Mediastinal Lymphadenopathy

By

Gamal Rabie Agmy , MD , FCCP Professor of Chest Diseases ,Assiut University

Lymph nodes

Anatomic Considerations

Retrosternal Prevascular Retrocaval

Aortic window Carinal

Subcarinal Hilar

Z-esophageal Circm-cardiac

3 3

Lymph nodes

Anatomic Considerations

Retrosternal Prevascular Retrocaval

Aortic window Carinal

Subcarinal Hilar

Z-esophageal Circm-cardiac

6 5

Lymph nodes

Anatomic Considerations

Retrosternal Prevascular Retrocaval

Aortic window Carinal

Subcarinal Hilar

Z-esophageal Circm-cardiac

7

7

8

9

Lymph nodes

X-Rays

Enlarged hilar shadow with lobulated outlines

Normal

Lymph nodes

CT MRI

Multiple masses at the anatomic locations of lymph nodes

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Regional lymph node classification for lung cancer staging adapted from the American Thoracic Society mapping scheme

Supraclavicular nodes 1. Low cervical, supraclavicular and sternal notch

nodes

From the lower margin of the cricoid to the clavicles

and the upper border of the manubrium.

The midline of the trachea serves as border between

1R and 1L.

Superior Mediastinal Nodes 2-4

2R.Upper Paratracheal

2R nodes extend to the left lateral border of the

trachea.

From upper border of manubrium to the intersection

of caudal margin of innominate (left brachiocephalic)

vein with the trachea.

2L.Upper Paratracheal

From the upper border of manubrium to the superior

border of aortic arch.

2L nodes are located to the left of the left lateral

border of the trachea.

•

Regional lymph node classification for lung cancer staging adapted from the American Thoracic Society mapping scheme

3A. Pre-vascular These nodes are not adjacent to the trachea like

the nodes in station 2, but they are anterior to the

vessels.

3P.Pre-vertebral Nodes not adjacent to the trachea like the nodes

in station 2, but behind the esophagus, which is

prevertebral.

4R. Lower Paratracheal From the intersection of the caudal margin of

innominate (left brachiocephalic) vein with the

trachea to the lower border of the azygos vein.

4R nodes extend from the right to the left lateral

border of the trachea.

4L. Lower Paratracheal From the upper margin of the aortic arch to the

upper rim of the left main pulmonary artery.

•

Regional lymph node classification for lung cancer staging adapted from the American Thoracic Society mapping scheme

Aortic Nodes 5-6 5. Subaortic These nodes are located in the AP window lateral

to the ligamentum arteriosum.

These nodes are not located between the aorta

and the pulmonary trunk but lateral to these

vessels.

6. Para-aortic These are ascending aorta or phrenic nodes

lying anterior and lateral to the ascending aorta

and the aortic arch.

Inferior Mediastinal Nodes 7-9

7.Subcarinal Nodes below carina.

8. Paraesophageal 9. Pulmonary Ligament Nodes lying within the pulmonary ligaments.

Regional lymph node classification for lung cancer staging adapted from the American Thoracic Society mapping scheme

Hilar, Lobar and (sub)segmental

Nodes 10-14 These are all N1-nodes.

10. Hilar nodes

These include nodes adjacent to the main

stem bronchus and hilar vessels.

On the right they extend from the lower rim

of the azygos vein to the interlobar region.

On the left from the upper rim of the

pulmonary artery to the interlobar region.

1. Supraclavicular zone nodes

1. Supraclavicular zone

nodes

These include low cervical,

supraclavicular and sternal

notch nodes.

Upper border: lower margin of

cricoid.

Lower border: clavicles and

upper border of manubrium.

The midline of the trachea

serves as border between 1R

and 1L.

2R. Right Upper Paratracheal

2R nodes extend to the left lateral

border of the trachea.

Upper border: upper border of

manubrium.

Lower border: intersection of

caudal margin of innominate (left

brachiocephalic) vein with the

trachea.

2L. Left Upper Paratracheal

Upper border: upper border of

manubrium.

Lower border: superior border of

aortic arch.

On the left a station 2 node in front

of the trachea, i.e. a 2R-node.

There is also a small prevascular

node, i.e. a station 3A node

3. Prevascular and Prevertabral

nodes

Station 3 nodes are not adjacent to

the trachea like station 2 nodes.

They are either:

3A anterior to the vessels or

3B behind the esophagus, which

lies prevertebrally.

Station 3 nodes are not accessible

with mediastinoscopy.

3P nodes can be accessible with

endoscopic ultrasound (EUS).

3A and 3P nodes

On the left a 3A node in the

prevascular space.

Notice also lower paratracheal

nodes on the right, i.e. 4R nodes.

4R. Right Lower Paratracheal

Upper border: intersection of

caudal margin of innominate (left

brachiocephalic) vein with the

trachea.

Lower border:lower border of

azygos vein.

4R nodes extend to the left lateral

border of the trachea.

On the left we see 4R

paratracheal nodes.

In addition there is an aortic

node lateral to the aortic arch,

i.e. station 6 node.

4L. Left Lower Paratracheal 4L nodes are lower paratracheal nodes

that are located to the left of the left tracheal border, between a horizontal

line drawn tangentially to the upper

margin of the aortic arch and a line

extending across the left main bronchus

at the level of the upper margin of the

left upper lobe bronchus.

These include paratracheal nodes that

are located medially to the ligamentum

arteriosum.

Station 5 (AP-window) nodes are

located laterally to the ligamentum

arteriosum.

On the left an image just above the level of the

pulmonary trunk demonstrating lower

paratracheal nodes on the left and on the right.

In addition there are also station 3 and 5 nodes

On the left an image at the level of the lower trachea just

above the carina.

To the left of the trachea 4L nodes.

Notice that these 4L nodes are between the pulmonary trunk

and the aorta, but are not located in the AP-window, because

they lie medially to the ligamentum arteriosum.

The node lateral to the pulmonary trunk is a station 5 node.

5. Subaortic nodes Subaortic or aorto-pulmonary window nodes are lateral to the ligamentum

arteriosum or the aorta or left pulmonary artery and proximal to the first

branch of the left pulmonary artery and lie within the mediastinal pleural

envelope.

6. Para-aortic nodes Para-aortic (ascending aorta or phrenic) nodes are located anteriorly and

laterally to the ascending aorta and the aortic arch from the upper margin

to the lower margin of the aortic arch.

7. Subcarinal nodes These nodes are located caudally to the carina of the trachea, but are not

associated with the lower lobe bronchi or arteries within the lung.

On the right they extend caudally to the lower border of the bronchus

intermedius.

On the left they extend caudally to the upper border of the lower lobe

bronchus.

On the left a station 7 subcarinal node to the right of the esophagus.

8 Paraesophageal nodes

These nodes are below the carinal nodes and extend caudally

to the diaphragm.

On the left an image below the carina.

To the right of the esophagus a station 8 node.

On the left a PET image demonstrating FDG uptake in a

station 8 node.

On the corresponding CT image the node is not enlarged

(blue arrow).

The probability that this is a lymph node metastasis is

extremely high since the specificity of PET in unenlarged

nodes is higher than in enlarged nodes.

9. Pulmonary ligament nodes

Pulmonary ligament nodes are lying within the pulmonary

ligament, including those in the posterior wall and lower part

of the inferior pulmonary vein.

The pulmonary ligament is the inferior extension of the

mediastinal pleural reflections that surround the hila.

10 Hilar nodes

Hilar nodes are proximal lobar nodes, distal to the mediastinal

pleural reflection and nodes adjacent to the intermediate

bronchus on the right.

Nodes in station 10 - 14 are all N1-nodes, since they are not

located in the mediastinum.

10 Hilar nodes

Hilar nodes are proximal lobar nodes, distal to the mediastinal

pleural reflection and nodes adjacent to the intermediate

bronchus on the right.

Nodes in station 10 - 14 are all N1-nodes, since they are not

located in the mediastinum.

Axial CT of Lymph Nodes Scroll through the images on the left.

1-Sternal notch nodes are just seen at this level

and above this level

2-Upper Paratracheal: below clavicles and on the

right above the intersection of caudal margin of

innominate (left brachiocephalic) vein with the

trachea and on the left above the aortic arch.

3-Pre-vascular and Retrotracheal : anterior to the

vessels (3A) or prevertebral (3P)

4-Lower Paratracheal : below upper margin of

aortic arch down to level of main bronchus

5-Subaortic (A-P window): nodes lateral to

ligamentum arteriosum or lateral to aorta or left

pulmonary artery

6-Para-aortic: nodes lying anterior and lateral to

the ascending aorta and the aortic arch beneath

the upper margin of the aortic arch

7-Subcarinal

8-Paraesophageal (below carina)

9-Pulmonary Ligament: nodes lying within the

pulmonary ligament.

10--14: nodes are all N1 nodes

Axial CT of Lymph Nodes

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Conventional mediastinoscopy The following nodal stations can be biopsied by cervical

mediastinoscopy: the left and right upper paratracheal nodes

(station 2L and 2R), left and right lower paratracheal nodes

(station 4L and 4R) and the subcarinal nodes (station 7).

Station 1 nodes are located above the suprasternal notch and

are not routinely accessed by cervical mediastinoscopy.

Axial CT of Lymph Nodes

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Mediastinoscopy and EUS

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Extended mediastinoscopy Left upper lobe tumors may metastasize to the subaortic lymph nodes (station

5) and paraaortic nodes (station 6). These nodes can not be biopsied through

routine cervical mediastinoscopy. Extended mediastinoscopy is an alternative

for the anterior-second interspace mediastinotomy which is more commonly

used for exploration of mediastinal nodal stations.

This procedure is far less easy and therefore less routinely performed than

conventional mediastinoscopy.

EUS-FNA

Endoscopic Ultrasound with Fine Needle Aspiration can be

performed of all the mediastinal nodes that that can be assessed

from the oesophagus. In addition the left adrenal gland and the

left liver lobe can be visualized.EUS particularly provides access

to nodes in the lower mediastinum (station 7,8 and 9)

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