What is the recommended diagnostic work‑up for autoimmune orchitis in a man presenting with painless or mildly painful testicular enlargement, gradual loss of testicular volume, or infertility after infectious, traumatic, neoplastic, and hormonal causes have been excluded?

Diagnostic Work-Up for Autoimmune Orchitis

When infectious, traumatic, neoplastic, and hormonal causes have been excluded in a man presenting with painless or mildly painful testicular enlargement, gradual testicular volume loss, or infertility, the diagnostic work-up for autoimmune orchitis should prioritize detection of anti-sperm antibodies (ASA) and testicular biopsy to identify characteristic lymphocytic infiltration patterns.

Clinical Presentation and Classification

Autoimmune orchitis presents in two distinct forms that require different diagnostic approaches:

Primary Autoimmune Orchitis

• Primary autoimmune orchitis is typically asymptomatic and presents with isolated infertility without systemic disease, characterized by ASA in 100% of cases directed against the basement membrane or seminiferous tubules. 1
• The condition manifests as gradual, painless testicular volume loss rather than acute inflammation, making it difficult to diagnose during the active inflammatory stage. 2
• Testicular atrophy develops progressively as the chronic inflammatory process damages the seminiferous epithelium irreversibly. 2

Secondary Autoimmune Orchitis

• Secondary autoimmune orchitis presents with symptomatic orchitis and/or testicular vasculitis associated with systemic autoimmune diseases, particularly vasculitis syndromes. 1
• Patients typically demonstrate testicular pain, erythema, and/or swelling, distinguishing it from the primary form. 1
• ASA are detected in up to 50% of secondary cases, especially in systemic lupus erythematosus patients. 1

Essential Diagnostic Tests

Anti-Sperm Antibody Testing

• Serum ASA testing is the cornerstone non-invasive diagnostic test for autoimmune orchitis, with ASA present in approximately 5-12% of infertile male partners. 3
• ASA cause immobilization and/or agglutination of spermatozoa, blocking sperm-egg interaction and resulting in infertility. 1
• The presence of ASA directed to the basement membrane or seminiferous tubules confirms the autoimmune nature of the orchitis. 1

Testicular Biopsy

• Testicular biopsy is required for definitive diagnosis when non-invasive techniques fail to establish the etiology, as systematic histopathological analyses show a high prevalence of asymptomatic inflammatory reactions in infertile men. 4
• The characteristic histological finding is lymphocytic infiltration surrounding the tubuli recti, which then induces spermatogenic disturbance. 2
• Focal lymphocytic infiltrates correlate with the degree of damage to spermatogenesis and corresponding clinical and endocrinological parameters of testicular function. 4
• Biopsy should be performed when testicular volume is <12 mL with elevated FSH, as this combination warrants exclusion of intratubular germ cell neoplasia in addition to inflammatory processes. 5

Scrotal Ultrasound with Doppler

• Scrotal ultrasound with Doppler is indicated to quantify testicular volume, assess architecture, and rule out masses, with volumes <12 mL considered definitively atrophic. 5
• Ultrasound can identify reactive hydrocele and increased peritesticular blood flow that may accompany inflammatory processes. 6
• High-frequency probes (>10 MHz) should be used to maximize resolution and accurate caliper placement for precise volume assessment. 5

Hormonal Evaluation

• Morning serum FSH, LH, and total testosterone should be drawn between 08:00–10:00 h on at least two separate occasions to obtain reliable baseline values. 5
• Elevated FSH (>7.6 IU/L) in the context of testicular atrophy indicates reduced testicular reserve and impaired spermatogenic capacity. 5, 7
• The LH pattern helps distinguish primary testicular dysfunction (elevated LH) from secondary causes (low or normal LH). 5

Semen Analysis

• At least two semen analyses separated by 2-3 months should be performed, as single analyses can be misleading due to natural variability. 5
• Semen analysis evaluates concentration, motility, morphology, and total count, which collectively reflect testicular function better than any single parameter. 8
• The presence of increased round cells in semen may indicate spermatogenic problems with spermatocytes and/or round spermatids present in the ejaculate. 7

Diagnostic Algorithm

1. Confirm exclusion of other causes:

   • Rule out infectious orchitis with appropriate cultures and serologies
   • Exclude testicular neoplasm with tumor markers (AFP, β-hCG, LDH) and scrotal ultrasound 6
   • Verify normal hormonal function or identify specific patterns of dysfunction 5

2. Perform initial non-invasive testing:

   • Obtain serum ASA testing as the primary screening test 3, 1
   • Conduct scrotal ultrasound with Doppler to assess testicular volume and architecture 5
   • Measure morning FSH, LH, and testosterone on two separate occasions 5
   • Obtain two semen analyses separated by 2-3 months 5

3. Proceed to testicular biopsy if:

   • ASA are positive with unexplained infertility and testicular atrophy 1
   • Testicular volume is <12 mL with elevated FSH (>7.6 IU/L) 5
   • Non-invasive testing is inconclusive but clinical suspicion remains high 4
   • Multiple biopsies should be performed to exclude intratubular germ cell neoplasia when volume is <12 mL 5

Critical Diagnostic Pitfalls

• Chronic asymptomatic inflammations of the testicles are underestimated as a primary cause or cofactor of male fertility disorders because non-invasive diagnostic techniques are not yet widely available. 4
• The majority of patients with testicular autoimmunity have chronic and asymptomatic development of the inflammatory reaction, making diagnosis at the ongoing stage very difficult. 2
• Histopathology of idiopathic spermatogenic disturbance in the clinic may represent the post-active inflammation stage of autoimmune orchitis, when irreversible damage has already occurred. 2
• Testicular biopsy should be considered for infertile men with atrophic testes (<12 mL) and testicular microcalcification, as this combination increases the risk of testicular germ cell tumors. 8

Management Considerations After Diagnosis

• Glucocorticoids and immunosuppressive drugs are indicated in autoimmune orchitis associated with active systemic autoimmune diseases, though there are no standardized treatment options. 3
• Assisted reproductive technologies (intrauterine insemination, in vitro fertilization, and intracytoplasmic sperm injection) are therapeutic options for male infertility associated with ASA. 3
• ICSI is considered the best choice for patients with severe sperm autoimmunity, particularly in males with low semen counts or motility. 3
• Sperm cryopreservation should be performed immediately if any sperm are present in ejaculate, banking 2-3 separate collections to provide insurance against progressive decline. 5