anterior mediastinum, middle mediastinum, posterior mediastinum
The mediastinum is divided into three sections

What are mediastinal tumors?

Tumors (also called neoplasms) are masses of cells. They can be benign (not cancer) or malignant (cancer). Mediastinal tumors are growths that form in the area of the chest that separates the lungs. This area, called the mediastinum, is surrounded by the breastbone in front, the spine in back, and the lungs on each side. The mediastinum contains the heart, aorta, esophagus, thymus, trachea, lymph nodes and nerves. The thymus is an organ that is part of the immune system. The lymph system, or lymphatic system, is also part of the immune system and helps to protect the body.

Who is affected by mediastinal tumors?

In general, mediastinal tumors are rare. Mediastinal tumors are usually diagnosed in patients aged 30 to 50 years, but they can develop at any age and form from any tissue that exists in or passes through the chest cavity.

The location of tumors within the mediastinum varies according to the age of the patient. In children, tumors are commonly found in the posterior (back) mediastinum. These mediastinal tumors often begin in the nerves and are typically not cancerous.

In adults, most mediastinal tumors occur in the anterior (front) mediastinum and are generally malignant (cancerous) lymphomas or thymomas.

Is a mediastinal tumor serious?

Due to their location, mediastinal tumors that are not treated can cause serious problems, even if they are not cancerous. These problems include spreading to the heart, pericardium (the lining around the heart), and great vessels (the aorta and vena cava). Tumors located in the posterior (back) mediastinum can cause compression of the spinal cord.

What causes mediastinal tumors?

There are several types of mediastinal tumors, with their causes linked to where they form in the mediastinum.

Anterior (front) mediastinum
  • Lymphoma: These malignant tumors include both Hodgkin's disease and non Hodgkin's lymphoma.
  • Thymoma and thymic cyst: These are the most common causes of a thymic mass. The majority of thymomas are benign and surrounded by a fibrous capsule. However, about 30% of these may be more aggressive and grow through the sac into other tissue.
  • Germ cell: The majority of germ cell neoplasms (60 to 70%) are benign and are found in both males and females.
  • Thyroid mass mediastinal: This is usually a benign growth, such as a goiter.
Middle mediastinum
  • Bronchogenic cyst : This is a benign growth with respiratory origins.
  • Lymphadenopathy mediastinal: This is an enlargement of the lymph nodes.
  • Pericardial cyst: This is a benign growth that results from an "out-pouching" of the pericardium (the heart's lining).
  • Tracheal tumors: These can be benign or malignant.
  • Esophageal tumors: These can be benign or malignant.
  • Esophageal abnormalities: These include achalasia esophageal, diverticulum, and hiatal hernia.
  • Vascular abnormalities: These include aortic aneurysm and aortic dissection.
Posterior (back) mediastinum
  • Neurogenic tumors: The most common cause of posterior mediastinal tumors, these are classified as nerve sheath neoplasms, ganglion cell neoplasms, and paraganglionic cell neoplasms. Approximately 70% of neurogenic neoplasms are benign.
  • Lymphadenopathy: This refers to an enlargement of the lymph nodes.
  • Extramedullary haematopoiesis: This is a rare cause of masses that form from bone marrow expansion and are associated with severe anemia.
  • Neuroenteric cyst: This is a rare growth, which involves both neural and gastrointestinal elements.
  • Paravertebral abnormalities: These include infectious, malignant and traumatic abnormalities of the thoracic spine.
  • Vascular abnormalities: These include aortic aneurysms.

What are the symptoms of a mediastinal tumor?

Almost 40% of people who have mediastinal tumors experience no symptoms. Most of the growths are often discovered on a chest X-ray that is performed for another reason. Symptoms often result from the pressure put by the tumors onto surrounding structures, such as the spinal cord, heart or the pericardium (the heart's lining), and may include:

  • Cough
  • Shortness of breath
  • Chest pain (somewhat rare)
  • Flushing
  • Fever
  • Chills
  • Night sweats
  • Coughing up blood
  • Hoarseness
  • Unexplained weight loss
  • Lymphadenopathy (swollen or tender lymph nodes)
  • Wheezing
  • Stridor (high-pitched and noisy breathing, which could mean a blockage)
  • Eye issues (drooping eyelid, small pupil) on one side of the face

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