Scrotum and Testicles

Question 1

What should always be evaluated if an intratesticular mass is seen?

Answer 1

The retroperitoneum! Conversely, if retroperitoneal adenopathy is seen in a reproductive-age male, the testicles should always be examined.

Question 2

Most scrotal masses are __________ relative to normal testicular parechyma.

Answer 2

Hypoechoic

Question 3

On Doppler, most scrotal masses will have _________ vascularity with ____ diastolic flow, producing a _____ resistence waveform.

Answer 3

• Increased vascularity
• high diastolic flow
• low resistance waveform

Question 4

What is the most common testicular malignancy?

Prognosis? Epidemiology?

What marker may be elevated, albeit uncommonly?

US appearance?

Name the subtype.

Answer 4

• Seminoma is the most common testicular malignancy.
• It has a favorable prognosis.
• Seminoma typically occurs in middle-aged men.
• Uncommonly, hCG may be elevated.
• The spermatocytic subtype of seminoma occurs in slightly older men (mid 50s) and has an excellent prognosis with orchiectomy only. Tumor markers are not elevated.

Question 5

What are the nonseminomatous germ cell tumors?

Answer 5

• Embryonal CA
• Teratoma
• Yolk sac (endodermal sinus) tumor
• ChorioCA
• Mixed germ cell tumor

Way to remember: Think of all the tissus that comprise a viable pregnancy: Embryo (also a terror! ~ teratoma) - [and these first two most commonly make up the mixed germ cell tumor], yolk sac, and placenta (chorioCA)

Question 6

What is the most common Nonsemitomatous germ cell tumor?

Answer 6

Mixed germ cell tumor

Question 7

What are the most common components of a mixed NSGCT?

Talk about each one.

Answer 7

• Embryonal CA
  
  • Comprised of immature, primitive cells. Forms a hemorrhagic mass with necrosis, and in its pure form is rare. In adults it is typically seen as a component of mixed germ cell tumors. (infantile form is the yolk sac tumor)
  • Chemotherapy may result in differentiation into another type of germ cell tumor (eg teratoma)
• Teratoma
  
  • Rare in its pure form in adults, but is seen in 50% of mixed NSGCT. Teratoma is classified as mature, immature, and malignant. In adults, teratomas are usually malignant. In children, teratomas are usually benign, with the mature subtype most commonly seen. AFP or b-hCG may be elevated.

Question 8

What is the most common testicular tumor of infancy?

What marker is characteristically elevated?

Answer 8

• Yolk sack tumor
• AFP is elevated

Question 9

What is the US appearance of nonseminomatous (NSGCT) germ cell tumors?

NSGCT epidemiology? Local invasion into what structures is common?

Answer 9

• A heterogeneous testicular mass that contains solid and cystic components and coarse calcification is a typical appearance for an NSGCT. It is not possible to distinguish the various subtypes of NSGCT on sonography.
• NSGCT generally occur in younger patients compared to seminomas, typically in young men in their 20s and 30s. NSGCT tend to be more aggressive than seminomas. Local invasion into the tunica albuginea and visceral metastases are common.

Question 10

What is the most aggressive testicular tumor?

It is a malignant tumor of what cells lines?

Where doe in like to metastasize to via what route?

What marker is characteristically elevated? What may result?

Answer 10

• Choriocarcinoma
• Malignant tumor cells of syncytio- and cytotrophoblasts
• Spreads early hematogenously to brain and lung and mets tend to be hemorrhagic
• bHCG is elevated (a-subunit of hCG is similar to that of FSH, LH and TSH)
• Therefore, may lead to hyperthyroidism or gynocomastia

Question 11

What is a burnt-out germ cell tumor?

Characteristic US appearance?

Treatment?

Answer 11

• Burnt-out germ cell tumor is a primary testicular neoplasm that is no longer viable in the testicle even though there is often viable metastatic disease, especially retroperitoneal.
• In the testicle, focal calcification with shadowing is characteristic. A mass may or may not be present.
• Treatment is orchiectomy in addition to systemic chemotherapy.

Question 12

What is the name for multiple punctate testicular calcifications?

What is considered the limited form?

What characteristic appearance may be seen on US?

Answer 12

• Microlithiasis
• At least five microcalcifications must be present per image to be called microlithiasis. If there are fewer than five microcalcifications the term limited microlithiasis is used.
• Microlithiasis can produce a starry sky appearance if calcifications are numerous.
  
  • In the liver, hepatitis can cause a starry sky appearance due to increased echogenicity of the portal triads.

Question 13

What is the most common metastases to the testis and why?

Present in what age group and which side?

Possible US appearance?

Answer 13

• The most common metastases to the testicles are leukemia and lymphoma
  
  • Usually of diffuse large B-cell type
• The relevant chemotherapeutic agents do not cross the blood-testis barrier.
• Hematologic malignancies typically present in older patients (most common cause of testicular mass in males > 60yo) and tend to be bilateral.
• May be infiltrative with diffuse testicular enlargement.

Question 14

What is an epidermoid tumor and how does it appear on testicular US?

Management?

Answer 14

• An epidermoid is a keratin-filled cyst with a distinctive onion-ring appearance of concentric alternating rings of hypo- and hyperechogenicity.
• If suspected, local excision is performed instead of the standard orchiectomy typically performed for presumed malignant masses.

Question 15

What are the benign testicular tumor mimics?

Answer 15

• Congenital adrenal rests are embryologic remnants of adrenal tissue trapped within the testis. These are typically seen in newborns with congenital adrenal hyperplasia.
  
  • Adrenal rests appear as bilateral hypoechoic masses and classically enlarge with ACTH exposure.
• Polyorchidism/supernumerary testis: An extra testicle has an identical imaging appearance to the normal testicular parenchyma.
  
  • Extranumerary testes carry a slightly increased risk of torsion and testicular cancNext​er.

Question 16

Talk to me about sarcoidosis of the testis!

Involvement? US appearance?

Answer 16

• Sarcoidosis may involve either the testis, the epididymis, or both. Scrotal involvement is rare but presents clinically as painless scrotal enlargement.
• The ultrasound appearance of testicular sarcoid is indistinguishable from a solid malignant mass. If sarcoidosis is suggested by clinical history, the testicular mass must be biopsied to exclude malignancy. Without tissue pathology, a mass cannot be assumed to be sarcoid.

Question 17

What is the most common extratesticular neoplasm overall?

What is the most common epididymal neoplasm?

Answer 17

• Spermatic cord lipoma is the most common extratesticular neoplasm overall.
• Benign adenomatoid tumor of the tunica albuginea is the most common epididymal neoplasm.

Question 18

What is a testiclar hydrocele and its cuauses? What about a hematocele?

Answer 18

• A hydrocele is an excess of fluid in the scrotum surrounding the testicle. most are asymptomatic. d
• A hydrocele may be congenital (due to patent processus vaginalis in utero or infancy), idiopathic, or post-inflammatory.
• Regardless of etiology, there is never fluid at the bare arrea where the testicle is attached to the tunica vaginalis.
• Hematocele is blood in the scrotum due to trauma or torsion.

Question 19

What is a varicocele? What can it cause?

Answer 19

• A varicocele is a dilated venous pampiniform plexus in the scrotum. A primary varicocele is due to incompetent valves of the internal spermatic vein. A secondary varicocele is due to increased venous pressure caused by an obstructing lesion.​
• Varicocele is a common cause of infertility, seen in up to 40% of males presenting to an infertility clinic.

Question 20

US appearance of a varicocele

Answer 20

• On ultrasound, varicoceles appear as multiple tubular and serpentine anechoic structures >2 mm in diameter in the region of the upper pole of the testis and epididymal head. The varicoceles follow the spermatic cord into the inguinal canal and can be compressed by the transducer. Careful optimization of Doppler parameters shows the slow venous flow within the varicocele.

Question 21

Which side or varicoceles more common and why?

A _____-sided vacicocele is associated with what neoplasm?

An isolated right-sided varicoele should prompt what?

Answer 21

• Varicoceles are much more common on the left as the left testicular vein drains into the left renal vein and the superior mesenteric artery can compress the left renal vein.
• Left-sided varicocele is Associated with left-sided RCC because it RCC often invades renal vv.
• In contrast, the right testicular vein drains directly into the infrarenal IVC.
• 85% of varicoceles are left-sided and 15% are bilateral. An isolated right-sided varicocele should prompt a search for a right-sided retroperitoneal mass.

Question 22

What is an epididymal cyst?

What about a spermatocele and its common location and classic US appearance?

Answer 22

• An epididymal cyst is an anechoic fluid-containing cyst that can occur anywhere in the epididymis.
• A spermatocele is cystic dilation of the epididymis filled with spermatozoa, usually occurring in the epididymal head. Classic ultrasound appearance is an epididymal cyst with internal low-level mobile echoes.
• A simple epididymal cyst and a spermatocele cannot always be reliably distinguished by ultrasound.

Question 23

What is tubular ectasia of the rete testis? Cause? Accompanied with?

More common in what population and which side?

US appearance? Confirmatory test?

Treatment?

Answer 23

• Tubular ectasia of the rete testis is nonpalpable, asymptomatic, cystic dilation of the tubules at the mediastinum testes caused by epididymal obstruction.
• Tubular ectasia is often accompanied by an epididymal cyst or spermatocele.
• Tubular ectasia of the rete testis is common in older patients and may be bilateral.
• Imaging shows numerous tiny dilated structures in the region of the mediastinum testis and to confirm a sagittal US will show elongation of the cystic dilation.
• Important to be aware of only as a tumor mimic. Tubular ectasia is benign and no treatment is necessary.

Question 24

What is a simple testicular cyst and what is the US appearance?

Answer 24

• A simple testicular cyst meets sonographic criteria for a simple cyst (smooth posterior wall, imperceptible wall thickness, completely anechoic, posterior through transmission).

Question 25

What is a tunical cyst, how does it present, US appearance and treatment?

Answer 25

* The tunica albuginea is the capsule overlying the testis. * A cyst of the tunica albuginea **presents as a palpable superficial nodule that resembles a BB**. * Sonography shows a typical **small, simple, extra-testicular cyst**. * No treatment is necessary.

Question 26

What is a testicular torsion, prognosis, and what deformity predisposes to torsion?

Answer 26

* Testicular torsion is twisting of the testicle around the spermatic cord and the vascular pedicle. Torsion presents with acute scrotal pain and is a surgical emergency. * Torsion may lead to **irreversible testicular infarction** if not de-torsed within a few hours. * De-torsion within 6 hours has an excellent prognosis. * De-torsion after 24 hours has a poor prognosis for testicular salvage. * The **bell-clapper deformity** (failure of normal posterior anchoring of the gubernaculum) predisposes to torsion due to a small testicular bare area. The bare area is the testicular attachment site and normally prevents the testicle from rotation.

Question 27

What are the time elapsed US findings of testicular torsion?

Answer 27

* **Hyperacute** (within a few hours): Ultrasound shows a hyperechoic and shadowing torsion knot of twisted epididymis and spermatic cord, with **no blood flow in the affected testicle.** * **Acute** (between a few hours and 24 hours): Affected testicle is enlarged and heterogeneous. * **Missed torsion** (\>24 hours): Affected testicle is **enlarged and mottled, with scrotal skin thickening and increased flow in the scrotal wall**. A complex or septated hydrocele may be present.

Question 28

What is segmental infarction of the testis? What can cause it? What age group? Presentation? US appearance? What is the primary DDx?

Answer 28

* Segmental infarction is a focal testicular infarction that can be due to **microvascular thrombosis from acute inflammation, vasculitis, or sickle cell disease.** * Patients are typically in their **30s and present with acute pain which may mimic epididymitis or torsion clinically**. * The typical appearance of infarction is a **wedge-shaped hypoechoic area with no flow on doppler**. * The primary **differential consideration of infarction is a hypovascular tumor.** Infarcted tissue may undergo necrosis, making differentiation from tumor even more difficult. * MRI may be helpful to distinguish infarction from a tumor in ambiguous cases to potentially spare the patient from orchiectomy.

Question 29

What is the US appearance of an acute scrotal hematoma?

Answer 29

* US appearance of acute scrotal hematoma is an echogenic, extratesticular mass with no Doppler flow. When large, the hematoma can compress the testicle. * When the hematoma evolves into a complex, multiseptated mass-like lesion, the distinction between the extratesticular hematoma and the testicle may become difficult. * Proper distinction is necessary to avoid mistaking the hematoma for a testicular mass.

Question 30

What is the US appearance of testicular contusion?

Answer 30

* Testicular contusion produces a **peripheral, hypoechoic lesion that may mimic** **tumor****.** * Even with a history of trauma, a suspicious testicular lesion requires further evaluation to exclude malignancy, typically with a short-term follow-up.

Question 31

What is testicular rupture? Management? Fertility issues? If so, why?

Answer 31

* Testicular rupture causes capsule disruption, often with protrusion of testicular parenchyma through the defect. Rupture is often associated with a testicular hematoma or contusion. * **Prompt diagnosis is critical**, as testicular viability is dependent upon timely repacking of the seminiferous tubules back inside the capsule. * Testicular rupture results in disruption of the blood-testis barrier and may be associated with future infertility due to the **formation of anti-spermatozoa antibodies.**

Question 32

What is Fournier gangrene? Etiology? Key imaging finding?

Answer 32

* Fournier gangrene is necrotizing fasciitis of the scrotum and perineum, a highly morbid and surgically emergent condition. * Infection is usually polymicrobial. * The key imaging finding is **subcutaneous gas, which appears on ultrasound as multiple echogenic reflectors in the subcutaneous tissues with dirty shadowing**.

Question 33

What is epididymitis and in what setting is it almost always found in? Clinical presentation? Name the main differential and contrast it to epididymitis. Name the Key US finding.

Answer 33

* Epididymitis is an infection of the epididymis, almost always ascending from the urinary tract. * The classic clinical presentation of epididymitis is acute unilateral scrotal pain. * The main differential based on clinical presentation is testicular torsion. In contrast to torsion, **epididymitis features normal testicular blood flow.** * A key ultrasound finding of epididymitis is an enlarged epididymis with increased doppler flow relative to the testicle (normally, the epididymis has less doppler flow than the testicle). An associated hydrocele may be present, which often contains low-level echoes.

Question 34

What is epidiymo-orchitis? US appearance? What is a risk factor for?

Answer 34

* Epididymo-orchitis is an infection that has spread from the epididymis to the testicle. * Epididymo-orchitis has a similar ultrasound appearance to epididymitis, but blood flow to the testicle will also be increased. * Infection and secondary inflammation can cause venous hypertension, which is a risk factor for focal testicular ischemia.