1. SURGICAL DISORDERS OF MEDIASTINUM AND DIAPHRAGM
Sina Ercan MD
Professor of Thoracic Surgery

2. Anatomy of the Mediastinum
Mediastinum is the central space within the thoracic cavity bounded by:
Sternum anteriorly
Lungs and parietal pleura laterally
The vertebral column posteriorly
The thoracic inlet superiorly
The diaphragm inferiorly
Thoracic inlet is composed of 1. ribs, claviculas, suprasternal nodgeand T1 vertebrae. The mediastinal structures are seperated from the thoracic cavity by parietal pleura.

6. Compartments of mediastinum
Anterior mediastinum: the area posterior to the sternum and anterior to the heart and great vessels
Thymus, substernal thyroid
glands, parathyroid,
lymph nodes,
connective tissue

7. Middle mediastinum: the area between the posterior border of the anterior mediastinum and a line placed along the posterior aspect of the trachea and the heart
Heart, pericardium, aortic arc,
brachiocephalic vessels, vena cava ,
main pulmonary vessels, trachea,
main bronchi, phrenic and upper
parts of the vagus nerve,
lymph nodes

8. Posterior Mediastinum: The area between the posterior aspect of middle mediastinum and the vertebrae
Esophagus, azygos and hemiazygos veins, thoracic duct, descending aorta, autonomic ganglia, symphathetic chain,
lower portions of the vagus nerve,
lymph nodes and connective tissue
It is important to know which tissues are present in different compartments of the mediastinum in order to differentiate the origin of a disorder.

9. Mediastinal Pathologies
Non neoplastic diseases
Mediastinitis
Pneumomediastinum
Congenital pathologies
Cysts
Hernias
Acquired lesions
Benign
Malignant

10. Mediastinal Pathologic Lesions
In adults 65% of the mediastinal lesions are anterior
In children 52% of the mediastinal lesions are posterior
40-50% of the mediastinal lesions are malignant in children compared to 25% malignancies in adults

11. Anterior mediastinal disorders
Thymic disorders
Thymoma, Thymic carcinoma
Thymic carcinoid
Thymolipoma
Thymic cyst
Thymic hyperplasia
Thyroid disorders
Intrathoracic goiter
Germ cell tumors
Teratoma
Seminoma
Others
Lymphoma
Hodgkin’s disease
Non-Hodgkin’s
Parathyroid adenoma
Mesenchymal tumors
The origin of the most frequent lesions in adults are Thymic, Thyroid disorders and Teratomas but lymphomas should always be in the differential diagnosis.

12. Thymoma Most common adult 10 mediastinal neoplasm Usually >40 y/o
40-70% have symptoms related to parathymic syndromes
Myasthenia Gravis,
Hypogammaglobulinemia
Pure red cell aplasia
Nonthymic malignancies
Usually discovered incidentaly on plain chest radiography as rounded , well circumscribed anterior mediastinal enlargement.

13. Thymomas represent neoplastic proliferation of thymic epithelial cells mixed with mature lymphocytes
CT demonstrates a homogenious soft tissue mass
CT guided needle biopsy, mediastinoscopy, mediastinotomy or VATS for diagnosis

14. Thymoma

15. Thymic Carcinoma: Thymic carcinoid: Thymolipoma:
Malignant histologic features
Pulmonary, regional lymph node or pleural metastasis can be present
Thymic carcinoid:
a rare agressive neoplasm that originates from thymic neuroendocrine cells
Thymolipoma:
a rare benign tumor composed of mature adipose and thymic tissue

16. CT image of a Thymolipoma (Exhibits fat and thymic soft tissue)

17. Thymic cysts: May be congenital or acquired in association with inflammation or malignancy
Thymic hyperplasia: May be a rebound phenomenon after lymphoma or germ cell tumor treatment or seen in MG

18. Mediastinal Lymphoma 10-20% of all mediastinal neoplasms in adults
May be 1o in anterior or middle mediastinum or part of systemic malignancy
20-30% of patients are asymptomatic
Symptoms of local invasion or systemic symptoms (fever, weight loss, pruritis)

19. Hodgkin’s disease: Bimodal age peak (20-30 years; >50 years)
Majority of patients have asymmetric, bilateral mediastinal LAP

20. Non-Hodgkin’s Lymphoma: Usually in older patients
Usually systemic upon presentation and spreads unpredictably
Diffuse Large B-cell Lymphoma
Lymphoblastic Lymphoma

21. Mediastinal Germ-Cell Tumors
Teratomas:
Account 60-70% of cases
Consist of tissue that may derive from more than one of the germ cell layers
Mostly benign, radiologically spheric, lobulated, well circumscribed and may contain calcification
Seminomas:
Affect men in 3rd and 4th decades
40-50% of mediastinal malignant germ cell tumors

22. Teratoma (well formed teeth within the mass is diagnostic)

23. Germ cell tumor

24. MIDDLE MEDIASTINAL DISORDERS
Lymphoma
Benign lympadenopathy
Granulomatous disease
Infectious
Non infectious
Miscellaneous
Amyloidosis
Drugs
Metastatic lymphadenopathy
Cysts
Bronchogenic cysts
Pericardial cyst
Vascular Lesions
Aneurism
Hemangioma
Miscellaneous
Diaphragmatic hernias
Pancreatic pseudocyst
Metastatic lymphadenopathy due to lung, breast, renal cell, gastrointestinal, prostate.

25. Benign mediastinal lymphadenopathy
Infectious
Tuberculosis: Usually unilateral and asymmetric, may have calcification
Fungal infections
Histoplasmosis
coccidioidomycosis
Non infectious
Sarcoidosis: Usually bilateral, symmetric
Silicosis: nodal calsification with eggshell configuration

26. Normal mediastinal lymph nodes

27. Sarcoidosis
Unilateral hiler enlargement

28. Cysts
Bronchogenic cyst: Originate from abnormal budding of ventral foregut
Commonly in subcarinal and paratracheal regions 15% in pulmonary paranchyme
Lined by respiratory epithelium and may contain serous fluid, mucus, milk of calcium, blood or purulent material
Radiologic imaging a well cicumscribed spheric mediastinal mass with fluid density on CT

29. Bronchogenic cyst

30. Diaphragmatic hernias:
Enterogenous cysts:
Esophageal dublication and neurenteric cysts
Located in the middle or posterior mediastinum
Pericardial Cysts:
In the cardiophrenic angles (R>L)
Fibrous walls and contain clear fluid
Diaphragmatic hernias:
Hiatal hernia
Morgagni hernia
Bochdalek hernia
Morgagni hernia is seen as a right cardiophrenic angle mass. Bochdaleck hernia is located in the posterior mediastinum

31. Pericardial cyst

32. Vascular lesions: Constitute approximately 10% of the mediastinal masses
May originate from the arterial or venous portions of the systemic or pulmonary circulation
They may mimic neoplasms on chest radiographs

33. Thoracic aortic aneurisym
Vascular lesions
Thoracic aortic aneurisym

34. Superior Vena Cava Syndrome: (Facial, upper limb swelling, headache, shortness of breath, superficial venous dilatation, conjunctival hyperemia)
Lung cancer (50-75%) (small cell most common)
Lymphoma
Germ cell tumors of the mediastinum
Thymic malignancies
Benign causes (5-10%)
Syphilitic aneurism
Tuberculosis lymphadenopathy
Mediastinal fibrosis

35. Posterior Mediastinal Disorders
Neurogenic tumors
Peripheral nerve
Schwannoma, neurofibroma etc
Sympathetic ganglia
Ganglioneuroma, neuroblastoma etc
Paraganglionic tumors
pheochromocytoma
Esophageal disorders
Benign tumors
Esophageal diverticulum
Spinal
Lateral thoracic meningocele
Paraspinal abscess
Miscellaneous
Thoracic duct cysts

36. Extramedullary hematopoiesis
CT of neurofibroma

37. Symptoms and signs in mediastinal pathologies
Benign ones usually asymptomatic
Chest pain (Traction of the mediastinal structures, bone erosion)
Cough
Dyspnea (Compression of tracheobronchial tree, mediastinal shift)
Dysphagia (Compression of esophagus)
Hoarseness (Recurrent laryngeal paralysis)
Horner syndrome (Compression of the stellate ganglion)
Horner Syndrome: Myosis, pitosis, enophtalmia, unilateral anhydrosis

38. Superior Vena Cava Syndrome
Weakness/Myastenia Gravis Symptoms
Mental Confusion (Hypercalcemia due to parathyroid adenoma or carcinoma)
Neurogenic symptoms (Neurogenic tumors)
Diaphragmatic paralysis (Phrenic nerve paralysis)
Pleural effusion/Chylothorax (Obstruction of thoracic duct)
Arrhytmias (Cardiac compression or involvement of myocardium with tumor)
Pericardial tamponade (Lymphoma)
Gynecomastia (Germ cell tumors)

39. Diagnostic Procedures
Physical examination (Signs of Sup. V. Cava or Horner Syndrome)
Plain Chest Radiography (PA and Left lateral)

40. CT
Arteriography/ Venography

41. Histologic evaluation
Ultrasound
MRI
Barium esophagram
Histologic evaluation
Fine needle aspiration
Mediastinoscopy/mediastinotomy
Thoracoscopy (VATS)
Thoracotomy

42. Non neoplastic Disorders of the Mediastinum
Pneumomediastinum
Pneumopericardium
Acute Mediastinitis
Chronic Mediastinitis

43. Pneumomediastinum Caused by alveolar overdistention and rupture
Air moves through the bronchovascular sheath toward mediastinum. As the pressure rises in mediastinum, air moves to cervical, subcutaneous and retroperitoneal soft tissue places.

44. Etiology of pneumomediastinum
Spontaneous
Acute asthma attack
Scuba diving
Mechanic ventilation
Vomiting
Trauma
Surgery
Tracheostomy
Bronchoscopic procedures
Respiratory tract infections
Dental infections or procedures
Acute mediastinitis
Pneumoperitoneum
Esophageal perforation

45. Substernal chest pain is the most frequent symptom
Crepitation; air dissecting under the skin
Dyspnea
Dysphagia
Dysphonia
Hypotension (hemodynamic changes)

46. Physical examination reveals palpable subcutaneous emphysema in the neck
On auscultation of the chest a clicking sound over the pericardium synchronous with the heartbeat (Hamman’s sign)

47. Chest Radiograph: a thin radiolucent strip along the mediastinal fascial plane, left heart borderCT

49. Treatment: Supportive Supplemental oxygen Management of causes
Surgery, chest tube insertion when hemodynamic deterioriation is present or when associated with mechanical ventilation

50. Acute Mediastinitis A life threatening condition Etiology
Esophageal or tracheobronchial perforation
Sternotomy for cardiac surgery
Direct extension of infection from lung, spine or pancreas
Descending necrotizing mediastinitis (Oropharyngeal infections)
Anthrax Mediastinitis

51. Esophageal perforation
Iatrogenic esophageal perforation is the most common cause of acute mediastinitis
Can also be:
Postemetic (Boerhaave’s syndrome)
Trauma
Operative injury
Cancer erosion
Foreign body

52. Esophageal perforation

53. Clinical signs and symptoms
Abrupt onset of severe chest pain, fever, dyspnea, SVC symptoms
Tachypnea, tachycardia, hypotension, cervical emphysema
Shock develops quickly
Chest Radiology: Upper mediastinal enlargement, emphysema, hydropnomothorax, multiple air fluid levels

54. Mediastinitis

55. Treatment: Surgical debridement of the necrotic tissue
Closure of the perforation
Drainage
Broad spectrum antibiotics with anaerobic coverage
Mortality rises when the treatment delay is more than 24 hours

56. Poststernotomy mediastinitis:
Prolonged preoperative hospitalization, reoperation or reexploration, presence of D. Mellitus, use of internel thoracic artery grafts are the risk factors.
Staphlococcus epidermidis and aureus, various gram (-) organisms and candida and atypical mycobacteria are commonly isolated
Insidious presentation with low grade fever, leukocytosis, wound problems
Surgical debridement and prolonged proper antibiotic therapy is the treatment

57. Antrax Mediastinitis:
Caused by Bacillus anthracis (Gr + )
Farm animals are the main reservoir
Inhaled antrax spores are transported to the mediastinal lymph nodes by alveolar macrophages
A hemorrhagic mediastinitis occurs
Penicillin and streptomycin is the treatment of choice

58. Chronic Mediastinitis
Granulomatous mediastinitis
Tbc, histoplasmosis, nocardia and other fungi
Disease of mediastinal lymph nodes
Coalescence of caseous mediastinal lymph nodes can result in a single large mass, encapsulation and mediastinal granuloma
Compression of trachea, superior V. Cava or esophagus can occur
Right paratracheal area is the most common site

59. Excision is the treatment of choice (if possible)
Specimens for culture and special stains for diagnosis at the time of operation

60. Fibrosing Mediastinitis:
Dense fibrosis surrounding trachea, hila of the lungs.
Compression of the airway, pulmonary arteries or veins may occur
Etiology:
Tuberculosis
Histoplasmosis or other fungi
Silicosis
Drugs (Methisergide)
Autoimmune disorders
Familial multifocal fibrosclerosis

61. Symptoms are caused by the compression of vital organs
Treatment is symptomatic
Methisergide should be stopped for the relief of symptoms
END

62. Diseases of the Diaphragm
Diaphragma is a dome shaped musculotendinous structure that separates thoracic and abdominal cavities
It consists of two parts:
Right hemidiaphragm
Left hemidiaphragm
Middle portion is made of the central tendon that doesn’t contract, it has two holes on
The caval opening
The esophageal hiatus

63. Diaphragma thoracic view

64. Diaphragma abdominal view

65. The muscle fibers of the crural part originate from lomber vertebrae
The muscle fibers of the costal part originate from the processus xiphoideus and 7-12 ribs
The costal part contraction lowers the diaphragm and increases the rib cage
When the crural part contracts only the diaphragm moves downward

66. Motor inervation comes from cervical motor neurons (C3-5) conducted via N. Frenicus
Diaphragm is the major inspiratuar muscle responsible from 70% of normal breathing.

67. Contraction of the diaphragm has the following effects that promote air movement into the lungs
It decreases intrapleural pressure
It raises and inflates the rib cage
It expands the rib cage by generating positive intraabdominal pressure

68. Diaphragmatic paralysis:
Can be bilateral or involve only one side (unilateral)
In this setting the accessory muscles of the respiration assume some or all the work of breathing

70. Patients with bilateral diaphragmatic paralysis typically present with dyspnea. It is associated with tachypnea and rapid shallow breathing
Paradoxal motion of the anterior abdominal wall during inspiration can be detected
Hypoxemia is common due to atelectasis and V/Q mismatch which worsens with sleep
Disease progression is associated with progresive hypercapnia

71. Chest radiograph reveals elevated hemidiaphragms, small lung volumes, atelectasis
In pulmonary function test 50% decrease in VC in supine position is thypical (should be up to 10% in normal individuals). PI-max is lowered
Electromyography may show either neuropathic or myopathic pattern
The gold standart is the measurement of transdiaphragmatic pressure

72. Unilateral diaphragmatic paralysis is more common
Often discovered incidentally on a chest radiograph and diagnosis can be made only by radiology (fluoroscopic sniff test)
Patients who do not have underlying lung disease are usually asymphtomatic
In fluoroscopic sniff test paradox elevation of the paralysed hemidiaphragm is positive >90% of the patients

73. Diaphragmatic Fatique
Can be seen in several conditions that effect motor neurons, neuromusculer junction or muscle cells

74. N. Spinalis and peripheric nerve pathologies Myoneural block
Acute ant. Poliomyelitis
Peripheric neuropathies
Infection
Alcohol
Toxic
Metabolic
Guillain barre syndrom
Myoneural block
Myastenia gravis
Myastenia of Carsinomatozis
Anticholinesterase
Musculer pathologies
Progressive muscular distrophia
myopathies

75. Diaphragmatic Eventration
Eventration of the diaphragm is a disorder in which all or part of the diaphragmatic muscle is replaced by fibroelastic tissue.

77. Eventration of the diaphragm can be congenital or acquired
Many patients are asymptomatic, especially when the eventration is localized
Can be seen incidentally on chest x ray and The diagnosis is confirmed by fluoroscopy or ultrasonography.
In infants the management depends on the extent of the respiratory distress, often no need to treatment
In infants surgical pilicatiomn can be performed

78. Diaphragmatic Hernia Hiatal Hernias: Traumatic rupture
Result when an abdominal structure usually the stomach extends through the diaphragmatic esophageal hiatus into the thorax. Manifests as a retrocardiac mass in the middle mediastinum
Traumatic rupture
Seen in 1-4% of blunt chest or abdominal trauma usually on the left posterolateral region

79. Traumatic rupture of the left hemidiaphragm

80. Congenital Hernias:
These are due to the failure of the normal fusion of the diaphragmatic components during embryologic development
Morgagni hernias: herniation of omentum and other abdominal contents into the thorax manifest as a right cardiophrenic angle mass
Bochdaleks hernias: May protrude into the posterior mediastinum
Diagnosis can be established in diaphragmatic hernias by gastrointestinal barium study or CT. Treatment is surgical in symptomatic cases.

81. Morgagni hernia

82. Bochdaleks hernia

83. Diaphragmatic infections
Subdiaphragmatic abscess: Can be seen due to perforation or abdominal surgery. Local pain, fever, tachicardia, leucocytosis are common. Ipsilateral hemidiaphragm is elevated on chest radiology. Pleural efusion, pulmonary infiltration or atelectasis can also be present. Surgical drainage with appropiate antibiotics is the treatment
Parasitic infections: Amebiasis, trichinella spiralis

84. Diaphragmatic neoplasms
Metastatic: Breast, ovarian and gastric cancer metastasis are the most common type. Lung cancer and mesothelioma are also seen
Primary benign neoplasms:
Fibroma
Angiofibroma
neurofibroma,
Neurilemmoma
Hemangioperistoma

85. Primary malign neoplasms:
Fibrosarcoma
Myosarcoma
Fibrangioendothelioma
Sarcoma
Neurofibrosarcoma
Hemangioendothelioma
Hemangioperistoma
Leiomyosarcoma
Malign snovioma
They are all mesenchimal tumors. Fibrosarcoma is the most common type