What are germ cell tumours?

Germ cell tumours develop in germ cells. These are the cells in the body that develop into sperm and eggs. Germ cell tumours most often develop in the ovary or testicle because this is where most germ cells are.

But germ cells can sometimes be left behind in other parts of the body from when you developed in the womb. So these tumours can develop anywhere in your body where there are germ cells.

Germ cell tumours that grow outside the ovary or testicle are very rare. Doctors call them extragonadal germ cell tumours (EGGCT). 

The main treatments are surgery and chemotherapy. Your treatment depends on your type of germ cell tumour and whereabouts it is in your body. 

Types of germ cell tumour

Doctors use different names to describe the different types of germ cell tumours. The name describes:

• whereabouts in the body it started - such as ovarian or testicular
• what the tumour looks like under the microscope

Germ cell tumours can start in the:

• testicles
• ovaries
• chest (mediastinal tumour)
• back of the tummy (retroperitoneal tumour)
• brain (pineal region tumour)
• lower spine (sacrococcygeal tumour)

Some tumours are non cancerous (benign). And some are cancerous (malignant):

Benign germ cell tumours include mature teratomas.

Malignant germ cell tumours are split into 2 main groups:

• seminoma germ cell tumours (in females these are called dysgerminomas)
• non seminoma germ cell tumours (in females these are called non dysgerminomas)

Malignant non seminoma tumours include:

• immature teratomas
• yolk sac tumours
• choriocarcinomas
• embryonal carcinomas

Some non seminomas develop from just one type of cell. And some develop from a mixture of cell types. So, for example, a tumour can contain a mix of some teratoma cells and some embryonal carcinoma cells.

Seminomas are sometimes called pure seminomas. They only contain one type of cell. Some germ cell tumour contain both seminoma cells and non seminoma cells. Doctors usually class and treat these as non seminoma tumours.

Testicular germ cell tumours

Most testicular cancers are germ cell tumours. The 2 main types of testicular germ cell tumours are seminomas and non seminomas.

Ovarian germ cell tumours

Women can develop ovarian germ cell tumours. Many of these are non cancerous (benign). But some are cancerous. Only about 1 or 2% of ovarian cancers are this type. 

Most ovarian germ cell tumours occur in teenagers or young women, although they also occur in women in their 60s.

Ovarian teratoma is a type of ovarian germ cell tumour.

Types of extragonadal germ cell tumour (EGGCT)

Cancers that develop from germ cells in other parts of the body are rare. The medical name for germ cell tumours that develop outside of the ovaries or testicles is extragonadal germ cell tumour (EGGCT).

Germ cell tumours can start in:

• a part of the chest called the mediastinum (mediastinal germ cell tumours) 
• the brain (pineal region tumour)
• the back of the tummy (retroperitoneal germ cell tumour)
• the lower spine (sacrococcygeal germ cell tumour)

The mediastinum is the area between the lungs, which contains the heart. It is the most common place for extragonadal tumours in adults.

Pineal region tumours are rare brain tumours. The pineal gland is in the middle of the brain, just behind the brain stem. The most common type of pineal region tumour is a type of germ cell tumour called germinoma.

Retroperitoneal germ cell tumours start in the retroperitoneum. The retroperitoneum is the area at the back of the tummy (abdomen). It is where there are organs such as the kidneys, pancreas, bladder and some major blood vessels.

The treatment for retroperitoneal germ cell tumours is similar to testicular germ cell tumours. 

Sacrococcygeal germ cell tumours develop at the bottom of the spine by the tailbone (coccyx). This area is called the sacrococcygeal region. 

Although this is the most common type of germ cell tumour in children, it is very rare in adults. Some babies are diagnosed with a sacrococcygeal tumour before they are born, during a pregnancy (antenatal) scan. These tumours are often non cancerous (benign). 

Treatment for germ cell tumours

Your treatment depends on:

• where the tumour is
• the size and whether it has spread (the stage)
• the type of germ cell tumour

The main treatments are surgery and chemotherapy.

Surgery

You usually have surgery to remove germ cell tumours. This might be all the treatment you need if the tumour is small and easy to remove. 

Chemotherapy

You might have chemotherapy after surgery. Germ cell tumours generally respond very well to chemotherapy. Most people are cured. Even cancers that have spread are still very treatable with chemotherapy.

You can read more about the treatment for your type of germ cell tumour at the links above. 

Coping

Coping with a diagnosis of a rare cancer can be especially difficult. Being well informed about your cancer and its treatment can help. It can make it easier to make decisions and cope with what happens.

Talking to other people who have the same thing can also help.

Our discussion forum Cancer Chat is a place for anyone affected by cancer. You can share experiences, stories and information with other people.

You can call our nurse freephone helpline on 0808 800 4040. They are available from Monday to Friday, 9am to 5pm. Or you can send them a question online.

The Rare Cancer Alliance offer support and information to people with rare cancers. It has a forum where you might be able to meet others with the same cancer as you.