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Flashcards in Lymphatic system (test 1) Deck (68):
1

what are the 3 primary processes (DfDx) for lymphadenopathy

hyperplasia
inflammation (lymphadenitis)
neplasia (lymphoma)

2

Which of the following is TRUE regarding canine lymphoma?

A.Without treatment, virtually all affected dogs succumb to pulmonary metastasis.

B.Even with treatment, virtually all affected dogs eventually succumb due to pulmonary metastasis.

C.In a significant percentage of dogs, chemotherapy can affect a cure.

D.Immunophenotype (B cell versus T cell) is an important prognostic indicator.

E.In all cases, definitive diagnosis ultimately requires biopsy.

D.Immunophenotype (B cell versus T cell) is an important prognostic indicator.

3

what is a common problem associated with Corynebacterium pseudotuberculosis? and what is the pathogenesis?

Caseous lymphadenitis

Skin wounds (shearing) -> bacteria enter skin -> bacteria drain to regional lymph nodes and form abscesses -> fibrous capsule encloses abscess -> repeated cycles of abscess formation and encapsulation (lamination) -> caseous lymphadenitis

4

Define Leukemia

neoplastic disorder of hematopoietic cells characterized by the presence of neoplastic cells in the peripheral blood or bone marrow

5

what are the two classifications of leukemia's according to cell line of origin

a] Lymphoid [arising from lymphoid cells]

b] Myeloid [arising in bone marrow]
can arise from virtually any bone marrow precursor cells
erythroid cells, granulocytes, monocytes, or megakaryocytes

6

what is the most common canine lymphoma

Multicentric (~80% of cases)

7

what are the 6 forms of lymphoma

multicentric
alimentary
mediastinal
cutaneous
leukemicextranodal

8

what are the two potential presentations of alimentary lymphoms

a] a mass that causes obstruction and/or intestinal hemorrhage (can be multiple masses)
b] diffuse infiltration of the intestinal mucosa - causing malabsorption and chronic protein- loss into the feces

9

what are the two forms of cutaneous lymphoma

•Epitheliotropic (epidermal)
•neoplastic T-lymphocytes that “home” to the epidermis

•Non-epitheliotropic (dermal)
•usually B cell – maybe T-cell rich B cell lymphoma especially in horses

10

what are some examples of extranodal lymphoma's

Localized lymphoma to an organ
•Eyes
•Central nervous system
•Bone
•Testes
•Bladder
•Heart
•Nasal cavity

11

what are the 5 clinical stages of lymphoma

I
Involvement of a single lymph node or lymphoid tissue in a single organ.

II
Involvement of more than 1 lymph nodes in the same side of the diaphragm (regional lymphadenomegaly).

III
Generalized lymphadenomegaly (enlarged lymph nodes in more than one region).

IV
Liver and/or spleen involvement (with or without lymph node involvement)

V
Manifestation in the blood, bone marrow involvement and/or other organs (e.g. gastrointestinal, skin, nervous system)

12

what are some clinical signs associated with mediastinal lymphoma

dyspnea
exercise intolerance

13

what are two forms of bovine lymphoma

ENZOOTIC (viral) - occurs in characteristic sites
SPORADIC (not viral)

14

Which serology result would have greater diagnostic significance in a case where you had BLV-associated LYMPHOMA listed as a DfDx?

•A positive serology (BLV-positive)
•A negative serology (BLV-negative)

A negative serology (BLV-negative)

15

define Enzootic

of, relating to, or denoting a disease that regularly affects animals in a particular district or at a particular season.

16

what is the most common lymphoma in horses

multicentric/disseminated

•Multicentric > skin > gastrointestinal

17

what are the 6 primary causes of lymph node hypoplasia/atrophy

a) Developmental disorders Lymphoid hypoplasia - immunodeficiency dz’s (ex. SCID horses – see thymus section)

b) Viral infections ; drugs Lympholysis
•BVDV, CDV; some viruses stimulate lymphoid tissue though
•drugs (e.g. corticosteroids)
•stress

C) Cachexia and malnutrition Lymphoid atrophy

D) Aging Senile lymphoid atrophy

E) Fibrosis Sequel to inflammation / injury

F) Lack of antigenic stimulation Specific Pathogen Free animals

18

what are the two main arteries that supply the spleen

L. gastroepiploic
splenic

19

how would you compare the spleen and the lymphatic system

The spleen is to the circulatory system as lymph nodes are to the lymphatic system

20

what are the 4 primary functions of the spleen

1] Filtration of unwanted elements from the blood – via phagocytosis – red pulp

2] Host immune response – white pulp

3] Hematopoiesis – red pulp

4] Blood Storage Pool – red

21

what are some consequences to a splenectomy in VetMed

↑ Susceptibility to hemoparasites & some infectious diseases (esp. bacteremia)

22

what are some reasons that you would want to remove the spleen?

* Rupture (e.g. trauma)
* Torsion
* Neoplasia
* Symptomatic splenomegaly
* Autoantibodies to RBCs (immune-mediated hemolytic anemia (IMHA) or platelets (Idiopathic thrombocytopenic purpura - ITP) = controversial

23

what are some examples of primary splenic tumors

Primary Splenic Tumors
a. Hemangiosarcoma (mass)
b.Lymphoma (diffuse or multinodular)
c.Mast cell tumor (cats) (Diffuse)
d.Other
i. Other sarcomas
ii. Hemangioma
iii.Myeloid neoplasms (diffuse)

24

T or F
They prototypic behavior for a Splenic Hemangiosarcoma is that it is slow to metastisize.

FALSE
Prototypic behavior → Rapidly metastatic
–Liver, omentum, mesentery
–Lung
–Hematogenus & abdominal seeding

25

T or F
You can grossly differentiate between a splenic hemangiosarcoma and hematoma

FALSE
Grossly, splenic hemangiosarcomas are usually indistinguishable from splenic hematomas.

26

what is....
Malignant tumor arising as a soft tissue mass from dendritic cells.
the spleen is one of several common sites however the most common is subcutis
it is locally invasive → metastasize via lymphatics to lymph nodes and then distantly

Localized Histocytic Sarcoma

27

what is a important DfDx for splenomegaly that is unique to cats?

Splenic mast cell tumors

28

what is the 2/3's rule for splenic masses in dogs

~2/3 of splenic masses are malignant neoplasms, and of those ~2/3 will be histosarcomas (↑ to 70% with hemoperitoneum)

29

what is the most common splenic neoplasm in cats

Mast cell tumor

30

Which of the following are cause of splenic
congestion?
• A. Portal hypertension
• B. Splenic torsion
• C. Left sided heart failure
• D. A and B
• E. All of the above

• A. Portal hypertension
and
• B. Splenic torsion

31

what are the most common causes of splenomegaly

blood storage
↑ cells of monocyte-MP system,
lymphoid hyperplasia,
inflammation
neoplasia

32

what are the most common causes of nodular spleens

Abscesses
granulomas
hematomas
lymphoid hyperplasia
neoplasia

33

Common causes of a congestive (bloody) spleen in a horse

Septicemia – anthrax, salmonellosis (peracute)
Hemolytic dz – EIA (acute)

34

Common causes of a firm (meaty) spleen in a horse

Septicemia – salmonellosis
Hemolytic dz – EIA, IMHA
Neoplasia – LSA, metastatic neoplasia

35

Common causes of a congestive (bloody) spleen in a ruminant

Septicemia – anthrax, salmonellosis (acute)
Hemolytic dz – babesiosis (acute)

36

Common causes of a firm (meaty) spleen in a ruminant

Septicemia – salmonellosis
Hemolytic dz – babesiosis (subacute), anaplasmosis, trypanosomiasis,
hemotropic mycoplasmosis
Neoplasia - LSA

37

Common causes of a congestive (bloody) spleen in a pig

Septicemia – salmonellosis (peracute)
Splenic torsion

38

Common causes of a firm (meaty) spleen in a pig

Septicemia – salmonellosis, erysipelas
Hemolytic dz – hemotropic mycoplasmosis
Neoplasia - LSA

39

Common causes of a congestive (bloody) spleen in a dog or cat

Barbiturate euthanasia or anesthesia
Gastric torsion
Neoplasia – hemangioma or HSA (nodular)

40

Common causes of a firm (meaty) spleen in a dog or cat

Hemolytic dz – IMHA
Hematopoietic neoplasia – MCT (cat), LSA, histiocytic sarcoma
Granulomatous dz – histoplasmosis
Lymphoid hyperplasia (nodular)
Amyloidosis

41

what are some causes of Splenic Congestion

- Heart failure (right sided)
- Portal hypertension (e.g. cirrhosis)
- Splenic torsion ( the stomach is usually, but not always involved)
- Pharmacologic ( e.g. tranquilizers, phenobarbital, anesthesia, euthanasia)

42

what is characterized by a Regional proliferation of components cells normally found in the splenic parenchyma found in dogs, and rarely bulls and cats.
It is like a splenic hematoma, which causes a potential diagostic delemma

nodular hyperplasia

43

what is reactive hyperplasia

Diffuse hyperplasia of the white pulp

“Activation" of spleen – immune reactions to
remove:
• Abnormal or opsonized cells (e.g. RBC's)
• Blood-borne microbial agents

44

what are some examples of diffuse (reactive) splenic hyperplasia

􀂾 Immune-mediated hemolytic anemia (IMHA)
􀂾 Hemoparasite infections
􀂾 Bacteremia
􀂾 Autoimmune thrombocytopenia (ITP)

45

what are some lesions that are consistant with Diffuse (reactive) splenic hyperplasia?

Lesions:
􀂾 Lymphocyte hyperplasia
􀂾 Hyperplasia of macrophages
􀂾 Congestion
􀂾 Hemosiderosis +/- erythrophagocytosis

46

what is a common cause of diffuse splenitis?

blood borne infections

47

what are the two main types of splenitis?

• Purulent splenitis
• Hematogenous bacterial spread
• i.e. thromboembolic
endocarditis, reticuloperitonitis
in bovines

• Granulomatous splenitis
• Bacterial infections
• Necrobacillosis, tuberculosis,
pseudotuberculosis, fungal
infection

48

What are (hemo)siderotic plaques?

• A. An plaque like mass of acute hemorrhage
in the spleen capsule

• B. A plaque like mass of hemorrhage and
fibrin in/on the spleen capsule

• C. iron and calcium deposition
(mineralization) in the capsule of the spleen

C. iron and calcium deposition
(mineralization) in the capsule of the spleen

49

what are the consequences of a splenic torsion if not addressed quickly

Severe congestion →necrosis→
rupture →hemoabdomen

50

what are some of the important structures near the thymus that can cause potential problems in thymic pathology?

Trachea
Esophagus
Thoracic duct
Cranial vena cava

51

what are the two primary causes of decrease in thymic size

Hypoplasia
Atrophy

52

what are some consequences of thymic hypoplasia

SCID = Severe Combined Immunodeficiency of Arabian Foals


SCID in dogs: X-linked severe combined immunodeficiency (XSCID)

53

what is the pathology of SCID in dogs

SCID in dogs: X-linked severe combined immunodeficiency (XSCID)
–Basset Hound, Corgi, Jack Russell Terrier
–Male pups lack mature functional T cells
–Produce IgM but not IgG or IgA
–Very small thymus with small dysplastic lobules and unidentifiable LN and other lymphoid tissues

54

what are some causes of thymic atrophy?

•Infectious agents
–Viruses
•Canine distemper virus
•Equine herpes virus 1
•Feline parvovirus, FIV
•Bovine viral diarrhea virus
•Porcine circovirus 2, Hog cholera virus

•Toxins
–Lead, mercury, PCBs
–Fumonisins B1 and B2, aflatoxin

•Chemotherapeutic agents
•Ionizing radiation
•Malnutrition/cachexia
•Aging

55

This is a tumor that is considered to be derived from the epithelial component of the thymus.
It is a neoplastic change (not viral) and therefore usually seen in adult animals and can occur in all species but especially common in goats.
Unlike lymphomas, metastasis and invasion of adjacent structures is not common

Thymoma

56

define paraneoplastic syndrome

Paraneoplastic syndromes are nonmetastatic complications of cancer with effects distant from the primary tumor

57

what are some of the paraneoplastic events that are a sequelae of myasthenia gravis?

Paraneoplastic myasthenia gravis (MG) has been strongly associated with the presence of thymic disease. MG can manifest as systemic weakness, or more focally, especially as megaesophagus. In one review of canine thymoma, 47% of the dogs had MG, 33% had concurrent nonthymic cancer (including pheochromocytoma, mammary adenocarcinoma, or pulmonary adenocarcinoma), and 20% had concurrent signs of polymyositis. Dogs with thymoma-associated MG often have antibodies to nicotinic acetylcholine receptors, which can be used to diagnose and/or monitor treatment response. These dogs may produce autoantibodies to several other neuromuscular antigens, including ryanodine (a skeletal muscle calcium-release channel receptor) and the muscle protein titin. Other tumors that have rarely been reported to cause MG include osteosarcoma, lymphoma, and bile duct carcinoma. MG can improve with imunosuppression or treatment of the underlying tumor but may also be persistent or occur after removal of a thymoma.

58

compare and contrast thymic lyphoma and thymoma

Lymphoma – a tumor of lymphocytes / lymphoblasts

Thymoma – a tumor of the epithelial component of the thymus
Contains neoplastic thymic epithelium
May contain NORMAL lymphocytes – which can actually outnumber the neoplastic cells

59

T or F
Thymomas typically will occur in the first few years of life

False
Thymomas usually occur late in life – arising from remnants of the involuted thymus

60

T or F
In cats, mediastinal lymphomas can occur early in life in association with FeLV infections

True
arising in thymic tissue or intrathoracic lymphoid tissue

61

T or F
In bovine, mediastinal lymphomas occur in less than 2-year-old and are not BLV associated

True

62

what are some hematologic changes seen in Multiple Myeloma?

Monoclonal gammopathy = hyperproteinemia
- dysproteinemia due to tumor's production and secretion of antibody; comes from a single clonal population so antibody is all of the same subclass and spcificity.
- hyperproteinemia can cause a plasma Hyperviscosity Syndrome

- Hypercalcemia (due to multifocal lysis of bone)

-Immunoglobulin light chain proteinuria (Bence Jones, due to the production of Ig light chain by tumor cells)

-Non-regenerative anemia, leukopenia, thrombocytopenia (can lead to hemorrhagic diathesis, due to growth of neoplastic plasma cells in bone marrow and effects on other cell lines)

63

Thymic Lymphosarcoma is most common in young ____ and ______

Cats
Cattle

64

what are some DfDx of lymph node hypoplasia

Developmental disorders
lack of antigenic stimulation
cachexia and malnutrition
aging
viral infections

65

what is the pathology behind generalized lymphnode hyperplasia?

regional LN draining area or widespread if systemic dz, ↑ # lymphoid follicles, have active germinal centers with high # mitoses, later germinal centers depleted and pale with mainly stromal and precursor cells, medullary cords packed with plasma cells (migrate from follicles)

66

what is the pathology behind generalized acute lymphadenitis

usually regional LN draining site that becomes infected, suppuration usually d/t pyogenic bacteria (Strep equi, Strep porcinus, A. pyogenes), early have neuts and RBC in sinuses and later sinus histiocytosis; T. gondii and Salmonella cause focal areas of necrosis in infected LN

67

what are some examples of chronic lymphadenitis

chronic suppurative lymphadenitis (encapsulated abscesses)

focal granulomatous lymphadenitis

focal coalescing granulomatous lymphadenitis

diffuse granulomatous lymphadenitis

mixed inflammatory response

68

Corynebacterium pseudotuberculosis in sheep and goats is an example of what type of lymphadenitis?

chronic suppurative lymphadenitis (encapsulated abscesses): ex. Corynebacterium pseudotuberculosis in sheep and goats (also causes ulcerative lymphangitis in cattle and pectoral abscesses in horses), in sheep enters skin through wounds and drains to regional LN (usually around legs), originally have microabscesses with eos in cortical sinuses, later coalesce and caseate and become encapsulated; in goats usually head and neck LN