American Urological Association - Hydrocele


Home Education AUAUniversity Education Products & Resources Pathology for Urologists Testis Non-neoplastic Conditions Hydrocele


  • Results from accumulation of serous fluid between parietal and visceral tunica vaginalis of the testis.
  • Congenital hydrocele occurs when a patent processus vaginalis within the spermatic cord communicates with the peritoneal cavity.
  • Prevalence of congenital hydrocele: 6% at birth and 1% in adulthood.
  • Most cases are idiopathic but may be associated with trauma, inguinal hernia, epididymoorchitis, or tumors of the testicular/ paratesticular region.
  • Possible causes may include excessive secretion within the testicular tunics by parietal mesothelial cells, decreased reabsorption, and congenital absence of the efferent lymphatics.
  • Gross: translucent cyst filled with clear or serous fluid (unless there has been trauma or secondary infection).
  • Histology:
    • Hydrocele is lined by a single layer of cuboidal or flattened mesothelial cells, sometimes with prominent atypia.
    • Underlying connective tissue stroma with or without fibrosis and chronic inflammation.
    • In some cases progressive fibrosis narrows or obliterates the cyst lumen, creating adhesions and multiple cysts.
    • Fluid should not contain sperm unless a spermatocele has ruptured into the hydrocele sac.