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Thymus gland tumours

This page is about tumours in the thymus gland. There is information about


The thymus gland

The thymus is a gland in the chest. It is at its largest in adolescence and then gradually shrinks away throughout adulthood, being replaced with fatty tissue. It is involved in the development of white blood cells called T lymphocytes.

Cancer of the thymus can happen. But it is not all that common. Most tumours in the thymus are called thymomas. There is also a much rarer form of thymus gland cancer called thymic carcinoma. Most thymus tumours are in the front of the chest but more rarely, they develop in the neck.



Thymomas are generally slow growing tumours found most often in people between the ages of 40 and 60. The tumours vary in how they behave. Some grow very slowly. Others grow more quickly and can spread to the lungs or the covering of the lungs (the pleura). It is very unusual for them to spread anywhere else in the body.

Like many other cancers, we don't know exactly what causes thymomas. About 4 out of 10 people diagnosed (40%) have another condition called myasthenia gravis. Myasthenia gravis is an autoimmune disease. Thymoma has been linked to other autoimmune diseases, such as systemic lupus erythematosus (SLE) and rheumatoid arthritis. Thymoma has also been linked to blood conditions such as pernicious anaemia.

Many people don't have any symptoms from their thymoma. They can be found by accident, when you are having a chest X ray for something else. If you do have symptoms, they may include difficulty swallowing, a cough and tiredness.

The main treatment for thymoma is an operation to remove it. Many thymomas are covered in a fibrous sheet called a capsule. These thymomas are often quite easy to remove and are usually cured with surgery alone.

Other thymomas don't have the fibrous capsule and are more difficult to remove completely. If your thymoma can't be completely removed, or if there is a risk that it will come back, you might have a course of radiotherapy after surgery. Most people with thymoma are cured with either surgery alone or surgery followed by radiotherapy.

If the cancer does come back you might have chemotherapy. There is no standard treatment because this is a rare condition. But chemotherapy often includes a drug called cisplatin. Unfortunately, if your thymoma does come back, it isn't usually possible to get rid of it altogether. But treatment can often keep it under control for some time. Your doctor will be able to tell you more, by keeping a close eye on how your tumour responds to treatment.


Thymic carcinoma

Thymic carcinoma is much rarer than thymoma. It tends to grow and develop more quickly and is more likely to spread to other parts of the body. Thymic carcinomas are found in all age groups but are most common in middle aged and older adults. Most people have symptoms. These include a cough, shortness of breath and chest pain. It is much rarer to also have an autoimmune condition such as myasthenia gravis with thymic carcinoma than it is with thymoma.

Most people have treatment with surgery and either radiotherapy or chemotherapy, or both. The most common type of treatment is surgery followed by radiotherapy. The surgeon will take out as much of the tumour as possible. They then use radiotherapy to try and kill off any cancer cells left behind.

Unfortunately, thymic carcinoma is harder to cure than thymoma. This is because it often spreads quite early on. The cancer can spread to the lungs and lymph nodes in the chest. In some cases, it may also spread to the bones or to the liver. It is difficult to find reliable statistics for the outlook of conditions as rare as thymic carcinoma. But around a third of the people diagnosed with thymic carcinoma are likely to live for at least 5 years.


More information about chemotherapy and radiotherapy

We have more detailed information about radiotherapy and chemotherapy. You can find out more about what these treatments involve and about the likely side effects.

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Updated: 19 February 2015