Why is my testicular volume decreasing despite a normal follicle‑stimulating hormone level, normal sperm concentration, and a subclinical left varicocele?

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Testicular Atrophy with Subclinical Varicocele

Direct Answer

Your testicular volume is likely decreasing because the subclinical left varicocele is causing progressive testicular damage, even though it hasn't yet significantly impaired your sperm count or caused symptoms. 1, 2


Understanding Your Current Situation

Your FSH of 9.6 IU/L sits in a critical zone—it's technically within the laboratory reference range but represents borderline testicular dysfunction that warrants investigation. 1, 3 This level indicates your pituitary gland is working harder than normal to maintain sperm production, suggesting reduced testicular reserve even though your sperm count remains adequate at 56 million/mL. 1, 4

The subclinical varicocele is the most likely culprit. Even grade 1 (subclinical) varicoceles can cause:

  • Progressive testicular atrophy over time 2, 5
  • Elevated FSH levels that normalize after surgical repair 5
  • Hormonal alterations including decreased testosterone and elevated gonadotropins 2

Why This Matters Despite Normal Sperm Count

Testicular volume strongly correlates with total sperm count and sperm concentration—volumes below 12 mL are considered atrophic and associated with impaired spermatogenesis. 1, 6 Your current sperm count of 56 million/mL is reassuring, but the shrinking testicular volume combined with borderline-elevated FSH indicates progressive testicular damage is occurring. 1, 5

The absence of symptoms does not rule out varicocele-related damage. Subclinical varicoceles can cause:

  • Chronic oxidative stress to testicular tissue 2
  • Impaired Leydig cell function (testosterone production) 2, 5
  • Decreased Sertoli cell function (sperm production support) 2, 5

Essential Next Steps

1. Complete Hormonal Evaluation

Measure the following between 08:00–10:00 h on two separate occasions: 1, 3

  • LH and total testosterone to distinguish primary testicular failure from secondary causes 1, 4
  • Free testosterone and SHBG if total testosterone is low 1
  • Prolactin to exclude hyperprolactinemia 3

The pattern of these hormones will clarify whether your testes are failing primarily or if there's a hypothalamic-pituitary issue. 1, 4

2. Repeat Semen Analysis

Obtain at least two semen analyses 2–3 months apart after 2–7 days of abstinence to establish whether your parameters are stable or declining. 1, 3 Single analyses are misleading due to natural variability. 4

3. Scrotal Ultrasound

Request high-frequency ultrasound (>10 MHz) with explicit attention to: 1

  • Accurate testicular volume measurement using the Lambert formula (Length × Width × Height × 0.71) 1
  • Varicocele grading and venous reflux assessment 1
  • Exclusion of testicular masses or structural abnormalities 1

4. Address Reversible Factors Before Making Decisions

Before any intervention, optimize: 3

  • Body weight: Obesity impairs the hypothalamic-pituitary-gonadal axis; weight loss can normalize gonadotropins 3
  • Metabolic health: Check for diabetes, thyroid dysfunction, or other metabolic stressors 3
  • Medications: Avoid anabolic steroids or testosterone supplements, which will completely suppress spermatogenesis 1, 4, 3

Varicocele Management Decision

Varicocele repair should be strongly considered given: 1, 4, 5

  • Documented testicular atrophy (volume <12 mL) 1
  • Borderline-elevated FSH suggesting compensatory pituitary response 1, 5
  • Evidence that varicocelectomy can halt progression and potentially reverse damage 5

Expected outcomes from microsurgical varicocelectomy: 5

  • FSH levels decrease significantly (mean reduction from 15.2 to 10.8 mIU/mL in one study) 5
  • Testosterone levels increase (mean increase from 5.6 to 8.4 ng/mL) 5
  • Sperm motility improves significantly 5
  • Testicular volume may stabilize or improve 2, 5

The key is timing—repair is most effective before irreversible testicular injury occurs. 1, 5


Fertility Preservation Strategy

Bank sperm now, before any intervention or further decline: 1, 4

  • Collect 2–3 separate ejaculates with 2–3 days abstinence between collections 4
  • Each collection should be split into multiple vials for staged use 4
  • This provides insurance against technical failures, poor post-thaw recovery, or need for multiple treatment attempts 4

Once azoospermia develops, even microsurgical testicular sperm extraction (micro-TESE) only achieves 40–50% sperm retrieval rates. 1, 4 Banking now—while your count is 56 million/mL—is far superior. 4


Critical Pitfalls to Avoid

Never Start Testosterone Therapy

Exogenous testosterone will completely suppress FSH and LH through negative feedback, causing azoospermia that can take months to years to recover. 1, 4, 3 This applies even if you feel fatigued or have low libido—testosterone replacement is contraindicated if you want to preserve fertility. 1, 4, 3

Don't Delay Genetic Testing If Parameters Worsen

If repeat semen analysis shows sperm concentration <5 million/mL: 1, 4

  • Obtain karyotype analysis to screen for Klinefelter syndrome 1, 4
  • Perform Y-chromosome microdeletion testing (AZFa, AZFb, AZFc regions) 1, 4

Complete AZFa or AZFb deletions predict near-zero sperm retrieval success and would contraindicate testicular sperm extraction. 1, 4

Monitor for Rapid Decline

Repeat semen analysis every 6–12 months to detect early decline in sperm parameters. 1, 4 Risk factors that could accelerate decline include: 4

  • Chemotherapy or radiotherapy (impairs semen quality for up to 2 years) 4
  • Anabolic steroid use (causes complete suppression) 4
  • Uncontrolled metabolic disease 3

Long-Term Surveillance

Given your borderline testicular volume (<12 mL), you have increased cancer risk: 1

  • Men with testicular volume <12 mL and age <30–40 years have ≥34% risk of intratubular germ cell neoplasia if testicular cancer develops 1
  • Perform monthly testicular self-examinations 1
  • Report any palpable masses, rapid testicular atrophy, or new symptoms immediately 1

Size discrepancy between testes >2 mL or 20% warrants ultrasound evaluation to exclude pathology, regardless of absolute volume. 1

References

Guideline

Testicular Size and Volume Measurement

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2026

Research

Varicocele: An Endocrinological Perspective.

Frontiers in reproductive health, 2022

Guideline

Management of Men with Borderline FSH Levels

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2026

Guideline

Non-Obstructive Azoospermia Causes and Diagnosis

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2026

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Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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