What are the indications for a testicular ultrasound in male patients with low testosterone, particularly those of reproductive age with suspected testicular pathology or infertility concerns?

Indications for Testicular Ultrasound

Testicular ultrasound should NOT be routinely ordered in the workup of low testosterone, but is specifically indicated only when physical examination is inadequate or when a testicular mass is suspected. 1

When Ultrasound is NOT Indicated

The standard evaluation of low testosterone relies on hormonal assessment and physical examination alone—imaging is not part of routine workup. 1 This is because:

• Most causes of testosterone deficiency are either secondary (pituitary/hypothalamic) or do not produce structural testicular abnormalities detectable by ultrasound 1
• Testicular pathology severe enough to cause hypogonadism typically presents with palpable abnormalities that can be detected on physical exam 1
• Reflexive ordering of ultrasound wastes resources when hormonal evaluation and physical examination are sufficient 1

Specific Indications for Testicular Ultrasound

Physical Examination Limitations

Ultrasound is indicated when adequate testicular palpation cannot be performed due to: 1

• Obesity preventing adequate palpation
• Scrotal edema or inflammation obscuring examination
• Patient discomfort limiting examination

Suspected Testicular Mass

Any solid testicular mass identified by physical exam or imaging must be managed as malignant until proven otherwise. 2 Ultrasound with Doppler should be obtained for: 2, 1

• Palpable nodule or irregularity
• Asymmetric testicular consistency
• Unexplained testicular enlargement
• Any hypoechoic mass with vascular flow (highly suggestive of malignancy) 2

Infertility Evaluation Context

In men with low testosterone AND infertility concerns, ultrasound may be warranted when: 1

• Abnormal semen analysis is present
• Objective measurement of testicular size is needed
• Varicoceles are suspected but not clearly identified on physical exam

Note that incidental testicular lesions found during infertility evaluation are usually benign, particularly lesions <5mm with negative tumor markers, and may be managed conservatively with serial ultrasound rather than immediate orchiectomy. 3

Essential Physical Examination Components (Before Considering Ultrasound)

A thorough physical exam should assess: 1, 4

• Testicular size, consistency, and presence of masses (usually accomplished by palpation alone)
• Varicocele presence (typically detected clinically)
• Body habitus and virilization status (hair patterns in androgen-dependent areas)
• Gynecomastia (breast tissue examination)

Critical Pitfall to Avoid

The most common error is focusing on testicular imaging when the problem is central (pituitary/hypothalamic). 1 Always measure LH/FSH to distinguish primary from secondary hypogonadism before considering testicular ultrasound—if LH is low or low-normal, the problem is NOT in the testes and ultrasound will not be helpful. 4

Management of Indeterminate Findings

For patients with normal tumor markers (hCG and AFP) and indeterminate findings on physical exam or testicular ultrasound, repeat imaging should be performed in 6-8 weeks rather than proceeding immediately to biopsy or orchiectomy. 2 Up to 50-80% of non-palpable or incidentally detected masses <2cm are not cancerous. 2

What Ultrasound Should NOT Be Used For

• MRI should not be used as the initial evaluation of a testicular lesion suspicious for neoplasm 2
• Testicular microlithiasis alone (>5 small echogenic non-shadowing foci) without solid mass or risk factors does not require further evaluation, as it does not confer increased malignancy risk 2