Most men’s testicles are about the same size, but it’s common for one to be slightly bigger than the other. It’s also common for one testicle to hang lower than the other.
The testicles should feel smooth, without any lumps or bumps, and firm but not hard. You may feel a soft tube at the back of each testicle, which is called the epididymis.
If you notice any changes or anything unusual about your testicles, you should see a GP.
What causes lumps and swelling in the testicles?
There are several causes of testicular lumps and swellings:
   varicocele – caused by enlarged veins in the testicles (may look like a bag of worms)
   hydrocele – a swelling caused by fluid around the testicle
   epididymal cyst – a lump caused by a collection of fluid in the epididymis
   testicular torsion – a sudden painful swelling that happens when a testicle becomes twisted (this is a medical emergency and requires surgery as soon as possible)
   epididymitis – a chlamydia infection in the epididymis can cause inflammation, swelling and tenderness inside the scrotum (ball sack); a few men will notice that the whole of the scrotum is red and tender (this is called epididymo-orchitis)
   testicular cancer – an uncommon cause of lumps
What are the signs of testicular cancer?
The early signs of testicular cancer are easy to spot. Look out for one or more of the following:
   a hard lump on the front or side of a testicle
   swelling or enlargement of a testicle
   an increase in firmness of a testicle
   pain or discomfort in a testicle or in the scrotum (the sac that holds the testicles)
   an unusual difference between one testicle and the other
If you find a lump or swelling, or have any of the above signs, it’s important to get it checked out by a doctor.
Source: www.nhs.uk
