Mediastinal neoplasms pt.2

Question 1

What is the mediastinum divided into?

Answer 1

• Superior and inferior mediastinum
• Inferior mediastinum further divided into anterior, middle, and posterior
• New classification into three compartments (prevascular, visceral and paravertebral)

Question 2

Borders of the anterior mediastinum

Answer 2

Posterior to the sternum and anterior to the pericardium

Question 3

Borders of the middle mediastinum

Answer 3

Bounded by the pericardium (anterior aspect of pericardium (anterior) - posterior aspect of pericardium)

Question 4

Borders of the posterior mediastinum

Answer 4

posterior to the pericardium and anterior to the vertebrae

Question 5

Contents of the middle mediastinum

Answer 5

• Pericardial sac
• Heart
• Origins of great vessels
• Tracheal bifurcation and main bronchi

Question 6

Contents of the anterior mediastinum

Answer 6

• Inferior portion of thymus remanents
• Fat
• Connective tissue
• Lymph nodes
• Mediastinal branches of internal thoracic vessels
• Sternopericardial ligaments

Question 7

Contents of the posterior mediastinum

Answer 7

Descending thoracic aorta and its branches
Azygos and hemiazygos venous systems
Thoracic duct & cisterna chyli
Esophagus and esophageal plexus
Vagus nerves
Thoracic splanchnic nerves (greater, lesser, least)
Lymphatics

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Question 8

Contents of the superior mediastinum

Answer 8

Thymus, trachea, esophagus, thoracic duct, aortic arch, veins (superior vena cava, brachiocephalic, left superior intercostal), nerves (vagus, phrenic, left recurrent laryngeal), lymphatics, other small arteries and veins
- Try To Eat Toast And Vitamins Now Little Oscar

Question 9

Borders of mediastinum inferiorly

Answer 9

Diaphragm

Question 10

Borders and contents of the prevascular compartment of the mediastinum

Answer 10

• superior: thoracic inlet
• inferior: diaphragm
• lateral: parietal mediastinal pleura
  posterior: anterior aspect of the pericardium
• Its primary contents are the thymus, and the left brachiocephalic vein.

Question 11

Borders and contents of visceral compartment of mediastinum

Answer 11

• superior: thoracic inlet
• inferior: diaphragm
• anterior: posterior boundaries of the prevascular compartment
• Posterior: vertical line that connects a point on each thoracic vertebral body, 1 cm posterior to its anterior border
• It contains the trachea, esophagus, heart, the ascending and descending aorta, along with the aortic arch and its branches, the superior vena cava, the pulmonary arteries and the thoracic duct

Question 12

Superior, inferior, and lateral borders of the mediastinum

Answer 12

Bordered superiorly by the thoracic inlet and inferiorly by the diaphragm and limited laterally by the parietal mediastinal pleura

Question 13

Borders and contents of paravertebral compartment of the mediastinum

Answer 13

• paravertebral mediastinum:
  superior: thoracic inlet
  inferior: diaphragm
  anterior: posterior boundaries of the visceral compartment
  posterior: a vertical line along the posterior margin of the chest wall at the lateral aspect of the transverse processes
• Thoracic spine, paravertebral soft tissues, sympathetic trunk and azygos/hemiazygos venous system

Question 14

Landmark seperating superior and inferior mediastinum

Answer 14

T4

Question 15

Advantages of VATS

Answer 15

 Complete mediastinal exposition, excellent anatomic view also allows biopsy of tissue anywhere in the mediastinum, even immediately adjacent structures such as the aorta, other great vessels, or the heart
 Good tissue sampling

Question 16

When is VATS considered

Answer 16

VATS biopsy is generally performed only if another method has failed to achieve diagnosis

Question 17

How is VATS performed?

Answer 17

• Can be performed from either side of the chest with an incision in the anterior axillary line
• Uni or multi-portal access

Question 18

Laboratory studies performed on patients suspected of having mediastinal tumor

Answer 18

Peripheral blood collection and analysis for tumor markers can support a presumptive diagnosis in some instances of anterior mediastinal masses. Tumor markers are most helpful when thymoma or germ cell tumor is suspected. In general, the following laboratory tests are reasonable to routinely check for patients in whom a diagnosis has not already been established:
For germ cell tumors: Alpha-fetoprotein (AFP), Beta-human chorionic gonadotropin (beta-hCG), and Lactate dehydrogenase (LDH)
For Neurogenic tumors: Catecholamines and VIP
Anti-acetylcholine receptor antibodies can also be performed

Question 19

When do we find elevated AFP levels?

Answer 19

Elevated levels of AFP are found in malignant germ cell tumors; specifically, 60 to 80 percent of nonseminomatous dysembryomas are serum AFP positive

Question 20

When do we find elevated beta-HCG levels?

Answer 20

Beta-HCG is associated with seminoma (10 percent) and nonseminomatous (30 to 50 percent) germ cell tumors

Question 21

When do we find elevated Anti-acetylcholine receptor antibodies?

Answer 21

This may be positive in some patients with thymic tumors and indicate or herald the presence of myasthenia gravis

Question 22

When do we find elevated LDH levels?

Answer 22

• LDH may be elevated in patients with nonseminomatous dysembryoma, though this laboratory finding is generally not as specific as AFP or beta-hCG
• Additionally, LDH may be elevated in patients with lymphoma.