Definition

The mediastinum is a cavity in the chest area located between the two lungs. This cavity is surrounded by ribs on the front side, vertebrae on the back side, and lung organs on the right and left sides. It contains various organs such as the heart, large and major blood vessels (aorta), esophagus or gullet, thymus gland, tracheal duct, lymph nodes, and nerves.

A tumor is a condition of abnormal and uncontrolled cell growth in the body. Tumors can disrupt and affect the functions of the human body. They are divided into benign tumors and malignant tumors (cancer). Mediastinal tumors are those that grow from the outset in the mediastinum or originate from organs located in the mediastinal cavity, such as the thymus and lymph glands. They can also appear as metastasis from cancer that initially originates in other organs of the body. These tumors are rare and cannot be prevented.

Mediastinal tumors can occur in both children and adults. In children, tumors are more likely to be located in the posterior mediastinum, initially growing from nerves, and tend to be benign. Meanwhile, in adults, tumors are more likely to appear in the anterior mediastinum area and generally tend to be malignant.

Causes

There are several types of mediastinal tumors based on their location:

Anterior mediastinum (front side)

• Lymphoma, a malignant tumor that grows from the lymph nodes
• Thymomas, the most frequently found tumors that originate from the thymus gland. The majority of thymomas are benign, and a capsule typically envelops the tumor tissue. But around 30% of thymomas are cancerous, and the capsule sheath can allow cancer cells to escape
• Germ cell tumors, approximately 60-70% of germ cell cancers are benign and can be found in both men and women
• Mediastinal thyroid enlargement (goiter), generally this case is also mild

Middle mediastinum (middle side)

• Bronchogenic cyst, a sac filled with fluid or mucus in the lower respiratory tract
• Mediastinal lymphadenopathy, enlargement of lymph node cells in the mediastinum
• Pericardial cyst, a benign growth protruding from the membrane covering the heart (pericardium)
• Tracheal tumor, a tumor that originates from the trachea, can be benign or malignant.
• Esophageal tumor, a tumor that originates in the esophagus, can be malignant or benign
• Vascular abnormalities, enlargement of the aortic wall and aortic rupture can cause 'masses' in the mediastinum, not considered tumors

Posterior mediastinum (back side)

• Neurogenic tumors, the most commonly found tumors in the posterior mediastinum, originate from nerve tissue. About 70% are benign
• Lymphadenopathy, enlargement of lymph nodes in the posterior mediastinum
• Extramedullary hematopoiesis, the formation of blood cell components and blood plasma outside the bone marrow, is associated with severe anemia
• Paravertebral abnormalities, including infectious, malignant, or traumatic conditions in areas alongside the spine

Risk Factor

The factors that can increase the risk of developing a mediastinal tumor are still not well understood. These tumors are often found between the ages of 30 and 50, but they can develop at any age. In children, mediastinal tumors are commonly found in the posterior mediastinum, originating from nerve tissue and typically not malignant. However, in adults, mediastinal tumors are often located in the anterior region and tend to be malignant cancers such as lymphoma or thymoma.

Symptoms

About 40% of patients with mediastinal tumors do not experience any symptoms. Typically, tumor growth is incidentally discovered during chest x-ray examinations for other purposes. However, if symptoms occur, they are often due to the pressure of the tumor on surrounding structures, such as the spinal cord, heart, and pericardium. Symptoms may include:

• Cough
• Shortness of breath
• Chest pain (less commonly)
• Reddened face
• Fever
• Chills
• Night sweats
• Coughing up blood
• Hoarseness
• Unplanned and significant weight loss
• Enlarged lymph nodes
• Wheezing (shrinking) when breathing
• Vision disturbances (drooping eyelids, pupil constriction) on one side of the face

Diagnosis

The doctor will establish a diagnosis of a mediastinal tumor based on symptoms and diagnostic tests. They will look for signs and typical symptoms that point to a mediastinal tumor, such as fever, additional breathing sounds (stridor) when inhaling, coughing up blood, enlargement of lymph nodes, weight loss, and wheezing.

Diagnostic tests need to be conducted to visualize and evaluate the tumor and the possibility of spreading. Examinations are done according to indications. These examinations include:

• Chest X-ray
• Chest CT scan
• Biopsy
• MRI
• Mediastinoscopy and biopsy, a procedure used to determine the type of tumor and establish a definitive diagnosis, performed under general anesthesia
• Laboratory tests, such as complete blood count, metabolic panel, and tumor markers
• Testicular examination is often performed if there is suspicion of cancer metastasis to the testes if physical examination is not sufficient to establish a diagnosis.

Management

The treatment of mediastinal tumors depends on the type of tumor and its location.

• Thymoma requires surgical procedures to remove the tumor, followed by radiotherapy
• Thymic carcinoma requires surgery, radiation, and chemotherapy
• Lymphoma needs to be treated with radiation, and surgery is needed for diagnosis confirmation and lymphoma type
• Neurogenic tumors can be treated with surgical procedures
• Some benign masses that do not pose specific dangers can be observed in the long term

Your doctor will provide an overview of surgical preparation, techniques used, advantages and disadvantages of specific techniques, and the time required for recovery. Chemotherapy can cause different side effects depending on the substance given. Chemotherapy and radiation therapy can be administered before surgery to shrink the tumor size.

Complications

Each type of mediastinal tumor has different cure rates, depending on whether the tumor is benign or malignant, its location, and the individual's general health condition. Untreated mediastinal tumors can be dangerous to the body, as they can easily spread to organs within the mediastinum, such as the heart, pericardium, and major blood vessels.

Complications that can arise from mediastinal tumors include:

• Tumors located on the back side of the mediastinum can compress the spinal cord
• Tumor spreading to surrounding structures, such as the heart, pericardium, and major blood vessels (aorta, vena cava)
• Severe pleural effusion
• Superior vena cava syndrome, a disorder that occurs when blood flow through the vena cava slows down
• Sepsis or multi-organ damage as complications of systemic infection
• Radiation, surgical procedures, and chemotherapy can also cause side effects

Prevention

Mediastinal tumors cannot be prevented. However, you can reduce the risk of complications through early diagnosis and management.

When to See a Doctor?

Consult your doctor for further evaluation and management if you experience shortness of breath, cough, or other symptoms that persist for more than two weeks.