Lymphoid system pathology

Question 1

What happens to the thymus at sexual maturity?

Answer 1

It involutes

Question 2

When is a very small thymus abnormal?

Answer 2

In neonates

Question 3

What occurs in thymus atrophy?

Answer 3

Loss of cortical lymphocytes and lobular shrinkage

Question 4

What can cause thymus atrophy?

Answer 4

Viruses/infectious agents
Stress
Malnutrition
Immunotoxicants - radiation
environmental contaminants

Question 5

What are thymic haemorrhages most common in?

Answer 5

Young dogs

Question 6

What can cause thymic haemorrhage?

Answer 6

Trauma
Neoplasms
Rodenticide poisoning
Idiopathic

Question 7

What is the benign tumour of the thymus called?

Answer 7

Thyoma - epithelial cell tumour

Question 8

What is a malignant tumour of the thymus called?

Answer 8

Thymic carcinoma

Question 9

What thymic tumours are common in cats and cows?

Answer 9

Thymic lymphomas

Question 10

What are the two main structures that make up the spleen?

Answer 10

Red and white pulp

Question 11

What is the red pulp for in the spleen?

Answer 11

Erythrocyte storage and filter

Question 12

What is the white pulp made up of in the spleen?

Answer 12

Macrophages, antigen presenting cells, lymphocytes

Question 13

What can cause splenic atrophy?

Answer 13

Cachexia (wasting)
Chronic radiation
Being old

Question 14

What is an incidental finding in the spleens of old dogs?

Answer 14

Siderotic plaques - crusty bits from haemosiderin/calcium deposits

Question 15

What can build up in the spleen abnormally?

Answer 15

Erythropoietin - iron deposits

Amyloid

Question 16

What is splenic infarction?

Answer 16

Local area of peracute ischaemia

Question 17

What can cause splenic infacrction?

Answer 17

Thrombi

Neoplasia

Question 18

What does an acute infarct look like?

Answer 18

Dard red, raised, ahemorrhagic

Question 19

What does a chronic infarct look like?

Answer 19

Grey/white, wedge shaped, sharply demarcated

Question 20

What are affected by splenic torsion/volvulus

Answer 20

Large dog breeds

Pigs

Question 21

What happens in splenic torsion?

Answer 21

Complete twist of the gastrosplenic ligament

Question 22

What can splenic rupture cause?

Answer 22

Haematoma

Spleen fragments disseminate into omentum

Question 23

What is a splenic haematoma?

Answer 23

Bulging mass on spleen

Question 24

What are some examples of pathogens causing splenitis?

Answer 24

Anthrax
Salmonellosis
Strep
TB

Question 25

What is nodular hyperplasia of the spleen found in?

Answer 25

Older dogs

Question 26

What are predominantly in nodular hyperplasia of the spleen?

Answer 26

Lymphocytes | Can lead to haematoma

Question 27

What is extramedullary haematopoiesis?

Answer 27

Development of blood cells in tissues outside the medullary cavity of bone

Question 28

What are the two main tumours of the spleen?

Answer 28

Haemangiosarcoma - malignant tumour from vascular endothelium Lymphoma

Question 29

What can cause atrophy of the lymph nodes?

Answer 29

``` Viral infections Malnutrition/cachexia Old age Toxins Absence of antigenic stimulation ```

Question 30

What causes haemosiderin deposition in the lymph nodes/spleen?

Answer 30

Haemorrhage or prolonged stasis Iron injections in piglets Melanin

Question 31

What can cause gas accumilation in lymph nodes?

Answer 31

Drainage of emphysematous lesions

Question 32

What can cause lymph cysts?

Answer 32

Poor downstream drainage so lymph accumilates

Question 33

What pathogens can cause lymphadenitis (inflammation of lymph node)?

Answer 33

Corynebacterium pseudotuberculosis Strep equi equi TB Feline coronavirus

Question 34

What bacteria causes caseous lymphadenitis?

Answer 34

Corynebacterium pseudotuberculosis

Question 35

What bacteria cause granulomatous lymphadenitis?

Answer 35

Mycobacterium bovis - TB

Question 36

What is the main primary tumour of lymph nodes?

Answer 36

Lymphoma

Question 37

What is the main secondary tumour of the lymph nodes?

Answer 37

Carcinomas - metastatic

Question 38

What can lymphatic rupture cause?

Answer 38

Chylothorax

Question 39

What is a lymphoma?

Answer 39

Neoplastic lymphoid cells in solid lymphoid organs/tissues

Question 40

What is leukaemia?

Answer 40

Neoplastic cells arising from the bone marrow that may have detectable neoplastic cells circulating in the blood

Question 41

What is the most common type of lymphoma?

Answer 41

Multicentric lymphoma

Question 42

What cells are affected in multicentric lymphoma?

Answer 42

B and T lymphocytes

Question 43

Where does multicentric lymphoma originate from?

Answer 43

The lymphoid and non lymphoid organs

Question 44

What cells does cutaneous lymphoma affect?

Answer 44

T cells

Question 45

What is the name for cutaneous lymphoma which targets the epithelium?

Answer 45

Mycosis fungoides

Question 46

What are the main symptoms of cutaneous lymphoma/mycosis fungoides?

Answer 46

Diffuse erythema, scaling, hypopigmentation, nodules

Question 47

What are the different types of alimentary lymphoma?

Answer 47

Segmental or diffuse | T or B cell

Question 48

Where do alimentary lymphomas metastasise to?

Answer 48

Mesenteric lymph nodes

Question 49

What viruses can cause lymphoma?

Answer 49

Feline leukaemia virus Gammaretrovirus Bovine leukaemia virus

Question 50

How does feline leukaemia virus cause lymphomas?

Answer 50

Neoplastic transformation caused by insertional mutagenesis

Question 51

How does bovine leukaemia virus cause lymphomas?

Answer 51

Carries additional genes that encode differnet proteins

Question 52

What lymphoma can affect calves that isnt BLV?

Answer 52

Sporadic lymphoma

Question 53

What is a lymphomatous disease of domestic fowl?

Answer 53

Marek's disease

Question 54

What is marek's disease caused by?

Answer 54

Alpha herpes virus