15 - lymphoid and myeloid neoplasms Flashcards
what are myeloid neoplasms
neoplasms of all non-lymphoid blood cells
—– arise from bone marrow
what are lymphoid neoplasms
neoplasms of lymphocyte origin, including plasma cells
— bone marrow (leukemia, multiple myeloma)
— lymph nodes, spleen, thymus
— tissue lymphoid populations, such as GI or skin
what does the term leukemia mean
the term leukemia refers to neoplastic cells in blood and/or marrow
where do true leukemias arise from
from the marrow
what is the difference between acute vs chronic leukemias
- acute have many blast cells in marrow
- chronic progresses more slowly
- myeloid neoplasms much more difficult to treat
- acute myeloid leukemia (AML) worst leukemia, chronic lymphocytic leukemia (CLL) best leukemia
what develops in the bone marrow but it not called leukemia
multiple myeloma
what method would you use to get a panel of antibodies (especially for lymphoid cells)
immunohistochemistry and flow cytometry
what are some cytochemical stains for myeloid cells
myeloperoxidase
nonspecific esterase
what is lymphoma
solid tumors that develop outside the marrow
what is lymphoid leukemia
refers to neoplasia in marrow and/or blood not associated with solid tumors
– acute lymphoblastic leukemia (ALL)
– chronic lymphocytic leukemia (CLL)
lymphoma with leukemia or lymphosarcoma cell leukemia
?
what can help differentiate lymphoma from leukemia
cluster of differentiation 34 (CD34) surface marker may help differentiate ALL (often positive) from lymphoma with leukemia (often negative)
what are 2 types of plasma cell tumors and where are they located
- multiple myeloma develops within marrow
plasmacytoma develops outside the marrow
lymphoid markers
what is PCR for antigen receptor rearrangements (PARR)
It is an assay that assesses clonality in a population of lymphoid cells
what does PARR do and what it is used for
– amplifies DNA encoding the variable regions of B and T cell receptors
– differentiate inflammatory/reactive (PARR negative) vs. neoplastic (PARR positive) lymphocyte populations
when can you get false positives in PARR tests
false positive tests in small number of cases with ehrlichia canis, rickettsia rickettsia and borrelia burgdorferi in dogs
what are the reasons for marrow biopsy - ??
unexplained leukopenia and thrombocytopenia
rare abnormal “lymphocytes” in blood
what is present in bone marrow with acute lymphoblastic leukemia
neoplastic prolymphocytes or lymphoblasts present in bone marrow
—- differentiate from other blast cells using special stains and or CD surface markers
what are the types of ALL in cats
generally T-lymphocyte type (most FelV positive, some FIV positive)
what are the types of ALL in dogs
may be T-lymphocyte, B-lymphocyte, NK cell or null cell types
what is the difference between ALL lymphocytes and reactive lymphocytes in dogs blood
add photo
what is a PARR test used for
to differentiate reactive vs neoplastic lymphocytes
When is chronic lymphocytic leukemia primarily seen
in old animals
what is seen with the lymphocytes in chronic lymphocytic leukemia
lymphocytosis involving normal-appearing lymphocytes
in chronic lymphocytic leukemia what lymphocyte type is more common (also what subset predominated in dogs vs cats)
T-lymphocyte type is more common than B lymphocyte type in dogs and cats
- dogs: cytotoxic T lymphocyte (CD8+) subset predominates with granular lymphocyte morphology
- cats: Th lymphocyte (CD4+) subset predominates
what type for CLL develops outside the marrow (ex in the spleen) with secondary involvement of the marrow
T-lymphocyte type CLL
B-type CLL in dogs have what accompanying it
monoclonal hyperglobulinemia
what are some classifications of lymphomas
add photo
in dogs with lymphoma when will you see neoplastic lymphocytes in the blood and in the marrow
neoplastic lymphocytes recognized in blood in 10%-20% of dogs with lymphoma
neoplastic lymphocytes may be recognized in bone marrow at times when not appreciated in blood
what kind of lymphoma predominates canine cases
multicentric, intermediate to high grade lymphoma accounts for 80% of canine cases
- often present with painless peripheral lymphadenopathy
- most commonly (60-70%) diffuse large B-cell lymphomas
- high-grade peripheral T-cell lymphomas have more variably- sized calls with irregular nuclei
what are some other forms of lymphoma
involving the thymus: CD3+, CD4-, CD8-
skin: usually T-cell
digestive system: usually T-cell
liver/spleen: T-cell
nervous system and other organs
what is seen in 20-40% of T-cell lymphomas
hypercalcemia
how does lymphoma generally present in felines
cats are generally ill with presented to the vet
- superficial lymphadenopathy is uncommon
- many tumor involve deep extranodal sites, especially in the gastrointestinal and upper resp tracks
- tend to contain more heterogenous lymphoid populations than typically seen in dogs
what lymphoma predominated prior to widespread FeLV testing and vaccination
- mediastinal and multicentric forms
- primarily in younger cats
- most FeLV pos
what lymphoma predominated after widespread FeLV testing and vaccination
Alimentary form predominated (both B and T cells)
- primarily in older cats
- most FeLV neg
T/F FIV positive cats are 5x more likely to develop lymphoma than FIV and FeLV negative cats
true
what enzootic form can cause bovine lymphoma
- chronic bovine leukemia virus (BLV) infections
—— in mature cattle (peak 5-8 yrs old)
—— B cell type - multicentric form
In addition to lymphoma what does BLV also cause
BLV also causes a persistent benign lymphocytosis
what is associated with the sporadic form of bovine lymphoma
young cattle - multicentric calf, thymic and skin types
not BLV associated, may be B or T cell
what is multiple myeloma or plasma cell myeloma
plasma cell tumor of bone marrow
what are the characteristic of multiple myeloma (plasma cell myeloma)
monoclonal hyperglobulinemia (IgG or IgA is usually present
—- (rarely biclonal protein, only light chains or heavy chains, or no monoclonal protein)
- Bence-jones proteins (light chains) in urine at times
- focal lytic or diffuse osteoporotic bone lesions are often present
- plasma cell infiltrates may be found in other tissues including spleen, liver, lymph nodes, and kidneys ( especially cats)
what is seen with plasma cell tumors in cats
much more likely to exhibit metastasis, whether they begin within or outside the bone marrow
- consequently, the term “myeloma-related disorders” has been used in cats
-typically FeLV and FIV negative
- atypical plasma cell morphology, a nonregenerative anemia and hypocholesterolemia are common
- some cases also have light-chain proteinuria and thrombocytopenia
what term is often used in dogs with extramedullary plasma cell tumors
plasmacytoma
what is seen with plasmacytomas in dogs
generally benign solitary tumor(GI tract, oral cavity, skin, digits, and forelegs, ears)
- usually no monoclonal hyperglobulinemia measured in serum in dogs
what is usually seen with cats and extramedullary plasma cell tumors
some skin tumors appear benign like dogs and other tumors are aggressive, producing paraprotein and quickly metastasizing
what are myeloid neoplasms
neoplastic disorders characterized by the purposeless proliferation of nonlymphoid marrow cells
myelodysplastic syndrome (MDS) appears to be…
clonal and may develop into acute myeloid leukemia
where do neoplastic transformations generally occur in myeloid neoplasms
in pluripotent progenitor cells
T/F abnormalities in more than one cell line are often present in myeloid neoplasms
true
T/F some myeloid neoplasms evolve into one another
true
what does the classification of acute vs chronic myeloid neoplasm depend on
depends on present blast cells in bone marrow
cats are generally FIV and FeLV neg or pos with myeloid neoplasms
positive
myeloid markers ?
what are the types of myeloid neoplasms (myeloproliferative disorders)
-myelodysplastic syndromes (MDS)
- acute myeloid leukemias (AML)
- myeloproliferative neoplasms (MPNs) - formerly chronic myeloproliferative disorders
what are some clinical signs of myeloid neoplasms
- unexplained or frequent infections
- pale mucous membranes
- slow healing ulcerations of mucous membranes or skin
- lethargy, weight loss, fever
- splenomegaly and/or hepatomegaly
** excluded primary erythrocytosis and thrombocythemia
what can be some blood findings with myeloid neoplasms
- anemia (generally severe) with no reticulocytosis
- nucleated erythrocytes are often present in blood
- moderate to marker anisocytosis may be present
- MCV is often increased in cats
- leukocyte counts may be low, normal, or high
- platelet counts are frequently decreased
- abnormal morphology may be present one or more blood cell lines
what can be found in the bone marrow with myeloid neoplasms
- usually hypercellular with increased cellularity in one or two cell lines and decreased cellularity in others
- increased immaturity of cells (including increased blast cells) in one or more cell lines
- myelofibrosis may occur as a secondary even
- stainable iron may be increased
what are some characteristics of myelodysplastic syndromes
- likely clonal neoplastic disorder
- nonregenerative anemia
- generally, leukopenia and/or thrombocytopenia
- bone marrow is often hypercellular
- dysplastic cells in more than one hematopoietic cell line
- less than 20% blasts cells
T/F MDS (<20% blasts) can transition to AML (>20% blasts)
true
what does acute myeloid leukemia look like on blood work and marrow exam
- non regenerative anemia
- leukocyte counts may be low or normal, but more often are increased
- platelet counts are usually decreased
- abnormal blood cell morphology if generally present including blast cells
- bone marrow is hypercellular with greater then 20% blasts
- one, or sometimes two, cell types dominate the marrow cellularity
what will you see in the bone marrow with AMLs
20% or greater blasts in bone marrow
what will you see in the bone marrow with chronic myeloid neoplasms
much less than 20% blasts in marrow
what species is CML seen primarily
dogs
what can be seen on blood work with chronic myeloid neoplasms
- leukocyte count exceeds 50x10^3/uL
- marked neutrophilic left shift
- few or no myeloblasts in blood
- increased blood monocytes, eosinophils, and/or basophils may be present
- less than 20% myeloblasts in bone marrow
primary erythrocytosis
essential thrombocythemia
