Is a slightly smaller left testicle (sonographer's report) a concern?

A Slightly Smaller Left Testicle Is Generally Not a Concern

A slightly smaller left testicle reported on ultrasound is typically a normal anatomical variant and does not require intervention unless specific risk factors or pathological features are present. 1

Normal Anatomical Variation

• Mild asymmetry between testicles is common and physiologically normal in most men 1
• The key distinction is whether the testis is "slightly smaller" versus truly atrophic (defined as <12 mL volume) 2, 3
• A slightly smaller testis with normal vascularity on Doppler and homogeneous internal architecture is reassuring and does not indicate permanent infertility or dysfunction 1

When Size Difference Becomes Clinically Significant

The following thresholds and features determine if further evaluation is needed:

Volume-Based Criteria

• Testicular volumes <12 mL are considered atrophic and warrant further investigation 2, 3, 4
• In adolescents with varicocele, size differences >2 mL or 20% between testicles require intervention 2
• Volumes <12 mL are associated with >34% risk of intratubular germ cell neoplasia and impaired spermatogenesis 3

Ultrasound Architecture Features That Indicate Pathology

• Non-homogeneous testicular architecture (coarse, nodular patterns) represents testicular dysgenesis and irreversible damage 1
• Reduced blood flow on Doppler assessment suggests dysfunction 1
• Testicular microcalcifications (>5 small echogenic non-shadowing foci) increase cancer risk 18-fold and correlate with spermatogenic dysfunction 2, 1

Risk Factors Requiring Further Workup

If any of the following are present, additional evaluation is indicated:

• History of cryptorchidism (undescended testicle) - even after surgical correction, these testicles remain at higher risk for atrophy, infertility, and malignancy 2, 4, 5
• Infertility concerns - testicular biopsy should be offered to infertile men with testicular microcalcifications and atrophic testes 2
• Personal or family history of testicular cancer 2, 5
• Presence of a solid mass - any solid mass must be managed as malignant until proven otherwise 2

Recommended Next Steps

If No Risk Factors Present

• No further imaging, tumor markers, or testicular biopsy is needed for isolated mild size asymmetry without risk factors 2
• Teach testicular self-examination for early cancer detection 2, 5
• Routine clinical follow-up is sufficient 2

If Risk Factors Are Present

• Obtain serum FSH and testosterone levels - FSH >7.6 IU/L with atrophy indicates spermatogenic failure 4
• Perform two properly collected semen analyses at least one month apart if fertility is a concern 1
• Consider testicular biopsy if volume is <12 mL with additional risk factors (infertility, cryptorchidism history, testicular microcalcifications) 2
• Genetic testing (karyotype and Y-chromosome microdeletion) if severe oligospermia or azoospermia is documented 4

Common Pitfalls to Avoid

• Do not order routine follow-up ultrasounds for isolated mild asymmetry without risk factors - this leads to unnecessary anxiety and cost 2
• Do not assume size alone predicts fertility - men with unilateral cryptorchidism (often resulting in smaller affected testis) have paternity rates nearly equivalent to normal men 1
• Do not confuse testicular microlithiasis with microcalcifications - isolated microlithiasis without solid mass or risk factors does not require further evaluation 2