Diagnostic Ultrasound - Abdomen and Pelvis

Focal Extratesticular Mass
1018
Differential Diagnoses: Scrotum
DIFFERENTIAL DIAGNOSIS
Common
• Epididymitis
• Spermatocele
• Epididymal Cyst
• Varicocele
• Spermatic Cord Torsion
Less Common
• Hematoma
• Adenomatoid Tumor
• Inguinal Hernia
• Fatty Deposition
• Encysted Hydrocele of Cord
• Papillary Cystadenoma
• Lipoma
• Epididymal/Scrotal Wall Abscess
• Fibrous Pseudotumor
• Leiomyoma
Rare but Important
• Sarcoidosis
• Rare Tumors
○ Liposarcoma of Spermatic Cord
○ Sclerosing Lipogranuloma
○ Leiomyosarcoma
○ Malignant Schwannoma
○ Epididymal Rhabdomyosarcoma
• Metastases
• Tuberculous Epididymitis
• Funiculitis
• Vasitis
ESSENTIAL INFORMATION
Key Differential Diagnosis Issues
• Diagnosis based on combination of clinical and sonographic
features
• Acute pain
○ Epididymitis
○ Hematoma
○ Torsion
○ Strangulated inguinoscrotal hernia
• Chronic pain
○ Varicocele
○ Tumors
• Incidental finding
○ Epididymal cyst
○ Spermatocele
Helpful Clues for Common Diagnoses
• Epididymitis
○ Most common cause of acutely painful scrotum
○ Hyperemic epididymis &/or testis on color Doppler
ultrasound
– Compare with contralateral side
– Epididymis appears hypervascular compared to
adjacent testicle
○ Acute epididymitis
– Enlarged, heterogeneous, predominantly hypoechoic
epididymis
– Reactive thickening of scrotal wall ± hydrocele
– Urinary tract pathogens typical in older men
– STDs in younger men
○ Chronic epididymitis
– Granulomatous infection caused by tuberculosis,
brucellosis, syphilis, and fungal infection
– Usually bilateral involvement
– Enlarged epididymis with heterogeneous appearance,
ranging from hypoechoic to hyperechoic, ±
calcification
• Spermatocele
○ Size: 1-2 cm, may be very large
○ Retention cyst of tubules connecting rete testis to head
of epididymis
– Obstruction and dilatation of efferent ductal system
– Usually seen in individuals with previous vasectomy
○ Appearance
– Cystic with low-level mobile internal echoes
– Contain nonviable sperm
– Rarely spermatoceles may be hyperechoic
– Large spermatoceles may have internal septations
– Acoustic streaming of low level internal echoes:
Falling snow sign on color Doppler sonography
• Epididymal Cyst
○ Usually ≤ 1 cm
○ Well-defined anechoic lesion with posterior acoustic
enhancement
○ Large cysts (true cysts or spermatocele) may have
septation and may be confused with hydroceles
– Cysts displace testis, while hydrocele envelop it
• Varicocele
○ Dilatation of veins of pampiniform plexus > 3 mm in
diameter due to reflux in internal spermatic vein
○ Best imaging tool: Color Doppler US
– Dilated serpiginous veins behind superior pole of
testis
– Veins enlarge with Valsalva maneuver
• Spermatic Cord Torsion
○ Twisting of testicle and spermatic cord within scrotum
leads to testicular ischemia and infarction
○ Twisted spermatic cord cranial to testis and epididymis
often becomes edematous and mass-like, which can
appear as extratesticular torsion knot with whirlpool
appearance
– Surgical emergency requiring emergent reduction to
preserve viable testis
Helpful Clues for Less Common Diagnoses
• Hematoma
○ Associated with trauma, torsion
○ Complex echogenic fluid with layering debris ± internal
septation; varies with chronicity
○ Must confirm intact testicular vascularity as enlarging
hematoma may compress testicular vessels
○ Carefully evaluate tunical albungina of testicle for
associated testicular rupture (surgical emergency)
• Adenomatoid Tumor
○ Most common tumor of epididymis
– 1/3 of all paratesticular neoplasms