What is a hydrocele?

What is a Hydrocele?

A hydrocele is an abnormal collection of serous fluid between the parietal and visceral layers of the tunica vaginalis, the mesothelial lining that surrounds the testis and spermatic cord. 1

Pathophysiology

• The condition results from an imbalance between fluid secretion and reabsorption by the tunica vaginalis 1
• The embryological basis involves the processus vaginalis, a peritoneal extension that accompanies testicular descent through the inguinal canal between 25-35 weeks of gestation 2
• Normal development requires complete obliteration of the processus vaginalis, leaving only the tunica vaginalis surrounding the testis 2
• Incomplete involution of the processus vaginalis creates the anatomical substrate for different hydrocele types 2

Classification

Communicating (Congenital) Hydrocele

• A patent processus vaginalis maintains open communication between the peritoneal cavity and tunica vaginalis 2
• Peritoneal fluid travels through the patent processus vaginalis and accumulates in the scrotum, with size fluctuating based on position and intra-abdominal pressure 2
• Up to 80% of term male infants have patent processus vaginalis, declining to 33-50% by age 1 year and 15% by age 5 years 2
• Congenital hydroceles usually resolve spontaneously within 18-24 months 2
• The risk of developing an inguinal hernia with patent processus vaginalis is 25-50% 2

Non-Communicating (Acquired) Hydrocele

• In adolescents and adults, hydrocele is typically acquired and idiopathic in origin 3
• The pathogenesis involves an imbalance in normal fluid production and reabsorption processes 3
• Secondary causes include post-varicocelectomy (especially with non-artery-sparing procedures), trauma, infection, or underlying testicular pathology 3

Encysted Hydrocele of Spermatic Cord

• Caused by defective closure at both proximal and distal ends of processus vaginalis, without communication to the peritoneal cavity 4
• Presents as a translucent swelling in the inguinal canal or upper scrotum, located above the testis 5
• Can clinically mimic incarcerated inguinal hernia, inguinal lymphadenopathy, undescended testis, or cord tumors 4

Clinical Presentation

• Typically presents as painless scrotal swelling that transilluminates 1, 3
• Key diagnostic feature: Taking a thorough history is essential to identify any fluctuation in size, which indicates a patent processus vaginalis 3
• In epididymitis cases, hydrocele may be present as a reactive finding along with scrotal wall thickening 6
• Giant hydroceles (equal to or bigger than the patient's head) are rare but can significantly affect quality of life, causing complications with infertility, sexual function, and work capacity 7

Diagnostic Approach

• Diagnosis is usually clinical based on history and physical examination showing a fluid-filled, transilluminating scrotal mass 3
• Scrotal ultrasound is mandatory when clinical diagnosis is uncertain or when the testis is nonpalpable to exclude underlying testicular pathology, particularly solid masses requiring inguinal exploration 2, 3
• Ultrasound findings include anechoic fluid collection surrounding the testis with normal testicular echotexture and vascularity 1

Management

• For congenital hydroceles in infants: Observation is appropriate as most resolve spontaneously within 18-24 months 2
• For persistent or symptomatic hydroceles: Open hydrocelectomy via scrotal incision is the standard treatment for idiopathic hydroceles 3
• Post-varicocelectomy hydroceles: Initial management should include observation with or without aspiration; large persistent hydroceles require open hydrocelectomy 3
• Cord hydroceles: Irreducible cases require open surgical approach, while reducible cases may be managed laparoscopically 5
• Conservative management options include observation or fluid aspiration, though aspiration has high recurrence rates 1

Important Clinical Pitfalls

• Do not confuse reactive hydrocele seen with epididymitis or testicular torsion/detorsion with primary hydrocele 6
• In acute scrotal pain presentations, hydrocele may be present alongside serious pathology like torsion or infection, requiring color Doppler evaluation of testicular perfusion 6
• Encysted cord hydroceles in adults can mimic incarcerated inguinal hernias and require careful clinical differentiation 4
• Always consider the 25-50% risk of inguinal hernia development in patients with patent processus vaginalis 2