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Mediastinal germ cell tumours

Find out about mediastinal germ cell tumours.

What are mediastinal germ cell tumours?

A germ cell tumour is a tumour that develops from reproductive cells. They are sperm cells in men and egg cells in women.

They usually develop in the testicles or ovaries but can grow in other areas of the body, such as the stomach (abdomen), brain or mediastinum (pronounced media-sty-num).

The mediastinum is the area in the centre of the chest, between the lungs. It contains the heart, windpipe (trachea), food pipe (oesophagus), large main blood vessels and the lymph nodes that surround the heart.

Germ cell tumours that grow outside the ovary or testicle are very rare tumours. Doctors call them extragonadal germ cell tumours (EGGCT). The mediastinum is the most common place for extragonadal tumours to develop.

Doctors aren’t certain how these germ cell tumours develop in the mediastinum. There are some theories about how the cells get outside the testicle and ovary.

These include:

  • the cancer develops from very early cells that became misplaced during our development in the womb
  • the cancer started in the testicle or ovary and spread at a very early stage, but the original cancer has either disappeared or is too small to find

Types

A number of different types of germ cell tumours can develop in the mediastinum. These are much more common in males than females.

They are generally put into 2 main groups:

  • non seminoma germ cell tumours (in females these are called non dysgerminomas) - including teratomas, choriocarcinomas, embryonal carcinomas and yolk sac tumours
  • seminomas (in females these are called dysgerminomas)

Some teratomas can be non cancerous (benign).

Symptoms

Many people with a tumour in the mediastinum don’t have any symptoms. The doctor might spot the tumour on a chest X-ray you had for another reason.

If symptoms are present they might include:

  • shortness of breath
  • pain in the chest
  • a cough
  • raised temperature
  • weight loss
  • night sweats

Diagnosing

Doctors use various tests to diagnose mediastinal germ cell tumours. These might include:

  • a chest X-ray
  • blood tests – germ cell tumours often produce chemicals or hormones (tumour markers) that can be measured in the blood
  • mediastinoscopy (a test to look inside the chest)
  • CT scan
  • an ultrasound scan of the ovaries or testicles to check for signs of cancer
  • MRI scan

Treatment

The treatment for mediastinal germ cell tumours will depend on the type of germ cell tumour you have.

It may include chemotherapy, surgery, radiotherapy or a combination of these treatments. 

Benign teratomas are removed with surgery. The tumours can be very large and this is often major surgery due to the position of the tumour.

Chemotherapy is the most common treatment for non seminoma germ cell tumours. This is usually a combination of chemotherapy drugs.

The most commonly used combination is called BEP (bleomycin, etoposide and cisplatin). You may be offered treatment on a clinical trial, or intensive chemotherapy using different drugs. 

Once you have finished chemotherapy, your doctor will probably arrange a scan and more blood tests to check how well the treatment has worked.

The tumour may shrink away altogether. If there is any sign that the cancer is still there after chemotherapy, you may have surgery. 

During the operation, the surgeon will remove any tumour left behind. They send this to the lab, where a specialist examines it.

The type of surgery depends on where the remaining tumour is and whether it is close to any important body structures such as main blood vessels.

Your surgeon will be able to explain exactly what is involved if you need an operation.

If there is still cancer left behind your doctor may consider further treatment with chemotherapy.

The treatment depends on the size of the tumour. If the tumour is small, people usually have radiotherapy and this can often get rid of the tumour completely. 

If the tumour is large the usual treatment is chemotherapy. This is usually a combination of chemotherapy drugs and the most common type is BEP (bleomycin, etoposide and cisplatin). The treatment can get rid of the tumour completely for some people. 

If these treatments do not get rid of all of the tumour and the remaining area is smaller than 3cm your doctor is likely to suggest that you have monitoring (observation) to see if the tumour grows again.

If the tumour is larger than 3cm your doctor may offer observation or they may suggest surgery to remove the tumour.

Follow up

After treatment, you will have regular check ups, including tests for any sign of the cancer coming back.

Tests will include chest X-rays, and blood tests to check for any changes in the level of the tumour markers.

Last reviewed: 
27 Apr 2016
  • Textbook of uncommon cancer 4th Edition. D Raghavan and others. 2012. Wiley-Blackwell. 

  • Cancer and its management, Tobias and others. 6th Ed, Wiley-Blackwell, 2010.

  • Residual mass: an indication for further therapy in patients with advanced seminoma following systemic chemotherapy. R Motzer and others. Journal of clinical oncology. 1987 July;5(7):pages 1064-70.

  • Extragonadal Germ Cell Tumors Treatment (PDQ®)
    Health Professional Version
    PDQ Adult Treatment Editorial Board.

    Published online: February 25, 2015.

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