Scrotum pathology

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For normal anatomy and scanning protocol

Scrotal pathology can be broadly divided into:

  1. Intratesticular
  2. Extratesticular

And then with or without pain.

Scrotal swelling or lump with pain

4 main causes:

  • Torsion (20%) – age dependant.
  • Infection/inflammation (75-80%) – Epididymitis, Orchitis or Epididymo-orchitis
  • Haemorrhage
  • Hernia

See below for more details.

Ruptured Testis

  • Damage of the testicle is usually from an extremely forceful trauma directly to the testicle.
  • It leads to haemorrhage , laceration and contusion.
  • Unfortunately it could also cause torsion of the testis.
  • If there is not uniform homogeneity throughout the testis then with the history of blunt trauma a ruptured testis must be assumed until proven otherwise.
  • Blood Flow should be checked with Colour Doppler and Pulsed Doppler.
  • There may be a fracture line but it is only seen in less than 20% of cases.
  • Look for a significant hematocele as this is an indirect finding for possible testicular rupture.

Ultrasound image- There is a hypoechoic fracture line seen in this ruptured testis.

Acknowledgement : Mrs. Alison Deslandes

Intratesticular Masses

MICROLITHIASIS

Ultrasound image- Microlithiasis is classified as multiple echogenic foci scattered throughout one or both testes.

There is a suspected association between testicular microlithiasis, intratubular germ cell neoplasia, and testicular tumor.

SARCOIDOSIS

Ultrasound image- Sarcoidosis

Is a rare condition associated with a pre existing condition.This is extremely difficult to differentiate from seminomas or lymphoma

Ultrasound image- Hyperaemia in sarcoidosis mimicks orchitis.

MUMPS

Ultrasound image- Post Mumps
An area of preserved normal testicuar parenchyma is evident at the lower pole.

Ultrasound image- Past history of mumps as an adult results in atrophy of the testis.

Testicular carcinoma

Germ Cell tumours

Comprise 90% of all testicular tumours.

  • 50% of these are Seminomatous
  • Non Seminomatous – Mixed-type is most common
    (1.Embryonal carcinoma 2.Teratocarcinoma 3.Differentiated teratoma
    4.Choriocarcinoma 5.Yolk sac tumour)
  • At least 2/3 produce elevated serum markers of BHCG or AFP.
  • Non Germ Cell tumours
    The remaining 10% of testicular tumours.

Examples include:

  • Leydig cell tumors – often benign. Less than 10mm. 1/3 secrete testosterone.
  • Sartoli cell tumours – may be associated with autsomal dominant Carney complex
  • Gynaecomastia (30% association)

SEMINOMA

Ultrasound image- Seminoma
Is the most common tumour in adults.It is a round solid lesion that can cause scrotal enlargement.Testicular Tumours 90-95% tumours are malignant.The most common solid malignancy of young men.Mostly present as a painless lump or fullness, or as a diffuse enlargement of the whole testis.Typically occur in younger men between the ages of 20 and 40 Occasionally may be painful.97-98% are germ cell origin.Germ Cell Tumours exhibit rapid growth,Initial lymphatic spread to retroperitoneal nodes.Classified as either 1. Seminoma 2. Nonseminoma

Ultrasound image- Be cautious not to misdiagnose tubular ectasia of the rete testis as a mass.

GERM CELL TUMOR

Ultrasound image- Testicular microlithiasis and a Germ cell tumor.

Ultrasound image- Transverse of the germ cell tumor and power doppler confirming internal flow.

Ultrasound image- Patient with Kleinfelters Syndrome
Areas of hemorrhage and calcification in this non seminoma.This patient has Kleinfelter’s syndrome.

Ultrasound image – Germ Cell Tumours
Non seminoma 1.Embryonal carcinoma 2.Teratocarcinoma 3.Differentiated teratoma 4.Choriocarcinoma

5.Yolk sac tumour at least 2/3 produce elevated serum markers BHCG or Alpha-fetoprotein Nonseminoma Ultrasound Appearances ” Contains some cystic spaces ” Borders not easily defined ” heterogeneous ” embryonal carcinoma is seen on ultrasound as a large, irregular tumor with loss of the normal architectural contour of the testis. ” The mass has a heterogeneous appearance, predominantly hypoechoic. ” It may be seen to infiltrate the tunica albuginea with extension into the spermatic cord structures. ” Areas of necrosis are seen as cystic spaces within the tumor. ” Sometimes, areas of hemorrhage and calcification may also be noted as hyperechoic foci.

Testicular cysts/ ductal ectasia

Ultrasound image- testicular cyst.

Ultrasound of ductal ectasia in a testis. Longitudinal view. The red arrows indicate the dilated (ectatic) ducts. The blue arrow indicating the ectasia extending into the epididymal head.

Ultrasound of testicular ductal ectasia in a transverse plane at rete testis. The ‘multimicro-cystic appearance is typical. Colour doppler is used to prove it is not a vascular lesion.

Epididymal cysts/ spermatoceles

EPIDIDYMAL CYSTS

Epididymal cysts  are the most common abnormality seen pathology.

Ultrasound Appearances include:

  • Obviously cystic, smooth walls, no internal blood flow.
  • Epididymal Cysts are also called spermatoceles if they contain sperm in which case the fluid is opalescent (ie contains low level echoes, particularly when viewed with high gain settings). These are clear fluid, typically 1-2 cm wide. They are most commonly seen in the head,usually painless,sometimes palpable.
  • Epididymal Cysts may be multilocular & quite large. When palpating it is different to a hydrocele where the testis may be difficult to define.
  • A Hydrocele may co-exist with Epididymal cysts.

Ultrasound of small epididymal cysts in the head of epididymus.

Ultrasound of a large epididymal cyst adjacent to the testis.

Ultrasound of several epididymal cysts. The epididymus is seen to be displaced.

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Hydrocele

Ultrasound image- Hydroceles are very common and are the most common cause of scrotal swelling.

Ultrasound image- Large hydrocele.

Ultrasound image- Bilateral Hydroceles.

Ultrasound image- A Large hydrocele pinning the testis to the postero-lateral wall.

Epididymo-Orchitis

Patients present with scrotal swelling,erythema and pain.

Acute epididymitis may be unilateral or bilateral in 5% of cases. Epididymitis presents first and severe cases extend to the testis resulting in orchitis.

Symptoms can mimic torsion, trauma, abscess formation, testicular tumour, hernia or a hydrocoele.

Ultrasound image- Epididymo – orchitis
Increased Vascularity with oedema surrounding the testis and epididymis are seen will help with the diagnosis of inflammation.
Scrotal wall thickening may be uni or bilateral.
A striated appearance within the testis my appear with oedema of the testis.

Ultrasound image- The epididymis when enlarged and can be hypoechoic or hyperechoic.There is diffuse testicular involvement which results in testicular enlargement and inhomogeneous echotexture.

Ultrasound image- demonstrating the increased colour flow indicative of an inflammation (epididymitis).

Acknowledge: Mrs Alison Deslandes

Varicocele

  • Occurs in 15-20% of the male population and up to 40% of those with male infertility (possibly due to thermoregulation during spermatogenesis).
  • Far more common on the left than the right (8-9:1). This is due to the longer course of the left testicular vein compared to the right. The right is shorter and enters pelvic veins whilst the left ascends to join the left renal vein. This applies greater hydraulic pressure on the venous valves which often fail.
  • Follow the testicular vein in the spermatic cord to the left renal vein if possible.
  • Most varicoceles have no extrinsic cause. But if clinically concerned, look for a mass that could be compromising the testicular vein such as a Psoas muscle abscess, renal tumour, renal vein thrombus, lipoma, IVC narrowing or post vasectomy scarring.

Ultrasound image- Varicocele- intra and extratesticular.

Ultrasound of a varicocele with power doppler. Increased flow is seen during straining / valsalva.

Varicocele ultrasound
Ultrasound of a varicocele with power dopppler. Straining generates retrograde flow if there is venous incompetence as in this case.

Nut-cracker syndrome:

  • Compression of the left renal vein between the aorta and superior mesenteric vein.
  • Creates back pressure on the renal vein resulting in reflux into the left gonadal (tesicular) vein and a varicocele.
  • More common in thin habitus patients.

Ultrasound image- Varicocele- intra and extratesticular.

Ultrasound image nut cracker syndrome- Compressed left renal vein.

The stenotoc segment is seen with aliasing on colour doppler.

Ultrasound image nut cracker syndrome- Dilatation of the left renal vein proximal to it’s passage between the SMA and aorta.

Ultrasound image- This is a sagittal view of the testicular vein draining into the left renal vein.

Highlighted left testicular vein as it joins the left renal vein.

Ultrasound of nutcracker scrotal syndrome. Longitudinal plane sowing the compressed left renal vein between the abdominal aorta and sma. Highlighted anatomy.

Torsion Testicular Appendix

Appendix epididymis/testis

  • Four testicular appendages (remnants of embryonic ducts) include the appendix testis, appendix epididymis, vas aberrans, and the paradidymis.
  • 92% of males have an appendix testis, and 34% have an appendix epididymis.
  • The appendage testis seen here on the upper pole of the testis is identified commonly particularly if there is a hydrocele present such as this case.

Ultrasound of an appendix epididymus cyst

Ultrasound image- Appendix Testis.

Torsion of the appendage is a differential diagnosis that should always be considered in the presentation of acute focal unilateral pain with no trauma.

Ultrasound image- There is no colour flow in the appendix. It is enlarged and extremely painful. A standoff pad is used to help better appreciate and visualise .

Acknowledgment: Mrs Alison Deslandes

TUNICA ALBUGINEA CYSTS OR MASSES.

Ultrasound image- Tunica albuginea masses.

Ultrasound image- Tunica albuginea mass using thick gel as a standoff to allow use of less pressure so the small hydrocele could better delineate it’s margins.

SCROTAL PEARLS / SCROTOLITH

  • A mobile extratesticular focus in the tunca vaginalis space.
  • Usually rounded.
  • Often calcified.
  • Uncertain aetiology
  • Benign and assymptomatic

Scrotal Pearl

Ultrasound image- Scrotal pearl is seen as a mobile rounded, generally calcified painless lump.

HAEMORRHAGE/ HAEMATOMA

May be:

  • Intrascrotal
  • Of the scrotum

Causes include:

  • Trauma
  • Post surgical
  • Descending scrotal haematoma from pelvic/ abdominal causes.

Ultrasound image- A large, traumatic right sided haematoma pinning the testis anteriorly.

Ultrasound image- The complex multiseptated appearance of an organising haematoma.

Ultrasound image- The hematoma is visible adjacent to the left testis and a left varicocele.

Hernia

panoramic ultrasound image- Scrotal hernia.

The arrows show herniated omental fat through the inguinal canal down into the scrotum.

EPIDIDYMAL ADENOMATOID TUMORS

  • Benign.
  • Ultrasonically these may be cystic or solid.

Granuloma                                                                       Agenesis Epididymis

Ultrasound image- Spermatic cord granuloma post vasectomy.

Ultrasound image- Agenesis Epididymis.The cause of aspermia was found to be an absent body and tail of epididymis.

Rhabdomyosarcoma of the epididymis

  •  A malignant condition.
  • These are exceedingly rare.
  • Clinically they are small,firm and painless.

Ultrasound image- Extratesticular Mass – Rhabdomyosarcoma

Cryptorchidism

testicular descent animation ultrasoundpaedia
  • The gubernaculum (blue) contracts pulling the testicle downwards.
  • As the testicle descends through the inguinal canal (green box), the epididymus folds becoming the head, tail and vas deferens (red).
  • A reflection of the peritoneum is also pulled down into the scrotum, the tunica vaginalis or processus vaginalis (green)

Also referred to as Testicular-Maldescent or undescended testes. Most testicles descend from the abdomen into the scrotum by 35 weeks of foetal life Cryptorchidism occurs in 3-5% of male full term neonates, 20-30% in premature neonates and 1% of boys over 1year old.

3 Types

  1. Truly maldescended
  2. Ectopic
  3. Retractile

If impalpable, the maldescended testis may be intra-abdominal or absent. If left malpositioned, there is an increased risk of testicular cancer and increased risk of infertility.

Ultrasound Appearances

  • They are found usually in the inguinal canal.
  • Look like normal testes, merely malpositioned; but can be confused with lymph nodes.
  • Gently try to reduce the testis to the scrotum and note where it’s “at-rest position” is.

Ultrasound image- The undescended testis with a small hydrocele is superior to pubis in the inguinal canal. A small hernia sac also descended with straining.

Ultrasound image- A subtle undescended testis in the groin of a toddler ( young child ).

Ultrasound image- Cryptorchid Abdominal.

Ultrasound image- Retractile testis moving. This is a 5year old boy who presented with an absent testis. The right testis was found to be sitting in the inguinal canal. With straining or external pressure, it moved in and out of the scrotum.

Ultrasound image- The undescended testis in this case was found to lie lateral to the common iliac vessels on the right side. This can be difficult to see if there is a lot of overlying gas so fasting if possible is recommended.

Acknowledgement: Mrs Alison Deslandes

Cryptorchidism
The testis is situated in the inguinal canal. Bimanual probe and hand pressure was used to attempt to reduce the testis to the scrotum. The testis can be seen sliding within the canal and again ascends when pressure is released. The retracted gubernaculum is visible at the lower pole

A maldescended tesitis being relocated with transducer pressure.

As soon as the pressure is released, the testis again ascends.

Infection

  • Can be intra or extratesticular.
  • Usually post trauma or surgery.

Ultrasound image-A large complex fluid collection laterally in the scrotum. Note the similar echotexture to the testis. Gentle compression with prove the fluid nature. Aspiration proved to be an ascess.

Ultrasound image-The abscess extends into the scrotal wall.

Ultrasound image-Scrotal Abscess demonstrating some dirty shadowing with B Mode, When you mouse over you can appreciate the increased colour flow indicative of an abscess.

Acknowledge: Mrs Alison Deslandes

Torsion

  • Deficiency of the gubernaculum (gubernacular ligament) may allow the testis to rotate (tort).
  • Enough twisting of the spermatic cord will compromise the blood supply to the testis. It has been suggested that 720degrees rotation is required to fully occlude arterial supply.
  • As the testicle rotates it will be pulled superiorly into a horitontal lie (bell-clapper).
  • A cord knot may be visible. Scan through the vascular plexus looking for a ‘swirl-sign’. (see videos below)

Ultrasound of a torted right testis.
heterogeneous and no flow on colour doppler.
This case is a 15yo on his 3rd attendance for pain over 2 years. the 2 previous attendances showed vascularity.

Image courtesy of Rachel Vietch

Torsion of the appendix/appendage epididymis or testis:

  • Focal tenderness/pain
  • The appendage will be oedematous and avascular.
  • The peripheral oedema may create a fasicular ‘mini ovary’ appearance (termed coined by Mr L Stow)
  • The oedema will cause subtle posterior enhancement.

Ultrasound image- Torsion of the appendix tesits or epididymis.

Images courtesy of Mr Lincoln Stow (who coined the term..the ‘ovary sign’)

Ultrasound image- The subtly enlarged appendix testis is visible. Note that the appendage has hypoechoic cystic appearing change peripherally. It is usually homogeneous.

No flow on colour doppler

Torsion cord knot ultrasound
Partial torsion with visible twist in testicular vessels (clinically suspected tort-untort). Imgae courtesy of Mr L Stowe
B mode cord knot
B mode ultrasound of a cord knot in testicular torsion. The rotating epididymal tail and vascular plexus are visible on the bottom left of the clip.

References

Diagnostic Ultrasound. St Louis:Mosby.1998. Charboneau,j.William, Rumack,Carol M: Wilson,Stephanie R

Intratesticular varicocele:evaluation using grey scale and color Doppler Ultrasound. World Journal of Urology. Bucci S, Ligouri G,Amodeo A,Salame L, Trombetta C , Belgrano E (2007)

Mesoaortic compression of the left renal vein (nutcracker syndrome): case reports and review of the literatre. Annals of vascular surgery. Rudloff U, Holmes RJ. Prem JT. Faust GR, Moldwin R, Siegel D (2006)

Ultrasonography of the
scrotum: technique, anatomy, and pathologic entities.
J Ultrasound Med 2002;21:171–185. Ragheb D, Higgins JL Jr.


Sonography of the scrotum. Radiology 2003;227:
18–36. Dogra VS, Gottlieb RH, Oka M, Rubens DJ.

Sonography of benign intrascrotal lesions. Ultrasound Q 2006;22:
121–136.Bhatt s, Rubens DJ, Dogra VS

Ultrasound diagnosis of paratesticular rhabdomyosarcoma . Br J Radiol2004;77:250-252 MakCW, Chou CK, Su CC, Huan SK , Chang JM

Extratesticular scrotal masses: radiologicpathologic correlation. RadioGraphics 2003; 23: 215-240 Woodward PJ, Schwab CM , Sesterhenn IA.

Cryptorchidism: strategies in detection: Eyr Radiol1999; 9: 336-343 . NguyenHT, Coakley F, Hricak H.

Ultrasound Appearances of the testicular appendages: pictorial review Eur Radiol 2003;13: 127-135