Should I be concerned about a slightly smaller left testis (testicle) reported by the sonographer (ultrasound technician)?

Slightly Smaller Left Testis: Clinical Significance

A slightly smaller left testis identified on ultrasound warrants clinical correlation with physical examination and consideration of additional evaluation, but is not automatically concerning if the size difference is minimal (<2 mL or <20%) and there are no other abnormal findings. 1

Key Considerations for Assessment

Normal Testicular Asymmetry

• Mild asymmetry between testes is common and often physiologically normal, particularly when the difference is small and both testes are within normal volume range (12-30 mL). 1
• Physical examination with a Prader orchidometer provides a good surrogate for ultrasound volume measurement and is cost-effective for routine assessment. 1

When Size Difference Becomes Clinically Significant

A persistent testicular size difference >2 mL or >20% requires further evaluation and monitoring, particularly in the following contexts: 1

• Adolescents or young men: This degree of asymmetry may indicate underlying pathology such as varicocele, which should be treated if confirmed on two visits 6 months apart. 1
• History of cryptorchidism: Even unilateral undescended testis can affect the contralateral descended testis, resulting in smaller volume and structural abnormalities. 1
• Infertility concerns: Smaller testicular volume may indicate impaired spermatogenesis and warrants hormonal evaluation. 1

Critical Red Flags Requiring Immediate Action

Testicular Mass or Structural Abnormalities

Scrotal ultrasound plays a crucial role in detecting testicular tumors, for which infertile males and those with testicular abnormalities are at higher risk. 1

• Any solid hypoechoic mass with vascular flow is highly suggestive of malignancy and requires urgent urological referral. 1
• Non-homogeneous testicular architecture or microcalcifications may indicate testicular dysgenesis or increased cancer risk. 1
• Men with cryptorchidism history have 3.6-7.4 times higher risk of testicular cancer than the general population. 1

Associated Findings That Change Management

The ultrasound report should be reviewed for: 1

• Varicocele: Prominent pampiniform plexus, particularly if associated with testicular size discrepancy
• Epididymal abnormalities: Enlargement, cystic lesions, or fibrosis suggesting obstruction
• Rete testis dilation: Indirect sign of obstruction
• Microcalcifications: In isolation without mass and no risk factors, does not require further evaluation 1

Recommended Clinical Approach

Immediate Steps

1. Correlate ultrasound findings with physical examination: Palpate both testes, assess consistency, and evaluate for masses or varicocele. 1
2. Quantify the size difference: Determine if the discrepancy is >2 mL or >20%, which is the threshold for clinical significance. 1
3. Review for additional ultrasound findings: Assess for masses, structural abnormalities, or signs of obstruction. 1

When to Pursue Further Evaluation

Additional workup is indicated if: 1

• Size difference is >2 mL or >20% and persistent on repeat examination
• Any solid mass or suspicious lesion is present
• Patient has infertility concerns or abnormal semen parameters
• History of cryptorchidism, testicular trauma, or family history of testicular cancer
• Associated symptoms (pain, heaviness, hormonal symptoms)

Follow-Up Strategy

• For minimal size difference (<2 mL) with no other abnormalities: Reassurance and routine self-examination education is appropriate. 1
• For borderline findings: Repeat ultrasound in 6-8 weeks if there is clinical concern but no definitive mass. 1
• For significant asymmetry (>2 mL or >20%): Repeat assessment in 6 months to confirm persistence, which would warrant specialist referral. 1

Common Pitfalls to Avoid

• Do not dismiss testicular asymmetry in the context of infertility: Even mild size reduction may reflect impaired spermatogenesis. 1
• Do not rely solely on imaging for cryptorchidism evaluation: Ultrasound has poor sensitivity (45%) for localizing nonpalpable testes. 1
• Do not assume microcalcifications alone require intervention: Without mass or risk factors, they do not increase cancer risk. 1
• Do not delay evaluation of any palpable or visible mass: Solid testicular masses should be managed as malignant until proven otherwise. 1