What is the workup for scrotal and penile swelling without pain?

Workup for Scrotal and Penile Swelling Without Pain

Ultrasound duplex Doppler of the scrotum is the first-line diagnostic test for evaluating painless scrotal and penile swelling to differentiate between benign and potentially serious conditions. 1

Initial Diagnostic Approach

Imaging

• Ultrasound Duplex Doppler: Gold standard initial imaging
  • Includes both grayscale and Doppler examination of bilateral scrotal and inguinal areas
  • Sensitivity of 96-100% and specificity of 84-95% for vascular conditions 1
  • Can differentiate between extratesticular (mostly benign) and intratesticular (potentially malignant) lesions 2
  • Evaluates:
    • Testicular and epididymal architecture
    • Vascular flow patterns
    • Scrotal wall thickness
    • Presence of fluid collections

Laboratory Testing

• Urinalysis: To evaluate for infectious causes
• Complete blood count: To assess for inflammatory/infectious processes
• Inflammatory markers (ESR, CRP): If systemic inflammatory condition suspected

Differential Diagnosis Based on Imaging Findings

Extratesticular Causes

1. Acute idiopathic scrotal edema

   • Usually painless with marked scrotal wall thickening
   • Heterogeneous striated edematous appearance with increased vascularity on ultrasound
   • Normal testes and epididymis 1, 3
   • Self-limiting condition, more common in children
   • May present with intense scrotal pruritus 3

2. Hydrocele/Spermatocele

   • Anechoic fluid collection on ultrasound
   • No increased vascularity
   • Transilluminates on physical exam 2

3. Varicocele

   • Dilated veins of the pampiniform plexus
   • "Bag of worms" appearance on ultrasound
   • Increased flow on color Doppler 2

4. Inguinal hernia

   • Bowel loops or omentum in scrotum
   • Reducible mass on exam
   • Variable echogenicity on ultrasound 2

Intratesticular Causes

1. Testicular tumor

   • Solid or complex mass within testis
   • Increased vascularity on Doppler
   • May have associated hydrocele 2

2. Metastatic disease/Lymphoma

   • Multiple hypoechoic lesions or diffuse testicular enlargement
   • Abnormal flow patterns on Doppler 2

Systemic Causes

1. Crohn's disease

   • Genital swelling can precede intestinal symptoms in 88% of cases
   • May require evaluation of gastrointestinal tract if suspected 4

2. Henoch-Schönlein purpura

   • Associated with purpuric rash, arthritis, abdominal pain
   • Scrotal involvement must be distinguished from testicular torsion 5

Management Algorithm

1. If ultrasound shows normal testicular architecture with scrotal wall edema:

   • Consider acute idiopathic scrotal edema
   • Conservative management with scrotal support and anti-inflammatory medications
   • Resolution typically occurs within 24 hours 3

2. If ultrasound shows extratesticular fluid collection:

   • Hydrocele/spermatocele: Observation if asymptomatic, surgical correction if large or symptomatic
   • Varicocele: Urological referral for evaluation

3. If ultrasound shows intratesticular mass or abnormality:

   • Immediate urological referral
   • Consider additional imaging (CT/MRI) for staging if malignancy suspected

4. If ultrasound is inconclusive:

   • Consider MRI for better tissue characterization
   • Contrast-enhanced ultrasound may be helpful, though not FDA-approved for scrotal imaging as of 2018 1

Special Considerations

• Systemic disease evaluation: If no local cause is identified, consider workup for systemic conditions:

  • Inflammatory bowel disease (particularly Crohn's disease) 4
  • Vasculitis (e.g., Henoch-Schönlein purpura) 5
  • Heart/liver/kidney disease causing fluid retention

• Pediatric patients: Acute idiopathic scrotal edema is more common in children and typically self-resolves 1, 3

Common Pitfalls to Avoid

• Assuming all painless swelling is benign: Testicular tumors can present as painless scrotal swelling
• Missing systemic causes: Genital swelling may be the first manifestation of systemic conditions like Crohn's disease 4
• Inadequate imaging: Ensure both grayscale and Doppler components are performed during ultrasound evaluation 1
• Focusing only on testes: Evaluate the entire scrotal contents including epididymis and cord structures

By following this systematic approach with appropriate imaging and clinical correlation, the underlying cause of painless scrotal and penile swelling can be accurately identified and appropriately managed.