2. INTRODUCTION
There are several types of mediastinal tumors, with
their causes linked to where they form in the
mediastinum.
Anterior mediastinum
Germ cell - The majority of germ cell neoplasms
are benign and are found in both males and females.
Lymphoma – Malignant tumors that include both
Hodgkin’s disease and non Hodgkin’s lymphoma.
Thymoma and thymic cyst - The majority of
thymomas are benign lesions. However, about 30%
of these may be more aggressive and become
invasive.
Thyroid mass mediastinal – Usually a benign growth,
such as a goiter, these can occasionally be
cancerous.
3. INTRODUCTION
Middle mediastinum
Bronchogenic cyst
Lymphadenopathy mediastinal – An enlargement of
the lymph nodes.
Pericardial cyst
Thyroid mass mediastinal – Usually a benign growth,
such as a goiter, these can occasionally be
cancerous.
Tracheal tumors – These include tracheal neoplasms
and benign tumors .
Vascular abnormalities including aortic aneurysm
and aortic dissection
4. INTRODUCTION
Posterior mediastinum
Extramedullary haematopoiesis
Lymphadenopathy mediastinal – An enlargement of
the lymph nodes.
Neuroenteric cyst mediastinal
Neurogenic neoplasm mediastinal – The most
common cause of posterior mediastinal tumors,
these are classified as nerve sheath neoplasms,
ganglion cell neoplasms, and paraganglionic cell
neoplasms. Approximately 70% of neurogenic
neoplasms are benign.
5. SIGNS & SYMPTOMS
Almost 40% of people who have mediastinal
tumors experience no symptoms.
Most of the growths are often discovered on a
chest x-ray that is performed for another reason.
When symptoms are present they are often a
result of the compression of surrounding
structures, such as the spinal cord, heart or the
pericardium .
7. CHEST X-RAY
o
o
o
Chest radiography is the first study that would be
performed in an individual with symptoms
referable to the thorax.
The PA view allows for determination of
bilaterality and superior or inferior location, while
the lateral chest radiograph determines the
specific compartment.
This information, combined with the age, and
associated clinical findings, aids the physician in
the proper choice of subsequent diagnostic
studies.
8. CHEST X-RAY
Whenever one sees a mass on a chest x-ray that
is possibly located within the mediastinum, the
goal is to determine the following:
Is it a mediastinal mass?
Is it in the anterior, middle or posterior
mediastinum?
Is it possible to characterize the lesion by
determining whether it has any fatty, fluid or
vascular components?
9. CHEST X-RAY
It is important to remember the following:
Most masses are:
Neurogenic Tumors
Lymphadenopathy
Thymomas
Benign Cysts
Lymphomas
In children the most common are:
Neurogenic tumors
Germ cell tumors
Foregut cysts
In adults the most common are:
Lymphomas
Lymphadenopathy
Thymomas Thyroid masses
10. CHEST X-RAY
The following characteristics indicate that a lesion
originates within the mediastinum:
Unlike lung lesions, a mediastinal mass will not
contain air bronchograms.
The margins with the lung will be obtuse.
Mediastinal lines (azygo esophageal recess,
anterior and posterior junction lines) will be
disrupted.
There can be associated spinal, costal or sternal
abnormalities.
13. CHEST X-RAY
The mediastinum can be divided into anterior,
middle and posterior compartments.
On the lateral radiograph the anterior and
middle compartments can be separated by
drawing an imaginary line anterior to the trachea
and posteriorly to the inferior vena cava.
The middle and posterior compartments can be
separated by an imaginary line passing 1 cm
posteriorly to the anterior border of the
vertebral bodies.
16. C T SCAN
CT has become a routine part of the diagnostic
evaluation of mediastinal tumors, cysts, and other
masses.
This test can greatly assist in determining the
exact location of the mediastinal tumor and its
relationship to adjacent structures.
It also is useful in differentiating masses that
originate in the mediastinum from those that
encroach upon the mediastinum from the lung or
other structures.
17. C T SCAN
It also detects pulmonary and mediastinal
metastasis and differentiates from mediastinal
fatty mass.
The CT scan is very useful in differentiating
tissue densities. This assists greatly in
distinguishing structures that are cystic or
vascular from those that are solid.
CT scanning can reveal evidence of local invasion
of adjacent structures by a mass or the
presence of intra thoracic metastases.
18. MAGNETIC RESONANCE IMAGING
MRI is useful in both the initial diagnosis of a
mediastinal mass and in follow-up evaluation after
treatment.
It provides superior vascular images and can help
better delineate the relationship of an identified
mediastinal mass to nearby intrathoracic vascular
structures.
MRI can help differentiate between a possible
mediastinal mass and a vascular abnormality such as
an aortic aneurysm.
19. MAGNETIC RESONANCE IMAGING
MRI offers direct multi planar imaging.
It can be used when iodinated contrast is
contraindicated.
MRI provides increased detail in the sub carinal and
aorto pulmonary window areas and in the inferior
aspects of the mediastinum at the level of the
diaphragm.
20. MAGNETIC RESONANCE IMAGING
MRI is more useful than the CT scan in the
evaluation of invasion or extension of tumors,
especially tumors closely associated with the
heart.
MRI is superior to the CT scan for the evaluation
of masses located at the thoracic inlet or at the
thoraco abdominal level.
CT is superior in detecting pulmonary metastasis,
spacial relationship to other mediastinal
structures, and bony destruction.
21. MAGNETIC RESONANCE IMAGING
MRI is especially superior to CT for the
evaluation of neurogenic tumors of the
mediastinum and can eliminate the need for
additional studies such as myelography.
It can be augmented with magnetic resonance
angiography if more extensive evaluation of
associated vascular structures is needed,
eliminating the need for separate conventional
angiography studies.
MRI is used increasingly for evaluation of
residual or recurrent disease after treatment of
lymphoma.
22. LABORATORY INVESTIGATIONS
Hemoglobin, hematocrit, and white blood cell
count Red blood cell aplasia is found in
approximately 5% of patients with thymoma and
manifests as a normochromic-normocytic anemia.
Although rare, neutropenia can be found in
association with thymomas.
Gamma globulin levels Hypogammaglobulinemia
is associated with some cases of thymoma
23. LABORATORY INVESTIGATIONS
Beta human chorionic gonadotropin
Elevated levels of bhCG virtually always are
found in association with non seminomatous germ
cell tumors.
Seminomas generally do not produce elevated
levels of this substance. Less than 10% of
patients with seminoma have an elevated bhCG
level, and the measured level is usually much
lower than that found with non seminomatous
tumors.
24. LABORATORY INVESTIGATIONS
Alpha-fetoprotein
AFP almost always is elevated in individuals with
non seminomatous germ cell tumors.
Elevation of the AFP level is not found in
individuals with pure seminoma.
Lactate Dehydrogenase
25. LABORATORY INVESTIGATIONS
Thyroid-stimulating hormone and thyroid
function studies Functioning thyroid adenomas
can develop in ectopic mediastinal thyroid tissue
and can cause thyroid stimulating hormone
suppression and associated elevation of serum
triiodothyronine levels.
Serum and 24-hour urinary catecholamine
levels should be measured in all infants and
children who present with a posterior
mediastinal or paravertebral mass. These levels
are frequently elevated in patients with
neuroblastoma and ganglioneuroblastoma.
26. LABORATORY INVESTIGATIONS
Adrenocorticotropic hormone (ACTH) levels
The thorax should always be investigated for the
source of ectopic ACTH production. A
neuroendocrine or carcinoid tumor of the thorax
should be excluded. These tumors occur in the
mediastinum, particularly in the thymus gland,
and in the lung.
Antidiuretic hormone levels: These may be
elevated with some neuroendocrine tumors of
the thymus.
27. RADIONUCLIDE SCANNING
Nuclear imaging can be used selectively in the
workup of mediastinal masses when specific tumors
are suggested.
Gallium Ga 67 is used commonly in the evaluation of
mediastinal lymphoma, both for initial evaluation
and for post therapy follow-up.
The iodine I 131 or iodine I 123 scans are very
helpful in distinguishing thyroid tissue from other
masses. They are often used in identifying an
anterior mediastinal mass located at the level of
the thoracic inlet as the sub sternal extension of a
cervical thyroid goiter.
28. RADIONUCLIDE SCANNING
Scanning with technetium Tc 99m sestamibi may be
useful in the identification of mediastinal
parathyroid tissue.
The octreotide scan, using indium In 111–labeled
pentetreotide, is useful for localizing various
neuroendocrine neoplasms, including carcinoid
tumors, pheochromocytomas, and para gangliomas.
29. ECHOCARDIOGRAPHY & ULTRASONOGRAPHY
Ultrasonographic methods have been used to help
differentiate solid from cystic mediastinal masses
and to assist in determining the connection
between a mass and adjacent structures.
The findings from these studies are more useful in
the evaluation of masses associated with the heart
and in vascular abnormalities.
In general, given the accuracy and detail provided
by CT scan images, MRI, and selected radionuclide
scan findings, ultrasound techniques are generally
not used as a primary tool in the evaluation of
mediastinal tumors and cysts.
30. POSITRON EMISSION TOMOGRAPHY
PET scan findings have been studied extensively
for the evaluation of a number of neoplasms such
as lung, colorectal, breast, lymphoma, and
melanoma. The usefulness of this study in the
evaluation of mediastinal tumors is being evaluated.
PET has proven a useful test in for helping identify
some pheochromocytomas.
Some results of using PET scan for thymomas
suggest that a high 18-fluorodeoxyglucose (FDG)
uptake on PET scan reflects the invasiveness of
malignant nature of thymic tumors and can be used
to differentiate these from benign thymomas.
31. ARTERIOGRAPHY
Conventional Angiography findings have been used
to differentiate mediastinal masses from vascular
abnormalities and to exhibit the relationship
between known masses and adjacent vascular
structures.
MRI and Magnetic Resonance Angiography have
replaced conventional angiography in most cases.
32. TRANSTHORACIC NEEDLE BIOPSY
CT-guided fine-needle aspiration (FNA) and core
needle biopsy techniques increasingly are used
with success at several centers.
Differentiation of thymomas, lymphomas, and
germ cell tumors can be made in a number of cases
when tissue obtained from a core needle biopsy is
subjected to special histologic staining methods,
including immunohistochemical techniques.
In some cases, lymphoma subtypes can be
identified as well.
33. TRANSTHORACIC NEEDLE BIOPSY
Considerable expertise in tissue processing and
analysis is necessary for diagnostic accuracy, which
is reported to be 85-95%.
FNA has been used occasionally to aid in the
diagnosis of primary bronchogenic cysts. However,
most authorities do not recommend aspiration of a
cyst because a sample of the cyst wall, required for
diagnosis, is not obtained by this method.
FNA has been described for neurogenic tumors,
although because surgical resection is the
treatment for these lesions after adequate workup,
needle biopsy may be deemed an unnecessary step.
34. MEDIASTINOSCOPY
Cervical Mediastinoscopy is a commonly used
surgical diagnostic procedure for evaluation of the
retro vascular pre tracheal area of the
mediastinum.
This procedure is used most commonly for staging
of bronchogenic carcinoma and for evaluation of
hilar and para tracheal lymphadenopathy,
but it can be modified into what has been termed a
Sub-sternal Extended Mediastinoscopy to evaluate
the pre vascular area of the mediastinum.
35. MEDIASTINOSCOPY
Thymic masses and any tumors found in the
anterior mediastinum (eg, germ cell tumors), as well
as lymph nodes of the aorto pulmonary window, are
accessible for obtaining a biopsy using this
approach.
Tumors located in the posterior mediastinum,
where most neurogenic tumors are found, are not
approachable using this method.
Some lesions of neurogenic origin, when located
high in the mediastinum in the region of the
thoracic inlet, may be approached and resected
through a cervical approach.
36. MEDIASTINOTOMY
Anterior Mediastinotomy - this para sternal
approach to the mediastinum has been used most
commonly in situations in which standard cervical
mediastinoscopy was believed or found to be
inadequate.
It classically is performed in the upper left para
sternal area for access to the aorto pulmonary
window and areas of the anterior mediastinum
inferior to the aortic arch.
Anterior Mediastinotomy is being replaced in many
centers either by Extended Cervical
Mediastinoscopy or by Video-Assisted Thoracic
Surgical (VATS) techniques.
37. MEDIASTINOTOMY
Posterior Mediastinotomy - this is a rarely used
procedure for biopsy of some of the posteriorly
situated lymph nodes or a mass in the
paravertebral sulcus.
Performed most commonly on the right side in a
paravertebral location immediately lateral to the
paravertebral muscles.
It is rarely used for mediastinal tumors and cysts
because these are more appropriately managed by
either standard Thoracotomy or VATS techniques.
38. VIDEO ASSISTED THORACOSCOPY
VATS techniques have been used successfully
for biopsy of various mediastinal masses and are
used commonly for the sampling of perihilar
lymph nodes.
VATS is one of the commonly used methods for
evaluation of mediastinal lymphoma.
39. STERNOTOMY & THORACOTOMY
In spite of the numerous minimally invasive options
available for histologic diagnosis of mediastinal
tumors and cysts, open surgical access is needed at
times.
In some cases, standard Sternotomy or
Thoracotomy may be the safest method available to
obtain an adequate tissue diagnosis.
Some surgeons perform a Partial Upper
Sternotomy, in which only the superior portion of a
typical Sternotomy is performed. It is a less
invasive technique that is safe and effective for
accessing the anterosuperior mediastinum.
40. THYMOMA WORK UP
Upto 50% patients – asymptomatic with anterior
mediastinal mass on CXR
Others – symptoms due to local compression or as
paraneoplastic syndrome ( eg. – Myasthenia Gravis )
CXR (PA) -rounded/oval lesion with smooth or
lobulated border near the junction of ht. & gt. vsls.
CXR (Lat)-opacity at anterior cardiac window
CT Scan-helps in evaluating extent of mass
MRI-investigating vascular invasion
Indium labelled octreotide scan
CT Guided FNAC
Surgical Biopsy
41. EXTRA GONADAL G C T WORK UP
More than 90% of patients have symptoms due to
local compression or invasion to adjacent
structures (dyspnoea, cough, chest pain, SVCO,etc)
CXR - mass in the antero superior mediastinum
CT Scan Thorax, Abdomen, Pelvis – evaluation of
the mass, screening for metastasis &
lymphadenopathy
USG Scrotum – detecting occult primary
Tumour Markers – AFP, Beta HCG, LDH
CT Guided FNAC with cytologic staining for tumour
markers
42. LYMPHOMA WORK UP
CBC count with differential and platelets.
Electrolyte panel and liver function tests.
Elevation in the serum lactic dehydrogenase (LDH)
or β-2 microglobulin level value is an adverse
prognostic feature.
The markers alpha-fetoprotein and β-human
chorionic gonadotropin (βHCG) are often highly
elevated in patients with mediastinal germ cell
tumors, constituting an important differential
diagnosis .
43. LYMPHOMA WORK UP
CXR (PA, lateral)- A mass larger than one third of
the diameter of the thorax is considered bulky and
indicates a poor prognosis.
CT scans (chest, abdomen, pelvis)- Extension to
the pleura, pericardium, and even the chest wall is
common. Invasion of the liver, kidneys, and
peripheral lymph nodes is more common at the time
of recurrence.
Findings on a gallium scan are almost always
strongly positive.
PET scans represents a convenient, and probably
more sensitive, alternative to a gallium scan.
44. LYMPHOMA WORK UP
Adequate diagnostic biopsy is needed and may
require surgery.
Ancillary studies, which include
immunohistochemistry, immunophenotyping
(flow cytometry), and gene rearrangement
studies, are often necessary to establish the
diagnosis.
Bone marrow aspirate and biopsy are necessary
for staging.
45. LYMPHOMA WORK UP
Biopsy of a lymph node or of the mediastinal
mass with the use of mediastinoscopy or
parasternotomy is necessary
Fine-needle aspiration is usually not diagnostic
in this disorder due to lack of morphologic
architecture .
Other tests should be performed if clinically
indicated (eg, thoracentesis for pleural effusion,
lumbar puncture for for neurologic symptoms).