What is the management plan for constitutional small testes (microorchidism)?

Management of Constitutional Small Testes (Microorchidism)

Constitutional small testes require comprehensive evaluation to distinguish benign variants from pathological conditions, with management focused on assessing fertility potential, hormonal function, and cancer risk through testicular volume measurement, hormonal testing, and selective use of scrotal ultrasound in specific clinical scenarios.

Initial Assessment and Testicular Volume Measurement

• Measure testicular volume using a Prader orchidometer as the primary assessment tool, which is cost-effective and correlates well with ultrasound measurements 1
• Define testicular atrophy/microorchidism as testicular volume <12 ml or a size difference >2 ml (or >20%) compared to the contralateral testis 2
• Perform scrotal ultrasound selectively in cases where physical examination is difficult or unreliable, including: large hydrocele, thickened scrotal skin, epididymal enlargement disproportionate to testicular volume, or when testicular architecture assessment is needed 1

Hormonal and Fertility Evaluation

• Obtain comprehensive hormonal testing including: total testosterone, LH, FSH, and inhibin B to assess both Leydig cell and Sertoli cell function 3
• Order semen analysis in men of reproductive age to evaluate fertility potential 1
• Consider anti-müllerian hormone (AMH) measurement as an additional marker of Sertoli cell function, particularly if bilateral small testes raise concern for testicular dysgenesis 1

Cancer Risk Stratification and Surveillance

• Recognize that men with small testes (<12 ml) and infertility have significantly elevated testicular cancer risk (pooled OR 1.91 for infertile men; hazard ratio 11.9 for oligozoospermic men) 1
• Perform testicular biopsy to exclude germ cell neoplasia in situ (GCNIS) in high-risk patients, specifically those with: history of cryptorchidism, bilateral testicular microcalcifications, atrophic testes (<12 ml), or infertility 1, 2
• Counsel all patients with small testes to perform regular testicular self-examinations for early cancer detection, regardless of other risk factors 1, 2

Management Based on Underlying Etiology

If History of Cryptorchidism:

• Men with unilateral small testis from cryptorchidism and normal contralateral function should be offered orchidectomy due to 3.6-7.4 times higher cancer risk 1, 2
• For bilateral small testes with impaired hormonal function or fertility, orchiopexy may be considered if technically feasible, with mandatory biopsy for GCNIS 1
• Provide counseling that paternity rates are near-normal with unilateral cryptorchidism but reduced to 35-53% with bilateral cryptorchidism 1

If Constitutional (No Cryptorchidism History):

• Monitor hormonal function longitudinally with serial testosterone, LH, and FSH measurements 3
• Initiate testosterone replacement therapy if biochemical hypogonadism develops (low testosterone with elevated LH/FSH) 2
• Discuss fertility preservation options including sperm cryopreservation before any planned surgical intervention 1

Imaging Considerations and Pitfalls

• Do not routinely perform ultrasound screening in all men with small testes, as this may lead to overdiagnosis of incidental findings requiring unnecessary surveillance 1
• Reserve ultrasound for assessment of testicular architecture (homogeneity, microcalcifications), tumor detection in high-risk patients, or when physical examination is inadequate 1
• Avoid ultrasound as a screening tool in isolation—always combine with clinical context, hormonal evaluation, and cancer risk assessment 1

Long-Term Surveillance Strategy

• Establish regular follow-up with monitoring of: testicular volume changes, hormonal function (annually or biannually), and development of masses 2, 3
• Screen for hypogonadism symptoms including decreased libido, erectile dysfunction, fatigue, and loss of muscle mass 3
• Provide comprehensive counseling regarding: increased infertility risk, elevated testicular cancer risk (even without cryptorchidism history if severe oligozoospermia present), and importance of self-examination 1, 2

Critical Pitfalls to Avoid

• Never dismiss bilateral small testes without hormonal evaluation and consideration of disorders of sex development, particularly in young males 1
• Do not delay cancer risk assessment in men with small testes and infertility—this population requires proactive surveillance 1
• Avoid hormonal therapy (GnRH or hCG) to increase testicular size in adults, as evidence demonstrates poor success rates 1
• Do not perform testicular biopsy, serial ultrasounds, or tumor markers in isolated testicular microcalcifications without additional risk factors 1