A hydrocele is the accumulation of fluids around the testicle, within the tunica vaginalis or processus vaginalis.

  • Communicating hydrocele: fluid passing from peritoneal cavity into patent processus vaginalis
  • Noncommunicating hydrocele: fluid confined within the processus vaginalis (hydrocele of the cord) or tunica vaginalis
  • Abdominal-scrotal hydrocele: fluid collection within processus vaginalis, extending into retroperitoneum
  • Reactive hydrocele (noncommunicating): accumulation of fluid within tunica vaginalis caused by infection, trauma, or other inflammatory conditions


  • 2–5% of male neonates have hydrocele.
  • Male more common than female
    • Female: “cyst” or “hydrocele” in the canal of Nuck; may be communicating or noncommunicating
  • Right more common than left
  • Majority asymptomatic
  • Simple (noncommunicating): commonly seen at birth, frequently bilateral, may be large
    • Majority spontaneously resolve in 12 to 24 months.
  • Persistent hydroceles beyond 24 months and those presenting after birth more likely to be communicating
  • Age >12 years old: majority noncommunicating
  • Adolescent/adult hydroceles are generally acquired (reactive) and idiopathic in origin.

Risk Factors

  • Similar to inguinal hernia
  • Prematurity, low birth weight, gestational progestin use, connective tissue anomalies, cystic fibrosis, cryptorchidism, posterior urethral valves, and other syndromic disorders
  • Trauma or infection
  • Lymphatic obstruction (i.e., varicocelectomy, filariasis, pelvic radiation, malignancy)


  • Communicating hydrocele can become indirect inguinal hernia, with potential for incarceration.
  • Noncommunicating hydrocele generally thought to be low clinical concern.
  • Potential damage in large, tense hydroceles
    • Raised intrascrotal temperature can cause potential testicular harm.
    • Tense hydrocele may cause pressure atrophy.
    • Increased resistive index observed in subcapsular artery and absent testicular diastolic flow indicate risk for permanent damage.


  • Communicating hydrocele similar to indirect inguinal hernia (defined by contents entering through patent processus vaginalis: peritoneal fluid versus fat or visceral organ)
  • In testicular descent, lip of peritoneum descends with testicle, the processus vaginalis, and covers testicle, tunica vaginalis.
  • Patent processus in girls (canal of Nuck) related to descent of round ligament to labia, female equivalent of gubernaculum
  • Related to delayed closure of processus vaginalis
    • Complete closure on both side in 18% of newborns
    • 40% close in first 2 months of life
    • 60% close by 2 years
    • Patent processus vaginalis commonly associated with undescended testicles
    • Adult autopsy data demonstrate 15–30% patent.
  • Reactive (acquired) hydrocele is imbalance between fluid production and absorption.
    • Majority are idiopathic.
      • Defective lymphatic drainage
      • Aspirated fluid similar protein content to lymphatic fluid
    • Result of inflammation from trauma, testicular torsion, torsion of testicular appendage, epididymo-orchitis
    • Postvaricocelectomy second most common cause

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