Diagnostic Ultrasound - Abdomen and Pelvis

Decreased Testicular Size
Differential Diagnoses: Scrotum
DIFFERENTIAL DIAGNOSIS
Common
• Testicular Infarction
• Scrotal Trauma
• Chronic Mass Effect
• Undescended Testis
Rare but Important
• Hypogonadism
• Polyorchidism
ESSENTIAL INFORMATION
Key Differential Diagnosis Issues
• Consider testicular atrophy if combined axis measurements
of testes differ by ≥ 10 mm, or if testicular size < 4 x 2 cm
• Reduction in size considered significant if volume of
affected testis reduced to 50% of unaffected testis
• Critical to identify viability of testis to determine whether
orchiopexy or orchiectomy is needed
Helpful Clues for Common Diagnoses
• Testicular Infarction
○ Ischemic orchitis is known complication of inguinal hernia
surgery
○ Epididymoorchitis may result from severe
inflammation/induration of cord
– Venous infarction is a rare complication of orchitis
○ Missed torsion: In utero cord torsion (45%), or may
present later in life
○ Uniformly hypoechoic or focal mixed echogenicity of
testis, (or striated appearance) with absence of flow are
features of diffuse or focal infarction, respectively
– Reduced echogenicity is sensitive marker of poor
outcome compared to clinical parameters
• Scrotal Trauma
○ Acute testicular hematoma may lead to
ischemia/infarction of viable parenchyma due to raised
intratesticular pressure
– Resorption of nonviable testicular tissue leads to
atrophy or scarring
• Chronic Mass Effect
○ Longstanding extratesticular mass or hydrocele may
compromise testicular blood flow and result in atrophy
• Undescended Testis
○ Exhibits different degrees of atrophy with altered
parenchymal echogenicity
– Less echogenic and smaller than normally descended
testis
○ Testes < 1 cm often not detected by US
Helpful Clues for Rare Diagnoses
• Hypogonadism
○ Pituitary neoplasm, Kallmann syndrome,
hypogonadotrophic hypogonadism
○ Diffuse heterogeneous echogenicity
• Polyorchidism
○ Supernumerary or duplicated testis
– Tunica albuginea surrounds and separates bifid testis
– Epididymis may also duplicate
– Homogeneously echogenic oval structure with
echogenicity identical to that of normal testis, but
smaller in size
SELECTED REFERENCES
1. Loberant N et al: Striated appearance of the testes. Ultrasound Q. 26(1):37-
44, 2010
2. Patel SR et al: Prevalence of testicular size discrepancy in infertile men with
and without varicoceles. Urology. 75(3):566-8, 2010
3. Chu L et al: Testicular infarction as a sequela of inguinal hernia repair. Can J
Urol. 16(6):4953-4, 2009
4. Bhatt S et al: Role of US in testicular and scrotal trauma. Radiographics.
28(6):1617-29, 2008
5. Pinto KJ et al: Varicocele related testicular atrophy and its predictive effect
upon fertility. J Urol. 152(2 Pt 2):788-90, 1994
6. Desai KM et al: Fate of the testis following epididymitis: a clinical and
ultrasound study. J R Soc Med. 79(9):515-9, 1986
(Left) Transverse color and
spectral Doppler view of
bilateral testes shows the
right testicle is atrophic
and hypoechoic compared to
the left testicle in a 35-yearold
male with prior history of
right epididymoorchitis.
(Right) Sagittal color Doppler
ultrasound in a 8-year-old boy
with tenderness in his right
suprapubic region
demonstrates an avascular
hypoechoic small undescended
testis . Patients who have
an undescended testis have an
increased risk of development
of seminoma.
Testicular Infarction
Undescended Testis
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