1. Chest p95-98 (Mediastinal masses, Pulmonary arteries)

Question 1

Superior mediastinal masses (3)

Answer 1

Superior sulcus tumour
- to be a Pancoast tumour, must have Pancoast syndrome (shoulder pain, C8-T2 radicular pain, Horner syndrome)
- Most common to cause Pancoast syndrome is squamous cell lung Ca (or bronchogenic adenocarcinoma).

Question 2

When is a superior sulcus tumour unresectable (4)?

Answer 2

Brachial plexus involvement C8 or higher.
Diaphragm paralysis (infers C3,4,5 involvement).
>50% vertebral body.
Distal nodes or mets.

Question 3

Anterior mediastinal masses (6)

Answer 3

Thymus,
Teratoma (malignant germ cell tumour),
Thyroid Ca (See endocrine),
Thoracic aorta,
Terrible lymphoma (see later in chapter),
Pericardial cyst.

Question 4

Thymus mass causes (4)

Answer 4

Rebound
- Can become 1.5x normal size after stress or chemo and simulate a mass. Can be hot on PET.
Thymic cyst
- Congenital or acquired (thoracotomy, chemo or HIV).
- Unilocular or multilocular.
- T2 bright.
Thymoma
- range: non-invasive thymoma to invasive thymoma to thymic carcinoma.
- Calcification suggests more aggressive.
- Tend to invade into mediastinal fat and surounding structures.
- Average age = 50
- Can ‘drop met’ into pleura and retroperitoneum, abdominal imaging needed.
- Associated with Myasthenia Gravis, Pure Red Cell Aplasia and Hypogammaglobulinaemia.
Thymolipoma
- Fatty mass with interspersed soft tissue

Question 5

Mediastinal germ cell tumour

Answer 5

75% Teratomas:
- Commonest extragonadal germ cell tumour.
- Occur in kids <1yo and adults 20-30s.
- Benign, small malignant transformation risk.
- Mature subtypes equal in men and women. Immature more common in men.
- Mature teratomas associated with Klinefelter syndrome
- Imaging: cystic appearance (90%) and fat. Can have calcifications including teeth.

Question 6

Pericardial cyst

Answer 6

Rare and benign.
Classically right anterior cardiophrenic angle.

Question 7

Middle mediastinal masses (4)

Answer 7

Fibrosing mediastinitis.
Bronchogenic cyst.
Lymphadenopathy (reactive, infection, TB)
Mediastinal Lipomatosis.

Question 8

Fibrosing mediastinitis - definition/cause (3)

Answer 8

Proliferation of fibrous tissue in the mediastinum.
Commonest known cause is histoplasmosis.
Other causes include TB, radiation, sarcoid.

Question 9

Fibrosing mediastinitis - imaging (2)

Answer 9

Soft tissue mass with calcifications.
Infiltrates fat planes.

Question 10

Fibrosing mediastinitis - associations (2)

Answer 10

Known to cause superior vena cava syndrome.
Associated with retroperitoneal fibrosis when idiopathic.

Question 11

Bronchogenic cyst - imaging (3)

Answer 11

Usually within mediastinum (subcarinal space) or less commonly parenchymal.
Subcarinal ones cause obliteration of azygous line on CXR.
Waterish density on CT.

Question 12

Mediastinal lipomatosis - features (2)

Answer 12

Excess unencapsulated fat in the mediastinum.
Causes: iatrogenic steroids, cushings or obesity.

Question 13

Posterior mediastinal masses (2)

Answer 13

Neurogenic (most common):
Bone marrow

Question 14

Neurogenic posterior mediastinal masses (3)

Answer 14

• Schwannomas,
• Neurofibromas,
• Malignant peripheral nerve sheath tumours

Question 15

Bone marrow posterior mediastinal masses (6)

Answer 15

Extramedullary haematopoiesis (EMH) as a response to bone marrow failure to respond to EPO.
Causes:
CML,
Polycythaemia vera,
myelofibrosis,
sickle cell,
thalassaemia

Question 16

Pulmonary embolism - CXR (4)

Answer 16

Watermark sign - regional oligaemia
Fleishner sign - enlarged pulmonary artery
Hamptom’s hump - Peripheral wedge shaped opacity
Pleural effusion - seen in 30% of PEs

Question 17

Acute vs chronic PE (3)

Answer 17

Central vs Peripheral filling defect.
Venous dilation vs shrunken veins with collateral vessels.
Perivenous soft tissue oedema vs calcifications within thrombi & within venous walls.

Question 18

Pulmonary infarct mimics (2)

Answer 18

Pulmonary infarct is a wedge shaped opacity, which resolves slowly, can sometimes cavitate.
Cavitating lesions can raise suspicion for TB or cancer.

Question 19

Pulmonary artery aneurysm - Causes (6)

Answer 19

Iatrogenic (swan ganz catheter) is most common. “Pt in ITU”
Behcets. “Turkish, mouth and genital ulcers”
Chronic PE.
Hughes-stovin syndrome
Rasmussen aneurysm.
Tetralogy of Fallow repair.

Question 20

Hughes-stovin syndrome (2)

Answer 20

Similar to Behcets.
Recurrent thrombophlebitis and pulmonary artery aneurysm formation & rupture.

Question 21

Rasmussen aneurysm (2)

Answer 21

Pulmonary artery pseudoaneurysm secondary to TB.
Involves upper lobes in setting of reactivation TB.

Question 22

Tetralogy of Fallow repair - pulmonary artery aneurysm

Answer 22

Patch aneurysm from RVOT repair.

Question 23

Pulmonary hypertension - definition & types (3)

Answer 23

Pulmonary arterial pressure >25mmHg.
Causes:
Primary (rare, usually young women),
Secondary (most common).

Question 24

Secondary pulmonary HTN - causes (4)

Answer 24

Chronic PE,
Right heart failure/strain,
Lung parenchymal problems (emphysema and fibrosis),
COPD (PA > Aorta have more mortality).

Question 25

Pulmonary HTN - imaging (4)

Answer 25

Big PA (>29mm or >aorta),
Mural calcifications of central pulmonary arteries,
Right ventricular dilatation and hypertrophy,
Centrilobular ground glass nodules.

Question 26

Pulmonary veno-occlusive disease - features

Answer 26

Uncommon cause of pulmonary HTN, due to post capillary vasculature.
PAH + Normal wedge pressure.
Normal wedge pressure differentiates from other post capillary causes, such as:
- left atrial myxoma,
- mitral stenosis,
- pulmonary vein stenosis