Lecture 5 9/5/24 Flashcards
What are the indications for bone marrow sampling?
-persistent/unexplained abnormalities in peripheral blood
-suspicion of certain infectious organisms/neoplasms
-staging of certain neoplasms
-estimation of iron stores
What are the characteristics of a bone marrow aspirate?
-cytology evaluation
-better for evaluating individual cells
-more common
-individual cell morphology is important for diagnosing most bone marrow abnormalities
What are the characteristics of a bone marrow core biopsy?
-histopathology evaluation
-better for evaluating cellularity and megakaryocyte numbers
-typically performed when aspirates are unsuccessful
-important for diagnosing certain bone marrow abnormalities
What is the most common site of bone marrow collection in small and large animals?
small: proximal humerus
large: sternum/ribs
What type of sample is needed for a bone marrow aspirate?
blood and flecks of marrow in an EDTA/anticoagulant
What type of sample is needed for a bone marrow core biopsy?
solid piece of tissue in formalin
What is the importance of bone marrow cellularity evaluation?
identify if there is an increase or decrease in number of some cell type within the marrow
What is the myeloid:erythroid ratio?
relative numbers of myeloid cells to nucleated erythroid precursors
How is the myeloid:erythroid ratio interpreted?
along with marrow cellularity and CBC results
What abnormalities can a myeloid:erythroid ratio help identify?
-myeloid hyperplasia
-myeloid hypoplasia
-erythroid hyperplasia
-erythroid hypoplasia
What is the normal myeloid:erythroid ratio in most species?
between 1:1 and 2:1
What does an increased M:E ratio possibly indicate?
-increased myeloid cells/myeloid hyperplasia
-decreased erythroid cells/erythroid hypoplasia
What does a decreased M:E ratio possibly indicate?
-decreased myeloid cells/myeloid hypoplasia
-increased erythroid cells/erythroid hyperplasia
What is hyperplasia?
physiologic response to loss, consumption, or destruction of mature cells
What are some examples of hyperplasia?
-hemorrhage: leads to erythroid hyperplasia
-inflammation: leads to myeloid hyperplasia
-immune-mediated thrombocytopenia: leads to megakaryocytic hyperplasia
What is hypoplasia?
indication of suppressed hematopoiesis of one or more cell lines
What are some examples of hypoplasia?
-anemia of inflammation: leads to erythroid hypoplasia
-chronic kidney disease: leads to erythroid hypoplasia
What is ineffective hematopoiesis?
marrow tries to produce cells but they die before they mature (PIMA)
What is bone marrow hypoplasia/aplasia?
stem cell damage, which can result from chemotherapy or some infections
What is myelofibrosis?
increased fibrous tissue in the marrow
What are the general characteristics of lymphoma?
-common
-originates from lymphoid tissue outside of bone marrow
What are the general characteristics of leukemia?
-less common
-originates from hematopoietic tissue
What are the types of leukemia?
-acute lymphoid leukemia
-acute myeloid leukemia
-chronic lymphocytic leukemia
-chronic myeloid leukemia
Why do the chronic forms of leukemia have a better prognosis that the acute forms?
chronic forms involve mature cells, while acute forms involve immature cells
What are the characteristics of acute leukemia?
-blasts in bone marrow and often in blood
-typical CBC pattern includes anemia, neutropenia, thrombocytopenia, and a large number of blasts
What are the characteristics of chronic lymphocytic leukemia?
-neoplastic proliferation of mature lymphocytes
-good prognosis
-must distinguish from non-neoplastic lymphocytosis
-marked lymphocytosis
What are the characteristics of myelodysplastic syndromes?
-uncommon hematopoietic neoplasm
-associated with FeLV in cats
-defective maturation without apoptosis
What are the characteristics of plasmacytoma?
-often solitary masses
-skin or mucous membrane location
-often benign
What are the characteristics of multiple myeloma?
-systemic
-arises in bone marrow or spleen
-often produces a monoclonal gammopathy
What are the indications for advanced lymphoma/leukemia diagnostics?
-sure that a population of cells is lymphoid, but not sure if they are neoplastic
-sure that a population of cells is neoplastic, but want more information to guide treatment/prognosis
What are the characteristics of flow cytometry?
-detects a panel of molecules on cell membranes
-different hematopoietic lineages have different expression patterns that are detected
-liquid sample
-more widely available and common compared to PARR
What are the characteristics of PARR?
-PCR reactions amplify B or T antigen receptor genes from all lymphoid cells in a sample
-polyclonal result indicates non-neoplastic population
-monoclonal result indicates neoplastic population
-cytology slide sample
What are the characteristics of PARR false positives and negatives?
-false positives/false detection of clonality are not common, but can occur with poorly cellular samples or some tick-borne diseases
-false negatives occur when no clonality is detected despite the animal having neoplasia, and occur about 10-20% of the time
What is pancytopenia?
-anemia
-neutropenia
-thrombocytopenia
