It is important that all lumps within your scrotum, on or alongside your testicle are examined by a doctor.

Even if you think the swelling is non-cancerous, get it checked! If your doctor is not sure, he/she will arrange for you to have an ultrasound scan (which is painless). Also see your doctor if one testicle feels enlarged and heavy, or if when you squeeze it gently it feels much firmer than the other side.

In all these cases, it could be a cancer of the testicle. Testicular cancer is the most common type of cancer to affect young men in their 20s and 30s (but it can occur at any age). About 1 in 500 men will develop cancer of the testicle before the age of 50, but the good news is that 95% of men will survive their cancer for five years or more after diagnosis (ONS 2019). The earlier it is picked up, the better!

In fact, most swellings in the scrotum turn out to be non-cancerous. For example, it is common to have small lumps and cysts in the epididymis and in the spermatic cord. Surgeons do not usually remove these non-cancerous cysts unless they are large and troublesome.

Hydrocele (Fluid around the Testicle)

The most common cause of a painless swelling in the scrotum is a ‘hydrocele’, which is an accumulation of fluid around the actual testicle. Sometimes hydroceles go away on their own. If not, there are various possible treatments. The simplest is removal of the fluid through a needle, but the hydrocele is likely to recur over the following few months. To cure the problem once and for all, a surgical operation is necessary.

Hydrocele excision


Closer look at the testicle

Varicocele (‘Bag of Worms’)

If you feel something in your scrotum like a bag of worms (most obvious when you are standing), you probably have a varicocele.

What is a varicocele? The ‘spermatic cord’ that leads upwards from the scrotum carries a tube for sperms to reach the penis, and also veins and arteries. The veins of the spermatic cord can become swollen, elongated and looped, similar to varicose veins in the leg – this is a varicocele. If the veins are only slightly swollen they will be unnoticeable, but moderately swollen veins can often be felt. Varicocele does not usually cause any symptoms, although some men report discomfort or may feel embarrassed if the swollen veins are visible under the skin. About 15% of normal healthy young men have a varicocele, usually on the left side.

Varicocele and fertility. Doctors have been arguing for years about whether a varicocele affects fertility, by damaging the development of sperms in the testicle (Fertility and Sterility 2011;95:841–852). For example, the blood in the swollen veins could act like a hot water bottle, keeping the testicle too warm; developing sperms like to be cool, which is why the scrotum hangs outside the body. Varicoceles do seem to be more common in men with sperm problems.

It is also somewhat unclear whether treating a varicocele will improve fertility. In 2021, the Cochrane Collaboration (an international network of experts who examine scientific evidence about medical problems) investigated varicocele treatment for fertility. They concluded that it remains uncertain whether any treatment (surgical or radiological) compared to no treatment in subfertile men may be of benefit on live birth rates; however, treatment may improve the chances for pregnancy.

Treatment. There are several methods of treating a varicocele. Keyhole surgery now seems to be preferred by most specialists, using a special microscope that is inserted through the groin into the scrotum (microsurgery).

Varicocele ligation


First published on:
Reviewed and edited by: Matt Brewer
Last updated: May 2021

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