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Clinical Summary

Most hydroceles occur in older patients and develop gradually without significant symptoms. Hydrocele presents as a soft, pear-shaped, fluid-filled cystic mass anterior to the testicle and epididymis that will transilluminate. However, it can be tense and firm and will transilluminate poorly if the tunica vaginalis is thickened. Almost all hydroceles in children are communicating, resulting from the same mechanism that causes inguinal hernia. A persistent, narrow processus vaginalis acts like a one-way valve, thus permitting the accumulation of dependent peritoneal fluid in the scrotum. Acute symptomatic hydroceles are rarer and can occur in association with epididymitis, trauma, or tumor.

Management and Disposition

Most hydroceles accumulate slowly over time, and many do not require intervention. However, in an acute hydrocele, ultrasound can be helpful in cases of trauma or concern for infection or malignancy. Acute hydroceles should be referred to a urologist. Refer chronic accumulations to a urologist on a more routine basis for elective drainage. Congenital hydroceles in infants should have watchful waiting, as spontaneous resolution can occur.


Hydrocele. Painless swelling in the scrotum of a young boy (A). Transillumination of the swelling (B) identifies the hydrocele. (Photo contributor: Michael J. Nowicki, MD.)


  1. Ten percent of testicular tumors have a reactive hydrocele as the presenting complaint.

  2. A hydrocele may be mistaken for an inguinal hernia on initial exam; use transillumination or, if still unclear, ultrasound.

  3. Consider a reactive hydrocele from an secondary process if acute and/or painful.


Hydrocele. Hydrocele without (A) and with (B) transillumination. (Photo contributor: David Bryson. Reproduced from Bryson D. Transillumination of testicular hydrocele. Clin Med Img Lib. 2017;3(3):075.)

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