A variety of different tumors (neoplasms) can develop in the mediastinum. Mediastinal tumors can be benign or malignant. They can originate from the thyroid gland or the thymus gland, for example. Depending on where the mediastinal tumor has formed and what type of tissue is involved, the interdisciplinary tumor board will decide which therapy promises the most success.
What are mediastinal tumors?
The mediastinum (Latin: mediastinal cavity) is a space filled with connective tissue in the chest cavity (in the thorax). It extends from the diaphragm to the neck and from the sternum to the spine. The heart, trachea, oesophagus, thymus, bronchi, lymph nodes, nerves and blood vessels (veins, arteries) are located in this area. Many of the mediastinal tumors that can develop in the chest cavity are benign. However, malignant tumors can also form in the organs and different types of tissue in the mediastinum.
The mediastinum can also be the site of metastases from tumors that originally developed in other parts of the body. Such neoplasms in other locations are called metastases. In contrast, the original tumors are called primary tumors.
Benign tumors (benign tumors) displace other tissue, but do not destroy it and do not form metastases. Malignant tumors grow into other tissue and destroy it. They can also “spread”, i.e. form metastases.
Mediastinal tumors: mostly benign
As mentioned, mediastinal tumors can be benign or malignant. The most common primary tumors originating in the mediastinum are as follows:
- Tumors in the lymphatic tissue(lymphomas). These tumors usually originate from lymph nodes.
- Thymus gland tumors (thymomas). The thymus gland is located directly behind the breastbone. In children, it plays a decisive role in the formation of immune cells (lymphocytes). In adults, most of the glandular tissue has regressed and turned into fatty tissue. The remaining cells of the thymus gland can degenerate, resulting in tumors. Thymomas are mostly benign and only malignant in about a quarter of cases.
- Thyroid tumors. The thyroid gland is located in the neck, below the larynx and in front of the windpipe. It is not located in the mediastinum. But tumors of the thyroid gland can grow into the mediastinum.
- Tumors in nerve tissue (neurinomas). They affect nerves near the spinal column.
Some of the many different types of mediastinal tumors are always benign. For example these:
- Chondromas are benign tumors that consist of cartilage tissue.
- Lipomas are benign fatty tumors.
- Hemangiomas (“blood sponges”) affect blood vessels.
- Fibromas are tumors of the connective tissue.
- Thymolipomas are large, severe tumors consisting of fatty tissue and thymus cells.
In addition to the primary tumors mentioned above, metastases of cells from other regions of the body can also lead to mediastinal tumors in the mediastinum. These include, for example, the germ cell tumors that occur in men. Male germ cells (sperm) are formed in the testicles. Nevertheless, scattered germ cells may develop into mediastinal tumors in the mediastinum, which is far away from the abdomen.
Mediastinal tumors – frequency and age
Mediastinal tumors are rare. More than half of them are lymphomas, thymomas or thyroid tumors. Around 60 percent of these tumors are benign and around 40 percent are malignant. The majority of sufferers are adults. In children, mediastinal tumors tend to develop near the spine (in the posterior mediastinum). This is where tumors of the nerve cords (neurinomas) form.
Thymomas, mediastinal tumors of the thymus gland, are among the most common mediastinal tumors. Nevertheless, in Switzerland and other countries, fewer than five in a million people contract the disease each year. Thymomas often occur together with a concomitant disease. For example with anemia (anemia), thyroiditis or rheumatoid arthritis.
In more than 40 percent of cases, the accompanying disease of a mediastinal tumor of the thymus gland is a muscle disease called myasthenia gravis (severe muscle weakness or myasthenia). This is an autoimmune disease, i.e. a disease in which the function of the patient’s own immune system is disrupted. It attacks the muscle tissue and destroys it.
Patients who suffer from both a mediastinal tumor of the thymus gland and myasthenia are often 30 to 40 years old at the time of diagnosis. Patients without myasthenia gravis are usually older and often fall ill between the ages of 60 and 70.
Mediastinal tumors: causes and risk factors
If you have developed a malignant mediastinal tumor, it is almost impossible to determine the cause. It is only generally known that certain risk factors can promote cancer. These risk factors include
- chronic inflammation,
- strong or frequent radiation,
- contact with certain harmful substances (including tobacco smoke) and
- an unhealthy lifestyle (sweet and high-fat diet, lack of exercise).
If you have developed a benign mediastinal tumor, it may also be genetic. This means that you may have inherited a predisposition to this or that a similar mediastinal tumor already runs in your family.
Sometimes a malignant tumor in the chest cavity (in the mediastinum) can also develop from an originally benign tumor.
Lung and Thoracic Oncology Center
At the USZ, numerous specialist departments have joined forces to form a lung and thoracic oncology center. The center is certified according to the guidelines of the German Cancer Society (DKG). A team of experts specializing in the medical treatment of mediastinal tumours works closely together here for the benefit of our patients. At DKG-certified centers, patients are treated according to strict quality criteria and, according to current studies, have a better chance of survival on average.
Symptoms: Mediastinal tumors
There are no generally valid and reliable symptoms that could signal to you that you have a mediastinal tumor. A tumor of the mediastinum is most likely to make itself felt by pressing on other organs in the chest cavity, which are then affected. For example, if you have a mediastinal tumor, you may suffer from coughing, hoarseness, difficulty swallowing or shortness of breath. Chest pain can also occur. Neurinomas originating from nerve cords near the spine can cause pain, numbness or tingling in the back.
The symptoms of a mediastinal tumor often only become apparent at an advanced stage of the disease. Many of these tumors are therefore discovered rather late.
Mediastinal tumors: Diagnosis with us
If you are suspected of having a mediastinal tumor, we will first clarify whether it really is a tumor. This is because there is also the possibility that other, non-tumorous structures have enlarged in your chest cavity. For example, an overinflated lung (in pulmonary emphysema) or after a diaphragmatic hernia, the contents of the abdominal cavity are pushed up. They could produce symptoms similar to those of a mediastinal tumor.
If it has been established that there is a tumor in your chest cavity (in the mediastinum), we want to know whether it is benign or malignant. This can usually be determined by taking a tissue sample (biopsy): Under the microscope, benign tumors can be distinguished from malignant ones by examining the type and composition of the cells.
Depending on the case, the tissue sample is taken with a fine needle under local anesthesia or surgically under general anesthesia. Surgically, a rod chamber and long, thin instruments are inserted into the mediastinum (mediastinoscopy) or into the chest (thoracoscopy) through small incisions (keyhole surgery or minimally invasive surgery). Depending on the size of the tumor, it can also be removed completely.
There are also various methods available that we can use in hospital to identify the location and size of a mediastinal tumor from the outside:
The body’s own tumor markers can form in the blood of patients with certain mediastinal tumors. These are proteins or other components that indicate the existence of certain tumors. For example, germ cell tumors of the mediastinum become noticeable through the tumor marker beta-HCG, which is a hormone.
Second opinion for mediastinal tumors
When a cancer diagnosis is made, a second medical opinion is an important decision-making tool. The Comprehensive Cancer Center Zurich supports you with a professional expert opinion. They receive a thorough analysis of the situation as well as personal advice and quick answers to their questions.
Mediastinal tumors: prevention, early detection, prognosis
A large number of different mediastinal tumors can develop in the chest cavity with its different types of tissue. For this reason too, it is not possible to give general advice on how to prevent the formation of various benign and malignant neoplasms in the mediastinum. Especially as the cause of a mediastinal tumor often cannot be clarified.
Generally speaking, you should try to avoid the risk factors already mentioned. However, these risk factors – for example smoking, an unhealthy diet, radiation, lack of exercise – affect the development of tumors in general, not just mediastinal tumors.
The early detection of tumors in the chest cavity is just as difficult. They are often discovered by chance. For example, because they have displaced healthy tissue and then symptoms become noticeable that do not initially indicate a tumor. For example, hoarseness or difficulty swallowing.
Course and prognosis of mediastinal tumors
How the disease progresses with a mediastinal tumor and what the prognosis will be depends primarily on several factors:
- Tumor type and from which tissue
- How advanced the tumor is at the time of discovery
- Which therapy options (surgical, radio-therapeutic, oncological or combinations thereof) are possible
If it is a malignant tumor, metastases can form. As soon as a tumor has spread, i.e. formed metastases, the disease is considered advanced and the prognosis worsens.
If we detect a mediastinal tumor in time and treat it successfully, the prognosis can be quite good. For example, 90 to 100 percent of those affected by a germ cell tumor that is treated correctly and in good time are still alive after ten years.
Mediastinal tumors: effective treatment
How we treat a mediastinal tumor depends primarily on the type of tumor that has formed in your chest (in the mediastinum). Depending on the type of tissue and the stage of the tumor, the various treatment options (surgical removal, chemotherapy or radiotherapy) are used in combination.