Causes of Hydrocele
Primary (Congenital) Hydrocele
In infants and children, hydrocele results from incomplete involution of the processus vaginalis, which normally obliterates during fetal development, leaving no communication between the intra-abdominal peritoneal cavity and the scrotum. 1
- When the processus vaginalis remains patent, peritoneal fluid can travel and accumulate extra-abdominally as a hydrocele 1
- These congenital hydroceles typically resolve spontaneously within 18-24 months in the majority of cases 1
- The key distinguishing feature is whether there is fluctuation in size, which indicates a patent processus vaginalis and ongoing communication with the peritoneal cavity 2
Secondary (Acquired) Hydrocele in Adolescents and Adults
In the majority of affected adolescents and adults, hydrocele is acquired and idiopathic in origin, thought to result from an imbalance in the normal process of fluid production and reabsorption by the mesothelial lining of the tunica vaginalis. 2, 3
Specific Secondary Causes:
- Post-surgical: Varicocelectomy is the second most common cause of hydrocele in adolescents, with higher risk following non-artery-sparing procedures or those performed without microsurgical aid, and in surgery requiring cord dissection 2
- Inguinal surgery: Any inguinal surgical intervention can lead to subsequent hydrocele formation 4
- Infection/Epididymo-orchitis: Infectious or inflammatory processes affecting the scrotum can result in reactive fluid accumulation 1, 5
- Trauma: Scrotal trauma can disrupt the normal fluid balance mechanisms 4
- Testicular malignancy: Complex hydroceles in adolescents and young adults warrant high suspicion for underlying testicular cancer, as the tumor can cause reactive fluid accumulation 1, 6
Pathophysiology
Hydroceles develop from an imbalance between fluid secretion and reabsorption by the mesothelial lining of the tunica vaginalis, which is the remnant of the peritoneum covering the testicle. 3
- The tunica vaginalis has both parietal and visceral layers, and fluid accumulates in the potential space between these layers 2, 3
- Normal fluid production and reabsorption mechanisms become disrupted, leading to abnormal serous fluid collection 2, 3
Critical Clinical Pitfall
A hydrocele can mask an underlying testicular tumor, making physical examination of the testicle itself difficult even by expert physicians, potentially resulting in delayed diagnosis of metastatic testicular cancer. 6
- Scrotal ultrasound with Doppler is mandatory in cases where the testicle is nonpalpable to rule out a subtending testicular solid mass 1, 2
- Complex hydroceles on ultrasound require further evaluation for testicular malignancy, particularly in adolescents and young adults where infertile males have an 18-fold higher risk of testicular cancer 1