Pathology of lymphoid system

Question 1

List 3 primary lymphoid organs

Answer 1

Thymus
bone marroe
bursa of Fabricius

Question 2

List 3 secondary lymphoid organs

Answer 2

spleen
lymph nodes
lymph nodules (e.g. MALT)

Question 3

When you see one enlarged lymph node what should we do

Answer 3

Look at what area that drains as this will help narrow don where the problem is

Question 4

when is it indicated to investigate a lymph node

Answer 4

lymph node enlargement
suspect of an underlying infectious disease (e.g. Leishmania, FIP, fungi)
stage malignant neoplastic diseases
provide material for molecular testing

Question 5

Why when you are sampling a lymph node does the needle need to be directed tangentially

Answer 5

to avoid more central points
very large nodes may have areas of haemorrhage or necrosis

Question 6

List the key points of sample collection from lymph nodes

Answer 6

spread gently
non suction technique to minimise blood contamination
ideally take sample before giving steroids
avoid aspiration of centre

Question 6

Describe how a normal lymph node looks

Answer 6

small lymphocytes –> 90%
medium and large large lymphocytes –> <5-10%
plasma cells, macrophages mast cells, neutrophils are rare to see

Question 6

What are Lymphoglandular bodies

Answer 6

fragments of cytoplasm of disrupted lymphocytes

Question 7

list the 4 causes of lymphadenopathy

Answer 7

reactive hyperplasia
lymphoma
lymphadenitis
metastatic neoplasia

Question 8

What happens in primary lymphoid organs

Answer 8

Are where B and T lymphocytes proliferate, differentiate and mature

Question 9

What are the secondary lymphoid organs

Answer 9

resposinsible for the immune responses to antigen

Question 10

Describe what is seen on cytology with reactive hyperplasia in lymph nodes

Answer 10

cytologically can be indistinguishable from a normal lymph node
small lymphocytes are predominant
can see an increase in number of medium and large lymphocytes

Question 11

What is lymphadenitis

Answer 11

accumulation of inflammatory cells
can be classified based on what inflammatory cell is present

Question 12

What causes can neutrophilic lymphadenitis suggest

Answer 12

bacterial
immune mediated
neoplastic

Question 13

what can cause eosinophilic lymphadenitis

Answer 13

hypersensitivity reaction
parasites
idiopathic
paraneoplastic (e.g. mast cell tumour, lymphoma)

Question 14

List the causes of macrophagic/granulomatous lymphadenitis

Answer 14

chronic inflammatory conditions (e.e.g fungal infection, mycobacteriosis, leishmaniasis, FIP)

Question 15

Describe what is seen on cytology with lymphoma

Answer 15

homogenous appearance
most commonly increased percentage (>50%) of large immature lymphocytes
tingible bodies macrophages

Question 16

Describe what can be seen on cytology with metastatic neoplasia

Answer 16

presence of cells not normally found in lymph nodes ( e.g. carcinoma, sarcoma)
increased numbers of cells normally present with atypical morphology (e.g. mast cells)

Question 17

Decribe the function of red pulp the spleen

Answer 17

is a reservoir of blood
filter for senescent or damaged erythrocytes
iron metabolism

Question 18

Describe the function of the white pulp of spleen

Answer 18

immunity against blood borne antigens

Question 19

what is the function of the capsule of the spleen

Answer 19

can contract causing the release of blood in circulation (e.g. in response to acute blood loss)

Question 20

when is it indicated to investigate the spleen

Answer 20

enlargement
nodular or focal lesions
abnormal ultyrasound appearance
evaluation of haematopoiesis
tumour staging

Question 21

what are the key points when sampling the spleen

Answer 21

non-suction technique
spread gently
avoid contamination with lubricant gel
ideally take sample before giving steroids

Question 22

Describe the noraml cytological appearance of the spleen

Answer 22

small lymphocytes 90%
medium and large lymphocytes 5-10%
plasma cells, macrophages, mast cells rare
neutrophils present in blood proportions

Question 23

List the 5 causes of splenomegaly

Answer 23

reactive hyperplasia
lymphoma
splenitis
metastatic neoplasia
extramedullary haematopoiesis

Question 24

Describe the thyroid

Answer 24

is a primary lymphoid organ
located in the cranial mediastinum

Question 25

List 2 pathologies that affect the thymus

Answer 25

thymoma
lymphoma

Question 26

why is it important to distinguish thymoma from lymphoma

Answer 26

they come from different origins
have different treatments

Question 27

where do thymoma originate and how are they treated

Answer 27

epithelial cells
surgical treatment

Question 28

where do lymphoma originate and how is it treated

Answer 28

lymphocytes
chemotherapy- as systemic disease