Ankara Etlik City Hospital Chest, Cardiovascular Diseases Hospital
What is Mediastinum? What are the diseases?
The mediastinum or mediastinum is the part of the rib cage behind the lungs. The mediastinum is a cavity containing many organs and pathologies. Thymic pathology, germ cell neoplasms, neuroendocrine tumors, lymphomas, soft tissue tumors and metastatic tumors constitute the main pathology.
It extends from the top of the thorax to the diaphragm. It includes the heart, great vessels of the heart, esophagus, trachea, phrenic nerve, cardiac nerve, thymus, and mediastinal lymph nodes.
Unlike adults, children often have respiratory distress and recurrent lung infections. Pain and cough are the most common symptoms, and severe pain indicates an advanced and invasive disease. Recurrent pulmonary infections and hemoptysis due to airway compression, dysphagia due to esophageal compression, paralysis due to spinal column involvement, unilateral diaphragmatic elevation due to phrenic nerve damage, hoarseness due to recurrent laryngeal nerve involvement, Horner's syndrome due to sympathetic ganglion involvement and vena cava superior (VCS) ) compression-related VKS syndrome 3 (VCSS) are the compression symptoms that can be seen. As in thymoma, systemic findings of some mediastinal diseases can be detected.
It consists of three main parts;
Anterior mediastinum: (anterosuperior compartment or retrosternal space) It is located behind the sternum, in front of the pericardium. Thymus, extrapericardial aorta and its branches, great veins and lymphatic tissues are included in this section.
Middle mediastinum: (visceral area) It is bounded anteriorly by the anterior pericardium, posteriorly by the posterior pericardium, the diaphragm, and the thoracic inlet. This section includes the heart, intrapericardial great vessel, pericardium, and trachea.
Posterior mediastinum: It extends from the posterior margins of the pericardium to the posterior border of the vertebral bodies, from the 1st rib to the diaphragm. Esophagus, nervus vagus, thoracic duct, sympathetic chain and azygos vein system are included in this section.
DIAGNOSTIC APPROACH:
IMAGING - CT, MRI, Radionucleic study
TISSUE SAMPLING - Mediastinoscopy, Thoracoscopy, Needle aspiration, open lung biopsy
Barium X-ray - Hernia, Achalasia, Diverticulum
•I-131- Intrathoracic goiter
Mediastinal Diseases Short Facts
Anterior Mediastinal Mass
Thymoma: It is a tumor originating from epithelial cells of the thymus. It is the most common cause of primary mediastinal tumors and anterior mediastinal masses in adults.
Thymic carcinoma: Thymic carcinomas are a heterogeneous group of epithelial tumors with early local invasion and distant metastasis potential.
Thymic Carcinoid: Thymic carcinoid is a rare, aggressive tumor that typically affects men in the 4th and 5th decades (40-50 years) with neuroendocrine features.
Lymphoma: Lymphoma accounts for 10-20% of all mediastinal tumors in adults and is the second most common cause of primary anterior mediastinal masses after thymoma.
Germ cell tumors: They constitute 15% of anterior mediastinal tumors in adults and 24% in children. They can rarely be found in the posterior mediastinum.
Thyroid and parathyroid tissue: Intrathoracic thyroid tissue is usually an extension of a cervical goiter but may rarely be found ectopically in the mediastinum. Intrathoracic goiter are cervico-thoracic masses that compress the trachea, usually on the right side. Radiologically, it contains lobulated, sharp-edged, cystic and hemorrhagic changes and areas of calcification. Patients may develop symptoms such as shortness of breath, stridor, wheezing, and dysphagia.
Middle Mediastinal Mass
lymphadenopathy: Infectious (mycobacterial and fungal) and non-infectious granulomatous diseases (such as sarcoidosis and silicosis) may involve mediastinal lymph nodes.
Vascular lesions: They constitute approximately 10% of all mediastinal masses and arise from arteries or veins of the systemic or pulmonary circulation.
Posterior Mediastinal Mass
Neurogenic tumors: Mediastinal tumors are usually located in the paravertebral area and neurogenic tumors are examined in three groups according to the structure they develop as peripheral nerve, sympathetic ganglion and paraganglion tumors.
Mediastinal Cystic Lesions: Primary cysts of the mediastinum constitute 20% of all mediastinal lesions. This heterogeneous group includes pericardial cysts, bronchogenic cysts, enteric cysts, thymic cysts, and ductus thoracic cysts (43-47). Bronchogenic and enteric cysts are known together as enterogenic cysts.
Mediastinitis: The term mediastinitis is used to express various infectious or inflammatory conditions in the mediastinum. Acute mediastinitis develops due to reasons such as esophageal or tracheobronchial perforation, penetrating chest trauma, postoperative sternal wound healing, paravertebral abscess or spread of oropharyngeal infection, RT, malignancy. Patients usually have a sudden onset of high fever, sweating, chest pain, dyspnea, and dysphagia.
Pneumomediastinum: It occurs spontaneously or as a result of overstretching and rupture of the alveoli due to increased intrathoracic volume or pressure in conditions such as asthma, trauma, and mechanical ventilation.