PROF DR MAGESHKUMAR SIR UNIT DR.VANITHA

AN INTERESTING X-RAY OF THE WEEK

65 years old male, chronic smoker presented with the c/o cough,

chest pain, breathlessness for the duration of 1 month H/o loss of wt + H/o loss of appetite +

In Lung or mediastenum?

Anterior / middle / posterior compartment ?

Narrows down your diagnosis

ACUTE ANGLE– so it is in the lung probably

If it is mediastinum - Which compartment? HILUM OVERLAY sign

helps here

Hilum overlay sign

an anterior mediastinal mass will overlap the main pulmonary arteries, therefore they will be seen within the margins of the mass

Principle of hilum overlay the proximal segments of the R and L

main pulmonary arteries lie lateral to the cardiac silhouette on PA film

With pericardial effusion or cardiac enlargement, this relationship is unchanged

Overlies aorto-

pulmonary window

and hilum

Hilum overlay sign

: this must be an anterior mediastinal mass because it overlaps rather than “pushes out” the main pulmonary arteries

Can easily see

anterior location

DD of anterior mass

The 4 T’s Thymoma

Generally over age 40 Teratoma

Generally under age 40 Thyroid

Goiter or neoplasm Terrible lymphoma

Eg 2

Sharp margin, overlies hilum

See well-defined anterior

mass

Middle Mediastinum

Between anterior and posterior mediastinum

Contains esophagus, trachea, aortic arch, lymph nodes and vessels, pulmonary vessels

Accounts for 30% of masses

M

DD of middle mass The 4 A’s

Adenopathy TB/fungal Sarcoid Neoplasm (bronchogenic CA, mets, lymphoma,

leukemia) Infections (EBV, AIDS)

Awful primary neoplasm Tracheal, esophageal

Aneurysm/vascular Abnormalities of development

Bronchogenic cyst- often between carina and esophagus

Pericardial cyst Esophageal duplication cyst

Eg 2

Mass posterior to trachea

Posterior Mediastinum

Contains thoracic duct, azygos and hemiazygos veins, lymph nodes, sympathetic chains, inferior vagus nerves

P

DD of posterior mass

Neurogenic tumors most common Sympathetic ganglion tumors:

neuroblastoma, ganglioneuroma Nerve root tumors: schwannoma,

neurofibroma Less common

Vertebral body abscess or tumor Vascular: aneurysm or hematoma Developmental: neurenteric cyst,

Bochdalek hernia

Can easily see posterior location

Is it in the lung or mediastenum?

If in mediastenum, which compartment?

Then what is the differential diagnosis of the mass?

Hilum convergenceTo distinguish between enlarged pulmonary artery and mediastinal mass

If branches of the pulmonary artery converge toward a central mass enlarged PA

If branches of PA converge toward the heart rather than the central mass mediastinal tumor