Pathophysiology
Clinical meaning
A hydrocele is an abnormal collection of serous fluid between the parietal and visceral layers of the tunica vaginalis surrounding the testis. Communicating hydroceles in children result from a patent processus vaginalis allowing peritoneal fluid to flow into the scrotal sac; these often fluctuate in size (larger when upright, smaller when supine) and many resolve spontaneously by age 12-24 months. Non-communicating (simple) hydroceles in adults result from an imbalance between fluid production and absorption by the tunica vaginalis, often idiopathic or secondary to infection, trauma, tumor, or torsion. Secondary hydroceles warrant investigation for underlying testicular pathology. On examination, hydroceles transilluminate (light passes through the fluid-filled sac, appearing as a glowing red mass) differentiating them from solid testicular masses which do not transilluminate. Treatment is observation for small asymptomatic hydroceles; surgical hydrocelectomy for large, symptomatic, or secondary hydroceles; needle aspiration is discouraged due to high recurrence and infection risk.