Mediastinal masses

Question 1

Posterior mediastinum masses

Answer 1

1. Neurogenic tumors
   - benign mostly
   - Located in the paravertebral gutters
   - Can extend into the spine (MRI)

DDX:
- Peripheral nerve sheath tumors
—- Schwannoma
—- Neurofibroma (NF1)
———— NF-1 (check for malignant transformation with biospy)
- Malignant: NF1 (local invasion)

2. Hernia
   - Bochdalek - observe - fat density in posterior mediastinum
3. Extramedullary hematopoesis: Sickle cell, thalassemia
4. Esophageal
   - tumors, HH
5. Lateral menginocele (paraspinas cystic lesion)
6. Descending Aneurysm

Question 2

Middle mediastinum masses

Answer 2

Aneursyms (vascular)
— Angiofollicular LN hyperplasia (Castlemens)
— Paraganglioma (enhancing on CT)
— Malformations
— Metastatic disease from vascular cancers (renal, breast)

Abnormalities in Development
— Pericardial cyst
— Bronchogenic cyst

Adenopathy
— Malignant: Lymphoma
— Non-malignant: infxn, sarcoidosis

Question 3

Mediastinal Lipomatosis

Answer 3

Mediastinal widening due to fatty infiltration

Ddx: obesity, cushing, chronic steroids, ectopic ACTH

May have compressive sx

Question 4

Anterior Mediastinal Masses

Answer 4

Thymoma
Terrible- lymphoma, mets
Thyroid
Teratoma - Germ Cell

Question 5

Thymoma

Answer 5

Slow growing, malignant epithelial cell tumor
SX: compressive sx, MG, asx, goods syndrome

Can be encapsulated
Can be invasive- outside capsule
Can be metastatic (no thru blood or lymphs)- invade pleural and pericardium–> drop mets to pleural space

CT:
- Homogenous, well circumscribed mass anterior to the Aortic root

DX:
- Biopsy

Tx:
Resection
- resection cures MG in most however takes time 1-10years
- If invasive then chemo and resection

Follow up-
- Follow up for 10 years- very slow growing

Thymic Carcinoma
Thymic NEC- carcinoid/paraneoplastic
Thymic lymphoma
Thymic cyst

Question 6

Germ Cell Tumors

Answer 6

Middle mediastinum
>⅔ germ layers present
— therefore may have different tissues within the mass
—- May be Teratomas, Seminomas or non-seminomatous

.

Question 7

Teratoma

Answer 7

Benign GCT

Asymptomatic:
- Expectoration of hair, sebacous debris

CT:
- Well circumscribed
- heterogenous- fat, calcification, cystic regions etc

Tx: Resection

Question 8

Seminoma
- medistinal GCT

Answer 8

Malignant anterior mediastinal mass

CT:
- well circumscribed, homogenous anterior mass, lobular

Markers:
- AFP nl
- HCG: inc

Tx: radiation and chemo

Question 9

Non-seminomatous

Answer 9

Malignant anterior mediastinal mass
men in 20s

CT:
- Large, irregular, heterogenous mass
- Invasive, mets present
- LN enlarged, pleural effusions

Markers:
- AFP elevated
- HCG: elevated

Tx:
- Chemo
- Resection
- Lower survival than seminomatous

Question 10

Intra-thoracic Thyroid

Answer 10

Anterior mediastinum
Connection to thyroid
sx: usually compressive

CT:
lobular mass, discrete
continugous with thyroid
Heterogenous attenuation
May cause tracheal deviation/narrowing

Tx: resection

Question 11

Morgani Hernia

Answer 11

Right sided- abdominal contents- anterior mediastinum

surgical correction

Question 12

Mediastinal Lymphangioma

Answer 12

Congenital/acquired
Neck/mediastinal- middle

CT:
- solitary or lobulated cystic masses
- Variable sizes
- water attenuation

Tx: resection