Lymphatic system (test 1) Flashcards

1
Q

what are the 3 primary processes (DfDx) for lymphadenopathy

A

hyperplasia
inflammation (lymphadenitis)
neplasia (lymphoma)

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2
Q

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.

A

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

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3
Q

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

A

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

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4
Q

Define Leukemia

A

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

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5
Q

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

A

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

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6
Q

what is the most common canine lymphoma

A

Multicentric (~80% of cases)

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7
Q

what are the 6 forms of lymphoma

A
multicentric
alimentary
mediastinal
cutaneous
leukemicextranodal
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8
Q

what are the two potential presentations of alimentary lymphoms

A

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

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9
Q

what are the two forms of cutaneous lymphoma

A
  • 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
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10
Q

what are some examples of extranodal lymphoma’s

A
Localized lymphoma to an organ
•Eyes
•Central nervous system
•Bone
•Testes
•Bladder
•Heart
•Nasal cavity
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11
Q

what are the 5 clinical stages of lymphoma

A

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)

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12
Q

what are some clinical signs associated with mediastinal lymphoma

A

dyspnea

exercise intolerance

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13
Q

what are two forms of bovine lymphoma

A

ENZOOTIC (viral) - occurs in characteristic sites

SPORADIC (not viral)

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14
Q

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

A negative serology (BLV-negative)

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15
Q

define Enzootic

A

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

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16
Q

what is the most common lymphoma in horses

A

multicentric/disseminated

•Multicentric > skin > gastrointestinal

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17
Q

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

A

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

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18
Q

what are the two main arteries that supply the spleen

A

L. gastroepiploic

splenic

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19
Q

how would you compare the spleen and the lymphatic system

A

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

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20
Q

what are the 4 primary functions of the spleen

A

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

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21
Q

what are some consequences to a splenectomy in VetMed

A

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

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22
Q

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

A
  • Rupture (e.g. trauma)
  • Torsion
  • Neoplasia
  • Symptomatic splenomegaly
  • Autoantibodies to RBCs (immune-mediated hemolytic anemia (IMHA) or platelets (Idiopathic thrombocytopenic purpura - ITP) = controversial
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23
Q

what are some examples of primary splenic tumors

A

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)

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24
Q

T or F

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

A
FALSE
Prototypic behavior → Rapidly metastatic
–Liver, omentum, mesentery
–Lung
–Hematogenus & abdominal seeding
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25
Q

T or F

You can grossly differentiate between a splenic hemangiosarcoma and hematoma

A

FALSE

Grossly, splenic hemangiosarcomas are usually indistinguishable from splenic hematomas.

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26
Q

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

A

Localized Histocytic Sarcoma

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27
Q

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

A

Splenic mast cell tumors

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28
Q

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

A

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

29
Q

what is the most common splenic neoplasm in cats

A

Mast cell tumor

30
Q
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

• A. Portal hypertension
and
• B. Splenic torsion

31
Q

what are the most common causes of splenomegaly

A
blood storage
↑ cells of monocyte-MP system, 
lymphoid hyperplasia,
inflammation
neoplasia
32
Q

what are the most common causes of nodular spleens

A
Abscesses
granulomas
hematomas
lymphoid hyperplasia
neoplasia
33
Q

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

A

Septicemia – anthrax, salmonellosis (peracute)

Hemolytic dz – EIA (acute)

34
Q

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

A

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

35
Q

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

A

Septicemia – anthrax, salmonellosis (acute)

Hemolytic dz – babesiosis (acute)

36
Q

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

A

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

37
Q

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

A

Septicemia – salmonellosis (peracute)

Splenic torsion

38
Q

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

A

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

39
Q

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

A

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

40
Q

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

A
Hemolytic dz – IMHA
Hematopoietic neoplasia – MCT (cat), LSA, histiocytic sarcoma
Granulomatous dz – histoplasmosis
Lymphoid hyperplasia (nodular)
Amyloidosis
41
Q

what are some causes of Splenic Congestion

A
  • 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
Q

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

A

nodular hyperplasia

43
Q

what is reactive hyperplasia

A

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
Q

what are some examples of diffuse (reactive) splenic hyperplasia

A

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

45
Q

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

A
Lesions:
􀂾 Lymphocyte hyperplasia
􀂾 Hyperplasia of macrophages
􀂾 Congestion
􀂾 Hemosiderosis +/- erythrophagocytosis
46
Q

what is a common cause of diffuse splenitis?

A

blood borne infections

47
Q

what are the two main types of splenitis?

A
• Purulent splenitis
     • Hematogenous bacterial spread
          • i.e. thromboembolic
endocarditis, reticuloperitonitis
in bovines
• Granulomatous splenitis
     • Bacterial infections
          • Necrobacillosis, tuberculosis,
pseudotuberculosis, fungal
infection
48
Q

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

A

C. iron and calcium deposition

(mineralization) in the capsule of the spleen

49
Q

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

A

Severe congestion →necrosis→

rupture →hemoabdomen

50
Q

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

A

Trachea
Esophagus
Thoracic duct
Cranial vena cava

51
Q

what are the two primary causes of decrease in thymic size

A

Hypoplasia

Atrophy

52
Q

what are some consequences of thymic hypoplasia

A

SCID = Severe Combined Immunodeficiency of Arabian Foals

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

53
Q

what is the pathology of SCID in dogs

A

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
Q

what are some causes of thymic atrophy?

A
•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
Q

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

A

Thymoma

56
Q

define paraneoplastic syndrome

A

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

57
Q

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

A

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
Q

compare and contrast thymic lyphoma and thymoma

A

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
Q

T or F

Thymomas typically will occur in the first few years of life

A

False

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

60
Q

T or F

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

A

True

arising in thymic tissue or intrathoracic lymphoid tissue

61
Q

T or F

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

A

True

62
Q

what are some hematologic changes seen in Multiple Myeloma?

A

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
Q

Thymic Lymphosarcoma is most common in young ____ and ______

A

Cats

Cattle

64
Q

what are some DfDx of lymph node hypoplasia

A
Developmental disorders
lack of antigenic stimulation
cachexia and malnutrition
aging
viral infections
65
Q

what is the pathology behind generalized lymphnode hyperplasia?

A

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
Q

what is the pathology behind generalized acute lymphadenitis

A

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
Q

what are some examples of chronic lymphadenitis

A

chronic suppurative lymphadenitis (encapsulated abscesses)

focal granulomatous lymphadenitis

focal coalescing granulomatous lymphadenitis

diffuse granulomatous lymphadenitis

mixed inflammatory response

68
Q

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

A

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