Mediastinal Lymph Nodes

What are Mediastinal lymph nodes?

Lymph nodes, in general, are small bean shaped structures that are a very important part of your lymphatic system. Your lymphatic system is part of your immune system. The lymphatic system is an interconnected system of spaces, nodes, and vessels in your body that circulates lymph, which is a fluid made of various liquids and proteins. Your immune system is what keeps your body healthy and disease free. Lymph nodes are what acts as filters in your body fighting off bacteria and removing harmful particles. They also produce white blood cells to help fight infections. Because you are unable to notice when these lymph nodes are swollen if it is from cancer this medical condition can spread quickly through the mediastinal lymph nodes due to the location of adjoining lymph nodes.

Anatomy

Mediastinal lymph nodes are found in the region of your body called the mediastinum. This is the central compartment of your chest cavity between your heart and lungs. These lymph nodes surround your esophagus, pulmonary veins, and the central portion of your lungs, trachea, and aorta. The mediastinal lymph nodes are responsible for helping the thymus gland produce mature lymphocytes, which are a type of white blood cells, and helping to produce bone marrow. There are two major groups of mediastinal lymph nodes, which are, your:

• Anterior – these are located posterior, or behind, your sternum (breastbone) and anterior, or in front of, your heart. These lymph nodes surround the major vessels of your heart, thymus, and pericardium, the sac of fibrous tissue that surrounds your heart.
• Posterior – these are located posterior, or behind, your heart and anterior, in front of, your spinal column. These run in a vertical string along your thoracic cavity near your aorta, trachea, and esophagus.

Causes of enlargement

These particular lymph nodes can become enlarged due to various conditions that can include:

• Infection
• Cancer – chronic lymphocytic lymphoma, non-Hodgkin’s lymphoma, testicular cancer and other cancers of your lungs, esophagus, and stomach
• Sarcoidosis – this is an inflammatory disease that affects multiple organs in your body but mostly your lymph glands, skin, eyes, and lungs
  Lung diseases—these can be caused by a number of pathologic agents that include different types of fungi and bacteria

Diagnosis

Most lymph nodes in your body can be felt through your skin but mediastinal lymph nodes cannot. They can be evaluated only by using radiographic techniques. When using x-rays taken of your chest they can show a widening of your mediastinal region. To get a more definitive diagnosis they would need to do a CT scan of your chest. If you are being evaluated to see if the mediastinal lymph nodes are enlarged secondary to the spread of cancer the radiologist will use a positron emission technology scan (PET) to identify these lymph nodes.

Because mediastinal lymph nodes are not noticeable as they swell they may also do a procedure called a mediastinoscopy to see if these lymph nodes are swollen. When this procedure is done a tube will be inserted into your chest to look for the swelling of these lymph nodes and tumors. This procedure is done under general anesthesia as an outpatient procedure.

Why do a biopsy?

When mediastinal lymph nodes are abnormal they may be access surgically for a variety of reasons such as the suspicion of cancer. They may do a biopsy of the lymph node to see if it has been affected by the spread of cancer along with the prognosis. It can also help to determine what treatment would be best used. If a patient has enlarged mediastinal lymph nodes and a biopsy is done under a microscopic examination it can help the physician known what the underlying medical condition is for them being abnormally enlarged.

Treatment

If the mediastinal lymph nodes are cancerous what treatment used will depend on the stage and location of the cancer. If it is decided to treat these lymph nodes the surgeon can do a mediastinal lymphadenectomy, which was first performed in 1951. Although it can be used to stage lung cancer they have still not decided if the benefits from the surgery are worth the risks of the procedure, such as not increasing the survival rate and accuracy in staging the cancer. Because mediastinal lymph nodes cannot be treated easily it is best to detect any cancers of your esophagus, stomach, and lungs early.