School Health Service

Testicles are important organs for young men because they produce sperm and the male sex hormones (testosterone) which cause male developmental characteristics, including deep voice, chest hair, beard, muscle strength, mode and male pattern aggression.

Lumps and swellings in the testicles are a relatively common symptom in boys and men, and can have a number of different causes.

The vast majority of testicular lumps and swellings are caused by benign (non-cancerous) conditions that may not need treatment, but it's important that teenagers get to know what's normal for them and that they visit their GP if they notice any changes in their testicles so their GP can try to identify the cause.

What causes testicular lumps and swellings?

There are many possible reasons why a person’s testicles may become swollen or develop a lump. Some of the main causes are:

  • Varicoceles – swellings caused by swollen and enlarged veins within the scrotum
  • Hydroceles – swellings caused by a build-up of fluid around the testicle 
  • Epididymal cysts – lumps caused by a collection of fluid in the epididymis (a coiled tube behind the testicles)
  • Epididymo-orchitis – inflammation of the epididymis and testicles
  • Inguinal hernias – where fatty tissue or a part of your bowel pokes through into your groin, which can cause the scrotum to become enlarged

Testicular torsion

A sudden and severely painful swelling in one testicle can be a sign of a condition called testicular torsion, which is where the blood supply to a testicle is interrupted.

Testicular cancer

In rare cases, testicular lumps can be a sign of testicular cancer. Cancer Research UK estimates that fewer than four in every 100 testicular lumps are cancerous. (NHS choices, 2014)

Testicular cancer is becoming more common with research suggesting that the common age for a male to be affected is between 15 and 45 years. 45 per cent of those diagnosed are reported to be under 35 year old.

Possible risk factors include being born with an undescended testicle at birth, a brother or father with testicular cancer, repeated knocks or trauma to the scrotum and sedentary lifestyle (when a person has little or no physical exercise).

Recent research also suggests that men who smoke cannabis on a regular basis and develop testicular cancer may develop a more aggressive type.

Testicular self-examination

The most common symptom of testicular cancer is a hard lump in the testicles.

If caught early, testicular cancer is 98% curable.

Therefore it is really important that teenage boys are encouraged to look after their testicles by performing testicular self-examination on a regular basis. This should be at least once a month.

Testicular self-examination is easy to perform. It takes a few minutes, and it’s best to do this after a hot bath or shower.

Teenagers should be encouraged to get to know what is normal for them. For example, one testicle may be slightly bigger or hang lower than the other.

GPs are used to seeing young men with testicular swelling and the examination is simple.

For more information on risk factors, symptoms and video advice on testicular self-examination, visit the Your privates website.