How to differentiate testicular cancer from benign lesions like hydrocele and varicocele on physical examination?

Differentiating Testicular Cancer from Benign Lesions on Physical Examination

Any solid mass in the testis identified by physical exam should be managed as a malignant neoplasm until proven otherwise, and requires prompt evaluation with scrotal ultrasound and serum tumor markers. 1

Key Physical Examination Findings

Testicular Cancer

• Typically presents as a painless, firm, solid intratesticular mass
• Usually unilateral
• Non-transilluminating
• Fixed within the testis
• May have irregular contour or nodularity
• Often discovered incidentally

Hydrocele

• Fluid collection around the testis
• Smooth, fluctuant swelling
• Transilluminates (key distinguishing feature)
• Testis usually palpable separately from the fluid collection
• Can encircle the entire testis
• Usually painless unless very large

Varicocele

• Dilated veins of the pampiniform plexus
• Described as a "bag of worms" on palpation
• Usually left-sided (90% of cases)
• Becomes more prominent when standing and with Valsalva maneuver
• Typically decreases in size when supine
• May be associated with a dragging sensation

Diagnostic Algorithm

1. Initial Assessment:

   • Palpate both testes systematically in standing and supine positions
   • Assess for masses, nodules, or asymmetry
   • Perform transillumination test (hydroceles will transilluminate)
   • Check for "bag of worms" sensation and changes with position/Valsalva (varicocele)

2. When to Suspect Cancer:

   • Any solid intratesticular mass
   • Non-transilluminating mass
   • Fixed mass within testicular parenchyma
   • Irregular or nodular texture

3. Confirmatory Testing:

   • Scrotal ultrasound with Doppler is mandatory for any suspicious mass 1
   • Serum tumor markers (AFP, β-hCG, LDH) should be obtained 1

Ultrasound Characteristics

• Testicular Cancer: Hypoechoic mass with increased vascularity on Doppler 1
• Hydrocele: Anechoic fluid collection surrounding the testis 1
• Varicocele: Multiple anechoic serpentine structures that enlarge with Valsalva 1

Important Caveats

• Physical examination alone cannot definitively distinguish between benign and malignant lesions
• Approximately 50-80% of non-palpable or incidentally detected masses <2 cm are not cancerous 1
• Some testicular tumors may present with a "complex hydrocele" appearance on ultrasound 2
• Testicular microlithiasis alone without a mass does not require further evaluation unless other risk factors are present 1
• Never perform scrotal exploration or biopsy of a suspected testicular tumor; the inguinal approach is required 1

Red Flags Requiring Immediate Attention

• Sudden onset of scrotal pain (consider testicular torsion)
• Rapid growth of a scrotal mass
• Presence of gynecomastia (may indicate β-hCG producing tumors) 1
• History of cryptorchidism (increased risk of testicular cancer)
• Firm, non-tender testicular mass (highly suspicious for malignancy)

Remember that while physical examination is important for initial assessment, scrotal ultrasound with Doppler is the definitive imaging modality for distinguishing between testicular cancer and benign conditions, with nearly 100% sensitivity for detecting intrascrotal masses 1.