Mediastinal neoplasms pt.2 Flashcards
What is the mediastinum divided into?
- Superior and inferior mediastinum
- Inferior mediastinum further divided into anterior, middle, and posterior
- New classification into three compartments (prevascular, visceral and paravertebral)
Borders of the anterior mediastinum
Posterior to the sternum and anterior to the pericardium
Borders of the middle mediastinum
Bounded by the pericardium (anterior aspect of pericardium (anterior) - posterior aspect of pericardium)
Borders of the posterior mediastinum
posterior to the pericardium and anterior to the vertebrae
Contents of the middle mediastinum
- Pericardial sac
- Heart
- Origins of great vessels
- Tracheal bifurcation and main bronchi
Contents of the anterior mediastinum
- Inferior portion of thymus remanents
- Fat
- Connective tissue
- Lymph nodes
- Mediastinal branches of internal thoracic vessels
- Sternopericardial ligaments
Contents of the posterior mediastinum
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
Mnemonic:
DATE followed by Very Sexy Love
Contents of the superior mediastinum
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
Borders of mediastinum inferiorly
Diaphragm
Borders and contents of the prevascular compartment of the mediastinum
- 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.
Borders and contents of visceral compartment of mediastinum
- 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
Superior, inferior, and lateral borders of the mediastinum
Bordered superiorly by the thoracic inlet and inferiorly by the diaphragm and limited laterally by the parietal mediastinal pleura
Borders and contents of paravertebral compartment of the mediastinum
- 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
Landmark seperating superior and inferior mediastinum
T4
Advantages of VATS
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
When is VATS considered
VATS biopsy is generally performed only if another method has failed to achieve diagnosis
How is VATS performed?
- Can be performed from either side of the chest with an incision in the anterior axillary line
- Uni or multi-portal access
Laboratory studies performed on patients suspected of having mediastinal tumor
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
When do we find elevated AFP levels?
Elevated levels of AFP are found in malignant germ cell tumors; specifically, 60 to 80 percent of nonseminomatous dysembryomas are serum AFP positive
When do we find elevated beta-HCG levels?
Beta-HCG is associated with seminoma (10 percent) and nonseminomatous (30 to 50 percent) germ cell tumors
When do we find elevated Anti-acetylcholine receptor antibodies?
This may be positive in some patients with thymic tumors and indicate or herald the presence of myasthenia gravis
When do we find elevated LDH levels?
- 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.
