What are the diagnostic steps and treatment options for unilateral testicle atrophy?

Unilateral Testicular Atrophy: Diagnostic and Treatment Approach

Initial Diagnostic Evaluation

For unilateral testicular atrophy, immediately perform a thorough physical examination to determine if the atrophic testis is palpable or nonpalpable, assess for associated conditions (cryptorchidism, varicocele, prior trauma/surgery), and measure testicular volume—but do not routinely order imaging studies as they rarely change management. 1

Key Physical Examination Findings

• Measure testicular volume using an orchidometer, with atrophy defined as testicular volume <12 ml or a size difference >2 ml (or >20%) compared to the contralateral testis 1
• Assess for varicocele on physical examination, as this is the most common reversible cause of testicular atrophy, though testicular size discrepancy alone does not predict fertility outcomes 2
• Evaluate for cryptorchidism history or current undescended position, as these patients have 3.6-7.4 times higher risk of testicular cancer 1, 3
• Document any prior inguinal surgery (hernioplasty, orchiopexy), as surgical trauma to the spermatic cord can cause secondary testicular atrophy from venous thrombosis 4, 5

Laboratory Assessment

• Obtain hormonal evaluation including testosterone, LH, FSH, and inhibin B to assess Leydig and Sertoli cell function and determine if the contralateral testis is functioning normally 1
• Consider anti-Müllerian hormone (AMH) measurement if bilateral atrophy or concern for anorchia exists 1
• Do NOT routinely order scrotal ultrasound, CT, or MRI prior to specialist referral, as imaging has poor sensitivity (45%) and specificity (78%) for testicular evaluation and does not assist in clinical decision-making 1

Risk Stratification for Malignancy

All men with testicular atrophy, particularly those with associated risk factors (cryptorchidism, infertility, testicular volume <12 ml), require testicular biopsy to exclude intratubular germ cell neoplasia in situ (GCNIS). 1

High-Risk Features Requiring Biopsy

• Infertile men with testicular atrophy (<12 ml volume) should undergo testicular biopsy, as they belong to a higher-risk group for GCNIS 1
• History of cryptorchidism with atrophic testis mandates biopsy at the time of any surgical intervention, as these patients have a 2-6% lifetime risk of testicular tumors 1, 3
• Bilateral testicular atrophy or testicular microlithiasis with atrophy warrants biopsy evaluation 1
• Suspicious findings on physical examination require inguinal surgical exploration with testicular biopsy or orchidectomy after multidisciplinary discussion 1

Low-Risk Scenarios

• Do NOT perform testicular biopsy, scrotal ultrasound, tumor markers, or CT imaging in men with isolated testicular atrophy without associated risk factors (no infertility, cryptorchidism, testicular cancer history) 1

Treatment Algorithm

For Unilateral Atrophic Testis with Normal Contralateral Function

Offer orchidectomy to adult men with unilateral testicular atrophy and normal hormonal function/spermatogenesis in the contralateral testis (strong recommendation). 1, 3

• This approach eliminates the 3.6-7.4 times elevated cancer risk associated with atrophic testes 1, 3
• Perform testicular biopsy at the time of orchidectomy to exclude GCNIS if any high-risk features are present 1
• Counsel patients that orchidectomy is preferred over observation when the contralateral testis provides adequate hormonal and reproductive function 1, 3

For Unilateral Atrophic Testis with Impaired Contralateral Function

If the patient has biochemical hypogonadism and/or spermatogenic failure (infertility), consider orchiopexy if technically feasible to preserve androgen production and fertility potential. 1

• This is a weak recommendation and should be individualized based on the degree of testicular dysfunction and patient fertility goals 1
• Multiple biopsies are mandatory at the time of orchiopexy to exclude GCNIS, as this is a prognostic indicator for future testicular germ cell tumor development 1
• Offer sperm cryopreservation before any planned orchidectomy or if oncological therapies are anticipated 1

Special Consideration: Cryptorchidism-Related Atrophy

Do NOT use hormonal treatment (GnRH or hCG) for cryptorchidism in postpubertal men, as evidence shows poor success rates. 1

• For adult men with unilateral undescended/atrophic testis and normal contralateral function, orchidectomy is strongly recommended 1, 3
• For those with bilateral cryptorchidism or impaired contralateral function, orchiopexy may be offered if technically feasible, with mandatory biopsy for GCNIS detection 1

Varicocele-Associated Atrophy

For adolescents with varicocele and persistent testicular size difference >2 ml or >20%, offer surgical varicocelectomy confirmed on two visits 6 months apart. 1

• Do NOT treat varicocele in infertile men who have normal semen analysis or in men with subclinical varicocele 1
• Treat infertile men with clinical varicocele, abnormal semen parameters, and unexplained infertility when the female partner has good ovarian reserve 1
• Note that while varicoceles cause significant testicular atrophy, testicular size discrepancy alone does not reliably predict fertility outcomes 2

Long-Term Surveillance and Counseling

All men with testicular atrophy should perform regular testicular self-examinations and receive counseling about increased cancer risk, even after surgical intervention. 1, 3

• Men with unilateral atrophy typically have near-normal paternity rates if the contralateral testis is healthy 1, 3
• Men with bilateral atrophy have significantly reduced paternity rates of 35-53% and require appropriate fertility counseling 1, 3
• Orchiopexy performed before puberty reduces testicular cancer risk 2-6 fold compared to postpubertal surgery, but risk remains elevated compared to men without cryptorchidism 1, 3

Common Pitfalls to Avoid

• Do not delay referral for imaging studies, as ultrasound and other modalities rarely assist in decision-making and only postpone definitive management 1
• Do not assume isolated testicular atrophy is benign—always assess for associated risk factors that mandate biopsy (cryptorchidism, infertility, volume <12 ml) 1
• Do not overlook the contralateral testis in unilateral cryptorchidism, as it may also have structural abnormalities and reduced fertility markers 1, 6
• Do not attempt hormonal therapy in postpubertal men with cryptorchidism-related atrophy, as it is ineffective 1