Sys Path Exam 1

what are the gross pathology patterns of bone marrow?

• decreased/empty/replaced

• inflamed

• hemorrhagic

• extra

how can bone marrow become decreased/empty/replaced?

• increased destruction

• reduced production

• demand exceeds production capacity

• replacement (myelophthisis)

what can cause destruction of bone marrow?

• radiation

• estrogen

• chemotherapy

• immune mediated

• toxins

• infection

what can cause reduced production of bone marrow?

deficiencies

when can bone marrow demand exceed production?

overwhelming bacterial infection

what can cause replacement of bone marrow?

• myelofibrosis

• neoplasia

hyperplasia of bone marrow is due to prolonged…

increased demand

serous atrophy of fat

gelatinous transformation of fat due to cachexia or starvation

thymic involution

physiologic reduction in thymic size that occurs around the onset of puberty

what are the gross pathology patterns for thymus?

• absent/small

• inflamed

• hemorrhagic

• large

thymic hemorrhage differentials:

• idiopathic hemorrhage

• anticoagulant toxicity

• traumatic hemorrhage

localized thymic neoplasia is usually…

thymoma

diffuse thymic neoplasia is usually…

lymphoma

what is the pathogenesis for myasthenia gravis secondary to thymoma?

thymoma→develop autoantibodies against thymic myoid cells→antibodies in systemic circulation→bind to AChRs on postsynaptic membrane of neuromuscular junctions→ preventing ACh binding→preventing muscle contraction

what are the gross pathology patterns of spleen

siderotic plaques are benign brown discolorations on the edge of the spleen that are the most common spleen lesion in…

geriatric dogs

macrophage histiocytic sarcoma in the spleen has a _______________ appearance

diffuse meaty

dendritic cell histiocytic sarcoma in the spleen has a _______________ appearance

nodular meaty

what are causes of bloody splenic nodules?

• hematoma

• hemangiosarcoma

• acute infarct

what are causes of meaty splenic nodules?

• primary neoplasia

  • benign: myelolipoma, follicular lymphoma

  • malignant: splenic sarcoma, lymphoma, histiocytic sarcoma

• metastatic neoplasia

• nodular hyperplasia

• granuloma/abscess

• non-acute infarct

• siderotic plaques

differential diagnoses for splenic congestion:

• barbiturates

• volvulus

• acute septicemia

what are causes of bloody diffuse splenomegaly?

• acute septicemia

• barbiturates

• volvulus or torsion

• acute IMHA

• acute infectious disease

what are causes of meaty diffuse splenomegaly?

• neoplasia

  • histiocytic sarcoma (macrophage type)

  • lymphoma

  • phagocytosis

  • chronic IMHA

  • amyloidosis

  • chronic infectious disease

  • EMH

which neoplasms can present as nodules or diffuse enlargement in the spleen?

• mast cell tumor

• lymphoma

• histiocytic sarcoma

• multiple myeloma

splenosis

acquired, autoimplantation of splenic tissue following trauma

what are the gross pathology patterns of the lymph node?

lymphadenomegaly vs lymphadenopathy

lymphadenomegaly- big lymph node

lymphadenopathy- nonphysiologic lymph node change

what are some causes of lymphadenomegaly/ lymphadenopathy

• hyperplasia

• accumulation

• neoplasia

• infection

bastard strangles

strep equi infection causes lymph nodes to burst and drain into lungs where it will spread to abdominal lymph nodes

lymphoma

neoplastic lymphocytes form solid tumors and can lead to secondary neoplasia

leukemia

neoplastic lymphocytes in bone marrow and blood can lead to secondary formation of solid tumors in lymph nodes

sporadic bovine lymphoma types:

• multicentric (<6 months)

  • lymph nodes+organs+bone marrow

• thymic (6-24 months)

  • thymic enlargement

• cutaneous (6-24 months)

  • multifocal skin tumors

BLV bovine lymphoma is seen in what organs?

• lymph nodes

• uterus

• abdomen

• myocardium

• spinal

• lymphoid tissue behind eyes

alimentary/internal equine lymphoma is seen in what organs?

• GI lymph nodes

• liver

• spleen

• peritoneum

multicentric equine lymphoma is seen in what organs?

• peripheral lymph nodes

• abdominal lymph nodes

• mediastinal mass

lymphedema

accumulation of fluid in tissue secondary to lymphatic blockage/damage

lymphangitis

infection/inflammation of lymph vessels

lymphangiesctasia

abnormally dilated lymph vessels

lymphangiosarcoma

neoplasia of lymphatics

MALT atrophy can be caused by:

• viral infection

• malnutrition/cachexia

• aging

• chemotherapy

• radiation

• toxins

BVDV causes lymphocytolysis and necrosis of germinal centers in…

GALT and Peyer’s patches

MALT hyperplasia is caused by:

antigenic stimulation

conditions affecting the hemolymphatic system;

• hypoplasia or atrophy (immunodeficiency)

• hyperplasia (immune reactivity)

• inflammation (lymphadenitis)

• infection

• neoplasia

follicular hyperplasia is expansion of __ cells

B

paracortical hyperplasia is expansion of __ cells

T

hyperplastic lymph nodes will have enlarged…

germinal center and lymphoid follicle

what lab parameters are typically changed by a systemic immune response?

increased globulins

how would you clinically distinguish between lymphoid hyperplasia, lymphadenitis, and lymphoid neoplasia?

cytology

anaplasma phagocytophilum infects what cells?

granulocytes

ehrilichia canis infects what cells?

monocytes

ehrilichia ewingii infects what cells?

granulocytes

blood samples capture a snapshot of ________ production and ________ distribution

neutrophil, lymphocyte

how long does it take to increase erythroid or granulocyte production in bone marrow?

2-3 days depending on age of animal, illness and nutrition status

how long does it take to produce new neutrophils from undifferentiated precursors into blood?

about 6 days

what is the proportion of granulocyte to erythroid precursors in bone marrow?

about 1:1 in dogs and cats, 1:2 or 1:3 in large animals

myelofibrosis

overgrowth of bone marrow cavity by fibroblasts

what are causes of myelofibrosis?

• aberrant cytokine production by chronically stimulated bone marrow cells

• leukemia

• idiopathic

acute leukemia characteristics:

• undifferentiated cells

• marked cytopenia

• sick animal

• rapidly progressive and fatal

myelodysplastic syndromes characteristics:

• production of abnormal cells

• chronic cytopenia

• not very ill

• progresses slowly

chronic leukemia characteristics:

• fairly normal cells in blood

• slow progression

• organ infiltration

leukemia diagnosis:

• abnormal cells in peripheral blood and/or bone marrow + cytopenia

• bone marrow cytology and/or histo

• occasional splenic disease

lymphoma and lymphosarcoma are _____________ terms

interchangeable

nodal lymphoma

tumor occurs inside lymph node

extranodal lymphoma

tumor occurs outside lymph node (anywhere else where there is lymphatic tissue)

indolent lymphoma

slowly progessive

lymphoma in dogs age of onset is usually…

middle ages

most dog lymphomas are indolent/aggressive

aggressive

majority of of nodal lymphomas in dogs are of what cell origen?

B cells

all mediastinal lymphomas in dogs are of what cell origin?

T cell

how can T cell lymphomas lead to hypercalcemia?

tumors produce PTH-like molecule that causes increased bone resorption, intestinal calcium absorption, and renal calcium preservation

hypercalcemia from T cell lymphoma can lead to…

kidney mineralization

what kind of nodular lymphoma is most common in dogs?

diffuse

most dogs with lymphoma do/don’t have lymphocytosis

don’t (will have normal or reduced lymphocytes)

20-50% of dogs with lymphoma also have _______

mild anemia

T/F secondary leukemia is seen in some types of lymphomas in dogs

T

cat lymphomas are frequently nodal/extranodal

extranodal

how does lymphoma most commonly present in cats?

solitary intestinal mass in older cats

what is the common cell type making up cat intestinal lymphoma?

T cell

mediastinal lymphomas in cats are almost always of what cell origin?

T cell

how can feline leukemia virus cause lymphoma?

can activate cellular proto-oncogenes, and the gene product can be overexpressed

what location is lymphoma common in FeLV infected young cats?

mediastinum

how can FIV cause aggressive extranodal lymphomas in cats?

loss of CD4+ cells→chronic immune stimulation, lack of immunosurveillance, proliferation of other viral agents

lymphomas of what cell origin are most common in horses?

T cell

horse lymphomas are often associated with ______ and ______ likely due to production of cytokines that recruit other cells

inflammation; anemia

peripheral lymph nodes are commonly/rarely involved in horse lymphoma

commonly

cutaneous lymphomas in horses can change in response to…

estrogen and progesterone

horse mesenteric or intestinal lymphoma is often associated with…

IMHA

mediastinal lymphomas in horses are of what cell origin?

T cell

________________ is more common in horses with lymphoma than in other species

gammopathy (increased globulins)

lymphoma due to what infection is common in older dairy cattle?

BLV

what percent of cattle infected with BLV get lymphoma?

2-5%

methods to classify lymphoma:

1. histopathology

   • diffuse vs follicular

   • high, medium, or low grade

2. immunophenotype (flow cytometry or IHC)

3. cytogenetics, molecular genetics

laboratory quality assurance program

procedures and strategies to ensure that lab reports trustworthy results (assure precision and accuracy)

Pre-analytical variables:

• test selection

• history

• fasting

• tube selection

• order of tube filled

• volume

• collection technique

• tube labeling

• requisition form

• time lapsed before analysis

• storage/transport

disadvantages of in house tests:

• records legally required

• reference intervals needed

• in house result will be different from lab result

advantages of vet labs:

• gold standard

• properly validated reference intervals

• clinical pathologist

what is the ideal and minimum number of healthy animals needed to create a reference interval?

• ideal: >100

• minimum: 40

isoenzymes

occur in one or multiple tissues

increased enzymes enter plasma due to:

1. injury

2. increased production

3. decreased excretion

enzyme activity decreases with…

time and temperature