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A varicocele is like varicose veins of the small veins (blood vessels) next to one testicle (testis) or both testicles (testes).

What are the symptoms?

My guess is that the first doctor to write about a varicocele was a fisherman, because it is described as feeling like a bag of worms. I can't imagine why anyone would otherwise want to be walking round with a bag of worms, or even think of putting worms in a bag. Just think, if the first doctor to describe the condition was an amateur cook we might all be talking about a bag of spaghetti. But we are stuck with the worm thing. No matter.

Varicoceles are pretty common. Men have a good chance of getting one - about 1 in 7 - usually around the age of 15 to 25. Just the time in your life when it would be handy not to have a bag of worms between your legs. Mother Nature can be a cruel mistress.

Varicoceles are, like the rest of the body, prone to the effects of gravity. So you might get a bit of discomfort if you've been on your feet for a while. You can make a varicocele disappear by lying flat. A neat party trick, but not one likely to get you past the first round of Britain's Got Talent.

Read more about the symptoms of a varicocele.

What are the causes?

We're mainly back to gravity again. The veins are fitted with valves that are meant to keep blood flowing towards the heart and stop it from flowing backwards. This sort of thing happens when you stand up. If the valves leak, the blood hangs around in the veins, which expand to form a varicocele. The same sort of thing happens with varicose veins in the legs. Nobody knows why the valves stop working. We don't know everything. The same thing happens to my internet but I don't lose any sleep over it.

In older men, a blockage of larger veins in the tummy can cause a varicocele in the scrotum. This is only likely to happen in men aged over 40. It can be a sign that a tumour of the kidney has developed.

Learn more about the causes of a varicocele.

How is it diagnosed?

When a doctor examines you they will most likely be able to feel the swollen veins in your scrotum. Forgive them if they use the term 'bag of worms'. It's a reflex action which has been drummed into them at medical school.

These days you may end up having a type of scan called a colour Doppler ultrasound to confirm the diagnosis. They have these fancy toys, so you might as well use them.

Men over 40 are likely to have other tests because of the link with tumours such as kidney cancers.

Find out more about the diagnosis of a varicocele.

What are the options for treatment?

When I was a medical student there was an old joke doing the rounds which went like this:

Q. What does a surgeon operate on a varicocele for?

A. Fifty pounds.

As time's gone on we have come to realise that most varicoceles don't need treatment. . There are some notable exceptions. Persistent discomfort is a good reason, particularly if you do a lot of standing in your job. It's now generally accepted that varicoceles, like some brands of underpants, heat up the nether regions and affect sperm production. In young infertile men who meet certain criteria, removing the varicocele can help to restore fertility.

Teenagers in whom the testicle is demonstrated to be getting smaller may also benefit from treatment to prevent fertility reduction .

The treatment is to tie the enlarged veins off or inject them with a substance to make them shrink.

Sometimes, the veins left behind also enlarge and you have to go through the whole process again. Mother Nature can be a cruel ... oh sorry, I've already done that bit.

Read more about the treatment of a varicocele.

What is a varicocele?

Testis including small veins

A varicocele is a collection of enlarged (dilated) veins (blood vessels) in the scrotum. It occurs next to and above one testicle (testis) or both testes (testicles).

The affected veins are those that travel in the spermatic cord. The spermatic cord is like a tube that goes from each testis up towards the lower tummy (abdomen). You can feel the spermatic cord above each testis in the upper part of the scrotum. The spermatic cord contains the tube that carries sperm from the testes to the penis (the vas deferens), blood vessels, lymphatic vessels and nerves.

Normally, you cannot see or feel the veins in the spermatic cord that carry the blood from the testicles. If you have a varicocele, the veins become bigger (they dilate) and this makes them more noticeable. It is similar to varicose veins of the legs. The size of a varicocele can vary. A large varicocele is sometimes said to look and feel like a bag of worms in the scrotum.

What causes a varicocele?

Normal vein valves

In most cases, the reason why the veins (blood vessels) become larger is because the valves of the small veins in the scrotum do not function well. There are one-way valves at intervals along the veins. The valves open to allow blood to flow towards the heart, but close when blood flow slows to stop blood flowing backwards.

If these valves do not work well, blood can flow backwards (due to gravity) and pool in the lower parts of the vein to form a varicocele. (This is similar to how varicose veins form in legs.)

It is not clear why the valves do not work well.

Abnormal vein valves

A varicocele may (rarely) develop if there is a blockage of larger veins higher in the tummy (abdomen). This puts back-pressure on the smaller veins in the scrotum which then enlarge (dilate). This is only likely to occur in men older than 40. For example, if a varicocele suddenly develops in an older man, it may indicate a tumour of the kidney has developed which is pressing on veins.

It must be stressed, the vast majority of varicoceles develop in teenagers and young men and are not due to a serious condition.

How is a varicocele diagnosed?

The diagnosis is made by a doctor's examination. A colour duplex ultrasound scan (a scan using ultrasound to look at blood flow in an area) is sometimes done to confirm the diagnosis. A varicocele is associated with some cases of infertility. Therefore, a semen test may be asked for if you are part of a couple being investigated for infertility. In the rare situation of a varicocele first developing in a man aged over 40, tests to check out a possible underlying cause may be advised. Also, a solitary right-sided varicocele is unusual. If this occurs, you may need some tests to rule out any unusual cause.

When does a varicocele need treating?

If a varicocele is causing no symptoms or problems, then it is best left alone. It is usually harmless but there are some situations in which it can cause concern.

When can a varicocele cause concern?

Possible cause of infertility

Studies have shown that there is a higher rate of infertility in men with a varicocele compared with those who do not have a varicocele. The reason for this is not clear. One theory is that the pooled blood causes a slightly higher temperature in the scrotum than normal. This may reduce the number and quality of sperm made by the testicle (testis), which can reduce fertility. Even if you have a varicocele only on one side, both testicles (testes) can be warmed by the increased amount of blood pooled in the enlarged veins (blood vessels).

Research has shown that 25 in 100 men with problems showing up on sperm analysis have a varicocele and that treating the varicocele usually improves sperm quality. And remember, most men with a varicocele are not infertile.

Currently it's recommended that a varicocele should be treated if:

  • It's obvious on examination (as opposed to just showing up on a scan).
  • Sperm count is low; you've been infertile for two years or more.
  • Your infertility is otherwise unexplained.

Small testis

If a large varicocele develops in a teenager, the testis on the side of the varicocele may not develop as much as would be expected. For example, an annual measurement of the testes may be advised. The testis may end up being smaller than normal. This may contribute to infertility too.

Sudden onset of a varicocele in an older man

Very rarely, a varicocele quickly develops as a symptom of a blockage of a larger vein in the tummy (abdomen) - see above. This would normally only occur in men over the age of 40.

What treatments are available?

If there is just mild discomfort, supportive underpants (rather than boxer shorts) may help to ease or prevent discomfort.

Treatment involves tying off the veins (blood vessels) that are enlarged. Another method of treatment is to use a special substance injected into the veins to block them. Both methods are usually successful. Your surgeon will advise on the pros and cons of the different techniques.

However, after successful treatment, some men have a return (recurrence) of a varicocele months or years later. This is because the veins left behind to do the job of taking the blood from the testes may themselves enlarge (dilate) with the extra blood they will now have to carry. A recurrence can be treated in the same way as the first time.

Further reading & references

  • Guidelines on Male Infertility; European Association of Urology (2015)
  • D'Andrea S, Micillo A, Barbonetti A, et al; Determination of spermatic vein reflux after varicocele repair helps to define the efficacy of treatment in improving sperm parameters of subfertile men. J Endocrinol Invest. 2017 May 25. doi: 10.1007/s40618-017-0695-x.
  • Kolon TF; Evaluation and Management of the Adolescent Varicocele. J Urol. 2015 Nov;194(5):1194-201. doi: 10.1016/j.juro.2015.06.079. Epub 2015 Jun 25.

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. Patient Platform Limited has used all reasonable care in compiling the information but makes no warranty as to its accuracy. Consult a doctor or other healthcare professional for diagnosis and treatment of medical conditions. For details see our conditions.

Dr Laurence Knott
Peer Reviewer:
Dr Helen Huins
Document ID:
4379 (v41)
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