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Medical Author:

John Mersch, MD, FAAP

John Mersch, MD, FAAP

Dr. Mersch received his Bachelor of Arts degree from the University of California, San Diego, and prior to entering the University Of Southern California School Of Medicine, was a graduate student (attaining PhD candidate status) in Experimental Pathology at USC. He attended internship and residency at Children's Hospital Los Angeles.

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Medical Editor:

David Perlstein, MD, MBA, FAAP

David Perlstein, MD, MBA, FAAP

Dr. Perlstein received his Medical Degree from the University of Cincinnati and then completed his internship and residency in pediatrics at The New York Hospital, Cornell medical Center in New York City. After serving an additional year as Chief Pediatric Resident, he worked as a private practitioner and then was appointed Director of Ambulatory Pediatrics at St. Barnabas Hospital in the Bronx.

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What is a hydrocele?

A hydrocele is a scrotal collection of clear fluid ("hydro" = water) in a thin walled sack ("cele" = swelling) that also contains the testicle. Less frequently, due to the common embryological background of male and female gonadal structures, female children or women may also experience a hydrocele. In this case, the sack and connection exist in the labia majora (the outermost and larger of the two labial structures). Because of less potential concern for complications in females with hydroceles, this article will focus predominantly on the male gender. A hydrocele may involve either one side (unilateral) or both sides (bilateral) of the scrotum.

What causes hydroceles?

Embryology

Between the 28th and 36th week of gestation, the testes, associated blood vessels and nerves migrate from the upper posterior abdominal wall adjacent to the kidneys to the lower abdominal cavity and through a tunnel (inguinal canal) into the scrotum. As each gonad exits the pelvic region through the inguinal canal into the scrotum, it is preceded by a thinly lined "sack" called the process vaginalis. Once the testes and associated structures have entered the scrotum, the trailing end of the process vaginalis generally closes off, completely isolating the contents of the abdominal cavity and obstructing their passage into the inguinal canal or scrotum. Should this closure be incomplete and the communication narrow, free fluid in the abdominal cavity (peritoneal fluid) may seep into and through the process vaginalis and collect in the scrotum forming a hydrocele. If the connection is larger and a portion of the small intestine migrates out of the abdominal cavity into the inguinal canal and/or scrotum, a hernia has developed.

What are the physical features and types hydroceles?

A hydrocele is characterized as a non-painful, soft swelling of the scrotum (one or both sides). The overlying skin is not tender or inflamed. There are two types of hydroceles:

1. communicating, and
   
   
2. non-communicating.