Introduction to Hematopathology

Question 1

What is leukemia?

Answer 1

• Malignancy of hematopoietic cells
• Starts in BONE MARROW, can spread to blood, nodes
• Myeloid or lymphoid
• Acute or chronic

Question 2

What is lymphoma?

Answer 2

• Malignancy of hematopoietic cells
• Starts in LYMPH NODES, can spread to blood, marrow
• LYMPHOID only
• Hodgkin or non-Hodgkin

Question 3

What are the three main hematologic malignancies and what are their subclasses?

Answer 3

Leukemias (acute and chronic)
Lymphomas (Hodgkin and Non-hodgkin)
Plasma cell disorders (multiple myeloma)

Question 4

What are the two different types of myeloid leukemia?

Answer 4

• Acute myeloid leukemia

- Chronic myeloid leukemia

Question 5

What are the five different types of lymphoid leukemia?

Answer 5

• Acute lymphoblastic leukemia
• Chronic lymphocytic leukemia
• Hodgkin lymphoma
• Non-hodgkin lymphoma
• Multiple Myeloma

Question 6

How is a malignant hematopathology diagnosis made?

Answer 6

• Clinical setting (symptoms)
• Morphology (bone marrow biopsy/aspirate)
• Immunophenotyping
• Molecular studies
• Cytogenetics

Question 7

What is involved with a bone marrow biopsy?

Answer 7

• If it’s suspected to be malignant, they’ll get a bone marrow biopsy
• Often pathologists get best sample
• Aim for superior iliac crest on the lower back - find it by palpation
• Jamshidi needle used - it’s a hollow tube that you get the marrow stuck in, you twist the needle a little bit and gently pull it out - you’ll get a toothpick thick, inch long piece of bone

Question 8

What do you see when you get a bone marrow biopsy?

Answer 8

• Cellularity!!
• You get a good overview of bone composition
• First, look at its cellularity
• Then, look for large collection of odd cells
• As you age, cellularity drops 10% each year (starting in 30s) -In older agent shouldn’t be cellular at all (all filled with fat!)

Question 9

What do you see in a normal bone marrow biopsy?

Answer 9

-Many cells with some globs of fat, very pink staining

Question 10

What happens in bone marrow aspiration?

Answer 10

A needle and syringe is used to extract marrow. It will look like thick blood, but it’s bone marrow aspirate

Question 11

What does normal bone marrow aspirate look like?

Answer 11

• Pink, small very cellular
• Lots of red cells
• Smear it out from one end to the other

Question 12

What do acute leukemias look like in bone marrow aspirate?

Answer 12

• Many, much darker clumped together cells

- Look like very young cells

Question 13

What do chronic leukemias look like in bone aspirate?

Answer 13

-Come on more slowly, tend to have more mature cells (more banded/lobed cells)!

Question 14

What might you see and diagnose in the bone marrow aspirate or blood smear of hodgkin lymphoma?

Answer 14

• Reed Sternberg cell

- Looks like two fried eggs inside one cell (almost like owl eyes

Question 15

What are the two main stains used to look at these bone marrow cells?

Answer 15

Regular stain - Wright-Giemsa

Cytochemical stain - Non-specific esterase

Question 16

What are you doing in flow cytometry?

Answer 16

Looking at lymphocytes (WBCs) and sorting them by their cell surface markers (ex: CD3 & CD8)

Question 17

What are you doing in cytogenetics?

Answer 17

• Looking at DNA in cells
• You take a photo during metaphase & then line up the chromosomes and look at them
• Anything missing? Abnormalities?
• Ex: translocation between chromo 9 and 22 called the Philadelphia - in chronic myeloid leukemia

Question 18

How else can you look at hematopatholigical malignancies (genetically)?

Answer 18

DO PCR

• Take DNA of cells, put in tube and add primers that flank the sequence you’re looking for
• Then the strands are “cut and pasted” many many times - the you get a pure sample of the section of DNA and can run it on a gel
• You can start with a sample of a very small amount