mediastinal tumors

1. MEDIASTINAL TUMORS
BY:
Dr VIKAS KUMAR,
ASSOCIATE PROFESSOR,
DEPTT. OF CARDIOTHORACIC SURGERY,
AIIMS, BILASPUR,H.P.

2. ANATOMY OF THE
MEDIASTINUM
• SUPERIOR- thoracic inlet
• INFERIOR- diaphragm
• ANTERIOR- sternum
• POSTERIOR- spine
• LATERAL- pleural spaces

3. COMPARTMENTS OF
THE MEDIASTINUM
• Described by the Classic model and Shields’
model.
• According to the Classic model, the
mediastinum is divided into two
compartments:
• Superior, and
• Inferior, which is further subdivided
into:
• anterior
• middle, and
• posterior.

4. COMPARTMENTS OF
THE MEDIASTINUM
• Shields described an alternate model
consisting of three-compartment:
• Anterior compartment
• Middle (or visceral) compartment
• Posterior compartment
(paraverterbral sulcus).

5. COMPARTMENTS OF THE MEDIASTINUM
Classic model Shields’ model

6. COMPARTMENTS OF THE
MEDIASTINUM
• ANTERIOR- bounded by the Sternum anteriorly and
posteriorly by the great vessels and pericardium
(BLUE COLORED)
• MIDDLE- bordered posteriorly by the ventral
surface of the thoracic spine (ORANGE
COLORED)
• POSTERIOR- consists of potential spaces along
the thoracic vertebrae (GREEN COLORED)

7. COMPONENTS OF MEDIASTINAL COMPARTMENTS
ANTERIOR MIDDLE POSTERIOR
Thymus Pericardium/heart Sympathetic chain
Internal thoracic vessels Great vessels Proximal intercostals: nerve, artery, and
vein
Internal thoracic lymph nodes Trachea Posterior paraesophageal lymph nodes
Prevascular lymph nodes Proximal right and left main-stem
bronchi
Intercostal lymph nodes
Fat and connective tissue Esophagus
Phrenic nerve
Thoracic duct
Proximal azygos vein
Pretracheal lymph nodes
Pleuropericardial lymph nodes
Fat and connective tissue

8. COMPONENTS OF
MEDIASTINAL
COMPARTMENTS
A. Right lateral aspect. B,
Left lateral aspect.

9. COMPONENTS OF
MEDIASTINAL
COMPARTMENTS
• ANTERIOR MEDIASTINUM
• Thymus
• Internal thoracic vessels
• Internal thoracic lymph nodes
• Prevascular lymph nodes
• Fat and connective tissue

10. COMPONENTS OF MEDIASTINAL
COMPARTMENTS
• MIDDLE MEDIASTINUM
• Pericardium/heart
• Great vessels
• Trachea
• Proximal right and left main-stem bronchi
• Esophagus
• Phrenic nerve
• Thoracic duct
• Proximal azygos vein
• Pretracheal lymph nodes
• Pleuropericardial lymph nodes
• Fat and connective tissue

11. COMPONENTS OF
MEDIASTINAL
COMPARTMENTS
• POSTERIOR MEDIASTINUM
•Sympathetic chain
•Proximal intercostals: nerve, artery, and
vein
•Posterior paraesophageal lymph nodes
•Intercostal lymph nodes

12. MEDIASTINAL TUMORS

13. CLINICAL FEATURES
• Mediastinal lesions are symptomatic in 50%-75% of patients
• Symptoms can be caused by local mass effects, systemic effects of tumor derived hormones and peptides, or
infection.
• Local effects are dependent on the size and location of the lesion and result from compression of adjacent
structures
- Examples: cough, stridor, dyspnea, chest pain, and dysphagia
• Symptoms are also more common with malignant tumors that are more likely to fix, encase, and invade adjacent
structures.
- Examples: Superior vena cava syndrome, back pain, and neurological deficits such as Homer’s
syndrome or phrenic nerve palsy

14. CLINICAL FEATURES

15. INVESTIGATIONS
• ROUTINE
• Hemogram
• RFT
• Electrolytes
• LFT
• Coagulogram
• FBS
• PFT
• ECG

16. INVESTIGATIONS
• DIAGNOSTIC
• Chest X-ray- Postero-anterior and lateral views- First investigation
• CT scan- Investigation of choice
• MRI- Especially useful for Posterior mediastinal tumors
• Histology- FNAC and/or biopsy is diagnostic
• Echocardiography- for assessment of cardiac function
• FDG-PET- Required for staging of malignant tumors

17. APPROACH TO MEDIASTINAL MASSES
• Most mediastinal masses are (>60%)
• Thymomas
• Neurogenic tumors
• Benign cysts
• Lymphadenopathy
• In children most common mediastinal masses are (>80%)
• Neurogenic tumors
• Germ-cell tumors
• Foregut duplication cysts
• In adults the most common mediastinal masses are
• Lymphomas
• Lymphadenopathy
• Thymomas
• Thyroid masses

18. APPROACH TO MEDIASTINAL MASSES
Localize the mass to
the mediastinum
1
Localize the mass
within the
mediastinum
2
Characterize the
mass on CT or MR
3

19. LOCALIZE TO THE
MEDIASTINUM
As most mediastinal masses are initially detected on a
chest radiograph, the following features can help
localize a lesion to the mediastinum:
1) The margins of the lesion with the lungs will be
obtuse whereas if the lesion is in the lung, the
margins of the lesion with the lungs will be acute.
2) There will be disruption or alteration of the
mediastinal lines (such as the anterior and
posterior junction lines, right paratracheal stripe,
paraspinal lines, and the azygo-esophageal recess).
3) A mediastinal mass will contain air bronchograms.
4) Associated abnormalities may be seen in the spine,
sternum, and ribs.

20. • LEFT: A lung mass abutts the mediastinal surface and creates
acute angles with the lung.
• RIGHT: A mediastinal mass will sit under the surface of the
mediastinum, creating obtuse angles with the lung.
• On the x-ray on the left there is a lesion that has an acute
border with the mediastinum.
This must be a lung mass.
•
The chest radiograph on the right shows a lesion with an
obtuse angle to the mediastinum.
This must be a mediastinal mass.

21. LOCALIZE WITHIN THE MEDIASTINUM
• The hilum overlay sign is present if the edges of the
pulmonary vessels are appreciated, this implies the
cause of the opacity is not in contact with the hilum
and is, therefore, either anterior or posterior to it
• Anterior mediastinal masses can be identified when
both the hilum overlay sign and preservation of the
posterior mediastinal lines are present.
• The azygo-esophageal recess reflection is a
prevertebral structure and is, therefore, disrupted
by prevertebral disease. It has an interface with the
middle mediastinum; thus, the resulting line seen
at radiography can be interrupted by abnormalities
in both the middle and posterior compartments.

22. LOCALIZE WITHIN THE MEDIASTINUM
• A right paratracheal stripe 5 mm or
more in width is considered widened.
• A convex border between the AP
window and the lung is considered
abnormal.
• The paraspinal lines are disrupted by
paravertebral disease which
commonly includes diseases
originating in the intervertebral disks
and vertebrae and by neurogenic
tumors.

23. LOCALIZE WITHIN THE MEDIASTINUM
• Posterior mediastinal masses above the level
of the clavicles have sharp margins due to
their interface with lung whereas anterior
mediastinal masses do not have sharp
margins extending above the level of the
clavicles.
• Although there is no tissue plane separating
the divisions of the mediastinum, attempting
to more accurately localize an abnormality
with reference to the local anatomy of the
mediastinum helps in narrowing the
differential diagnosis and determining
appropriate further imaging

24. IMAGING FEATURES
ON CT OR MRI TO
CHARACTERIZE THE
MASS
• MRI is performed to analyze and characterize posterior mediastinal masses as majority
of these are nerve sheath
• If evaluation of osseous structures is needed a CT scan is more useful.
• Mediastinal masses can be further characterized by CT or MRI depending on whether
they contain fat, fluid, or are vascular.
• Anterior mediastinum:
• Fluid containing lesions: thymoma, thymic carcinoma, pericardial cyst, germ-cell
tumor, lymphoma
• Fat containing lesions: germ-cell tumor, thymolipoma, fat pad, Morgagni hernia
• Vascular lesions: thyroid, ascending aorta, cardiac or coronary
• Middle mediastinal lesions:
• Fluid containing lesions: duplication cyst, necrotic nodes, pericardial recess
• Fat containing lesions: lipoma, esophageal fibrovascular polyp
• Vascular lesions: arch anomaly, azygos vein, vascular nodes

25. IMAGING FEATURES
ON CT OR MRI TO
CHARACTERIZE THE
MASS
• Posterior mediastinal lesions:
• Fluid containing lesions: neuroenteric cyst,
schwannoma, meningocele
• Fat containing lesions: extramedullary hematopoiesis
• Vascular lesions: descending aorta
• Mediastinal lesions that disregard compartments:
• Fluid containing lesions: lymphangiomas, mediastinal
abscess (mediastinitis)
• Fat containing lesions: liposarcoma
• Vascular lesions: hemangioma, hemorrhage
• Other: lung cancer

26. TREATMENT
Depends upon the diagnosis
Surgical excision is the mainstay of the treatment
Chemotherapy for non-resectable malignancy

27. THANK YOU