How is a hydrocele (fluid accumulation in the scrotum) diagnosed?

Hydrocele Diagnosis

Hydrocele is diagnosed primarily through clinical history and physical examination, with scrotal ultrasound serving as the definitive imaging modality when clinical findings are equivocal or when underlying pathology needs to be excluded. 1

Clinical Diagnosis

History and Physical Examination

The diagnosis should begin with specific assessment of:

• Fluctuation in size: This is essential to identify a patent processus vaginalis, which indicates a communicating hydrocele rather than an acquired one 2
• Painless scrotal swelling: Hydrocele typically presents as non-tender, fluctuant scrotal enlargement 3, 4
• Transillumination: The fluid-filled sac will transilluminate with a light source, a classic bedside diagnostic maneuver 3

Key Clinical Pitfall

In young men with presumed hydrocele, be cautious of "complex hydrocele" findings, as these can rarely represent underlying testicular tumors. 4 A case report documented a multicystic testicular tumor (mixed germ cell tumor) that was initially misinterpreted as complex hydrocele on ultrasound. 4

Imaging Diagnosis

Ultrasound - The Diagnostic Standard

Scrotal ultrasonography is mandatory in the following situations: 2

• Non-palpable testicles: To rule out underlying testicular solid masses that would require inguinal exploration rather than simple hydrocelectomy 2
• Complex or septated fluid collections: To differentiate simple hydrocele from underlying pathology 4
• Uncertain clinical diagnosis: When physical examination findings are equivocal 1

Ultrasound Findings

• Simple hydrocele: Anechoic (fluid-filled) collection between the parietal and visceral layers of the tunica vaginalis 3
• Complex hydrocele: Fluid collection with septations, debris, or irregular walls—this finding should raise suspicion for underlying testicular pathology, particularly in young men 4

When Ultrasound is Essential vs. Optional

According to the American College of Radiology guidelines, ultrasound is the imaging modality of choice for palpable scrotal abnormalities when imaging is required. 1 However, if the clinical diagnosis is straightforward (painless, transilluminable, fluctuant scrotal swelling with palpable normal testicle), imaging may not be necessary before proceeding with treatment. 2

Diagnostic Algorithm

1. Obtain focused history: Specifically ask about size fluctuation (suggests patent processus vaginalis) and any associated pain or trauma 2

2. Perform physical examination: Assess for transillumination, palpate the testicle to ensure it is normal, and evaluate for fluctuation 3, 2

3. Order scrotal ultrasound if:

   • Testicle is non-palpable 2
   • Clinical findings suggest complexity (septations, solid components) 4
   • Patient is a young male with any atypical features 4
   • Diagnosis is uncertain 1

4. Proceed directly to treatment if: Simple, transilluminable hydrocele with clearly palpable normal testicle in appropriate clinical context 2

Classification Based on Diagnosis

Primary (idiopathic) hydrocele: Results from imbalance in fluid production and reabsorption by the tunica vaginalis; most common in adolescents and adults 3, 2

Secondary hydrocele: Develops as a reaction to underlying pathology such as infection, trauma, tumor, or post-surgical (particularly after varicocelectomy) 3, 2

Communicating hydrocele: Associated with patent processus vaginalis, identified by fluctuation in size with position changes 2