Scrotum Review

Malignant Testicular Masses

Symptoms include: painless lump, testicular enlargement, or vague discomfort in scrotum Locations: • Extratesticular masses are usually benign • Intratesticular masses are more likely to be malignant

Anatomy of the scrotum

Testes Epididymis Spermatic Cord • Vas deferens • Testicular Arteries • Venous Pampiniform Plexus • Lymphatics • Nerves • Cremaster muscle fibers

Hydroceles can form in space between the layers of the _____ _____.

Tunica vaginalis • a small bare area is formed at the posterior aspect of the testicle where these is an absence of the tunica vaginalis • fixes testicle to the scrotal wall preventing torsion • blood vessels, lymphatics, nerves, spermatic ducts travel through the bare area to the deep portions of the testicles

Varicocele

An abnormal dilation of veins of pampiniform plexus • diagnosed when diameter of vessels > 2 mm • primary varicoceles usually caused by incompetent venous valves within spermatic vein • more common on the left • sonographic appearance shows numerous tortuous tubes of varying sizes within spermatic cord • vessels increase in diameter with Valsalva maneuver

Testes sonographic appearance

Appears as smooth, medium gray structures with a fine echo texture.

Choriocarcinoma

Complex mass with irregular boarders

Teratoma

Complex mass with well-defined boarders

The cremasteric and deferential arteries accompany the testicular artery within the spermatic cord and branch to form:

Cremasteric artery • provides flow to cremaster muscle and peritesticular tissue Deferential artery • mainly supplies epididymis and vas deferens

Spermatoceles

Cystic dilation of the efferent ductules containing semen - Always located in the epididymal head - Associated with vasectomies

Epididymal cysts

Cystic formation of serous fluid located in the epididymis (hard to differentiate with U/S spermatocele and epihead cyst)

Tunica albuginea cysts

Cystic formation of serous fluid located within the layers of the tunica albuginea

Extratesticular Masses

Cysts Spermatoceles Epididymal cysts Tunica albuginea cysts

Epididymis sonographic appearance

Isoechoic or hypoechoic to testis with a slightly coarser echotexture

Tunica vaginalis

Lines inner walls of scrotum, covering each testis and epididymis. Consists of two layers: • Parietal layer - inner lining of scrotal wall • Visceral layer - surrounds testis and epididymis

Scrotal cysts

Most are extratesticular and located in the tunica albuginea or the epididymis - Patients are usually asymptomatic with a palpable mass

Metastasis to the testicle

Rare • Primary tumor may originate from prostate or kidneys • Metastasis to testicle is often bilateral, with multiple lesions found.

Testes flow chart

Seminiferous Tubules Straight Tubules Rete Testis Efferent Ductules Epididymis Vas Deferens

Appendix of the epididymis

Small protuberance of epididymal tissue from the head of the epididymis • unilateral in 34% of population, bilateral in 12% of population

Appendix testis

Small protuberance of testicular tissue between the head of the epididymis an the testis • unilateral in 92% of population, bilateral in 69% of population

The spermatic cord contains:

Vas deferens Testicular arteries Venous pampiniform plexus Lymphatics Autonomic nerves Fibers of the cremaster muscle

The epididymis contains 10 to 15 efferent ductules from the rete testis, which converge to form single duct in body and tail known as the _____ _____.

ductus epididymis

Each testis divided into conical lobules, each containing the _____ _____.

seminiferous tubules

Each testicle is surrounded by the _____ ______ (a fibrous capsule).

tunica albuginea

The ductus epididymis becomes the ____ _____ as it courses superiorly.

vas deferens (AKA ductus deferens)

Hematoceles

• Collection of blood • Associated with trauma, surgery, neoplasms, or torsion

Pyoceles

• Collection of pus • Associated with prolonged severe infection, or abscess rupture

Hydroceles

• Contain serous fluid • Most common cause of painless scrotal swelling • May be idiopathic • Commonly associated with infection or torsion

Infection of the scrotum

• Epididymitis is an infection of epididymis • Orchitis is an infection of the testicle • Epididymo-orchitis is an infection of the epididymis and testicle • Most commonly results from spread of lower urinary tract infection via spermatic cord • Sonographic Findings: • Enlarged, hyperemic, hypoechoic • Usually unilateral • Scrotal wall thickening • Hydrocele • Pyocele

The seminiferous tubules converge at the apex of each lobule to form the _____ _____ in the mediastinum.

rete testis

Polyorchidism

(aka Testicular Duplication) • Very rare disorder; more common on left side (75%); bilateral in 5% of cases • Increased incidence: malignancy, cryptorchidism, inguinal hernia, torsion with polyorchidism • Duplicated testis: usually small; efferent spermatic system completely absent (no function)

Cryptorchidism

(aka Undescended Testicle) • During fetal growth, testes first appear in retroperitoneum near kidneys • Testes should descend into the scrotum from the inguinal canal shortly before birth or early in neonatal period • May be located in abdomen, inguinal canal, or other ectopic location • Usually found in inguinal canal • Often palpable • Bilateral in 10-25% of cases

Mediastinum

- Testis are covered by a dense, fibrous tissue termed tunica albuginea - Posterior aspect of tunica albuginea reflects into testis to form vertical septum known as mediastinum - Often seen on sonography as a hyperechoic linear structure within the testis coursing craniocaudal

Epididymis

6-7cm tubular structure beginning superiorly and then coursing posterolateral to testis. Divided into: • Head (largest) • Body • Tail

Non-Germ Cell Tumors

Generally benign

Embryonal cell tumors

Hypoechoic with ill-defined boarders • Calcifications • May contain cystic areas

Seminoma

Hypoechoic with well-defined boarders

Germ Cell Tumors

Most common malignancy in men between ages of 15-35 • Good prognosis, one of the most curable forms of cancer • Undescended testes are 6 times more likely to develop cancer • Associated with elevated levels of HCG (human chorionic gonadotropin) and AFP (alpha-fetoprotein) • 95% of all testicular tumors are germ cell and highly malignant • Most common type of germ cell tumor are seminoma, followed by embryonal cell tumors and teratocarcinomas

Sperm Granulomas

Occur as chronic inflammatory reaction to extravasation of spermatozoa • Most frequently seen in patients with history of vasectomy • Well defined and may be located anywhere within epididymis or vas deferens

Bell clapper deformity

Occurs as result of abnormal mobility of testis within scrotum - the most common cause of this condition

Scrotal hernia

When bowel, omentum, or other structures herniate into scrotum • Bowel most commonly herniated structure, followed by omentum • Peristalsis of the bowel confirms the diagnosis • Doppler should be used to rule our incarceration

The rete testis drains into head of epididymis through _____ _____.

efferent ductules

Venous drainage of the scrotum occurs through the veins of the _____ _____, which exits from mediastinum testis and courses in spermatic cord.

pampiniform plexus

Hydrocele, Pyocele, & Hematocele all develop in the potential space between

the visceral and parietal layers of tunica vaginalis

Microlithiasis

• Microcalcifications are < 3 mm • Usually bilateral • Association with testicular malignancy • Associated with cryptorchidism, Klinefelter's syndrome, infertility, varicoceles, testicular atrophy, and male pseudohermaphroditism

Cyst (intratesticular)

• More common in men over 40 years of age • Usually located near mediastinum • Anechoic

Torsion

• Occurs when testis and epididymis twist within scrotum, cutting off the vascular supply to the testis, epididymis, and/or spermatic cord is compromised • Venous flow affected first, causing swelling • If torsion continues, arterial flow obstructed and testicular ischemia follows • Undescended testes are 10 times more likely to torse • Torsion is a true surgical emergency!! • If surgery performed within 5-6 hours of onset of pain, 80-100% of testes can be saved • Between 6 and 12 hours the salvage rate is 70% • After 12 hours only 20% will be saved

Anorchia

• Rare condition • More common on left side • Causes: testicular torsion or other forms of decreased vascular supply to testicle in utero

Tubular Ectasia of the Rete Testis

• Rete testis is located at hilum of testis where mediastinum resides. • Uncommon

Vascular supply

• Right and left testicular arteries arise from the abdominal aorta below the level of the renal arteries. • Testicular arteries course along the posterior aspect of the testis and pierce the tunica albuginea where the become the capsular arteries and branch over the testis • Capsular arteries give rise to centripetal arteries, which course from testicular surface toward mediastinum. • Before reaching the mediastinum, they curve backward forming recurrent rami (centrifugal arteries). • Recurrent rami branch further into arterioles and capillaries. Testicular → Capsular → Centripetal → Recurrent Rami → Arterioles → Capillaries

Testes

• Symmetric, oval-shaped glands residing in the scrotum • Normal testis appear as homogenous with a medium level echotexture

Sonographic Findings of Cryptorchidism

• Undescended testis: smaller and less echogenic than normal testis • Usually oval with homogeneous and isoechoic echotexture

Testicular Ectopia

• Very rare condition • Ectopic testicle cannot be manipulated into correct path of descent • Most common site for ectopic testicle to rest is superficial inguinal pouch