) 4: M C Fig. 8 Secondry tumours involving the urethr: direct extension. Vgin squmous cell crcinom invding the urethr. Axil T2weighted imge shows n infiltrtive mss centred t the vgin, extending nteriorly to invde the posterior-left wll of the urethr (rrows). Secondry tumours involving the urethr: direct extension. Histologicl specimen shows the squmous cell crcinom (*) undermining the norml vginl squmous mucos (M) ove. (Hemtoxylin nd eosin, originl mgnifiction 40 ) Fig. 9 Secondry tumours to the urethr: seeding of the urethr fter rdicl cystoprosttectomy for trnsitionl cell crcinom. Zoomed in coronl T1-weighted imge fter intrvenous gdolinium-sed contrst dministrtion demonstrtes multiple smll enhncing mucosl nodules within the urethr (rrows) Fig. 10 Secondry tumours to the corpor: renl cell crcinom metstsis. A 74-yer-old mn with metsttic renl cell crcinom presented with hesittion nd difficulty in urintion s well s plple firm mss in the right se of the penis. Axil T1-weighted imge fter intrvenous gdolinium-sed contrst dministrtion shows enhncing msses in the ilterl corpor cvernos (short rrows) nd corpus spongiosum (long rrow) s well s in the left ischil tuerosity (rrowhed). The corporl lesions re hypoenhncing reltive to djcent norml corporl tissue however hyperenhncing reltive to the nery musculture. Secondry tumours to the corpor: renl cell crcinom metstsis. Histologicl specimen using Ppnicolou stin shows metsttic crcinom with cler cell fetures, consistent with metsttic grde 3 (of 4) renl cell crcinom. There re clusters of poorly cohesive cells (C) with low nucleo-cytoplsmic rtio, undnt ple cytoplsm nd ple, vcuolted ckground (*) complex urethrl diverticulum, the fluid is intermedite signl on T2WI (Fig. 11), nd my enhnce heterogeneously. The MR chrcteristics of urethrl ulking gents vry sed on their composition nd the time since injection. The most commonly used gents re collgen suspension or coted microeds. Recently injected peri-urethrl collgen suspension is intermedite to hyperintense on T2WI nd lcks enhncement (Fig. 12). The collgen suspension ecomes isointense to hypointense with time on T1WI nd T2WI. Coted microeds re hypointense on T2WI nd T1WI nd lck enhncement, regrdless of ge [28]. Amyloidosis is often systemic condition, however, cn e dignostic dilemm when loclised to the urethr. The clinicl presenttion nd imging fetures overlp with tht of mlignncy. At MRI, myloid depositions re hypointense on T2WI (Fig. 13) nd hypointense on T1WI, with vid enhncement [29, 30].

8 468 Insights Imging (2013) 4: c Fig. 12 Urethrl tumour mimics: urethrl ulking gents. Axil T2weighted imge demonstrtes recently injected peri-urethrl collgen suspension to e reltively hyperintense. Urethrl tumour mimics: urethrl ulking gents. With T1-weighted imge fter intrvenous gdolinium-sed contrst dministrtion, recently injected peri-urethrl collgen suspension lcks enhncement (rrows) Penile ultrsonogrphy plys complimentry role, depicting intrmurl clcifictions s echogenic foci with posterior shdowing [30] (Fig. 13). Fig. 11 Urethrl tumour mimics: Complex/inflmed diverticulum mimicking mss. Axil T2-weighted imge shows high signl collection (rrow) long the right mrgin of the urethr (lock rrow), in keeping with n uncomplicted urethrl diverticulum. Urethrl tumour mimics: complex/inflmed diverticulum mimicking mss. In contrst, xil T2-weighted imge in different ptient demonstrtes n inflmed diverticulum s intermedite signl (rrow) long the right mrgin of the urethr (lock rrow). c Urethrl tumour mimics: complex/inflmed diverticulum mimicking mss. Histologicl section shows n intense cute nd chronic inflmmtory infiltrte throughout the imge (*), with mix of neutrophils, lymphocytes nd monocytes. (Hemtoxylin nd eosin, originl mgnifiction 400 ) Conclusion MRI is n importnt imging technique in the evlution of the spectrum of solid urethrl nd peri-urethrl lesions in dults. There is high ccurcy in locl stging of primry urethrl crcinoms in oth mles nd femles due to excellent soft tissue resolution. Disruption of the trget-like zonl ntomy of the femle urethrl wll indictes peri-urethrl extension. It is importnt to e wre of enign urethrl lesions, prticulrly those tht my mimic solid urethrl msses.

9 Insights Imging (2013) 4: Fig. 13 Urethrl tumour mimics: primry urethrl myloidosis. Sgittl T2-weighted imge shows nrrowing of the penile urethr y multiple hypointense myloid deposits (rrows). Reprinted with permission from Kwshim et l. [30]. Urethrl tumour mimics: primry urethrl myloidosis. Correltive ultrsound demonstrtes intrmurl clcifictions. Reprinted with permission from Kwshim et l. [30] Conflict of interest None. Open Access This rticle is distriuted under the terms of the Cretive Commons Attriution License which permits ny use, distriution, nd reproduction in ny medium, provided the originl uthor(s) nd the source re credited. References 1. Chudhri VV, Ptel MK, Douek M, Rmn SS (2010) MR imging nd US of femle urethrl nd periurethrl disese. Rdiogrphics 30(7): Hndel LN, Lech GE (2008) Current evlution nd mngement of femle urethrl diverticul. Curr Urol Rep 9(5): Rufford J, Crdozo L (2004) Urethrl diverticul: dignostic dilemm. BJU Int 94(7): Hhn WY, Isrel GM, Lee VS (2004) MRI of femle urethrl nd periurethrl disorders. AJR Am J Roentgenol 182(3): Prsd SR, Menis CO, Nrr VR, Middleton WD, Mukundn G, Smdi N, Heiken JP, Siegel CL (2005) Cross-sectionl imging of the femle urethr: technique nd results. Rdiogrphics 25(3): Kwshim A, Sndler CM, Wssermn NF, Leroy AJ, King BF Jr, Goldmn SM (2004) Imging of urethrl disese: pictoril review. Rdiogrphics 24:S195 S Ryu F, Kim B (2001) MR imging of the mle nd femle urethr. Rdiogrphics 21: Pretorius ES, Siegelmn ES, Rmchndni P, Bnner MP (2001) MR imging of the penis. Rdiogrphics 21 Spec No:S283 S298, discussion S Singh AK, Sokr A, Hhn PF, Hrisinghni MG (2005) Imging of penile neoplsms. Rdiogrphics 25(6): Dont SM, Cozzi PJ, Herr HW (2002) Surgery of penile nd urethrl crcinom. In: Wlsh PC, Reitik AB, Vughn ED Jr, Wein AJ (eds) Cmpell s urology, 8th edn. Sunders, Phildelphi, pp Hrick H, Mrotti M, Gilert TJ et l (1988) Norml penile ntomy nd norml penile conditions: evlution with MR imging. Rdiology 169: Wssermn NF (2000) Urethrl neoplsms. In: Pollck HM, McClennon BL (eds) Clinicl urogrphy, 2nd edn. Sunders, Phildelphi, pp Vpnek JM, Hrick H, Crroll PR (1992) Recent dvnces in imging studies for stging of penile nd urethrl crcinom. Urol Clin North Am 19: Shirkhod A, Slmnzdeh A, Jfri SZ, Konez O, Spencer W (2000) Urethrl leiomyosrcom: evlution y MRI with pthologic correltion. J Comput Assist Tomogr 24: Lynch DF Jr (2003) Crcinom of the urethr. In: Kufe DW, Pollock RE, Weichselum RR et l (eds) Hollnd-Frei cncer medicine, 6th edn. BC Decker, Hmilton 16. Bissd NK, Ykout HH, Fhmy WE, Gyed MS, Touijer AK, Greene GF, Hnsh KA (2003) Multi-institutionl long-term experience with conservtive surgery for invsive penile crcinom. J Urol 169(2): Kgeym S, Ued T, Kushim R, Skmoto T (1997) Primry denosqumous cell crcinom of the mle distl urethr: mgnetic resonnce imging using circulr surfce coil. J Urol 158: Morikw K, Togshi K, Minmi S et l (1995) MR nd CT ppernce of urethrl cler cell denocrcinom in womn. J Comput Assist Tomogr 19: Fsih N, Prsd Shnhogue AK, Mcdonld DB, Frser-Hill MA, Ppdtos D, Kielr AZ et l (2008) Leiomyoms eyond the uterus: unusul loctions, rre mnifesttions. Rdiogrphics 28: Lee MC, Lee SD, Kuo HT, Hung TW (1995) Ostructive leiomyom of the femle urethr: report of cse. J Urol 153(2): Uchid K, Fukut F, Ando M, Miiyke M (2001) Femle urethrl hemngiom. J Urol 166(3): Ro AR, Motiwl H (2005) Urethrl hemngiom. Urology 65(5): Sito S (2008) Posterior urethrl hemngiom: one of the unknown cuses of hemturi nd/or hemtospermi. Urology 71(1):168.e e Ait GA, Begliomini H, Mttos D Jr (2005) Firoepithelil polyp of the urethr. Int Brz J Urol 31: Slehi M, Flhtkr S, Neiroomnd H, Akrpour M (2009) Firoepithelil congenitl polyp of prosttic urethr in n dult mn. Urol J 6: Willims TR, Wgner BJ, Corse WR, Vestevich JC (2002) Firoepithelil polyps of the urinry trct. Adom Imging 27: Li H, Sugimur K, Boku M, Kji Y, Tchin M, Kmidono S (2003) MR findings of prosttic urethrl polyp in n dult. Eur Rdiol 13:L105 L Bridges MD et l (2005) Urethrl ulking gents, imging review. AJR Am J Roentgenol 185: Ichiok K, Utsunomiy N, Ued N, Mtsui Y, Yoshimur K, Teri A (2004) Primry loclized myloidosis of urethr: mgnetic resonnce imging findings. J Urol 64(2): Kwshim A, Allemn WG, Tkhshi N, Kim B, King BF Jr, LeRoy AJ (2011) Imging evlution of myloidosis of the urinry trct nd retroperitoneum. Rdiogrphics 31(6):