The testis, located in the muscular sac called the scrotum, contains multiple structures:
- The testis tissue itself — The egg-shaped structure that produces sperm
- The rete testis — The delicate network of tubes that carry sperm from the main testicular tissue toward the epididymis
- The epididymis — Attached to the back side of the testis; this structure stores sperm and moves it to the spermatic cord
- The spermatic cord (vas deferens) — The tube that carries sperm from the epididymis to the urethra inside the penis
- The tunica — The fibrous capsule that covers the testis
Any of these or one of its parts can fill with fluid (cystic). Technically, they could all be called "testicular cysts," but each type of cyst is generally referred to by the specific area that fills with fluid.
The most common type of cyst is a hydrocele, a collection of fluid around the capsule of the testis. This cyst can become quite large, is fluid filled, and can be generally diagnosed during a physical examination or by an ultrasound test. On occasion, the cyst may have to be drained or surgically removed because of its size.
A second type of cyst is a spermatocele, a collection of some sperm fluid surrounding the outside of the testis.
A third type of cyst is a varicocele, the collection of large veins that drain the testis. This is often referred to as a "bag of worms;" it is on the top of the testis. These sometimes have to be surgically corrected.
A fourth type is an epididymal cyst, which is a collection of fluid in the epididymis of the testis.
These four types of cysts are noncancerous (benign). It is important for the doctor who diagnoses a cyst to be sure that there is not an underlying cancer of the testis — sometimes associated with a cyst — or a twisting of the testis (called torsion). Generally, the problem can be determined by a good physical examination and an ultrasound of the testis and scrotum. Sometimes more specialized studies may be needed to make a definitive diagnosis.
Copyright 8/8/2007 Harvard University. All rights reserved. HHP/HMS content licensing handled by Belvoir Media Group.
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