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Testicular lumps and swellings

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What causes testicular lumps and swellings?

The testicles are part of the male reproductive system. They produce sperm and testosterone (male sex hormone). The testicles sit inside a loose sac of skin known as the scrotum, which hangs down behind the penis.

Testicular lumps and swellings can have many different causes. In rare cases, they can be a sign of testicular cancer. However, most lumps are benign (non-cancerous).

Types of testicular lumps and swellings

The four main types of testicular lumps and swellings are:

  • varicocele, a swelling caused by dilated (enlarged) veins within the scrotum
  • hydrocele, a swelling caused by fluid around the testicle
  • epididymal cyst, a lump caused by a collection of fluid in the epididymis (a coiled tube behind the testicles) – if it contains sperm, it is known as a spermatocele
  • testicular torsion, a sudden painful type of swelling that occurs when a testicle becomes twisted, interrupting the blood supply to the testicles – it is a medical emergency

Read more information about causes of testicular lumps and swellings.

When should I seek medical help?

See your doctor if you notice any lumps, swellings or changes to the testicles, as they should always be checked by a healthcare professional.

Testicular torsion is a medical emergency and will require urgent surgery within hours of it starting.

Other types of lumps may not require treatment because they often do not cause any symptoms. Hydroceles in newborn babies often disappear on their own during the first year or two.

If a lump causes pain or discomfort, it may be possible to have it surgically removed.

Read more information about diagnosing testicular lumps and swellings and treating testicular lumps and swellings.

Who is affected?

Varicoceles are relatively common, affecting about one in seven men. They usually become noticeable after puberty (when the body matures sexually) because by this time the testicles are fully grown and the blood flow to the affected veins increases.

Hydroceles affect one or two in every 100 newborn male babies. They can also occur in older boys or men after an injury or infection.

Epididymal cysts can develop at any age, but are most common in middle-aged men. They affect up to a third of men.

Testicular torsion usually develops in boys aged 13-17, but can also occur in men in their 20s. It is an uncommon condition, and figures from the US suggest that it affects one in every 4,000 males every year.

What are the signs of a testicular lump or swelling?

Always visit your doctor if you find a lump or swelling on one or both of your testicles.

In most cases, a lump or swelling is not cancerous, but you should always have it checked by a healthcare professional.


Varicoceles usually develop on the left side. This is due to the way the veins in the testicles drain into the abdomen (tummy).

They develop as a soft lump in the scrotum and can feel like a "bag of worms". The size of varicoceles can vary. Some may only be noticeable when you touch them. Others can be larger and seen easily. The side of the scrotum that contains the varicoceles may hang slightly lower than the other side.

In most cases, varicoceles do not cause any symptoms. However, up to one in 10 men may experience a heavy feeling or aching pain in their:

  • scrotum
  • groin

Varicoceles may be linked to infertility. However, there is no evidence that surgically removing them improves fertility rates.


Hydroceles can affect newborn babies. In almost all cases, the only symptom is a painless swelling of one or both testicles. Hydroceles can sometimes affect older boys or men, who may feel discomfort in the scrotum.

Epididymal cysts

An epididymal cyst is a small, smooth fluid-filled swelling that develops behind and above the affected testicle.

Epididymal cysts are often painless, but your testicle may ache or feel heavy. You may experience some pain and discomfort if the cyst puts pressure on structures in or around your testicle.

You should visit your doctor for a check-up if you have any symptoms that affect your testicles.

Testicular torsion

Unlike the other types of benign (non-cancerous) testicular lumps, testicular torsion is a medical emergency.

Call for an ambulance if you suspect that you or someone you know has testicular torsion.

In cases of testicular torsion, surgery needs to be carried out as soon as possible to avoid the loss of the testicle.

The symptoms of testicular torsion usually begin with a severe pain in one of your testicles. Other possible symptoms include:

  • swelling of the scrotum
  • nausea (feeling sick)
  • vomiting
  • abdominal (tummy) pain
  • a low grade fever
  • a frequent need to urinate

Some men with testicular torsion may have had episodes of testicular pain and swelling in the past.

What causes a testicular lump or swelling?

There are many different causes of testicular lumps and swellings.

Testicular cancer is a possible cause.

The main types of lumps and their causes are explained below.


The exact cause of varicoceles is unknown. However, most experts believe they are caused by abnormalities in the veins that drain the testicles. There may be a blockage in the veins, or a problem with the valves in the veins. The valves are flaps that prevent blood flowing in the wrong direction.

The abnormal veins do not circulate blood as efficiently as normal veins. This leads to a build-up of excess blood in the veins, which makes them swell.

During puberty (when the body matures sexually), blood flow increases to the testicles and they grow larger. This can make varicoceles more noticeable.


During pregnancy, a male baby's testicles develop inside his abdomen (tummy). Once formed, the testicles pass down through a passage and into the scrotum (the loose sac of skin that contains the testicles).

Usually, the passage closes before birth, but in some cases it stays open. If the passage remains open, fluid can pass from the abdomen into the scrotum, causing the swelling associated with a hydrocele.

In most cases, the fluid is absorbed into the surrounding tissue during the child's first year or two of life, and the hydrocele disappears.

Hydroceles that develop in men or older boys may be caused by inflammation (redness and swelling) of the scrotum, which is the result of:

  • an injury
  • an infection
  • a tumour (growth)

Epididymal cysts

The epididymis is a coil-like structure behind the testicles that helps to store and transport sperm. Sometimes, a fluid-filled swelling can appear on the epididymis, although the cause is usually unknown.

Testicular torsion

The testicles hang from a cord known as the spermatic cord. The spermatic cord should be loose enough to allow the testicles some movement within the scrotum but not so loose that they can move too freely.

Some boys are born with a spermatic cord that is too loose. This means there is an increased risk of a testicle moving too much and twisting the spermatic cord as a result.

If a spermatic cord becomes severely twisted, the main blood supply for the affected testicle can be interrupted. This is an emergency. If it is not treated immediately, the testicle may die. Immediate surgery is needed to untwist the cord, restore the blood supply and save the testicle.

Testicular torsion is most common among boys aged 13-17, although it can also occur in:

  • men in their 20s
  • unborn babies in the womb
  • newborn babies

Testicular torsion can sometimes occur if there is trauma to the testicle, such as in an accident. However, most cases happen for no apparent reason. Testicular torsion may be more likely if you have a history of undescended testicles (where a boy is born without one or both testicles in their scrotum).

Other causes

Other causes of testicular lumps or swellings include:

  • epididymitis – inflammation of the epididymis, which may be caused by a sexually transmitted infection or a urinary tract infection
  • epididymo-orchitis – epididymitis combined with orchitis (inflammation of the testicle), usually due to an infection
  • inguinal hernia – a piece of your bowel pokes through a weakness in the muscle or surrounding tissue wall into your groin (more than a quarter of men will have an inguinal hernia during their lifetime)

How is a testicular lump or swelling diagnosed?

Always visit your doctor if you notice any lumps or swellings in your testicles.

In very rare cases, a lump can be a sign of testicular cancer (less than four in 100 lumps).

Your doctor will ask you whether you have:

  • felt any pain – and if so, where it was, how severe it was and how long it lasted for
  • any other symptoms, such as pain when you urinate (which is a sign of a urinary tract infection) or any discharge from your urethra (the tube that carries urine from the bladder)
  • a history of trauma, such as a sports injury to your groin

Your doctor will also physically examine your testicles to check:

  • the size of your testicles
  • the position of the lump or swelling
  • whether the lump causes any pain when it is touched
  • whether the lump is firm or soft

If your doctor cannot confirm a diagnosis from the examination alone, you may need an ultrasound scan. This uses high-frequency sound waves to create an image of the inside of your body.


A varicocele can usually be diagnosed by your doctor asking about your symptoms and carrying out a physical examination. Further testing is not usually necessary.


In some cases, you may be referred to a urologist (a doctor who specialises in treating conditions that affect the urinary system). For example, if:

  • a varicocele suddenly develops
  • you have a single varicocele on the right side
  • there is uncertainty about the cause of your lump
  • you are in pain
  • it is causing you embarrassment

In these circumstances, you may be referred for an ultrasound scan to confirm the diagnosis and check for any problems.


As with varicoceles, a hydrocele can usually be diagnosed through a physical examination.

If a hydrocele develops in your child, your doctor will feel your child's scrotum to check that the swelling is caused by fluid and not something solid. The fluid is usually clear, so your doctor may shine a torch through the scrotum. If a hydrocele is present, the outlines of the testicles should appear against the background of the fluid.

If you have a hydrocele, your doctor will examine your scrotum as described above. If you are 20 to 40 years old, your doctor may refer you for an ultrasound scan to rule out testicular cancer.

If your doctor suspects your hydrocele may be caused by an infection, they may test a urine sample to make their diagnosis. Your doctor may also use a swab (small piece of absorbent material, such as gauze, attached to the end of a stick) to collect a sample of cells and fluid from your urethra. This sample can then be tested to see if you have an infection.

Epididymal cysts

An epididymal cyst can usually be diagnosed through a physical examination. Further tests are not usually required.

Testicular torsion

Testicular torsion is usually diagnosed by the distinctive symptoms of severe testicular pain and swelling.

If testicular torsion is suspected, you will usually undergo an operation urgently. Ultrasound may be used if you have had the pain for a long time.

What is the treatment for a testicular lump or swelling?

Treatment for your testicular lump will depend on the underlying cause of the lump.


In most cases, varicoceles do not require any treatment. If you have a varicocele and are in pain or discomfort, there are several things you can do to help ease your discomfort:

  • take painkillers, such as paracetamol
  • wear tight-fitting, supportive underwear

If your varicocele is still causing you pain or discomfort, surgery may be recommended.


A surgical technique called varicocele embolisation can be used to treat varicoceles. You will usually be referred to a urologist (a doctor who specialises in treating conditions that affect the urinary system) to discuss the risks and benefits of surgery.

Most cases of varicocele embolisation are carried out on an outpatient basis, which means you will not have to stay in hospital overnight. It is usually carried out under local anaesthetic (painkilling medication to numb the affected area).

Your surgeon will use X-ray equipment to guide a tiny tube into the affected veins in your testicles. They will use metal coils or a special liquid to block the veins. The blood will then bypass the blocked veins, reducing the swelling and removing the varicocele.

Varicocele embolisation is a very safe procedure, although there is a small risk of infection. If infection occurs, it can be treated with antibiotics (medication to treat bacterial infections). Other possible risks include:

  • the varicocele returning
  • numbness or pain in the scrotum

Some varicoceles require a different treatment in the form of surgery to directly divide the dilated (widened) veins. This is usually performed under general anaesthetic, so you will be unconscious. Your surgeon will make an incision (cut) in your groin and then find and remove the dilated veins.

More than nine out of 10 varicoceles are successfully removed through surgery.


Hydroceles in newborn babies usually disappear by the time the baby reaches two years of age. Treatment is usually only needed if they persist for longer than this, or cause pain or discomfort.


If you need treatment for hydroceles, a surgical procedure known as a hydrocelectomy may be recommended.

A hydrocelectomy is carried out under general anaesthetic. In children, an incision is made in the groin before sealing the passage between the abdomen (tummy) and the scrotum. In adults, the incision is made in the scrotum, the fluid is drained away and the incision is closed using dissolvable stitches. Most people will be able to return home soon after having the operation.

As with a varicocele embolisation, there is a small risk of infection after a hydrocelectomy. Children may be given antibiotics before or during the operation to prevent infection.

Epididymal cysts

Epididymal cysts do not usually require any treatment. However, if they are causing troublesome symptoms, you may be referred to a urologist.

Your urologist may recommend further treatment and suggest surgically removing the entire cyst under general anaesthetic.

Testicular torsion

If you have testicular torsion, you will need surgery as soon as possible to untwist the testicle. Permanent injury to the testicle can occur within four hours of having testicular torsion, which may affect your fertility or result in the loss of your testicle.

Surgery for testicular torsion is carried out under general anaesthetic. The surgeon will make a cut in your scrotum before untwisting the spermatic cord (the cord that the testicles hang from inside the scrotum). The testicle (or testicles) will then be stitched to the inside of the scrotum to prevent the spermatic cord twisting again.

The longer you wait before having surgery, the higher the risk that your surgeon will not be able to save the trapped testicle. Figures show that when people have surgery within six hours of testicular torsion occurring, nine out of 10 twisted testicles will be saved. However, if the surgery is delayed for 24 hours, only one out of 10 twisted testicles will be saved.

Following surgery for testicular torsion, you may need to avoid strenuous activity for about a week. Your surgeon will advise you about this.

Other types of lumps

Other types of lumps are treated differently, depending on their cause. For example, if your lump is caused by an underlying infection, the infection may be treated with antibiotics. Read more information about sexually transmitted infections (STIs) and urinary tract infections.

If you have been diagnosed with testicular cancer, it may be treated with surgery and radiotherapy. Read more information about treating testicular cancer.

If you have been diagnosed with an inguinal hernia, you will usually need to have an operation. Read more information about inguinal hernia repair.

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