Mediastinal lymph nodes are anatomic structures that play an important role the body's lymphatic system. They are located in a region of the body called the mediastinum, which is an area in the chest cavity between the heart and lungs. Unlike some of the body's other lymph nodes, these nodes cannot be felt through the skin, and can only be evaluated using radiographic techniques. These lymph nodes can be enlarged due to conditions such as cancer, infection, and sarcoidosis.
Structures that filter lymphatic fluid and help eliminate substances, lymph nodes are located throughout the body. While some lymph nodes have a more superficial location and can be felt through the skin, others are located in deeper regions of the body. The mediastinal lymph nodes, for example, are located centrally in the chest cavity, in the area between the two lungs. They surround the trachea, esophagus, aorta, pulmonary veins, and the central portion of the lungs.
Detection of enlarged mediastinal lymph nodes relies on imaging studies, as these structures are not palpable through the skin. An x-ray of the chest, for example, can show a widening of the mediastinal region. A more definitive diagnosis of enlarged mediastinal lymph nodes is often performed by doing a computed tomography (CT) scan of the chest. When evaluating to see if the nodes are enlarged secondary to the spread of a cancer, positron emission technology (PET) scans can identify these nodes as well.
Enlargement of the mediastinal lymph nodes can happen for a number of reasons. Cancers including non-Hodgkin's lymphoma, chronic lymphocytic lymphoma, or testicular cancer could cause an enlargement of these nodes. Lung disease caused by a number of pathologic agents including different types of bacteria and fungi can result in growth of these structures. Enlarged mediastinal lymph nodes are also associated with sarcoidosis, which is a condition that can cause lung problems, heart disease, and eye problems.
Abnormal mediastinal lymph nodes can sometimes be accessed surgically for a number of reasons. If a patient is suspected to have cancer, surgeons might try to take a sample of the mediastinal lymph nodes to see if they have been affected by the spread of these cancers. This provides important information about the prognosis of the cancer patient, and also helps determine what sort of treatment is best suited for that patient's disease. If a patient has enlarged mediastinal lymph nodes for unknown reasons, obtaining a sample of these structures can be important because a microscopic examination of the node contents can help in diagnosis of the underlying condition.
