Snaphot A 6-month old boy is brought to the pediatrician’s office for evaluation of a “lump” in his genital area. His birth history is unremarkable and he has been feeding and eating well. His parents report no other concerns. On physical exam, there is a tense and non-tender mass in the scrotum. The transillumination test is positive. The parents are counseled about his condition and reassured that this will most likely resolve spontaneously. Introduction Clinical definition swelling in scrotum due to fluid accumulation between parietal and visceral layers of tunica vaginalis communicating hydroceles incomplete closure of processus vaginalis account for most cases of hydroceles in infants and children non-communicating hydroceles complete closure of processus vaginalis most often idiopathic account for all cases of adult hydroceles Epidemiology incidence 1% of adult men 1-4.7% of male infants Etiology adults and adolescents trauma infection acute epididymitis mumps tumor mesothelioma 10% of testicular tumors present with hydrocele infants and children (congenital) incomplete obliteration of processus vaginalis Prognosis natural history of disease congenital hydrocele usually resolves spontaneously by 1 year of age Presentation Symptoms painless bulge of genitals Physical exam scrotum nontender tense fluid-filled enlarged scrotum transilluminates positive transillumination test Imaging Ultrasound indications only if diagnosis is uncertain or suspicion for tumor Differential Varicocele “bag of worms” Treatment Conservative monitoring indications monitor for 6-9 months for small noncommunicating hydrocele in adults monitor until after 1 year of age for communicating hydrocele in infants Operative surgical hydrocelectomy indications if hydrocele does not self-resolve Complications Testicular damage Subfertility