Testicular Atrophy and Semen Analysis Detection
Yes, testicular atrophy would almost certainly show abnormalities in a semen analysis performed today, though the specific findings depend on the severity and cause of the atrophy. 1, 2
Understanding the Relationship Between Testicular Atrophy and Semen Parameters
Testicular atrophy directly impairs spermatogenesis, resulting in measurable abnormalities on semen analysis. The severity of semen parameter abnormalities correlates with the degree of testicular volume reduction. 3
Expected Semen Analysis Findings
Men with testicular atrophy typically demonstrate significantly reduced total motile sperm counts compared to those with normal testicular volumes, with mean counts of 80 million versus 126 million sperm in men without atrophy. 3
Severe testicular atrophy (volumes ≤2 mL) is associated with non-obstructive azoospermia in the majority of cases, characterized by complete absence of sperm in the ejaculate even after centrifugation. 1, 2, 4
Moderate testicular atrophy (volumes <12 mL but >2 mL) typically presents with oligospermia (reduced sperm concentration), though some men may have azoospermia depending on the underlying cause. 1, 5
Hormonal Markers That Accompany Testicular Atrophy
Elevated FSH levels (>7.6 IU/L) are the hallmark hormonal finding in men with testicular atrophy, reflecting the pituitary's compensatory response to impaired spermatogenesis. 1, 2
FSH levels are negatively correlated with the number of spermatogonia, meaning higher FSH indicates fewer sperm-producing cells and worse semen parameters. 2
The combination of testicular atrophy on physical examination plus elevated FSH strongly suggests non-obstructive azoospermia due to primary testicular dysfunction. 1, 2
Critical Clinical Caveats
Not All Atrophied Testes Are Completely Non-Functional
Even men with severe testicular atrophy (≤2 mL volume) and markedly elevated FSH can have retrievable sperm in approximately 30-56% of cases. 6, 4
Research demonstrates that 30% of men with azoospermia, testicular atrophy, and FSH levels ≥3 times normal had mature sperm identified on testicular biopsy, most commonly showing severe hypospermatogenesis rather than complete Sertoli-cell-only pattern. 6
Microdissection testicular sperm extraction (micro-TESE) achieves 55-56% sperm retrieval rates even in men with testicular volumes ≤2 mL, with success rates comparable to men with larger testes. 4
Younger men with Klinefelter syndrome and severe testicular atrophy have the highest sperm retrieval rates (81.8% in men <30 years), while older men without Klinefelter syndrome have lower success (33%). 4
FSH Levels Cannot Definitively Predict Sperm Presence
FSH levels alone cannot determine whether sperm production is completely absent, as men with maturation arrest can have normal FSH despite severe spermatogenic dysfunction. 1, 2
Diagnostic Algorithm for Testicular Atrophy
Initial Assessment
Perform at least two semen analyses at least one month apart to confirm azoospermia or quantify oligospermia, with 2-3 days abstinence before collection. 1
Centrifuge the ejaculate and examine the pellet under microscopy for rare sperm, as this identifies motile or non-motile sperm in 18-23% of men initially diagnosed with azoospermia. 1
Measure serum FSH and testosterone levels as the primary hormonal assessment to distinguish obstructive from non-obstructive causes. 1, 2
Physical Examination Findings
Assess testicular size using Prader orchidometer or ultrasound, as volumes <12 mL are considered atrophic and strongly correlate with impaired spermatogenesis. 1, 5
Evaluate for varicocele, as testicular hypotrophy associated with varicocele indicates worse semen parameters and may be surgically correctable. 7, 3
Genetic Testing Indications
Obtain karyotype analysis for all men with azoospermia or severe oligospermia (<5 million/mL) to exclude Klinefelter syndrome and chromosomal abnormalities. 1, 2
Perform Y-chromosome microdeletion testing (AZFa, AZFb, AZFc regions) for men with sperm concentration <1 million/mL, as complete AZFa and AZFb deletions have near-zero sperm retrieval potential. 1, 2
Causes of Testicular Atrophy Affecting Semen Analysis
Acquired Causes
Testicular torsion with salvage results in testicular atrophy in approximately 47% of cases on long-term follow-up, with negative impact on serum testosterone but variable effects on semen parameters. 8
Varicocele-associated testicular hypotrophy occurs in 50% of men with unilateral varicoceles and is associated with significantly reduced total motile sperm counts. 3
Post-chemotherapy or radiation therapy can cause testicular atrophy, though spermatogenesis may recover 1-4 years after treatment in some cases. 7
Congenital and Genetic Causes
Klinefelter syndrome (47,XXY) is the most common chromosomal cause of testicular atrophy and non-obstructive azoospermia, with 72.6% prevalence among men with testicular volumes ≤2 mL. 4
History of cryptorchidism is associated with smaller testicular volumes and impaired spermatogenesis, even after orchiopexy. 7, 9
Bottom Line for Clinical Practice
If a patient has clinically apparent testicular atrophy, expect abnormal semen analysis results ranging from oligospermia to azoospermia. However, the absence of sperm in the ejaculate does not mean complete absence of spermatogenesis—testicular sperm extraction may still retrieve viable sperm for assisted reproduction in 30-56% of cases, particularly in younger men. 6, 4