Enhance your skillset in evaluating bone marrow specimens

In this lesson, you will learn bone marrow organization and hematopoiesis.

Learning Objectives:

• Describe the structure and function of cortical and trabecular bone
• List the components of the extravascular microenvironment of the bone marrow and discuss the function of each as they relate to hematopoiesis.
• Describe the maturation sequence, salient features, and lineage specific surface antigens of erythroid, myeloid, and megakaryocytic lineages.
• List surface molecules expressed by B- and T- lymphocytes and for monocytes/macrophages/dendritic cells.

In this lesson, you will learn to evaluate bone marrow aspirate cytology and histology biopsies. You will learn to examine cellularity, erythroid lineage, myeloid lineage, megakaryocytic lineage, lymphocytes, plasma cells, mast cells and other bone marrow cells, including stroma, vessels, and trabecular bone as well as distinguish bone marrow artifacts.

Learning Objectives:

• Describe the merits of evaluating a bone marrow aspirate versus a core biopsy.
• Explain how to assess bone marrow cellularity in both cytologic and histologic specimens and the effects of age, breed size and species
• Discuss the evaluation of erythroid, myeloid and megakaryocytic lineages in bone marrow specimens, including individual cell characteristics, topography, and the relationship of specific abnormal findings/features to underlying pathology.
• List and describe the various stromal and trabecular bone changes that may be observed in histologic sections of bone marrow.
• Recognize bone marrow artifacts such as inadequately decalcified bone, inadequately rinsed tissue sections, fragmented trabeculae, muscle, cortical bone, and cartilage.

In this lesson, you will learn to evaluate bone marrow aspirate and bone marrow core biopsy samples treated with or prepared using techniques including cytochemical and histochemical stains, immunocytochemistry, immunophenotyping, and cytogenetic analysis. You will be able to interpret many results from ancillary special stain and other techniques to establish a diagnosis.

In this lesson, you will learn about critical components to be taken into consideration when evaluating bone marrow to diagnose non-neoplastic disorders of the erythroid lineage. The topics covered are erythropoiesis, erythroid abnormalities, overview of anemia and approach, erythrocyte production defects, erythrocyte maturational defects, erythrocyte survival defects, and erythrocytosis.

Learning Objectives:

• Describe the various blood and bone marrow manifestations of immune mediated destruction of cells of the erythroid lineage (ie. IMHA, PIMA, PRCA)
• Compare and contrast the blood and bone marrow findings typically associated with chronic kidney disease (CKD), anemia of inflammatory disease (AID), and iron deficiency anemia (IDA)
• List blood, bone marrow, and other testing that support a diagnosis of primary erythrocytosis.

In this lesson, you will learn about critical components to be taken into consideration when evaluating bone marrow to diagnose non-neoplastic disorders of the myeloid lineage. The topics covered are disorders of neutrophils including both acquired and heritable disorders, abnormal granulocytic morphology, neutropenia and agranulocytosis, neutropenias of extrinsic etiology, neutropenias of intrinsic etiology, as well as disorders related to eosinophils and basophils, and monocytes.

Learning Objectives:

• Describe the distinguishing blood and bone marrow features for physiologic and non-neoplastic pathologic conditions/diseases associated with the myeloid lineage.
• Discuss specific blood and bone marrow features that raise your level of suspicion for a reactive versus neoplastic process.
• List bone marrow features that support a toxic insult to the myeloid precursors versus an immune mediated process (ie. production versus destruction process) leading to neutropenia.

In this lesson, you will learn about critical components to be taken into consideration when evaluating bone marrow to diagnose non-neoplastic megakaryocytic and platelet disorders. The topics covered are megakaryopoiesis and thrombopoiesis, classification of non-neoplastic megakaryocytic/platelet disorders, heritable thrombocytopenia, acquired thrombocytopenia, acquired thrombocytosis, and mimics of megakaryocytes.

Learning Objectives:

• Explain how to evaluate megakaryocyte numbers in bone marrow aspirate and core samples.
• Describe morphologic features of platelets and megakaryocytes, including findings that provide clues as to an underlying process/pathology for specific abnormalities.
• Discuss the normal and abnormal distribution of megakaryocytes in bone marrow and clinical indications for specific abnormalities.
• List the mechanisms of thrombocytopenia and thrombocytosis, including specific etiologies and bone marrow findings.

In this lesson, you will learn about aplastic anemia, a condition associated with bone marrow failure. While aplastic anemia is not a single entitiy, it is distinguished by a commone endpoint – multiple peripheral cytopenias with trilineage bone marrow aplasia and replacement with fat tissue. The topics covered will include congenital/inherited aplastic anemia as well as primary and secondary acquired aplastic anemias.

Learning Objectives:

• Define the pathologic endpoints for diagnosing aplastic anemia and explain how this differs from other causes of bone marrow failure.
• Explain the underlying mechanism of AA and its treatment, including the use of elthrombopag.
• List the most common causes of pancytopenia in dogs and cats.
• Discuss rule outs for AA, including blood and bone marrow features as well as additional testing to help establish a definitive diagnosis.

In this lesson, you will learn about bone marrow stromal responses, bony trabecular bone responses, and about pitfalls in grading of bone marrow fibrosis, collagen deposition, and osteosclerosis.

Learning Objectives:

• List rule outs and describe distinguishing features of ‘pink deposits’ in the bone marrow space.
• Compare and contrast the trabecular bone changes in osteopenia, osteosclerosis, and osteopetrosis.
• Describe the various bone marrow changes that may be observed in a patient with chronic kidney disease (CKD).
• Discuss pitfalls that may be encountered in grading of bone marrow fibrosis, collagen deposition, and osteosclerosis

Dr. Joanne B. Messick:
Education:
VMD, University of Pennsylvania;
Clinical pathology residency and PhD, Ohio State University;
Current position: Professor, Purdue University, West Lafayette, Indiana.
ASVCP: Member since 1988 and past president of the Society.

As a clinical pathologist, her interests include hematopoiesis and evaluation of the bone marrow, which she has been teaching for over a decade.

Dr. Rose Raskin:
Education:
DVM, Purdue University;
Residency and PhD, Michigan State University;

Dr. Raskin is the recipient of a life time achievement award from the ASVCP and is professor emerita of Purdue University College of Veterinary Medicine. Her textbook, Canine and Feline Cytology – A Color Atlas and Interpretive Guide, is a staple in many pathology offices. She has over 30 years of practice in diagnostic hematopathology and in retirement, continues to share her knowledge and provide bone marrow workshops.

Dr. Andrea P. dos Santos:
Education:
DVM, Federal University of Santa Maria (UFSM), Brazil;
MSc in Clinical Pathology, UFSM;
PhD, Federal University of Rio Grande do Sul, Brazil
Clinical Pathology Residency, Purdue University
Board Certified by the American College of Veterinary Pathology (Clinical)
Current position: Assistant Professor, Purdue University, West Lafayette, Indiana.

As a clinical pathologist, her interests include hematology, cytology, special techniques, including immunocytochemistry, flow cytometry, and molecular diagnosis.

Dr. Sanjeev Narayanan:
Education:
BVSc, Madras Veterinary College, India;
Residency and PhD, Kansas State University;
Diplomate, ACVP and American College of Veterinary Microbiologists

As a diagnostic pathologist, Dr. Narayanan has a particular interest in hematopoietic and lymphoid diseases. His primary research focus include vaccinology and antimicrobial resistance.

Dr. Melissa Swan:
Education:
BS Biology, DVM, Purdue University;

She is currently in her 3rd and final year of anatomic pathology residency training at Purdue. She is a gifted teacher and along the way has developed an interest the diagnosis of neoplastic and non-neoplastic hematopathology with an emphasis on bone marrow.