What is testicular cancer?
Testicular cancer is when abnormal cells in a testicle start to divide and grow in an uncontrolled way. The testicles are part of the male reproductive system.
The testicles
The testicles are two small oval shaped organs which hang below the penis in a pouch of skin called the scrotum.
From the age of 
the testicles produce sperm.
The collecting tubules inside the testicle join together to form a tube called the epididymis. This tube carries on and gets wider as it leaves the testicle. The wider tube is called the .
The spermatic cord forms a short tube called the ejaculatory duct. This duct opens into the urethra (the tube from the to the end of the penis).
Testosterone
The testicles produce the hormone testosterone. Testosterone helps with:
- the development of a deep voice
- the growth of facial hair
- muscle development
- the ability to have an erection
- sex drive (libido)
This video shows you different parts of the male reproductive system. It lasts for 1 minute and forty seconds.
The male reproductive system includes the penis, the testes and the epididymides held within the scrotum, the vas deferens and internally the seminal vesicles, and the prostate gland.
The penis is the male sex organ. It is made up of the shaft and the head. The head of the penis is covered by a moveable piece of skin called the foreskin
The urethra is a tube that runs from the bladder through the prostate gland and the middle of the penis, to carry urine out of the body. The penis has a rich blood supply, as well as a muscle layer and nerves. When sexually aroused the blood flow increases and it becomes erect. The testes produce sperm and the hormone testosterone.
At the back of each testis is the epididymis. A tube where sperm is stored. When the penis is erect sperm moves form the epididymis and through the vas deferens to the urethra
The seminal vesicles make a fluid that mixes with sperm in the urethra. The prostate gland is about the size of a walnut. It surrounds the first part of the urethra and adds more fluid to the sperm. During orgasm the prostate squeezes this fluid into the urethra and out of the body
For more information about cancers that can start in the male reproductive system, go to CRUK.org/cancer-types.
Where does testicular cancer start?
The testicles are made up of different types of cells. The type of cancer you have depends on the type of cell the cancer starts in.
Most testicular cancers develop in germ cells. These are the cells that make sperm. They are also called germ cell tumours. The 2 main types of testicular germ cell tumours are:
- seminoma
- non seminoma
Testicular cancer and the lymph nodes
are part of the lymphatic system that runs throughout the body. The lymph nodes and lymph vessels contain a yellow fluid called lymph that flows through the lymphatic system. It collects waste products and drains into veins for the waste to be removed.
Cancer can spread to the lymph nodes and make them bigger (enlarged). It is common for testicular cancer to spread to the lymph nodes in the back of the tummy (abdomen). These are called the retroperitoneal lymph nodes.
These lymph nodes are behind your bowel and just in front of your spine. They run alongside the major blood vessel in the abdomen (the aorta and the inferior vena cava).
How common is testicular cancer?
In the UK around 2,400 men are diagnosed with testicular cancer each year. Although testicular cancer is rare, it is more common in men in their early 30s. It then becomes less common as they get older.
Who gets it?
Younger men are more likely to get testicular cancer.
Trans women can also develop testicular cancer if they haven't had an operation to remove their testicles (orchidectomy).
