1
Q
Primary lymphoid tissue
A
- T lymphocyte production
- Thymus
- B cell production
- Bone marrow (primates and rodents)
- Ileal Peyer’s Patche (ruminants, pigs, horses)
- Bursa of Fabricius (birds)
2
Q
Secondary lymphoid tissue
A
- Lymph node
- Spleen
- MALT
3
Q
Circulating lymphocytes enter lymph nodes via
A
- high endothelial cell venules
- to encounter antigens presented by APCs
4
Q
Function of lymph nodes
A
- Expose lymph borne antigen to blood borne lymphocytes
- to enhance antigen detection and presentation
5
Q
Cells of lymph nodes
A
- Lymphocytes
- Macrophages
- interdigitating dendritic cells
- follicular dendritic cells
6
Q
Lymph node path changes
A
- enlargement (lymphadenomegaly)
- Size reduction
- atrophy
- hypoplasia
- Change in color
7
Q
Localized lymphadenomegaly
A
- localized infection
- regional metastasis
- antigenic stimulation
- lymphoid/macrophage hyperplasia
8
Q
Generalized lymphadenomegaly
A
- Bacteremia/septicemia
- chronic infectious disease
- immune mediated disease
- chronic systemic antigenic stimulatoin
- metastatic neoplasia (carcinoma more likely than sarcoma)
- lymphoid/macrophage hyperplasia
- hemotropic parasitic disease
9
Q
Diseases that cause lymphadenomegaly
A
- Metastatic neoplasia
- lymphoma
- suppurative lymphadenitis
- caseous lymphadenitis
- cervical lymphadenitis
- tularemia
- chronic lymphadenitis
- mycobacterium
- fungal infections
- blasto
- coccidio
- lymphoid hyperplasia
- malignant catarrhal fever
- bovine leukemia virus (BLV)
- feline immunodeficiency virus (FIV)
10
Q
Lymph node atrophy
A
- lymphocytes lost due to degenerative changes, necrosis or apoptosis
- causes
- viral infections (canine distemper, parvo)
- toxins (chemo drugs, ionizing radiation, malnutrition, cachexia)
- glucocorticoids (endogenous or exogenous)
11
Q
Lymph node hypoplasia
A
- caused by fialure of LN to develop properly
- normal architecture no (less) lympocytes
- causes
- primary immunodeficiency
- CID in Arab foals
- X-linked CID in basset hound dogs
- primary immunodeficiency
12
Q
Histo features:
atrophy of LN
A
generalized loss of lymphocytes from LNs due to necrosis or apoptosis
13
Q
Histo features:
hyperplasia of lymph node
A
- inc in lymphocytes
- T cell proliferation
- paracortical hyperplasia
- B cell proliferation
- follicular hyperplasia
14
Q
Histo features:
suppurative lymphadenitis
A
- infiltrated with neutrophils and necrotic debris
15
Q
Histo features:
lymphoma
A
- monoclonal population of cells
16
Q
Histo features:
LN hypoplasia
A
- generalized small LN
- normal architecture
- less lymphocytes present
17
Q
Histo features:
Granulomatous lymphadenitis
A
- obliteration of LN architecture by inflammatory cells
- macs
- multi-nucleated giant cells
18
Q
GALT
Function
A
- functions as primary and secondary lymphoid tissue
- portal of entry for infectious agents
- site of virus replication
- Peyers patches
- key producer of B cells in ruminants and pigs
19
Q
Infectious agents of GALT
A
- Rhodococcus equi
- Chlamydia
- Brucella abortus
- Mycobacterium paratuberculosis
20
Q
Viruses that replicate in GALT
A
- bovine viral diarrhea (BVD)
- Canine parvovirus
21
Q
Spleen anatomy/function
A
- Red pulp
- erythrocyte storage
- antigen removal
- hematopoiesis/erythropoiesis
- erythrocyte destruction
- White pulp
- Acquired immunity
- Periarteriolar lymphoid sheaths: T-cells
- Follicles: B cells
22
Q
Uniform splenomegaly that’s bloody on cut section
A
- congestion - terminal
- associated with euthanasia
- torsion
23
Q
Uniform splenomegaly that’s not bloody on cut section
A
- Bacteremia/septicemia
- granulomatous splenitis
- hemolytic anemia
- lymphoma
- extramedullary hempatopoiesis
- amyloidosis, storage disease
24
Q
splenic nodules/masses
bloody on cut section
TQ
A
- Hematoma
- Hemangioma/hemangiosarcoma
- Nodular hyperplasia with hyperemia
- Splenic infarct
- Incomplete splenic contraction
25
**Splenic Nodules/Masses**
**Firm, non-bloody on cut section**
**TQ**
* **Nodular hyperplasia**
* **Granulomatous splenitis, splenic abscess**
* **Lymphoma**
* **Metastatic neoplasm**
26
Thymus
structure and function
* primary lymphoid organ
* responsible for T cell development and maturation
* cortex
* primitive and maturing lymphocytes
* medulla
* Hassall's corpuscles, myoid cells, thymic epithelia cells, dendritic cells, lymphocytes
27
Small thymus path
* thymic hypoplasia (CID)
* maturation and aging (involution)
* thymitis
* thymic atrophy
* viral dz
* glucocorticoids
* nutritional deficiency
* toxins
28
Large thymus path
* thymic hemorrhage (young dog)
* lymphoma
* thymoma (epithelial component is neoplastic)
29
Lymphoproliferative dz def
* all neoplasms arising from lymphocytes
30
Lymphoma def
* malignant neoplasms of lymphocytes
31
leukemia def
* neoplasm of lymphocytes or hematopoietic cells arising from bone marrow
32
Anatomic classification lymphoma
* multicentric
* thymic
* alimentary
* cutaneous
* solitary
33
immunophenotypic classification of lymphoma
* B-cell
* T-cell
* other
34
Pattern classification lymphoma
* Diffuse
* follicular
35
Cytologic classification of lymphoma
* Well differentiated
* looks like mature lymphocytes
* Poorly differentiated
* looks immature: Large lymphocytes
36
Lymphoma in Dogs
* age 5-11 years old
* gamma herpes virus associated with some B cell lymphomas
* Distribution (most to least common)
* **multicentric**: gen lymphadeonomegaly, liver and spleen, kidney, heart, tonsil, bone marrow, CNS
* Alimentary: intestine and mesenteric LN
* Thymic: thymus and cranial mediastinum, associated with hypercalcemia
* Cutaneous: T cell cutaneous lymphoma, mycosis fungoides
* Solitary: brain, lung, etc
37
Lymphoma in Cats
* most common neoplasm in cats
* Distribution most to least common
* **Alimentary**: jejunum/ileum, mesenteric LN, liver/kidney, often **FeLV** negative
* Thymic: thymus and cranial mediastinum, often FeLV positive
* Multicentric: generalized, liver/spleen, CNS, often FeLV positive
* Solitary: often in kidneys
38
Lymphoma in cattle
* relatively common, most caused by Bovine Leukemia Virus (BLV)
* Distribution most to least common
* Multicentric: most common BLV association, LN, **right atrium and abomasum**, epidural fat-can cause posterior paresis
* Cutaneous
* Thymic: adolescent cows, bone marrow involvement
* Calf form: less than 6 mo, generalized nodes, bone marrow, blood, liver, spleen
* Alimentary - rare
* Solitary - spinal cord
39
Thymoma
* Thymic epithelial cells are key component
* often occur in goats
* locally invasive, but don't usually metastasize
40
Thymic lymphoma
* neoplasm is exclusively of neoplastic lymphocytes
* often metastasizes
41
All of the following resultin decreased size of the thymus and LN except
1. Parvovirus
2. Lymphoma
3. Corticosteroids
4. Canine Distemper
5. 1 and 4
Lymphoma
42
A uniformly enlarged dog spleen that bleeds on the cut surface is most likely
1. Hemangiosarcoma
2. Hemangioma
3. Lymphoma
4. Congestion
5. Nodular hyperplasia
congestion
43
An irregular dark red nodule in a spleen that bleeds on cut surface could be all of the following except
1. Hemangiosarcoma
2. Hemangioma
3. Granulomatous splenitis
4. Hematoma
5. Nodular Hyperplasia
Granulomatous splenitis
44
**Most common form of lymphoma in dogs?**
**Multicentric**
45
**Right atrial lymphoma is most commonly found in**
**Cattle**
46
**Most common form of lymphoma in cats**
**alimentary**
47
**Viral agents have been associated with lymphoma in**
1. Cattle
2. Cats
3. Dogs
4. 1 and 2
5. 1, 2 and 3
all of them
48
All of the following result in diffuse (generalized) splenomegaly EXCEPT
* Histoplasmosis
* Septic salmonellosis
* Lymphoma
* Hemangiosarcoma
* Congestion
Hemangiosarcoma
49
Which of the following viruses causes sytemic lymphoid atrophy?
1. Canine parvo type 2
2. canine distemper virus
3. feline calicivirus
4. 1 and 2
5. 1, 2, and 3
canine parvo type 2 and canine distemper virus (1, and 2)
50
Thymoma is a neoplasm of
1. Thymic epithelial cells
2. Thymic lymphocytes
3. Thymic smooth muscle
4. thymic macrophages
5. 1 and 2
Thymic epithelial cells
51
Which of the following are common sites for lymphoma in adult cattle with multicentric lymphoma?
1. LN
2. Abomasum
3. Heart
4. 1 and 2
5. 1, 2, and 3
All of them
52
All of the following commonly present with bloody nodular splenic masses in dogs except
1. Hematoma
2. Hemangioma
3. Hemangiosarmcoma
4. Lymphoma
5. Splenic infarct
Lymphoma
53
Which of the following diseases or infection can result in generalized lymphadenomegaly?
1. Multicentric lymphoma
2. Malignant catarrhal fever
3. Feline immunodeficiency virus
4. 1 and 2
5. 1, 2, and 3
all of them
54
Retrovirus infection has been identified as a cause of lymphoma in
1. dogs
2. cats
3. cattle
4. 1, 2 and 3
5. 2 and 3
cats and cattle (2 and 3)
55
All of the following often result in generalized (diffuse) splenomegaly in dogs **except**
1. Histoplasmosis
2. Septic salmonellosis
3. Lymphoma
4. Hematoma
5. Congestion
Hematoma
56
Which of the following is a morphologic diagnosis of the spleen?
1. Lymphoma
2. Hemangiosarcoma
3. Chronic multi-focal granulomatous splenitis
4. Focal acute infarct
5. All of the above
Chronic multi-focal granulomatous splenitis
2nd path test
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