NHL ?Involves the thorax in approximately 40% of patients at presentation. ? 50% of patients with NHL and intrathoracic disease have mediastinal nodal involvement, only 10% of NHL patients have disease that is limited to the mediastinum. ?

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NHL ?Involves the thorax in approximately 40 of
patients at presentation. ? 50 of patients with
NHL and intrathoracic disease have mediastinal
nodal involvement, only 10 of NHL patients have
disease that is limited to the mediastinum. ?
lymphoblastic lymphoma and diffuse large B-cell
lymphoma are the most common type that present
with mediastinal masses ? Lymphoma involving a
single mediastinal or hilar nodal group is much
more common in NHL than in Hodgkin disease. ?
NHL most commonly involves middle mediastinal and
hilar lymph nodes ? Juxtaphrenic and posterior
mediastinal nodal involvement is uncommon but is
seen almost exclusively in NHL.
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?Calcification in untreated lymphoma is extremely
uncommon presence within an anterior mediastinal
mass should suggest another diagnosis. ?clue to
the diagnosis ?Involvement of other lymph
nodes in the mediastinum or hila ? Enlarged
spleen.
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?Central necrosis, seen in 20 of patients, has
no prognostic significance ? Parenchymal
involvement is usually the result of direct
extranodal extension of a tumor from hilar nodes
along the bronchovascular lymphatics ? On MR,
untreated lymphoma appears as a mass of uniform
low signal intensity on T1WIs and uniform high
signal intensity or intermixed areas of low and
high signal intensity on T2WIs. ? low signal
intensity on T2WIs of untreated patients foci of
fibrotic tissue in nodular sclerosing Hodgkin
disease.
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?Monitor the response of lymphoma to therapyCT,
MR, gallium scintigraphy, (FDG) PET ?Assess
tumor regression and detect relapse CT ?The
appearance of high-signal-intensity regions on
T2WIs more than 6 months after treatment should
suggest recurrence.
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Germ cell neoplasms ?Teratoma, seminoma,
choriocarcinoma, endodermal sinus tumor, and
embryonal cell carcinoma ? Distinguishing
primary from metastasis presence of
retroperitoneal lymph node involvement in
metastatic gonadal tumors Majority
in the anterior mediastinum, Up
to 10 in the posterior
mediastinum.
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?The most common benign mediastinal germ cell
neoplasm is teratoma(60 to 70) ? Teratomas
may be cystic or solid ? Most common type of
teratoma in the mediastinum Cystic or
mature teratoma ? Solid teratomas are usually
malignant. ? Most germ cell neoplasms third or
fourth decade of life ? Benign tumors
female/male, 60/40), ? Malignant
tumors almost in men.
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Seminoma is the most common malignant germ cell
neoplasm, accounting for 30 of these tumors.
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Middle Mediastinal Masses
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Lymph Node Enlargement ?Most middle mediastinal
lymph node masses are malignant ? Benign causes
of middle mediastinal lymph node enlargement
sarcoidosis, mycobacterial and fungal
infection, angiofollicular lymph node hyperplasia
(Castleman disease), and angioimmunoblastic
lymphadenopathy
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Density of Mediastinal Nodes on CT
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lymphoma ?Nodal enlargement is bilateral but
asymmetric. ? Nodular sclerosing Hodgkin
disease commonly results in lymph node
enlargement, predominantly within the anterior
mediastinum and thymus. ? Isolated posterior
nodal enlargement is usually seen only in
patients with NHL Leukemia (T-lymphocytic ) ?
The lymph node enlargement is usually confined to
the middle mediastinal and hilar nodes..
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?The most common source of metastases to middle
mediastinal nodes is bronchogenic carcinoma ?
Lymph node enlargement is often unilateral on the
side of the visible pulmonary or hilar
abnormality. Paratracheal and aorticopulmonary
nodes are most commonly involved
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sarcoidosis ?Mediastinal lymph node enlargement
occurring in 60 to 90 with sarcoidosis? Nodal
enlargement is typically bilateral and symmetric
? Involves the hila as well as the mediastinum
(differentiation of sarcoidosis from lymphoma
and metastatic disease)? In sarcoidosis, the
enlarged nodes produce a lobulated appearance ?
Enlarged nodes do not coalesce(in contrast to
lymphoma and nodal metastases)
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?Most commonly infections can cause mediastinal
nodal enlargement histoplasmosis,
coccidioidomycosis, cryptococcosis, and
tuberculosis These patients have parenchymal
opacities on chest radiographs, but isolated
lymph node enlargement may be seen, particularly
in children and young adults. ? Other bacterial
infections cause mediastinal nodal enlargement
anthrax, bubonic plague, and tularemia
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Foregut and mesothelial cysts ?Asymptomatic
masses on routine chest radiographs in young
adults 80 to 90 ? May become secondary
infected or hemorrhagic ? Arise within the
mediastinum in the vicinity of the tracheal
carina ? on frontal chest radiographs Soft
tissue masses in the subcarinal or right
paratracheal space Less commonly involve the
hilum, posterior mediastinum, and periesophageal
region
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Pericardial cysts? Arise from the parietal
pericardium ? Most often arise in the anterior
cardiophrenic angles ? Right-sided lesions being
twice as common as left-sided lesions ?
Approximately 20 arise more superiorly within
the mediastinum
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Neurogenic Lesions Rarely, a neurofibroma
arising from the phrenic nerve may present as a
middle mediastinal juxtacardiac mass.
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Posterior Mediastinal Masses
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Neurogenic Tumors(1) Tumors arising from
intercostal nerves (neurofibroma, schwannoma)
(2) Sympathetic ganglia (ganglioneuroma,
ganglioneuroblastoma, and neuroblastoma) (3)
Paraganglionic cells (chemodectoma,
pheochromocytoma).? Neuroblastoma and
ganglioneuroma most common in children ?
neurofibroma and schwannoma more frequently in
adults
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Multiple neurofibroma and schwannoma in the
mediastinum, particularly bilateral are virtually
diagnostic of neurofibromatosis
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?Radiographically round or oval paravertebral
soft tissue masses. ? CT smooth or lobulated
paraspinal soft tissue mass, may erode the
adjacent vertebral body or rib. Extension from
the paravertebral space into the spinal canal via
an enlarged intervertebral foramen is
characteristic of a neurofibroma. ? MR is the
modality of choice for imaging a suspected
neurofibroma
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?sympathetic ganglia tumors present as elongated,
vertically oriented paravertebral soft tissue
masses with a broad area of contact with the
posterior mediastinum ? These findings may help
distinguish these lesions from neurofibromas,
which usually maintain an acute angle with the
vertebral column and posterior mediastinum and
therefore tend to show sharp superior and
inferior margins on lateral chest radiographs ?
Calcification, seen in up to 25 of cases.
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• Neurofibroma

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• Ganglioneuroma

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• Thanks for your attention

Thanks for your attention