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Anatomy of mediastinum and its disorders
Anatomy of mediastinum and its disorders
Anatomy of mediastinum and its disorders
Anatomy of mediastinum and its disorders
Anatomy of mediastinum and its disorders
Anatomy of mediastinum and its disorders
Anatomy of mediastinum and its disorders
Anatomy of mediastinum and its disorders
Anatomy of mediastinum and its disorders
Anatomy of mediastinum and its disorders
Anatomy of mediastinum and its disorders
Anatomy of mediastinum and its disorders
Anatomy of mediastinum and its disorders
Anatomy of mediastinum and its disorders
Anatomy of mediastinum and its disorders
Anatomy of mediastinum and its disorders
Anatomy of mediastinum and its disorders
Anatomy of mediastinum and its disorders
Anatomy of mediastinum and its disorders
Anatomy of mediastinum and its disorders
Anatomy of mediastinum and its disorders
Anatomy of mediastinum and its disorders
Anatomy of mediastinum and its disorders
Anatomy of mediastinum and its disorders
Anatomy of mediastinum and its disorders
Anatomy of mediastinum and its disorders
Anatomy of mediastinum and its disorders
Anatomy of mediastinum and its disorders
Anatomy of mediastinum and its disorders
Anatomy of mediastinum and its disorders
Anatomy of mediastinum and its disorders
Anatomy of mediastinum and its disorders
Anatomy of mediastinum and its disorders
Anatomy of mediastinum and its disorders
Anatomy of mediastinum and its disorders
Anatomy of mediastinum and its disorders
Anatomy of mediastinum and its disorders
Anatomy of mediastinum and its disorders
Anatomy of mediastinum and its disorders
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Anatomy of mediastinum and its disorders

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  • 1. ANATOMY OF MEDIASTINUM AND ITS DISORDERS
    Dr.G.GIREESH,
    P.G Resident
    Dept.Of Gen.Medicine.
  • 2.
  • 3. ANATOMY OF MEDIASTINUM
    It is the anatomic space that lies in the midthorax
    Separates the two pleural cavities.
    It is limited by the diaphragm below and the suprasternal thoracic outlet above.
    It contains several vital structures in a small space,
    Abnormalities can produce important symptoms.
    For clinical purposes, Divided into
    Anterior,
    Middle,
    Posterior compartments
  • 4. ANATOMY OF MEDIASTINUM
    The Anterior compartment contains
    The Thymus,
    Substernal extensions of the thyroid
    Parathyroid glands,
    blood vessels
    Pericardium
    Lymph nodes
  • 5. ANATOMY OF MEDIASTINUM
    The middle compartment contains the
    Heart,
    Great vessels,
    Trachea,
    Main bronchi,
    Lymph nodes,
    Phrenic and
    Vagus nerves.
  • 6. ANATOMY OF MEDIASTINUM
    The posterior compartment
    The vertebrae
    Descending aorta,
    Oesophagus,
    Thoracic duct,
    Azygous and Hemizygous veins
    Lower portion of the vagus,
    Sympathetic chains, and
    Posterior mediastinal nodes.
  • 7. Disorders of superior mediastinum
    Enlarged lymph nodes due to
    Tuberculosis
    Leukemia
    Sarcoidosis
    Lymphoma
    Tumors of the thymus
    Teratomas
    Abscesses
    Intrathoracic thyroid Aneurysm
    Cystic hygroma
    Carcinoma
    Vascular tumours
    Oesophageal lesions
  • 8. DISORDERS OF ANT.MEDIASTINUM
    These include
    Lymphoma
    Lymph node enlargement due to
    Tuberculosis
    Hodgkin’s disease
    Sarcoidosis
    Thymus tumours
    Diaphragmatic hernia
    Thyroid aneurysm
    Parathyroid aneurysm
  • 9. LYMPHOMAS
    These arise in the anterior Mediastinum
    Hodgkin's lymphoma is the most frequent
    Carries the best prognosis.
    Other malignancies with worst prognosis are
    Non-Hodgkin's lymphoma
    Plasmacytomas
    Angiomatous lymphoid hamartomas
  • 10. Thymus masses
    The thymus gland is relatively large at birth.
    After puberty, it regresses to a small size.
    A Thymic mass can be a Tumour
    Cysts
    Thymic lymphoma
    Cysts may be single or multiple.
    Usually asymptomatic
    They manifest on chest X-ray as an enlarged thymus.
  • 11. Thymus masses
    Thymoma is a common mediastinal tumour.
    It is usually malignant
    Usually associated with myasthenia gravis.
    Some are asymptomatic.
    Enlarging tumours present with features of mediastinal compression syndrome
    Chest x-ray -Rounded shadow in the Ant. Mediastinum.
    Lateral view gives better delineation of the tumour.
    Surgical resection is the best method of treatment.
  • 12. THYROID MASSES
    Retrosternal extension of an enlarged thyroid
    Majority are multinodular benign goitres
    Cystic areas with hemorrhage and calcification.
    X-ray-show a sharply defined and often lobulated outline.
    Rarely symptomatic
    Compress the trachea at the thoracic inlet and result in respiratory distress
    Occasionally cause superior vena cava syndrome.
    Thyroid cancer involves the mediastinum by
    Direct extension
    Metastases to
    nodes.
  • 13. TERATOMAS
    Identical to certain testicular and ovarian neoplasms,
    Arise from primitive germ cells
    Arise by migrating to the mediastinum during oncogenesis.
    Dermoid cysts contain disorganized mixture of all 3 layers.
    i.e. skin, hair, cartilage, bone, epithelium, and neural tissue.
    They often contain cystic areas.
    Should be excised To prevent further expansion
    To exclude malignant change
  • 14. TERATOMAS
    .
    Malignant germ cell tumours are classically divided into
    1) Seminomas.
    2) Teratomas.
    Non-seminomatous germ cell tumours (malignant teratoma) can range from well-differentiated to trophoblastic.
    Serum levels of α-FP and β-HCG are ↑sed
    Seminomas tend to be non-secretory.
    These tumours are very malignant and invade adjacent mediastinal structures.
    Not cured by surgery
    These are responsive to chemotherapy using cisplatin-based regimes.
  • 15. PERCARDIAL CYSTS
    Occur in the anterior compartment and cardiophrenic angle
    They contain clear liquid and a flattened endothelial or mesothelial lining with a bland fibrous wall.
    Develop embryologically in relationship to the pericardium,
    Rarely communicate with the pericardial sacs
    X-ray-Smooth, clear, demarcated densities
    D/D’S-Pericardial fat pad
    Hernia through the foramen of Morgagni.
    Aspiration reveals clear fluid.
    Surgical excision is not recommended.
  • 16. Middle mediastinum
    Aortic aneurysm
    Pericardial cyst
    Bronchogenic cyst
    Lipoma
    Lymphoma
    Neoplasm
    Morgagni’s hernia
  • 17. BRONCHOGENIC CYSTS
    Arise in association with the major airways
    Dvp. around the paratracheal area or carina
    Middle and posterior compartments
    Lined by respiratory epithelium.
    Contain inspissated mucus.
    Cough or wheezing due to local pressure on airways
    Occasionally they communicate with the trachea
    There is an increased tendency to recurrent infections.
    Symptomatic pt.s need surgical removals of the cysts
  • 18. MEDIASTINAL LYMPHADENOPATHY
    Middle mediastinum is the commonest site of intrathoracic lymphadenopathy.
    Gross lymphadenopathy is a feature of
    1)Tuberculosis
    2)Histoplasmosis.
    3) Metastatic carcinoma
    4) Lymphomas,
    5)Sarcoidosis.
  • 19. Giant follicular lymph node hyperplasia (Castleman's disease)
    Its Aetiology is unknown.
    The lesion consists of a vascular tumour with satellite lymphadenopathy.
    Two histological subgroups are described,
    (1) a more common hyaline vascular picture with lymphoid follicles and penetrating capillaries
    (2) a plasma cell type characterized by sheets of plasma cells between germinal centres.
    It causes pressure effects
    Systemic symptoms with fever, anaemia, and weight loss.
    Small group of patients with multicentric disease have progressive hyperplasia, recurrent infections, and subsequently develop a frank lymphoma.
  • 20. Posterior mediastinum
    Esophageal lesions
    Neurogenic tumours
    Cysts
    Diaphragmatic hernia
    Aortic Aneurysm
    Meningocoele
    Parasitic cysts
  • 21. BOCHDALEK HERNIA
  • 22. Enteric cysts
    Are located in the posterior mediastinum
    Lined by gastric or intestinal epithelium.
    All cysts may become1) Infected
    2) Bleed
    3)Rupture
    Rupture into the Mediastinum.
    Pleural cavity.
  • 23. Tumours of post.mediastinum
    Found in the paravertebral gutters,
    Neural in origin.
    Benign tumours tend to be asymptomatic,
    Malignant tumours cause pressure effects.
    Occasionally, spinal cord compression results from direct extension into the intravertebral foramen.
    Tumours arising from peripheral nerve cell sheaths include Neurilemmoma (Schwannoma)
    Neurofibroma
    Malignant counterparts.
    Tumours of the autonomic chain include Ganglioneuroma
    Neuroblastoma.
  • 24. NEUROGENIC TUMOURS
    There are 4 histological types.
    1.neurilemmoma
    Benign and is classically a dumbbell-shaped mass.
    compress the spinal cord and produce pressure symptoms.
    2.ganglioneuroma
    Benign, elongated and large.
    Usually occurs in children but may be found at any age.
    Causes flushing,hypertension,headache,sweating,diarrhoea.
    3.neurofibroma
    Associated with generalized neurofibromatosis
    (von Recklinghausen's disease).
    4.NEUROBLASTOMA
    Malignant and found frequently in children.
  • 25. AORTIC ANEURYSMS
    causes :
    Hypertension
    Atherosclerosis
    Blunt chest trauma
    Mycotic dissection
    Cystic medial necrosis in Marfans syndrome
    Ehlers- Danlos syndrome
    Aortitis in tertiary syphilis
    Coarctation of aorta
  • 26. VASCULAR TUMORS
    Vascular tumors may originate in the mediastinum.
    Vascular hamartomas
    Lymphangiomas and
    Hemangiomas are benign tumors.
    Hemangiopericytomas are malignant.
    Mesenchymal benign -lipoma
    Malignant-Liposarcoma
    Mesothelioma
    Rhabdomyosarcoma
    Mesenchymoma
    These rarely cause mediastinal masses.
  • 27. PNEUMOMEDIASTINUM
    There are 3 possible causes -
    1) penetrating chest wall injuries;
    2) tear or defect in trachea, bronchus or oesophagus;
    3) tear or defect in alveolar wall
    Air from alveoli enters the interstitial space,
    Travels along the perivascular sheath into the mediastinum
    Enters the subcutaneous tissues of the neck and chest wall
    Results in surgical emphysema.
    Pt. gets sudden pain in the substernal areas and dyspnoea.
    X-ray –Air accumulation parallel to the heart and aorta.
    In surgical emphysema-subcutaneous crepitations are felt .
    Treatment of the underlying disorder is necessary.
    Rarely needs surgical incision.
  • 28. MEDIASTINITIS
    It usually results from
    Oesophageal rupture
    Bronchial rupture
    Tuberculous lymphadenitis.
    Infection from subphrenic abscess
    Osteomyelitis of spine.
    Treatment-
    1.Appropriate Antibiotics.
    2.Surgery.
  • 29. CHRONIC FIBRINOUS MEDIASTINITIS
    Its a chronic slowly progressive fibrosis.
    Similar to idiopathic retroperitoneal fibrosis.
    Various theories have been put forward but not proven.
    Involves S.V.C, Azygos and Innominate veins.
    Apart from engorged neck veins, swelling of face and neck, one may get headache, breathlessness, giddiness and epistaxis.
    X-ray chest-Widening of the upper mediastinum.
    Secondary causes of mediastinal fibrosis like tuberculosis and histoplasmosis must be ruled out.
    Corticosteroids can be tried.
    Surgical removal of fibrotic bands relieves the symptoms.
  • 30. Superior Vena Cava Syndrome
    Obstruction of blood flow through the superior vena cava causes dilation of the collateral veins of the upper thorax and neck and edema and congestion of the face
    patients may have headache, dyspnea, dysphagia, and wheezes. Malignancy is the most frequent cause of this syndrome,
    bronchogenic carcinoma
    lymphoma a distant second.
    Fibrosingmediastinitis
    Methysergide ingestion.
    Aortic aneurysm
    Retrosternal thyroid
    Invasive procedures are contraindicated.
    When the obstruction is thought to be caused by tumor, effort must be made to obtain tissue elsewhere.
    Irradiation, chemotherapy, or stent placement should be initiated before attempts are made to obtain mediastinal tissue.
  • 31.
  • 32. Organ involvedSymptoms and signs
    1. Trachea, main bronchi -Stridor, dyspnoea, cough, features of lung collapse
    2. Oesophagus- Dysphagia (extrinsic compression on barium swallow)
    3. Superior vena cava -Engorged non-pulsatile neck veins, oedema and cyanosis of face, neck and arms
    4. Left recurrent laryngeal nerve- Hoarseness of voice, bovine cough
    5. Phrenic nerve- Hemi-diaphragm paralysis
    6. Sympathetic trunk- Horner’s syndrome
  • 33. Diagnostic approach
    1.chest x-ray
    2. Computed tomography (CT) –
    3. Magnetic resonance imaging-For spinal tumours.
    4.Fine-needle aspiration biopsy – valuable .
    5. Anterior mediastinotomy.
    6. Bronchoscopy –limited value
  • 34. THANK YOU
  • 35. Thymoma
     
    General Considerations
    Most common anterior mediastinal mass
    Accounts for 50% of anterior mediastinal masses and 25% of all mediastinal tumors
    Most are solid lymphoepithelial tumors of the thymus, some are cystic
    About 1/3 are malignant under 20 and over 40 years of age
    About half are malignant in those 20-40
    Rare in children — most common around 5th or 6th decade
    Mean age of 52
    They can be classified into four types which occur in about equal frequency
    Lymphocytic
    Epithelial
    Mixed
    Spindle cell (Hassall’s corpuscles in this type)
    There are World Health Organization classifications and surgical staging classifications as well
    Clinical Findings
    Most benign thymomas are asymptomatic
    Most with malignant thymomas are symptomatic
    Symptoms include
    Cough
    Chest pain
    Dyspnea
    Dysphagia
    Superior vena caval syndrome
    Red cell aplasia, hypogammaglobulinemia or collagen vascular disease such as dermatomyositisand lupus
    Imaging Findings
    Conventional radiographs of the chest may show 
    Oval round or lobulated soft tissue mass, sharply demarcated, usually smaller than teratomas
    Superior aspect of anterior mediastinum
    Project predominantly to one side or the other
    May displace heart and great vessels posteriorly
    On CT 
  • 36. Normal thymic tissue may be seen as a triangular density in the anterior mediastinum up to 30 years of age at which time fatty involution occurs
    Thymus should be < 1.8 cm up to 20 years and < 1 cm after 20 years
    A small percentage (5%) may contain curvilinear or amorphous calcification
    Absence of fat planes and invasion of adjacent structures favors malignancy
    A homogeneously enhancing capsule favors benignancy
    MRI
    May be more sensitive to small thymic masses than CT
    Hypointense to mediastinal fat on T1
    On T2, signal is isointense or hyperintense ro surrounding fat
    Differential Diagnosis
    Non-Hodgkin’s lymphoma can occur in thymus
    Thymolipomas are rare, fatty tumors of the thymus that have been associated with
    Aplastic anemia
    Hypogammaglobulinemia
    Grave’s disease
    Hodgkin’s disease
    Chronic lymphocytic leukemia
    Anterior Mediastinal Masses – 3 T’s and an L
    Thymoma 
    Teratoma 
    Thyroid enlargement 
    Lymphoma 
    Treatment
    Most thymomas are treated surgically
    Degree of invasiveness rather than histopathology is best determinant of malignancy versus benignancy
    Complications
    About 15% of patients with myasthenia gravis have thymomas and about 33-50% of patients with thymomas have myasthenia
    Thymomas are associated with leukemia
    Prognosis
    Surgical evaluation of encapsulation or invasion is better indicator of prognosis than actual histology
    In patients with myasthenia, about 50% improve following removal of the thymoma
    For those with invasive thymoma, 15 year survival is 12.5%
    For those with non-invasive thymoma, 15 year survival is 47%

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