A collection of serous fluid between the layers of the membrane (tunica vaginalis) that surrounds the testis or along the spermatic cord. Rarely, similar fluid collection can occur in females along the canal of Nuck.
Common in male infants and the newborn. Most paediatric hydroceles are congenital and, in the majority of cases, resolve within the first year of life.
May occur in adult men where they are found secondary to minor trauma, infection, testicular torsion, epididymitis, varicocele operation, or testicular tumour.
The main symptom is a painless, swollen scrotum on 1 or both sides, which feels like a water-filled balloon.
Treatment depends on the age of the patient and the degree of discomfort caused by the hydrocele. Surgery will only be performed if the hydrocele is causing problems.
Hydrocele is a collection of serous fluid between the layers of the membrane (tunica vaginalis) that surrounds the testis or along the spermatic cord. Rarely, similar fluid collection can occur in females along the canal of Nuck. There are 2 types of hydroceles: communicating and non-communicating (simple).
In communicating hydroceles, a patent processus vaginalis connects the peritoneum with the tunica vaginalis, which allows peritoneal fluid to flow freely between both structures. If the connection is large, abdominal contents (bowel, bladder, or omentum) may enter the groin, and this complication is termed an inguinal hernia. Inguinal hernias are classified into either direct or indirect, based on the relationship of the sac to the inferior epigastric artery. In a direct inguinal hernia, the hernial sac lies medial to the artery and the deep inguinal ring. In an indirect inguinal hernia, the hernial sac lies lateral to the artery (see our full content on inguinal hernia). 
A non-communicating or simple hydrocele occurs when the processus vaginalis is closed and more fluid is being produced by the tunica vaginalis than is being absorbed.
Professor of Surgery and Pediatrics
Albany Medical College
BAK has no competing interests.
Professor of Urology
Mersin University School of Medicine
Department of Urology
EE is an associate member of the Paediatric Urology Guidelines Working Panel.
Center for Male Fertility
Glickman Urological and Kidney Institute
ES declares that he has no competing interests.
Department of Urology
Section of Male Infertility and Andrology
University of Wisconsin School of Medicine and Public Health
DHW declares that he has no competing interests.
Senior Lecturer in Urology
University of Bristol
MD declares that he has no competing interests.
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