Radiologist's Assessment of "Comfortable Size" Testicles
When a consultant radiologist reports testicles are of "comfortable size," this indicates normal testicular volume that correlates with adequate testicular function and spermatogenesis, typically measuring ≥14-15 mL per testis on ultrasound or orchidometry. 1
What This Assessment Means Clinically
Normal Testicular Volume Parameters
- Normal adult testicular volume ranges from 15-25 mL per testis, with volumes ≥14 mL generally indicating preserved testicular function 2
- Testicular size directly correlates with spermatogenic function, with the strongest correlations seen with follicle-stimulating hormone (FSH) levels, total sperm count, and sperm concentration 2
- Both sperm quantity and quality become impaired when testicular volume falls below 14 mL 2
Clinical Implications of Normal-Sized Testes
In the context of fertility evaluation:
- Normal testicular size suggests obstructive rather than non-obstructive causes if azoospermia is present 3
- Normal-sized testes with normal FSH levels (<7.6 IU/L) typically indicate preserved spermatogenic potential 3
- The presence of normal testicular volume makes primary testicular failure (non-obstructive azoospermia) less likely 3
In the context of general health:
- Normal testicular size indicates adequate Leydig cell function and testosterone production 2
- Rules out conditions associated with testicular atrophy such as Klinefelter syndrome, prior orchitis, testicular torsion, cryptorchidism, or chemotherapy/radiation damage 4, 5
Why Ultrasound Assessment Was Performed
The European Association of Urology identifies specific scenarios where ultrasound measurement is superior to physical examination 1:
- Large hydrocele obscuring palpation 1
- Inguinal testis difficult to assess manually 1
- Epididymal enlargement or fibrosis making orchidometry inaccurate 1
- Thickened scrotal skin preventing accurate palpation 1
- Small testis with proportionally large epididymis requiring precise volume calculation 1
Additional Ultrasound Findings to Consider
Beyond size assessment, the radiologist likely evaluated 1:
- Testicular architecture: Homogeneous echogenicity indicates normal spermatogenesis, while non-homogeneous patterns suggest testicular dysgenesis 1, 3
- Presence of microcalcifications: Associated with 18-fold increased testicular cancer risk in infertile men 1, 3
- Epididymal anatomy: Dilated rete testis or epididymal cysts suggest obstruction 1
- Vascular flow patterns: Color Doppler assessment confirms adequate perfusion 1
Important Clinical Context
A common pitfall: Normal testicular size does not guarantee normal sperm production in all cases, as men with maturation arrest can have normal testicular volume and FSH levels despite severe spermatogenic dysfunction 3. However, this represents a minority of cases.
The reassuring interpretation: "Comfortable size" is radiologist terminology indicating the testicles fall within normal volumetric parameters, suggesting preserved testicular function and ruling out atrophic processes that would compromise fertility or hormonal function 1, 2.