This document discusses the anatomy and imaging of the scrotum. It begins with the anatomy of the scrotum, testis, epididymis and spermatic cord. It then covers imaging modalities used including ultrasound and MRI techniques and protocols. Common pathological conditions are summarized such as infections, trauma, tumors and congenital anomalies. Specific conditions like torsion, epididymitis and testicular cancer are described in detail with imaging findings.

1. IMAGING OF
SCROTUM
ROSHAN VALENTINE

2. ANATOMY OF SCROTUM
 Cutaneous bag containing the testis , epididymis and lower
part of spermatic cord
 Left hemiscrotum is lower than the right – Longer spermatic
cord

3. ANATOMY OF SCROTUM
LAYERS OF SCROTUM

4. ANATOMY OF SCROTUM
BLOOD SUPPLY
 Sup and deep External
pudendal A
 Scrotal br of Internal
Pudendal A
 Cremasteric br of inferior
epigastric

5. ANATOMY OF TESTIS
TESTIS
 Male gonad
 Size :
o At birth : 1.5cm(L) x 1.0cm(W)
o <12 years : 1-2cc
o 10-15cc (2x3x4cms-BaPL) in adults
 Puberty achieved : >4cc

6. ANATOMY OF TESTIS
EXTERNAL FEATURES
 Upper pole:Oriented forward and lateral
 Lower pole : Backward and medial
 Anterior border : Convex and smooth , fully covered by
tunica vaginalis
 Posterior border : Straight and partially covered by tunica
vaginalis – Epididymis along the posterolateral wall

7. ANATOMY OF TESTIS
COVERINGS OF TESTIS(Out to
in)
 Tunica vaginalis
 Tunica albuginea
 Tunica vasculosa

8. ANATOMY OF TESTIS
BLOOD SUPPLY OF TESTIS
 Testicular artery
 Collateral supply
o Cremasteric artery
o Artery to ductus deferens

9. ANATOMY OF TESTIS
LYMPHATIC DRAINAGE

10. EPIDIDYMIS

11. SPERMATIC CORD

12. IMAGING MODALITIES

13. USG
TECHNIQUE
 Supine position
 7-10Mhz linear array transducer
 Direct contact or stand off pad
 Examine in long and transverse axes
 Size and echogenicity of the testis and epididymis
 Scrotal skin thickness
 CDFI and PWD
 Valsalva and Upright positioning – Venous evaluation

14. USG ANATOMY
 Pre-pubertal testis : Low to medium echogenicity
 Post-pubertal : Homogenous and medium echogenicity
 Medistinum Testis: Echogenic band in C-C direction
 Hypoechoic thin rim of fluid around
 Epididymis
o Head : 5-12mm
o Body : 2-4mm
o Tail : 2-5mm
 CDFI and PWD(RI : 0.46-0.68)

16. USG ANATOMY
CDFI AND PWD
 Low resistance pattern
 Mean RI:0.62(0.48-0.75)

17. MRI OF SCROTUM
MRI PROTOCOL
 Supine position
 Support scrotum by towel
 T1 and T2wSE in coronal and
axial plane
 CE and Fat saturation seq
 Thin 4-5mm slices 8-20 cm
field of view
 Undescended testis : Lower
pole of kidneys
 Diaphragm : For staging

18. MRI OF SCROTUM
NORMAL MRI ANATOMY

19. PATHOLOGICAL CONDITIONS

20. SCROTAL WALL LESION
 Non inflammatory
 Inflammatory
 Malignant

21. SCROTAL WALL LESION
NON INFLAMMATORY
o Swelling : HF , idiopathic lymphedema
liver failure , venous and lymphatic obstruction
o Appearance : ONION RING

22. SCROTAL WALL LESION
INFLAMMATORY LESIONS
o Cellulitis
• Increased scrotal wall thickness
• Hypoechoic areas within
• Increased blood flow
o Fournier Gangrene
• Necrotizing fascitis of the wall
• KEPPSS bacteria
• Clinical > Imaging
• Gas within the scrotal wall
• Scrotal wall thickening with normal testis and epididymis

23. CONGENITAL ANOMALIES

24. CRYPTORCHIDISM
 One or both the testis fail to
migrate to the base of the
scrotum
 Course of testis
 80% in inguinal region
 Complication : Infertility ,
malignant degeneration,
torsion and inguinal hernia

25. CRYPTORCHIDISM
USG EXAMINATION
 Localisation
 Follow up post orchiopexy
 Areas: Inguinal canal ,
suprapubic and femoral
areas
 Intraabdominal testis – USG
less sensitive
 USG features : Iso to
hypoechoic , smaller in size ,
mediastinum testis

26. CRYPTORCHIDISM
MRI
 Look till lower pole of the kidneys
 Round/ovoid
 Along the path of descent
 ID
o Signal intensity pattern
• Hypointense – T1
• Hyperintense – T2
o Mediastinum Testis
o Differentiating from nodes:
Position

27. RETRACTILE TESTIS
 Due to hyperactive cremasteric muscle reflex
 Slides back and forth between scrotum and ext inguinal ring
 Self- limiting and no treatment
ECTOPIC TESTIS
 Location outside the descent path
 Sites : Femoral canal , suprapubic or even C/L scrotal pouch

28. ACUTE SCROTUM

29. EPIDIDYMITIS AND ORCHITIS
 MC cause in post-pubertal adults
 Cause : UTI by KEPPs>STDs
 If inflammation extends into testis : Epididymo-orchitis
 C/F : Pain , fever , dysuria +/- urethral discharge
 PREHN sign: pain relieved on elevating testis over pubic
symphysis
 Complications: Chronic pain , infertility , gangrene , abscess ,
infarction , atrophy and pyocele

30. EPIDIDYMITIS AND ORCHITIS
USG FINDINGS OF EPIDIDYMITIS
 Enlarged
 Hypo/heteroechoic
 Indirect signs of inflammation :
Hydrocele , scrotal wall thickening ,
pyocele
USG FINDINGS IN ORCHITIS
 Heterogeneous echogenicity
 Multiple hypoechoic lesions if focal
 Usually unilateral( diff from
Lymphoma & Leukemia)

31. EPIDIDYMITIS AND ORCHITIS
CDFI and PD
 100% sensitivity
 Hyperemia
 High flow , low resistance
pattern
 RI< 0.5
 Reversal of diastolic flow
in acute epididymoorchitis
– s/o Venous infarction

32. EPIDIDYMITIS AND ORCHITIS
MRI on Epididymitis
 Enlarged epididymis with
high signal intensity on
contrast enhanced T1W
 Area of hemorrhage and
hyper vascularity
MRI on Orchitis
 Homogeneous/heterogen
eous hypointense on T2W

33. TORSION
Torsion
Extravaginal
Neonates
Entire sac rotates
Intravaginal
In Vaginal sac
Pubertal

34. TORSION

35. TORSION
BELL CLAPPER DEFORMITY

36. TORSION
 Rotation of testis on long axis of spermatic cord
Torsion
Venous
Edema and
hemorrhage
Arterial
Ischemia
and necrosis

37. TORSION
SALVAGE RATE
o <6 hours – 100%
o 6-12 hrs – 70%
o 12-24 hrs - 20%

38. TORSION
CLINICAL FEATURES
 Sudden onset of pain
 Nausea
 Vomiting
 Low grade fever
 O/E : Swollen , tender and inflamed hemiscrotum

39. TORSION
USG features
 Vary with duration and degree of rotation
 Grey Scale – Nonspecific (Normal if hyperacute)
 < 6 hours : Testicular swelling and hypoechogenicity
 >24hrs: Heterogeneous due to congestion , hemorrhage and
infarction
 Enlarged hypoechoic epididymal head : if deferential artery is
involved
 Scrotal wall thickening
 Reactive hydrocele

40. TORSION
CDFI
 CDFI or PD signal present with clinical manifestation :
Doesnot exclude torsion
 Absence of identifiable intratesticular flow
o Sensitivity 86%
o Specific 100%
o Accuracy 97%

41. SPECTRUM OF APPEARANCES

42. Torsion of appendix testis
 Blue dot sign : Torsion of appendix
 USG
o Hyperechoic mass with central
hypoechoic area adjacent to
superior poleof
testis/epididymis
o Reactive hydrocele
o Scrotal skin thickening
o Increased peripheral flow on
CDFI
o To rule out testicular torsion
and acute epididymo-orchitis

43. TORSION
MRI
 Early diagnosis of incomplete torsion
 ‘WHIRLPOOL’ pattern : twisted cord as multiple low
intensity curvilinear pattern
 Torsion knot as signal void
 Intermittent torsion : Enlarged testis and Hyperintense
on T1 and T2
 MR Spectroscopy - Decreased levels of beta – ATP in
acute torsion

44. TORSION

45. TORSION
 Tc-99m Pertechnate scan

46. SCROTAL TRAUMA
 Mostly direct injury
 Open and penetrating injury – Immediate surgery usually
 Blunt injury
o Exclude testicular rupture(emergency)
o Hematoma from hematocele
o Follow up

47. SCROTAL TRAUMA
USG
 Hematoma – Well defined
hypoechoic SOL
 Rupture – Irregular contour,
hypo/hyperechoic areas
 Scrotal hematoma – Non
specific wall thickening
 Hematocele – Int echoes in
the fluid in vaginal sac
 Chronic hematocele – Thick
septae and wall thickening

48. SCROTAL TRAUMA
MRI
 When USG is non yielding
 Testicular rupture : Loss of integrity of tunica albuginea

50. TESTICULAR TUMORS

51. Testicular Cancer
CLASSIFICATION
o Germ Cell (90%) - Malignant
• Seminoma
• Non-seminoma (embryonal cell, choriocarcinoma, teratoma, yolk sac)
• Mixed
o Non-Germ cell –rare; usually benign
• leydig
• sertoli
o Secondary
• leukemia, lymphoma
• met (prostate)

52. TESTICULAR TUMOR
 MC malignancy affecting young men of 20-34 yrs of age
 Risk factors: Cryptoorchidism , testicular atrophy(mumps),
testicular microlithiasis, klinefelters ,downsyndrome
 C/F: Painless mass, vague discomfort
 USG : differentiate Intratesticular(malignant) and
Extratesticular(benign) lesions

53. TESTICULAR TUMOR
GERM CELL TUMOR
 90-95% of testicular cancers
GCT
Seminomatous
Non
Seminomatous

54. GERM CELL TUMORS
 TUMOR MARKERS
o LDH
o AFP(Never elevated in Seminoma)
o hCG(choriocarcinoma , majority of NSGCT)

55. SEMINOMA
 MC testicular tumor
 4th to 5th decade
 Best prognosis
 Chemosensitive and radiosensitive

56. SEMINOMA
Seminoma
Typical(85%) Anaplastic(10%)
Spermatocytic
(Best Px)

57. SEMINOMA
USG
 Homogenous hypoechoic lobulated lesion
 Entire testis replaced by tumor(>50%cases)
 Cystic components are rare
 Confined to Tunica albuginea
 Mets to Lung , brain

58. SEMINOMA

59. SEMINOMA
MRI
 T1W : Homogenous and relatively isointense
 T2W : Hypointense

60. NSGCT
 3rd – 4th decade
 Can have multiple histologic patterns
USG Inhomogneous echotexture(71%)
o Ill defined margins(45%)
o Echogenic foci(35%)
o Cystic components(61%)
MRI
o T1W : Isointense to Hyperintense
o T2w : Hypointense
o Gd-T1 :Heterogenous (necrosis, mixed cell types)

61. NSGCT

62. EMBRYONAL CARCINOMA
 3rd decade
 USG
o Predominantly
hypoechoic
o Poorly defined
margins
o Inhomogeneous
echotexture
o Invades Tunica and
distorts the
contour of testis

63. YOLK SAC TUMOR
 Endodermal sinus tumor/infantile embryonal carcinoma
 80% of pediatric testicular tumors
 AFP 
 USG
o Inhomogeneous
o Echogenic foci

64. CHORIOCARCINOMA
 Highly malignant
 Microvascular invasion – hence hematogenous mets
 USG : Heterogenous mass

65. TERATOMA
 Composed of all three
germ cell layers
 Any age group
 USG
o Large and
inhomogenous
mass
o Cystic components
more common

66. BURNT-OUT GERM CELL TUMOR
 When growth > supply
 Histology : No tumor
cells , but replaced by
scar and fibrous tissue
 USG
o Small echogenic
foci / hypoechoic
mass or merely an
area of calcification

67. MIXED GERM CELL TUMOR
 More common than any
other testicular tumor
except seminoma
 Any combination of cell
types
 variety of cell types
expressed in variable
appearance

68. NGCT
 Tumors of gonadal stroma(Leydig , sertoli and
gonadoblastoma
 May be endocrinally active – precocious puberty ,
gynecomastia
 5% of testicular cancer
• higher in peds
 90% benign
 Indistinguishable from GCT
 USG
o Small in size
o Smooth contour
o Homogenous hypoechoic

69. LEYDIG CELL TUMOR
 1-3% of all testicular
neoplasm
 Usually benign
 Hormonally active
USG
 Hypoechoic nodule
MRI
 T1W : Isointense
 T2W: Hypointense
 CE :Hyperenhance

70. SERTOLI CELL TUMOR
 1% of all testicular CA
 First 4 decades of life
 Mostly benign
 MRI imaging NOT
SPECIFIC

71. NGCT
LYMPHOMAS
 MC testicular neoplasm after
60 years
 Can involve C/L seminoma ,
epididymis and spermatic
cord
 Appearance
o Deposits as focal or
diffuse hypoechoic
hypervascular areas
o Enlarged usually
o T1 and T2 hypointense
lesions

72. NGCT
METASTASIS
 Rare and seen in older patients
 Primaries – Lung , Kidney and prostate
 USG : Non specific

73. STAGING OF TESTICULAR CANCER
 pTX: Primary tumor cannot be assessed (if no radical orchiectomy has
been performed, TX is used.)
 pT0: No evidence of primary tumor (e.g., histologic scar in testis)
 pTis: Intratubular germ cell neoplasia (carcinoma in situ)
 pT1: Tumor limited to testis and epididymis without lymphatic/vascular
invasion
 pT2: Tumor limited to testis and epididymis with vascular/lymphatic
invasion, or tumor extending through the tunica albuginea with
involvement of the tunica vaginalis
 pT3: Tumor invades the spermatic cord with or without
vascular/lymphatic invasion
 pT4: Tumor invades the scrotum with or without vascular/lymphatic
invasion

74. STAGING OF TESTICULAR CANCER
REGIONAL LYMPH NODES (N)
 NX: Regional lymph nodes cannot be assessed
 N0: No regional lymph node metastasis
 N1: Metastasis in a single lymph node, 2cm in greatest
dimension
 N2: Metastasis in a single lymph node, 2-5 cm in greatest
dimension; or multiple lymph nodes, 5 cm in greatest
dimension
 N3: Metastasis in a lymph node >5cm in greatest dimension

75. STAGING OF TESTICULAR CANCER
DISTANT METASTASIS (M)
 MX: Presence of distant metastasis cannot be assessed
 M0: No distant metastasis
 M1: Distant metastasis
 M1a: Non-regional nodal or pulmonary metastasis
 M1b: Distant metastasis other than to non-regional nodes
and lungs

76. STAGING OF TESTICULAR CANCER

77. STAGING OF TESTICULAR CANCER

78. RISK STRATIFICATION

79. CT
 MC for tumor spread , Staging and follow up
 Detection of lymphadenopathy
 Extranodal mets in Lung and liver
 Nodes <1cm suspicious if at the site of drainage
o Renal hila on left
o Aortocaval in right
 Cut off for nodes : 7mm
 NSGCT : Enlarged necrotic LN or heterogenous contrast
enhancement

80. PET(FDG-PET)
 Differentiation of active disease from fibrosis/mature
teratoma in patients with residual mass following
chemotherapy
 Initial staging and disease assessment after orchidectomy
 Identification of suspected recurrences in the context of
elevated circulating serum markers
 Predicting response to treatment.

81. BENIGN INTRATESTICULAR LESIONS

82. BENIGN INTRATESTICULAR LESIONS
CYSTS
 Incidentally
detected usually
 Symptomatic ,
palpable and solid
component :
? suspicious

83. BENIGN INTRATESTICULAR LESIONS
TUNICA ALBUGINEA CYST
 Small palpable masses
 Upper anterior/lateral
aspect
USG
 Cystic and peripheral
 Internal echoes are
rare
MRI
 Similar to fluid in all
sequences

84. BENIGN INTRATESTICULAR LESIONS
TUBULAR ECTASIA
 Multiple tiny cystic areas with no flow
on CDFI
 Associated with epididymal
obstruction
EPIDERMOID AND DERMOID CYSTS
 Rare
 Palpable simple cysts
 Echogenic margins
 No malignant potential

85. BENIGN INTRATESTICULAR LESIONS
ADRENAL RESTS
 Associated with CAH
 Common embryonic origin of
adrenals and gonads
 USG
o Multifocal
o Bilateral hypoechoic lesions

86. BENIGN INTRATESTICULAR LESIONS
CALCIFICATION
Calcification
Intratesticular
Macro(Calcifying
tumors)
Microlithiasis
Extratesticular Scrotoliths

87. BENIGN INTRATESTICULAR LESIONS
CALCIFICATION
 Testicular microlithiasis
o Multiple small hyperechoic foci +/- shadowing
o 5 /transducer field is abnormal
o 18-75% association with neoplasia
o Follow up required if seen

88. CALCIFICATIONS

89.  Occurs as a complication
of epidiymo-orchitis
 Can rupture into tunica
vaginalis – pyocele
 USG:
Fluid filled
hypoechoic/ echogenic
areas with peripheral
vascularity.
Should be correlated
with clinical symptoms.
TESTICULAR ABSCESS

90.  Can occur secondary to
torsion, vasculitis,
leukemia,
hypercoagulable state.
 Seen as peripherally
placed, wedge shaped,
hypoechoic mass, with
decreased or no
vascularity.
 Usually shows decrease
in size on follow up.
TESTICULAR INFARCTION

91. TESTICULAR INFARCTION
MRI
 T1W : Isointense
o Hemorrhagic infarct : Hyperintense
 T2W : Variable but usually hypointense
 CE : Rim enhancement

92. INTRATESTICULAR VARICOCELE
 ?etiology.
?significance
 May cause pain
 (+/-)extratesticular
varicoceles
 Findings
• tubular, serpiginous
structures with venous
doppler/color flow
which increases with
valsalva

93. EXTRATESTICULAR PATHOLOGIES

94. EXTRATESTICULAR PATHOLOGIES
HYDROCELE
 Serous fluid in tunica vaginalis
 Two types
o Congenital: Persistent processus
vaginalis
o Acquired : Idiopathic , post
inflammatory , torsion , trauma or
tumor
 USG
o Anechoic collection around the testis
o Internal echoes/Few septations : chronic

95. EXTRATESTICULAR PATHOLOGIES
HEMATOCELE AND PYOCELE
 Post hemorrhage and abscess formation
 USG
o Multiple septations
o Echogenic debris
o Thickening of scrotal skin
o Calcification

96. EXTRATESTICULAR PATHOLOGIES
INGUINOSCROTAL HERNIA
 Dx usually clinically
 May contain bowel or omentum
 Essential to distinguish obstructed from
non obstructed
 Strangulation
o Akinetic dilated bowel loop in the
sac
o Hyperemia of scrotal soft tissue and
bowel

97. EXTRATESTICULAR PATHOLOGIES
EPIDIDYMAL CYST and SPERMATOCELE
 MC scrotal lesion
 Spermatocele
o 20 to obstruction of spermatic
pathway
o Usually located in head of
epididymis
 Epididymal Cyst
o Less common
o Anywhere in epididymis
 USG : Anechoic well circumscribed
cysts

98. EXTRATESTICULAR PATHOLOGIES
SPERM GRANULOMA
 Post vasectomy or epididymal obstruction
 USG
o Hypoechoic lesion
o Focal calcification +/-

99. EXTRATESTICULAR PATHOLOGIES
POSTORCHIDECTOMY SCROTUM
 Empty hemiscrotum
 Fluid collection /hematoma – Early post-op period
 Thickened scrotal wall
 Poorly defined hypoechoic lesion – Recurrence
 Testicular prosthesis : Made of silicone
o Sharply defined anechoic structure with excessive
reverberations

100. EXTRATESTICULAR TUMORS
BENIGN
Adenomatoid
Hemangioma
Lipoma
Neurofibroma
Leiomyoma
MALIGNANT
Liposarcoma
Fibrosarcoma
Lymphoma(Adults)
Rhabdomyosarcoma in
(children)

101. EXTRATESTICULAR TUMORS
 Usually benign
 MC :
Adenomatoid
tumor of
epididymis/sper
matic cord
 USG
o Solitary , well
defined ,
round to oval
o Variable
echogenicity

102. LIPOMA
 MC benign
tumor of
spermatic cord
USG
 Well defined
homogenous
and hyperechoic
MRI
 Uniform and fat
signal intensity
in all sequences

103. SUMMARY
 Use of Gray-scale, pulsed, and color Doppler US can help to
establish the correct diagnosis of a variety of pathologic
conditions involving the scrotum.
 MRI is useful adjunct in many cases – to differentiate intra
and extratesticular masses .