An epididymal cyst is a fluid-filled sac that grows on the top of the testicle. It is benign (i.e., not caused by cancer). Some men have only one cyst; others have multiple cysts on both testicles. Rarely, they can be associated with diseases that cause cysts elsewhere in the body. Small cysts do not require treatment. Larger ones can be removed by a surgeon, especially if they are painful. Drainage with a needle (aspiration) is another option, but often this is not done.
What is an epididymal cyst?
A cyst is a sac filled with fluid or semi-fluid material. Cysts can occur in different locations on the body and originate in different parts of the body (tissues).
Epididymal cysts are non-cancerous (benign) growths filled with clarified fluid and are found at the tip of the testicle (testes) where the spermatic cord (vas deferens) attaches. This area is known as the epididymis.
Who gets epididymal cysts?
The men most likely to develop these cysts are those in their early to mid-40s. Children before their teenage years rarely have epididymal cysts. The number of people who have epididymal cysts is not known.
What are the symptoms?
The first thing you notice is a lump. An epididymal cyst does not cause discomfort, so very young, you may not know about it unless it gets bigger. Some epididymal cysts are found by chance when people have an ultrasound scan for other reasons. An ultrasound scan uses sound waves to take images of the body.
You may have several epididymal cysts, and they can appear on one side of the scrotum or on both sides. The mass may be small, but if it increases in size, you will likely feel it. It can grow to a size equal to that of a testicle. It has a smooth surface and its consistency has been described as fluctuating. This means that you can squeeze it between your fingers to feel like a small water-filled balloon, as opposed to squeezing a pebble and encountering hard resistance.
The mass can feel independent of the testicle. This is an important feature because a testicular cancer can be felt as a lump in the testicle itself and cannot be separated from it.
Because the cyst is filled with fluid, it is illuminated when the light from a flashlight passes through it. This is called transillumination.
What else could it be?
Seminal cyst: This is a cyst that feels like an epididymal cyst, but it is filled with sperm (semen).
Inflammation: Some diseases can cause thickening of the epididymis and surrounding structures that feel like an epididymal cyst; however, these swellings are not translucent.
Syringomyelia: This is caused by a buildup of fluid in the scrotum.
Varicocele: This is like a varicose vein that appears in one testicle (testicle) or in the small veins next to both testicles. It is often described as resembling an earthworm mass.
Lipoma: This is a fatty mass, which can sometimes be difficult to identify because it is felt independently of the testicle, like an epididymal cyst.
Do I need to get tested?
Most people do not need to have any tests. Your doctor can make a diagnosis just by examining you. If there is any doubt, an ultrasound scan can be arranged. Drainage of the cyst using a needle (to aspirate fluid) can be done, but is hardly necessary.
What are the associated diseases?
Most men who have an epididymal cyst are very healthy. However, epididymal cysts can sometimes be seen as part of another disease: the
Cystic fibrosis: a genetic condition that has cysts present in the lungs, pancreas and other parts of the body.
Polycystic kidney disease: a genetic condition that has cysts present in the kidneys and other parts of the body.
Von Hippel-Lindau disease: a genetic disorder with tumors occurring in the eyes, kidneys, and nervous system.
Epididymal cysts can sometimes occur in children whose mothers have been exposed to a chemical (hormone) called hexenestrol.
How are epididymal cysts treated?
If the cyst is small and not causing problems, you may not need treatment. You just need to watch it and seek medical attention if it gets bigger or becomes painful.
Children usually do not need treatment because most cysts go away on their own. However, if they become painful or do not shrink, surgical removal may be necessary.
Large or painful cysts can be removed surgically. The surgery is simple and recovery is usually smooth. Occasionally, an infection may develop or a blood clot may occur in the scrotum (scrotal hematoma).
Sclerotherapy was often performed in the past as an alternative to surgery. It involves injecting a fluid called a sclerosing agent into the cyst. However, it is currently not often performed because the cyst often grows back.
Are there any complications?
Epididymal cysts rarely cause complications. Very occasionally, a cyst can twist at its tip. This causes sudden pain and swelling on the side of the scrotum. If you experience this, it is very important to seek medical help as soon as possible, as it requires emergency surgery.
Paratesticular lesions.
There are many differential diagnoses for paratesticular lesions.
Epididymal cyst (the most common epididymal mass).
Adenoma-like tumor (the most common epididymal tumor).
Membranous cysts of the scrotum.
Sphincter cysts.
White membranous cyst.
Sphingomyelomeningocele.
Hematochezia of the scrotum.
Varicose veins of the spermatic cord.
Scrotal calculus (scrotal pearls).
Inguinal hernia.
Polyspermia (superfluous amount of testicles).
Seminal fluid cysts.
Sperm cell granuloma.
Scrotal lipoma.
Scrotal smooth muscle sarcoma.
Fibrous pseudotumor of the scrotum.
Papillary cystadenoma (epididymis): the most common epididymal mass in patients with Von Hippel-Lindau disease.
Scrotal nodular disease.
Tuberculous epididymitis/epidididymitis.
Spermatic cord.
Lipoma of the spermatic cord.
Liposarcoma of the spermatic cord.
Smooth muscle sarcoma of the spermatic cord.