6. Scrotum - AnatomyScrotum - Anatomy
ScrotumScrotum
layers of fascia, muscle andlayers of fascia, muscle and
connective tissueconnective tissue
Tunica VaginalisTunica Vaginalis
– visceral and parietal layersvisceral and parietal layers
– potential space around thepotential space around the
testestestes
Tunica AlbugineaTunica Albuginea
– thick layer of fascia investingthick layer of fascia investing
the testesthe testes
– Along the posterior surface ofAlong the posterior surface of
the testis, the tunica albugineathe testis, the tunica albuginea
thickens to form thethickens to form the
mediastinummediastinum
– The mediastinum projectsThe mediastinum projects
inward into the testisinward into the testis
7. Testes –Testes –
Embryology andEmbryology and
AnatomyAnatomy
TestesTestes
– 2X3X5 cm2X3X5 cm
– mediastinummediastinum
contain rete testis - spermcontain rete testis - sperm
containing channelscontaining channels
– Appendix of testesAppendix of testes
Mullerian duct remnantMullerian duct remnant
EpididymisEpididymis
Attatched to posterolateral testisAttatched to posterolateral testis
head, body and tailhead, body and tail
Appendix of the head and tailAppendix of the head and tail
paradidymisparadidymis
Spermatic cordSpermatic cord
vas, artery, veins and lymphaticsvas, artery, veins and lymphatics
Note: testicular lymphatics drainNote: testicular lymphatics drain
to paraaortic; while scrotum toto paraaortic; while scrotum to
inguinalinguinal
8. Testes - HistologyTestes - Histology
Connective tissueConnective tissue frameworkframework
– tunica albugineatunica albuginea
– mediastinum testismediastinum testis
– septa which divide the organ into lobules.septa which divide the organ into lobules.
Within theWithin the lobulelobules, the seminiferouss, the seminiferous
tubules produce sperm. Thetubules produce sperm. The
seminiferous tubulesseminiferous tubules consist of germconsist of germ
cells and Sertoli cells.cells and Sertoli cells.
– Germ cells (spermatogonia,Germ cells (spermatogonia,
spermatocytes, etc) -spermatocytes, etc) -
develop into spermatozoadevelop into spermatozoa
– sertoli cells - supporting cellssertoli cells - supporting cells
Between the tubules, theBetween the tubules, the interstitialinterstitial
tissuetissue includes connective tissue cellsincludes connective tissue cells
and fibers, vessels, and Leydig cellsand fibers, vessels, and Leydig cells
– Leydig cells -Leydig cells - produceproduce
testosterone.testosterone.
9. Imaging ModalitiesImaging Modalities
UltrasoundUltrasound
Modality of choiceModality of choice
– 99% sensitive99% sensitive
– 98% accurate at98% accurate at
intratesticular vsintratesticular vs
extratesticularextratesticular
techniquetechnique
– support scrotum onsupport scrotum on
toweltowel
– highest MHzhighest MHz
transducer (8 or 15)transducer (8 or 15)
– color and dopplercolor and doppler
– Do normal side first ifDo normal side first if
painpain
NormalNormal
– homogeneoushomogeneous
– bright mediastinumbright mediastinum
– TransmediastinalTransmediastinal
artery or appendixartery or appendix
testistestis
10. Imaging ModalitiesImaging Modalities
MRIMRI
problem solverproblem solver
when US inconclusivewhen US inconclusive
cryptorchidismcryptorchidism
TechniqueTechnique
support scrotum with warmsupport scrotum with warm
towelstowels
surface coil; small fovsurface coil; small fov
T1W and FSET2W (SSFSE),T1W and FSET2W (SSFSE),
several planesseveral planes
3mm3mm
Gd?Gd?
Screen abd/pelvis for nodesScreen abd/pelvis for nodes
NormalNormal
homogeneous, intermediatehomogeneous, intermediate
on T1W and bright on T2Won T1W and bright on T2W
tunica albiginea andtunica albiginea and
mediastinum darkmediastinum dark
11. Imaging ModalitiesImaging Modalities
CTCT
used for staging of testicular cancer and forused for staging of testicular cancer and for
inguinal hernias and infection (Fourniersinguinal hernias and infection (Fourniers
gangrene)gangrene)
Nuclear MedicineNuclear Medicine
?PET/CT?PET/CT
12. MassesMasses
Key: intra vs extratesticular; solid vs cystKey: intra vs extratesticular; solid vs cyst
IntratesticularIntratesticular
solid - most malignant and germ cell originsolid - most malignant and germ cell origin
mimics/tumor like lesions - infarcts,mimics/tumor like lesions - infarcts,
orchitis/abscess and hematomaorchitis/abscess and hematoma
– Orchiectomy for benign disease will occurOrchiectomy for benign disease will occur
cystcyst
ExtratesticularExtratesticular
solid - most are benignsolid - most are benign
CysticCystic
CalcificationsCalcifications
13. Testicular CancerTesticular Cancer
#1 cancer killer of young men#1 cancer killer of young men
peak age 20 -45; 90% whitepeak age 20 -45; 90% white
– Incidence of GCT increased inIncidence of GCT increased in
cryptorchidismcryptorchidism
PresentationPresentation
– painless mass, mild pain or heavinesspainless mass, mild pain or heaviness
– 10% present with acute scrotum10% present with acute scrotum
US study of choiceUS study of choice
95% survival rate95% survival rate
15. Testicular Cancer - GCTTesticular Cancer - GCT
SpreadSpread
– LymphaticLymphatic
follows veinsfollows veins
1st echelon nodes1st echelon nodes
– retroperitoneal at kidneysretroperitoneal at kidneys
Further tumorFurther tumor
– iliac nodesiliac nodes
– supraclavicularsupraclavicular
epididymal & skin involvementepididymal & skin involvement
lead to inguinal nodeslead to inguinal nodes
– hematogeneous and directhematogeneous and direct
invasion later (x chorio)invasion later (x chorio)
lung>liver and brainlung>liver and brain
17. Testicular Cancer - GCTTesticular Cancer - GCT
Tumor markersTumor markers
alpha-fetoprotein, human chorionicalpha-fetoprotein, human chorionic
gonadotropingonadotropin
well-established role in the diagnosis,well-established role in the diagnosis, staging,staging,
prognosis, and follow-up of germ cell tumorsprognosis, and follow-up of germ cell tumors
18. Testicular Cancer -Testicular Cancer -
ImagingImaging
UltrasoundUltrasound
hypoechoic masshypoechoic mass
heterogeneous, echogenic, calcification,heterogeneous, echogenic, calcification,
cystic, multiple or completely replace thecystic, multiple or completely replace the
testistestis
may show increased vascularitymay show increased vascularity
Small tumors usually hypovascularSmall tumors usually hypovascular
MRIMRI
Isointense on T1W and hypointense on T2WIsointense on T1W and hypointense on T2W
19. SeminomaSeminoma
Most common GCTMost common GCT
slightly older ageslightly older age
– does not occurdoes not occur
before pubertybefore puberty
uniform,uniform,
hypoechoichypoechoic
(hypointense), esp(hypointense), esp
when smallwhen small
excellent prognosisexcellent prognosis
23. Embryonal carcinomaEmbryonal carcinoma
In 90% of mixedIn 90% of mixed
GCT, rarely inGCT, rarely in
pure formpure form
MoreMore
aggressiveaggressive
Less wellLess well
defined and lessdefined and less
homogeneoushomogeneous
24. Yolk Sac TumorYolk Sac Tumor
(endodermal sinus(endodermal sinus
tumor)tumor)
80% of pediatric80% of pediatric
testicular tumorstesticular tumors
(Most common in(Most common in
children <2yo)children <2yo)
occurs in mixedoccurs in mixed
GCT in adultsGCT in adults
Elevated Alpha-Elevated Alpha-
fetoproteinfetoprotein
25. TeratomaTeratoma
#2 tumor in kids#2 tumor in kids
common in mixed GCTcommon in mixed GCT
in adultsin adults
tend to be benign in kidstend to be benign in kids
more unpredictable inmore unpredictable in
adultsadults
complex, cysticcomplex, cystic
appearanceappearance
controversial recontroversial re
epidermoid cystepidermoid cyst
26. ChoriocarcinomaChoriocarcinoma
Rare but mostRare but most
aggressive GCTaggressive GCT
EarlyEarly
hematogeneoushematogeneous
mets commonmets common
elevated HcGelevated HcG
Poor prognosisPoor prognosis
HeterogeneousHeterogeneous
massmass
27. Mixed Germ Cell TumorMixed Germ Cell Tumor
More common thanMore common than
any other testicularany other testicular
tumor excepttumor except
seminomaseminoma
Any combination ofAny combination of
cell typescell types
variety of cell typesvariety of cell types
expressed inexpressed in
variablevariable
appearanceappearance
28. ““burned out” Germ Cellburned out” Germ Cell
TumorTumor
Phenomenon of patientPhenomenon of patient
presents with widespreadpresents with widespread
metastatic disease withmetastatic disease with
involuted primary tumorinvoluted primary tumor
?etiology. ?outgrown blood?etiology. ?outgrown blood
supplysupply
Primary tumors have a variablePrimary tumors have a variable
appearance. Small and can beappearance. Small and can be
hypoechoic, hyperechoic, orhypoechoic, hyperechoic, or
merelymerelyan area of focalan area of focal
calcification.calcification.
Histologic analysis may revealHistologic analysis may reveal
minute amounts of residualminute amounts of residual
tumor or only dense depositstumor or only dense deposits
of collagenof collagen with scatteredwith scattered
inflammatory cellsinflammatory cells
22 yo presented with back pain and
lower extremity weakness. Initial
work-up showed an extradural mass,
retroperitoneal adenopathy, and lung
metastases. Physical examination of
the testes was negative. After biopsy
of a cervical node revealed
metastatic germ cell tumor, scrotal
sonography was performed
22 yo presented with back pain and
lower extremity weakness. Initial
work-up showed an extradural mass,
retroperitoneal adenopathy, and lung
metastases. Physical examination of
the testes was negative. After biopsy
of a cervical node revealed
metastatic germ cell tumor, scrotal
sonography was performed
29. CryptorchidismCryptorchidism
6% of full term neonates; 1% at one6% of full term neonates; 1% at one
year; 10% bilateralyear; 10% bilateral
Increased risk of:Increased risk of:
– Testicular carcinoma (most seminomas)Testicular carcinoma (most seminomas)
– InfertilityInfertility
Disordered embryogenesisDisordered embryogenesis
Associated with other GU anomalies:Associated with other GU anomalies:
agenesis/ectopy of kidney andagenesis/ectopy of kidney and
absence/cyst of SVabsence/cyst of SV
Risk of cancer increased in contra-lateralRisk of cancer increased in contra-lateral
testis, even if descendedtestis, even if descended
Risk of cancer not reduced appreciablyRisk of cancer not reduced appreciably
with orchiopexywith orchiopexy
– Note: single post-pubertal bxNote: single post-pubertal bx
recommended to identify intratubularrecommended to identify intratubular
germ cell neoplasm (cis) as marked riskgerm cell neoplasm (cis) as marked risk
factorfactor
30. CryptorchidismCryptorchidism
Clinical Problem: nonpalpableClinical Problem: nonpalpable
testistestis
– DDX: cryptorchidism vs agenesisDDX: cryptorchidism vs agenesis
– Important distinctionImportant distinction
Agenesis: no txAgenesis: no tx
Cryptorchidism: orchiopexy atCryptorchidism: orchiopexy at
2yrs; close exam and bx post-2yrs; close exam and bx post-
pubescentpubescent
– Role of imaging:Role of imaging:
MRI study of choice (US and CTMRI study of choice (US and CT
lack specificity)lack specificity)
– Laporoscopy: Many feel study ofLaporoscopy: Many feel study of
choice (dx and tx)choice (dx and tx)
31. Retractile TestisRetractile Testis
(Hyper)active cremasteric reflex, prompted(Hyper)active cremasteric reflex, prompted
by anxiety, trauma, etc., may pull the testisby anxiety, trauma, etc., may pull the testis
out of the scrotum (prescrotal orout of the scrotum (prescrotal or
intracanalicular)intracanalicular)
Not uncommon in trauma setting, especiallyNot uncommon in trauma setting, especially
in boys (2-3%).in boys (2-3%).
Recommend PE to differentiate retractileRecommend PE to differentiate retractile
testis from true cryptorchidismtestis from true cryptorchidism
33. MicrolithiasisMicrolithiasis
US diagnosisUS diagnosis
5 or more5 or more
calcificationcalcification
may be bl andmay be bl and
diffuse or focaldiffuse or focal
Risk or coexistentRisk or coexistent
or subsequentor subsequent
carcinomacarcinoma
controversialcontroversial
as is need andas is need and
duration of us followduration of us follow
upup
34. Non-Germ cell tumorsNon-Germ cell tumors
5% of testicular cancer5% of testicular cancer
higher in pedshigher in peds
Sertoli (sex cord) and LeydigSertoli (sex cord) and Leydig
(interstitial) cell(interstitial) cell
Also other rare cell linesAlso other rare cell lines
90% benign90% benign
Indistinguishable from GCTIndistinguishable from GCT
Calcifying Sertoli Cell TumorCalcifying Sertoli Cell Tumor
pediatric age grouppediatric age group
multiple calcified massesmultiple calcified masses
PJ and Carney syndromePJ and Carney syndrome
35. LymphomaLymphoma
5% of testicular tumor5% of testicular tumor
#1 in over 50 y/o#1 in over 50 y/o
only 1% of lymphomaonly 1% of lymphoma
patientspatients
May beMay be
only site of diseaseonly site of disease
along with other diseasealong with other disease
site of recurrencesite of recurrence
AppearanceAppearance
Indistinguishable fromIndistinguishable from
GCTGCT
Multiple, bl hypoechoicMultiple, bl hypoechoic
nodulesnodules
36. Leukemia and MetsLeukemia and Mets
Common site of recurrenceCommon site of recurrence
primary disease uncommon hereprimary disease uncommon here
Appearance variableAppearance variable
uni or bluni or bl
focal or diffusefocal or diffuse
hypo or hyperechoichypo or hyperechoic
Solid organ metsSolid organ mets
rare; usually disease widespreadrare; usually disease widespread
prostate and lungprostate and lung
37. Tumor-like lesionsTumor-like lesions
““intratesticular mass is cancer untilintratesticular mass is cancer until
proven otherwise”proven otherwise”
Traditional teaching: 95% malignantTraditional teaching: 95% malignant
BUT, more benign lesions being identifiedBUT, more benign lesions being identified
Not all testicular lesions are tumorsNot all testicular lesions are tumors
As many as 30% of orchiectomies for testicular lesionsAs many as 30% of orchiectomies for testicular lesions
end up being benignend up being benign ((Haas GP, Shumaker BP, Cerny JC. The high incidence ofHaas GP, Shumaker BP, Cerny JC. The high incidence of
benign testicular tumors. J Urolbenign testicular tumors. J Urol 19861986;136:1219 -1220);136:1219 -1220)
recognition of these entities may prevent needlessrecognition of these entities may prevent needless
orchiectomyorchiectomy
Still, rather needless orchiectomy thanStill, rather needless orchiectomy than
missed cancer. Thus will havemissed cancer. Thus will have
orchiectomy for benign disease.orchiectomy for benign disease.
38. Tumor-like lesionsTumor-like lesions
DDX:DDX:
orchitisorchitis
Hematoma/contusionHematoma/contusion
infarctinfarct
cyst (see next)cyst (see next)
– mimics teratomamimics teratoma
adrenal restsadrenal rests
– 2% of adults have2% of adults have
– Enlarged in CAH orEnlarged in CAH or
rarely Cushingsrarely Cushings
– BL hypo massesBL hypo masses
sarcoidosissarcoidosis
sperm extractionsperm extraction
39. Sperm Extraction*Sperm Extraction*
Sperm extraction forSperm extraction for
infertility are becominginfertility are becoming
more commonmore common
In a % (varies from20-In a % (varies from20-
80%) Focal testicular80%) Focal testicular
lesions can resultlesions can result
?hematoma, infarct?hematoma, infarct
FindingsFindings
anterior andanterior and
subcapsularsubcapsular
hypoechoichypoechoic
hyperechoic, calcifichyperechoic, calcific
History may allow closeHistory may allow close
F/UF/U *S Strauss, AJR 2001 176: 113
41. Tunica Albuginea CystTunica Albuginea Cyst
?etiology?etiology
Middle ageMiddle age
Key to diagnosisKey to diagnosis
peripheral locationperipheral location
simple cystsimple cyst
usually 2-5 mmusually 2-5 mm
42. Simple CystSimple Cyst
Usually >40 yoUsually >40 yo
2mm to 2cm2mm to 2cm
single or multiplesingle or multiple
Usually nearUsually near
mediastinummediastinum
43. EpidermoidEpidermoid
Keratonizing squamousKeratonizing squamous
epithelium filled withepithelium filled with
cheesy laminated stuffcheesy laminated stuff
appearanceappearance
echogenic rimechogenic rim
““onion skinned” due toonion skinned” due to
layerslayers
““solid” appearingsolid” appearing
avascularavascular
44. EpidermoidEpidermoid
Unable to totallyUnable to totally
exclude solid lesionexclude solid lesion
usually andusually and
orchiectomy oftenorchiectomy often
neededneeded
MRIMRI
high signal on T1high signal on T1
and T2and T2
45. Cystic Transformation ofCystic Transformation of
the Rete Testisthe Rete Testis
Due to obstruction of efferentDue to obstruction of efferent
ductules with resultant ectasiaductules with resultant ectasia
older menolder men
FindingsFindings
uni or bluni or bl
tubular cystic areastubular cystic areas
in/near mediastinumin/near mediastinum
epididymal cystsepididymal cysts
DDX: cystic GCT (esp teratoma)DDX: cystic GCT (esp teratoma)
usually has soft tissueusually has soft tissue
not tubularnot tubular
MRI can may be helpfulMRI can may be helpful
47. Intras-testicularIntras-testicular
VaricoceleVaricocele
?etiology. ??etiology. ?
significancesignificance
May cause painMay cause pain
(+-)extratesticular(+-)extratesticular
varicocelesvaricoceles
FindingsFindings
tubular, serpigineoustubular, serpigineous
structures withstructures with
venous doppler/colorvenous doppler/color
flow which increasesflow which increases
with valsalvawith valsalva
48. Testicular TorsionTesticular Torsion
Most common in adolescentsMost common in adolescents
Acute scrotumAcute scrotum
DDXDDX
– torsiontorsion
– orchitisorchitis
– traumatrauma
– tumortumor
Due to “bell and clapper”Due to “bell and clapper”
deformitydeformity
lackof normal fixation in thelackof normal fixation in the
scrotumscrotum
Urologic EmergencyUrologic Emergency
salvage rate related to timesalvage rate related to time
– 90%-100% detorsion within 690%-100% detorsion within 6
hours of painhours of pain
– 20%-50% after 12 hours20%-50% after 12 hours
– 0%-10% if detorsion greater0%-10% if detorsion greater
than 24 hoursthan 24 hours
consider doing own USconsider doing own US
49. Testicular TorsionTesticular Torsion
FindingsFindings
Early, testis is normal; laterEarly, testis is normal; later
becomes enlarged andbecomes enlarged and
hypoechoichypoechoic
Lack ofLack of SignificantSignificant
detectable flowdetectable flow
reactive hydrocelereactive hydrocele
51. Scrotal TraumaScrotal Trauma
2 Categories2 Categories
penetrating (surgery)penetrating (surgery)
blunt (imaging)blunt (imaging)
TesticularTesticular
Fracture/ruptureFracture/rupture
disruption of t. albugineadisruption of t. albuginea
with bleeding andwith bleeding and
extrusion of S.T.extrusion of S.T.
surgical emergencysurgical emergency
Trauma inducedTrauma induced
torsion/Infarct a knowtorsion/Infarct a know
complicationcomplication
Types of injury:
Contusion
Hematoma
Fracture/rupture
hematocele
Types of injury:
Contusion
Hematoma
Fracture/rupture
hematocele
52. Scrotal TraumaScrotal Trauma
UltrasoundUltrasound
Normal - excludes seriousNormal - excludes serious
injuryinjury
hematoma - echogenic orhematoma - echogenic or
hypoechoic; roundedhypoechoic; rounded
Hematocele - extratesticularHematocele - extratesticular
fluid; echoes or echogenicfluid; echoes or echogenic
Infarct - absent flowInfarct - absent flow
FractureFracture
– Heterogeneous testicle;Heterogeneous testicle;
diffuse or focaldiffuse or focal
– irregular or ill-defined contourirregular or ill-defined contour
or bulgeor bulge
– often just a “often just a “messmess””
53. Scrotal TraumaScrotal Trauma
MRIMRI
– May play future roleMay play future role
in detection ofin detection of
disruption of thedisruption of the
tunica albuginea (ietunica albuginea (ie
rupture)rupture)
54. Scrotal Trauma:Scrotal Trauma: extremeextreme
mountain bikersmountain bikers..
Krauscher F Radiology 2001May;219(2):427-31USKrauscher F Radiology 2001May;219(2):427-31US
55. Inflammatory DiseaseInflammatory Disease
Epididymitis/orchitisEpididymitis/orchitis
usually retrotrade infection from bladder and prostateusually retrotrade infection from bladder and prostate
rarely traumatic, surgical, etcrarely traumatic, surgical, etc
orchitis from epididymitis (except mumps)orchitis from epididymitis (except mumps)
““acute scrotum” in adolescents (kids,acute scrotum” in adolescents (kids,
elderly)elderly)
testicular torsiontesticular torsion
traumatrauma
infectioninfection
torsion of epididymal or testicular appendagestorsion of epididymal or testicular appendages
Imaging is to confirm diagnosis andImaging is to confirm diagnosis and
excluded complication (surgery)excluded complication (surgery)
abscessabscess
infarctioninfarction
60. Extratesticular VariantsExtratesticular Variants
Appendix of theAppendix of the
epididymisepididymis
Isoechoic to epididymisIsoechoic to epididymis
May calcifyMay calcify
Appendix of the testesAppendix of the testes
Isoechoic to testesIsoechoic to testes
Cyst of MorgagniCyst of Morgagni
Dilation of theDilation of the
paradidymisparadidymis
Cystic; can appearCystic; can appear
solidsolid
61. Spermatocele andSpermatocele and
epididymal cystepididymal cyst
very commonvery common
usually within/near head ofusually within/near head of
epididymisepididymis
usually asymptomatic andusually asymptomatic and
present incidently or aspresent incidently or as
palpable masspalpable mass
Epididymal CystEpididymal Cyst
Cystic on USCystic on US
SpermatoceleSpermatocele
UltrasoundUltrasound
– Cystic (may not be ableCystic (may not be able
to differentiate fromto differentiate from
epididymal cyst)epididymal cyst)
– Low level echoesLow level echoes
– Rarely hyperechoicRarely hyperechoic
62. Sperm GranulomaSperm Granuloma
Sperm extravasationSperm extravasation
can result in granulomacan result in granuloma
formationformation
Often occurs afterOften occurs after
vasectomyvasectomy
Painful (unlike tumor)Painful (unlike tumor)
UltrasoundUltrasound
Isoechoic toIsoechoic to
hyperechoic mass inhyperechoic mass in
the epididymisthe epididymis
Rarely may calcifyRarely may calcify
63. VaricoceleVaricocele
Dilated intrascrotal veinsDilated intrascrotal veins
incompetent valvesincompetent valves
in testicular veinsin testicular veins
rarely due to mass,rarely due to mass,
etcetc
Worry about unilateralWorry about unilateral
right sided varicoceleright sided varicocele
Infertility, heavinessInfertility, heaviness
Common (15-20%)Common (15-20%)
FindingsFindings
L>R, bl commonL>R, bl common
veins > 2-3mmveins > 2-3mm
dilation excacerbateddilation excacerbated
by valsalva andby valsalva and
standingstanding
64. Hydrocele (hematoceleHydrocele (hematocele
& pyocele& pyocele
Fluid w/I tunica vaginalisFluid w/I tunica vaginalis
HydroceleHydrocele
– Small amount of fluid normalSmall amount of fluid normal
– EtiologiesEtiologies
congenital - persistent peritonealcongenital - persistent peritoneal
communicationcommunication
AcquiredAcquired
– Reactive(trauma, infection, torsion)Reactive(trauma, infection, torsion)
– In adults, not uncommon withIn adults, not uncommon with
unknown etiology (diminishedunknown etiology (diminished
reabsorbtion)reabsorbtion)
HematoceleHematocele
– Echogenic fluid; trauma, tumor orEchogenic fluid; trauma, tumor or
surgerysurgery
PyocelePyocele
– Echogenic collection; septations andEchogenic collection; septations and
debrisdebris
65. HerniaHernia
Via patentVia patent
processus vaginalisprocessus vaginalis
complex masscomplex mass
look for peristalsislook for peristalsis
66. Extratesticular tumorExtratesticular tumor
Rare, mostly benignRare, mostly benign
Adenomatoid tumorAdenomatoid tumor
Only tumor with anyOnly tumor with any
frequencyfrequency
HamartomatousHamartomatous
lesionlesion
Adolescents andAdolescents and
young adultsyoung adults
Tail of epididymisTail of epididymis
most common sitemost common site
Isoechoic toIsoechoic to
hyperechoichyperechoic
Seminoma in an Undescended Testis -- Woodward 231 (2): 388 -- Radiology (Radiology 2004;231:388-392.) Diagnosis Please A 47-year-old man presented with a 1-month history of progressive abdominal pain. He was in good health until this time, and he had not previously undergone surgery. A right lower-quadrant mass was noted at physical examination. A computed tomographic (CT) examination was performed. Figure a. Transverse CT scans obtained after administration of intravenous and oral contrast material. (a) CT scan obtained through the level of the kidneys shows bowel within the right renal fossa (arrow) because the right kidney is absent. Note the small amount of free fluid. (b, c) Large right-sided soft-tissue attenuation mass with some areas of peripheral enhancement superiorly (white arrow in b) and necrosis inferiorly (white arrow in c). Note compressed inferior vena cava (black arrow). (d) CT scan obtained through the bladder base shows a normal left seminal vesicle (arrow) with absence of the right seminal vesicle. (e) Absent right spermatic cord and normal left spermatic cord (arrow). the right spermatic cord is absent, which indicates either incomplete descent or agenesis of the right testis. The differential diagnoses for a retroperitoneal mass are many and include both benign and malignant entities. Benign lesions include retroperitoneal fibrosis, which on occasion can make bulky masses, and extramedullary hematopoiesis. The large size and focal nature of this mass makes these diagnoses unlikely. Lymphoma and metastatic adenopathy are two of the most common soft-tissue masses seen in the retroperitoneum and should be considered. In addition, primary tumors of either neurogenic or mesenchymal origin should be included in the differential diagnoses. These tumors most commonly include paraganglioma (patients are usually symptomatic), liposarcoma (visible fat may not be depicted with CT in aggressive high-grade tumors), leiomyosarcoma, and malignant fibrous histiocytoma. There is a great deal of overlap in the imaging findings of many of these masses. None of the above diagnoses would account for the other findings, which include absence of the right spermatic cord, kidney, and seminal vesicle. One potential explanation would be a tumor within an ectopic kidney associated with agenesis of the right seminal vesicle and testis. None of the images, however, show normal renal parenchyma. Even with a very large or infiltrating renal tumor, some normal parenchyma can usually be identified. Given the lack of any identifiable kidney on the right side, it is more likely congenitally absent than ectopic. The findings of an absent right spermatic cord, kidney, and seminal vesicle—in combination with the soft-tissue mass located along the path of testicular descent—make the most likely diagnosis tumor within an undescended testis. Cryptorchidism results from the abnormal formation and descent of the testes. The testes form from genital ridges, which lie on both sides of the midline and extend from T6 through S2 vertebrae in the developing embryo. Between the 7th and 12th weeks of gestation, the testes contract and become more ovoid as they begin their descent into the pelvis. They remain near the deep inguinal ring until the 7th month of gestation, when they begin their descent through the inguinal canal into twin scrotal sacs. Passage through the inguinal canal is aided by both the processus vaginalis and the shortening of the gubernaculum. The processus vaginalis is a sock-like evagination of peritoneum that elongates caudally through the abdominal wall into the scrotum and creates a path for the descending testis. The gubernaculum is a ligamentous cord that extends from the testis to the scrotum. The testes remain retroperitoneal throughout their descent but are intimately associated with the posterior wall of the processus vaginalis (1,2). At approximately 8 weeks gestational age, the Leydig cells begin to secrete testosterone, thus inducing this process. In addition, because of this hormonal influence, the mesonephric (wolffian) ducts differentiate into the epididymis, vas deferens, seminal vesicles, and ejaculatory ducts. Concurrently, the Sertoli cells secrete müllerian inhibiting factor, which results in regression of the paramesonephric (müllerian) ducts. A vestigial remnant of this system may persist as the appendix testis (1,2). Cryptorchidism is present in approximately 6% of full-term neonates and approximately 0.8% of infants at 1 year of age. It can be bilateral in 10% of patients (3,4). Because of its association with other urinary tract abnormalities, cryptorchidism is thought to be one manifestation of a generalized defect in genitourinary embryogenesis. Other associated malformations include renal agenesis or ectopias, ureteral duplications, seminal vesicle agenesis or cysts, and hypospadias (5–9). Cryptorchidism is also associated with infertility and is a well-recognized risk factor for testicular carcinoma. Approximately 90% of these tumors are seminomas, especially those that occur in the abdominally located testis. Although the overall incidence of cryptorchidism is low (<1%), a history of an undescended testis is present in 3.5%–14.5% of patients with testicular tumors (9). The pathophysiology of malignant transformation in these testes is not completely understood. One hypothesis is that cryptorchidism is not merely incomplete descent of the testis, but that it reflects a generalized defect in embryogenesis and results in bilateral dysgenetic gonads. An embryologic defect in testicular formation is supported by several important clinical observations. The most compelling of these is that risk for testicular carcinoma is not limited to the undescended testis but extends to the contralateral testis, even if it is normally descended. Thus, the increased risk of carcinoma cannot be attributed to local environmental factors, such as increased temperature in the abdomen versus the scrotum. While it is true that the risk of carcinoma increases with the degree of ectopy (intraabdominal testes are at greater risk than those in the inguinal canal), this also supports the theory if it is assumed that the greatest degree of ectopy reflects the greatest perturbation of embryogenesis. The defective embryogenesis hypothesis is further supported by the observation that orchiopexy, even at an early age, does not appreciably decrease the risk of developing a tumor (9). The majority of cryptorchid testes lie distal to the external inguinal ring and are palpable. Nonpalpable testes are most commonly located within the inguinal canal, but they can be located anywhere along the path of descent from the abdomen. Testicular agenesis has been reported to be present in 15%–63% of patients with a nonpalpable testis (4,10). The distinction between agenesis and maldescent is critical, as orchiopexy should be performed in all patients with undescended testes. This is usually performed between 1 and 2 years of age. If performed later, the testis will have undergone marked morphologic change, with fibrosis and collagen deposition adversely affecting spermatogenesis and fertility (11). While orchiopexy improves fertility, it does not alter the risk of developing a carcinoma. Because of this increased risk, testicular biopsies have been recommended to aid in the identification of intratubular germ cell neoplasia of the unclassified type (carcinoma in situ). If the biopsy results are positive for intratubular neoplasia, the patient has a 50% chance of developing invasive carcinoma; however, if the biopsy results are negative for intratubular neoplasia, the patient does not have an increased risk for developing carcinoma. A single postpubertal biopsy of each testis at 18–20 years of age is suggested and appears to be adequate for identification of high-risk patients (9,12). Imaging can be helpful in localizing a nonpalpable testis. An undescended testis will appear hypoechoic with ultrasonography (US), and a mediastinum testis should be identified for confident diagnosis. There are many potential pitfalls, including possible confusion with lymph nodes and the pars infravaginalis gubernaculi, which is a bulbous termination of the gubernaculum (4,13). More importantly, agenesis cannot be discriminated from atrophy with US (3,4). CT also lacks the specificity and sensitivity that are needed to diagnose agenesis. Magnetic resonance (MR) imaging has the advantage of improved soft-tissue contrast, but reports have varied as to its usefulness (11,14). The results of a study by Lam et al (15) showed that gadolinium-enhanced MR venography performed in conjunction with routine pelvic MR imaging increased sensitivity for differentiation of agenesis from ectopia. Because surgery is obviated only if the testis can be proved to be absent, many urologists feel that the treatment of choice is laparoscopy, which can be both diagnostic and therapeutic (16,17). Some cases, however, will still require open inguinal exploration and abdominal laporotomy (18). Preoperative imaging may help in surgical planning in these patients.