4.4 Mediastinal tumours Flashcards Preview

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Flashcards in 4.4 Mediastinal tumours Deck (30):
1

What is the mediastinum?

All the structures of the thorax except the lungs and the pleura
The structures are surronded by loose connective tissue and can accommodate movement

2

What are the compartments of the mediastinum?

Superior, inferior (anterior, middle and posterior)

3

What are the borders of the mediastinum?

Superior thoracic aperture, sternum, diaphragm and thoracic vertebrae

4

What is in the superior mediastinum?

Thymus, thyroid, parathyroid, great vessels, oesophagus, trachea, thoracic duct

5

What is in the posterior mediastinum?

Inferior thoracic vertebrae, thoracic nerves, descending thoracic aorta

6

What is in the middle mediastinum?

Pericardium, heart, great arteries, phrenic nerves, main bronchi

7

What is in the anterior mediastinum?

In children contains the thymus

8

What are the common tumours of the mediastinum?

Thymoma, lymphoma and germ cell tumours

9

Where do you find thymoma?

Anterior superior mediastinum

10

What does the thymus develop from?

3rd and 4th pharygeal pouch

11

What is the weight of the thymus?

Birth: 15g
Pubetry: 40g
>60: 10 g

12

What is a thymoma?

Tumour arising from the thymic epithelial cells

13

Can a thymoma invade or metastasise?

Can locally invade but cannot metastasise

14

What is the presentation of thymoma?

Adults >40
Incidental discovery
Local pressure symptoms
Myastheia gravis (in up to 50%)
Mass lesion in anterior superior mediastinum

15

What is used for diagnosis of thymomoa?

CXR, CT (suggestive)
Percutaneous biopsy - cytology
Mediastinoscope and biopsy - histology

16

What is the micro appearance of thymoma?

Fibrous tissue dividing the tumour into lobules
Few epithelial cells
Immature T lymphocytes

17

What is the classification of thymoma?

Thymoma: well differentiated with no cellular atypia

Thymic carcinoma: poorly differentiated with cellular features of malignancy

18

What is the treatment of thymoma

Depends on extent and cell type

Primary: complete surgical removal and radiotherapy

Non resectable: palliative radiotherapy and chemo

19

What is Myasthenia Gravis?

An autoimmune disease where there are circulating antibodies to ACh blocking the receptors

Affects females > males

20

What is the manifestation of myasthenia gravis?

Weakness of extra ocular eye muscles (droopy eyelids and double vision)
Muscle power decreasing with use

21

What is Myasthenia gravis associated with?

65% with thymic hyperplasia
15% with thymoma

22

What are Non Hodgkin lymphomas comprised of?

T or B cells (85% B cell) - MONOCLONAL

23

What is the spread of hodgkin and non hodgkin lymphoma?

Hodgkin: Systemic spread - systemic treatment
Non: Orderly spread - local treatment

24

What is used for diagnosis of lymphoma?

Haematoxylin and eosin stain
Immunohistochemistry for cell differentiation and type
Cytogenetics for chromosomal abnormalities

25

How do you differentiate B and T cells?

B = CD20
T = CD3

26

What markers will you see in hodgkins lymphoma?

CD15 and CD30

27

What translocation do you see in follicular lymphoma?

t(14;18)leading to expression of bcl-2 which is an anti apoptotic gene

28

What is the usual presentation of mediastinal germ cell tumours?

Men 10-30
Anterior superior mediastinum
Symptoms due to compression

29

What are the different types of germ cell tumours and which are most common in the mediastinum?

Teratomatous: mature teratoma, immature

Non teratoma: seminoma, yolk sac tumour, chorioacinoma, embryonal carcinoma

Teratoma > seminoma > others

30

What is the most aggressive mediastinal germ cell tumour?

Non teratomatous
(mature teratoma = benign)