DISEASES OF MEDIASTINUM

Dr . Ahmed AlazzawiDr . Ahmed AlazzawiCardioThoracic&Vascular surgeonCardioThoracic&Vascular surgeonSulaimani University,College of MedicineSulaimani University,College of MedicineM.B.Ch.B,F.I.C.M.S,C.TH.V SurgM.B.Ch.B,F.I.C.M.S,C.TH.V Surg

Diseases of mediastinum

The mediastinum lies between the right and left pleuræ in and near the median sagittal plane of the chest. It extends from the sternum in front to the vertebral column behind, and from the upper thoracic inlet from above to the central tendon of diaphragm from below. It contains all the thoracic viscera excepting the lungs.

The mediastinum is conveniently divisible into sub compartments.

• The anterior mediastinum lies anterior to the heart and extends cephalad into the anterior half of the thoracic inlet.

• The posterior mediastinum lies behined the heart extending cephalad into the thoracic inlet .

• The middle mediastinum is the wedge in between with its base lying on the diaphragm and its apex at the top of the aortic arch.

• The anterior mediastinum contains the thymus ,along with a variable amount of adipose, areolar, and lymphatic tissue.

• The middle mediastinum contains the heart and pericardium,aorta,trachea and main stem bronchi,and associated lymph nodes.

• The posterior mediastinum containes the descending aorta,the esophagus,autonomic nerve trunkes ,and the thoracic duct.

• Most mediastinal lesions appear as mass lesions radio graphically ,most are neoplasms or cysts .

• Asmall number of mediastinal mass lesions are inflammatory or infectious .

• Vascular lesions,such as aneurysms,are considered elsewhere.

mediastinal tumors

• Growths that originate in the mediastinum are called primary mediastinal tumors. Most of them are composed of reproductive (germ) cells or develop in thymic, neurogenic (nerve), lymphatic, or mesenchymal (soft) tissue.

• Secondary (metastatic) mediastinal tumors originate in the lung, stomach, esophagus, and trachea, and spread through the lymphatic system to the chest cavity.

• Although still relatively rare, malignant mediastinal tumors are becoming more common. Usually diagnosed in patients between 30 and 50 years old, they can develop at any age and arise from any tissue that exists in or passes through the chest cavity.

The anterior compartment is defined by an imaginary line from the anterior border of the trachea extended to the xiphoid. The middle or visceral compartment is defined by the posterior margin of the anterior mediastinum and posteriorly by the anterior border of the spine. The posterior or paravertebral compartment lies behind the anterior margin of the spine in the para-vertebral sulci.

The mediastinum includes all of the structures The mediastinum includes all of the structures within the thoracic cavity except the lungs and within the thoracic cavity except the lungs and surrounding pleurae. This includes the heart, surrounding pleurae. This includes the heart, great vessels, trachea, oesophagus, thoracic great vessels, trachea, oesophagus, thoracic duct, vagus and phrenic nerves. Some of these duct, vagus and phrenic nerves. Some of these structures are in continuity with the neck structures are in continuity with the neck superiorly and the abdomen inferiorly. The region superiorly and the abdomen inferiorly. The region between them is filled with homogenous, elastic between them is filled with homogenous, elastic connective tissue; this permits the great deal of connective tissue; this permits the great deal of volume change and movement which is volume change and movement which is necessary for mediastinal structures e.g.:necessary for mediastinal structures e.g.:

passage of oesophageal boluses inferiorly passage of oesophageal boluses inferiorly descent of trachea and principal bronchi with descent of trachea and principal bronchi with

inspiration, the opposite movement for expiration inspiration, the opposite movement for expiration increased volume of venous return to the right increased volume of venous return to the right

side of the heart with inspirationside of the heart with inspiration

mediastinal emphysema(Ppneumomediastinum)• Air in the mediastinum.Most common cause is rupture of the alveoli (air then

enters the interstitial tissues and tracks to the mediastinum). Causes include:• raised intrapulmonary pressures e.g. vomiting, asthma, coughing • positive pressure mechanical ventilation• Other causes include:• penetrating neck injury • oesophageal and bronchial rupture Clinical features:• may be asymptomatic • chest pain that is worse on swallowing or breathing • crunching sound coincident with each heart beat Chest X-ray:• air in the upper mediastinum, around the heart, or within the soft tissues of

the neck • pneumothorax in 30% of cases Treatment:• treat underlying cause • treatment with high concentration inspiratory oxygen can hasten resolution

mediastinal masses

• Mediastinal masses on a chest X-ray can result from many causes.Subcutaneous or skin lesions may appear on a single chest X-ray as a mediastinal mass. Their true position is revealed by clinical examination and by taking different radiological views.

Causes include:Causes include:• lymphadenopathy e.g. lymphoma, lymphadenopathy e.g. lymphoma,

tuberculosis, carcinoma. tuberculosis, carcinoma. • thyroid derived e.g. thymoma, retrosternal thyroid derived e.g. thymoma, retrosternal

goitre. goitre. • aortic e.g. aneurysm, coarctation. aortic e.g. aneurysm, coarctation. • herniae e.g. hiatus hernia, diaphragmatic herniae e.g. hiatus hernia, diaphragmatic

herniae. herniae. • oesophageal e.g. achalasia, neoplasm. oesophageal e.g. achalasia, neoplasm. • cystic e.g. teratoma, dermoid, bronchial, cystic e.g. teratoma, dermoid, bronchial,

hydatid. hydatid. • neurogenic e.g. neurofibroma, neurogenic e.g. neurofibroma,

ganglioneuroma. ganglioneuroma. • others e.g. paravertebral abscess, others e.g. paravertebral abscess,

mesothelioma, lipoma.mesothelioma, lipoma.

clinical featuresclinical features

Mediastinal masses are asymptomatic in Mediastinal masses are asymptomatic in more than 50% of cases, the lesion being more than 50% of cases, the lesion being detected as an incidental detected as an incidental finding.Symptomatic masses usually finding.Symptomatic masses usually present with features due to pressure present with features due to pressure effects on the surrounding structures. effects on the surrounding structures. Features may include insidious onset of Features may include insidious onset of restrosternal chest pain, dysphagia or restrosternal chest pain, dysphagia or dyspnoea.dyspnoea.

investigationsinvestigations

Over 50% of mediastinal masses are detected as incidental Over 50% of mediastinal masses are detected as incidental findings on a chest X-ray. Further information necessary for findings on a chest X-ray. Further information necessary for management may be obtained from:management may be obtained from:

CT scan - axial imaging only CT scan - axial imaging only barium swallow - if oesophageal disease is suspected barium swallow - if oesophageal disease is suspected doppler sonography or venography of brachiocephalic veins or doppler sonography or venography of brachiocephalic veins or

superior vena cava superior vena cava arteriography arteriography MRI - when results of CT scan are equivocal; advantages over MRI - when results of CT scan are equivocal; advantages over

CT: CT: distinguishes vessels and masses distinguishes vessels and masses contrast media unnecessary contrast media unnecessary imaging in multiple planes imaging in multiple planes good delineation of hilar structuresgood delineation of hilar structures

biopsy - if suspected neoplasmbiopsy - if suspected neoplasm

Anterior Mediastinal Tumors The most common anterior mediastinal tumors are

thymomas, teratomas, lymphomas, and thyroid tissue that has become enlarged or displaced (ectopic).

Thymomas The cause of most adult mediastinal tumors and 15%

of those in children, thymomas almost always form at the spot where the heart and great vessels meet. These tumors usually develop between the ages of 40 and 60.

About half of the people who have thymomas do not have any symptoms. Between 35 and 50% experience symptoms of myasthenia gravis, such as

weakness of the eye muscles drooping of one or both eyelids (ptosis) fatigue Early treatment of these slow-growing tumors is very

effective. Most are benign, but thymomas can metastasize and should always be considered cancerous

Teratomas• Most common in young adults, teratomas are made up of

embryonic (germ) cells that did not develop normally and do not belong in the part of the body where the tumor is located. Found along the center of the body between the skull and kidneys, teratomas account for:

• 10%–15% of primary mediastinal tumors • 70% of germ cell tumors in children • 60% of germ cell tumors in adults• Teratomas may be solid or contain cysts. Malignant teratomas

usually develop between the ages of 30 and 40, and almost all (90%) of them occur in men.

• At least 90% of patients with these tumors experience:• chest pain • cough • fever • shortness of breath• These symptoms may not appear until the tumor has grown very

large.

Thyroid Tumors

• Most mediastinal thyroid tumors grow out of goiters and occur in women between the ages of 50 and 60. About 75% of these tumors extend to the windpipe (trachea). The rest extend behind it.

• Mediastinal thyroid tumors are encapsulated and do not metastasize.

The differential diagnosis of an anterior mediastinal mass includes:The differential diagnosis of an anterior mediastinal mass includes: Tumours:Tumours: thymoma thymoma germ cell neoplasm: germ cell neoplasm:

teratoma teratoma seminoma seminoma primary choriocarcinoma primary choriocarcinoma endodermal sinus tumour endodermal sinus tumour embryonal carcinomaembryonal carcinoma

thyroid lesion thyroid lesion parathyroid lesion parathyroid lesion lymphoma lymphoma lymphangioma lymphangioma lipoma lipoma Vascular:Vascular: unfolded aorta unfolded aorta aortic aneurysm aortic aneurysm aortic dissectionaortic dissection Gastrointestinal:Gastrointestinal: hernia through the foramen of Morgagnihernia through the foramen of Morgagni

The differential diagnosis of a middle mediastinal mass includes:• Lymph node enlargement:• lymphoma • leukaemia • sarcoidosis • metastatic carcinoma • infections:

– fungal – tuberculosis – infective mononucleosis

• Masses related to the airway:• bronchogenic cyst • primary tracheal neoplasm• Dilatation of blood vessels:• pulmonary artery • aorta or its branches • major mediastinal veins

The differential diagnosis of a posterior mediastinal mass includes:• Masses related to the spinal cord:• neurogenic neoplasms:

– neuroblastoma – neurosarcoma – neurofibroma

• meningocoele• Gastointestinal:• hernia through foramen of Bochdalek • primary lesions of the oesophagus:

– neoplasm – diverticulum – megaoesophagus – achalasia

• hiatus hernia• Disorders of the thoracic spine:• neoplasms • infectious spondylitis • fracture with haematoma• Various cysts:• neurenteric • gastroenteric • thoracic duct

Posterior Mediastinal TumorsTumors of the posterior mediastinum include: neurogenic

tumors, mesenchymal tumors, and endocrine tumors. Neurogenic Tumors• Representing 19–39% of mediastinal tumors, neurogenic

tumors can develop at any age. They are most common in young adults.

• Adult neurogenic tumors are usually benign. In children, they tend to be malignant and tend to metastasize before symptoms appear.

Malignant Schwannomas• Also known as malignant sheath tumors, malignant

sarcomas, and neurosarcomas, these tumors develop from the tube (sheath) enclosing the peripheral nerves that transmit impulses from the central nervous system (CNS) to muscles and organs.

• Usually large and painful, these rare, aggressive tumors may invade the lungs, bones, and aorta.

Neuroblastomas• The most common malignant tumors of

early childhood, neuroblastomas generally occur before the age of two. These tumors usually develop in the adrenal glands, neck, abdomen, or pelvis.

• Neuroblastomas often spread to other organs. Most patients have symptoms that relate to the part of the body the tumor has invaded. Likelihood of survival is greatest in patients who are less than a year old and whose tumor has not spread.

Symptoms• About 40% of people who have mediastinal tumors do not have any symptoms. When symptoms

exist, they usually result from pressure on an organ that the tumor has invaded, and indicate that the tumor is malignant.

• The symptoms most commonly associated with mediastinal tumors are:• chest pain • cough • shortness of breath• A person who has a mediastinal tumor may be hoarse, cough up blood (hemoptysis), or have:• fatigue • difficulty swallowing (dysphagia) • night sweats • systemic lupus erythematosus • inflamed muscles (polymyositis) • ulcerative colitis • rheumatoid arthritis • thyroid problems (thyroiditis, thyrotoxicosis,) • fever • glandular disorders (panhypopituitarism, adenopathy) • high blood pressure • low blood sugar (hypoglycemia) • breast development in males (gynecomastia) • wheezing • vocal cord paralysis • heart problems (superior vena cava syndrome, pericardial tamponade, arrhythmias) • neurologic abnormalities • weight lossand other immune, autoimmune, and endocrine system disorders.

mediastinal tumours• Primary mediastinal tumours are uncommon. The more common

ones include:• dermoid cysts:

– most common• neurogenic tumours:

– arising from nerve cells: • neuroblastoma • ganglioneuroma • phaeochromocytoma

– arising from nerve sheaths: – neurilemmoma

• neurosarcoma • neurofibroma

• thymoma• other very rare tumours:

– lipoma and liposarcoma – haemangioma – benign and malignant mesenchymal tumours of the heart – mesothelioma of the pericardium

• Lymphoma• Lymphoma is a term for cancers that occur in cells of the lymphatic

(immune) system. These cancers are subdivided into 2 big groups of either Hodgkin’s Lymphoma or non-Hodgkin’s Lymphoma. A multitude of specific subtypes exists, depending on which cell type is involved. Because lymph cells travel in the blood stream throughout the body, these cancers represent a systemic disease for which chemotherapy is the mainstay of treatment.

•  • Lymphoma is diagnosed by removing tissue samples of enlarged lymph

nodes. The location of these nodes will vary from each individual patient. Frequently enlarged lymph nodes will present as an anterior mediastinal mass in which case a thoracic surgeon will be involved in providing adequate tissue biopsies. These biopsies can be obtained by endoscopic or surgical techniques. Endoscopy involves the use of a camera at the tip of a scope that is introduced in the esophagus or the wind pipe (trachea and bronchi). These nodes can be sampled with or without the assistance of endoscopic (EUS) ultrasound or endobronchial ultrasound (EBUS). Sometimes these techniques are not sufficient for diagnosis and a surgical procedure is needed, either through a mediastinoscopy (a small incision above the breast bone) or by video-assisted surgery (VATS).

Invasive Procedures• Imaging studies play the most important role in initial

diagnosis of mediastinal tumors, but before doctors can determine the most effective treatment for any tumor, they must know what kind of cells it contains.

• Although invasive diagnostic procedures have been largely replaced by less invasive techniques (such as CT-guided percutaneous needle biopsy), some patients still require surgery.

• MEDIASTINOSCOPY Performed under general anesthesia, this relatively simple procedure enables doctors to accurately diagnose 80–90% of mediastinal tumors, and 95–100% of anterior mediastinal tumors.

• Mediastinoscopy is especially useful in providing the large tissue specimens needed to diagnose lymphomas.

MediastinitisMediastinitis

Mediastinitis is an infection involving the Mediastinitis is an infection involving the mediastinum. It is a surgical emergency mediastinum. It is a surgical emergency with a high mortality rate. Mediastinitis may with a high mortality rate. Mediastinitis may begin primarily from structures in the begin primarily from structures in the mediastinum, or it may be the result of an mediastinum, or it may be the result of an infection extending downward from the infection extending downward from the oropharynx, in which case it is called oropharynx, in which case it is called descending necrotizing mediastinitis.descending necrotizing mediastinitis.

The diagnostic criteria for descending The diagnostic criteria for descending necrotizing mediastinitis include the necrotizing mediastinitis include the following: following:

Clinical evidence of severe cervical Clinical evidence of severe cervical infection infection

Characteristic radiographic features of Characteristic radiographic features of mediastinitis mediastinitis

Documentation of necrotizing mediastinal Documentation of necrotizing mediastinal infection at operation or at postmortem infection at operation or at postmortem

Establishment of the relationship between Establishment of the relationship between the descending necrotizing mediastinitis the descending necrotizing mediastinitis and the oropharyngeal infectionand the oropharyngeal infection

Causes• Causes of mediastinitis may include the following:• Primary neck infection • Foreign body • Pharyngitis • Tonsillitis • Sinusitis • Otitis media • Dental infections • Sialadenitis • Suppurative thyroiditis • Endotracheal intubation 

Symptoms

• Chest pain

• Chills

• Coughing up blood

• Fever

• Malaise

• Shortness of breath

Signs

• Signs of mediastinitis in patients who have had recent surgery include:

• Chest wall tenderness

• Wound drainage

• Unstable chest wall

TreatmentTreatment

You may receive antibiotics if you You may receive antibiotics if you have an infection.have an infection.

You may need surgery to remove the You may need surgery to remove the area of inflammation if the blood area of inflammation if the blood vessels, windpipe, or esophagus is vessels, windpipe, or esophagus is blocked.blocked.

My Kid :Ibraheem Ahmed Ibraheem