Hydrocele [Greek: water - sac] occurs when the processus vaginalis fails to close. This tunnel between the scrotum and the peritoneal cavity allows peritoneal fluid to move into the space around the testis.

Incidence: 5% in newborns. Most of these will spontaneously resolve. Hydrocele is more common in premature babies because they may have been born before the normal gestational age at which closure of the processus vaginalis occurs (32-38 weeks). Hydrocele is also more common in children who have increased fluid in the peritoneum (i.e. ventriculoperitoneal shunt to drain hydrocephalus into the abdomen or peritoneal dialysis catheter).

This infant has large hydroceles on both sides. The spermatic cords and testes have been removed from the inguinal canal and the scrotum in order to close the hydroceles. The testes are contained with the cystic structures (the patent processes vaginalis).

Diagnosis: Transilluminate any mass in the scrotum. If light shines through the mass you are confident that it is cystic. The most common cystic scrotal mass in a child is a hydrocele or inguinal hernia. Hydroceles can also be seen along the inguinal canal. Rarely, an ultrasound is needed to confirm a loculated cystic mass on the spermatic cord. Many hydroceles vary in size, getting larger with crying or other activities which increase intra-abdominal pressure, thus pushing peritoneal fluid into the scrotum.

Treatment: If the hydrocele is very large or if it persists beyond age 12 months, surgery (to close the patent processus vaginalis) is indicated

See a case history.

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©David A. Hatch, M.D., 1996