262. Intro to Heme Malignancies

Question 1

Difference between primary lymphoid and secondary lymphoid tissue?

What cells are from myeloid and lymphoid lineages?

Answer 1

Primary: where cells originate and develop - bone marrow and thymus

Secondary: where immune response is activated - spleen tonsils LNs and other tissues (MALT, everywhere)

Myeloid: Neutrophils, Eosinophils, Basophils, Mast Cells, Antigen-Presenting Cells (macrophages, some DCs)

Lymphoid: B Cell, T Cell, NK Cell

Question 2

What are the main IHC markers for B Cells, T Cells, and NK Cells? Where do each originate and mature?

Answer 2

B Cells

• CD19+
• Bone Marrow (originate and mature)

T Cells

• CD3+, CD4/8+
• Bone Marrow (originate)
• Thymus (mature)

NK Cells
- CD56+ (CD16+)

Question 3

Explain the general difference between lymphoma, leukemia, myeloid sarcoma

Answer 3

Lymphoma: neoplasms from lymphoid cells, usually tissue-based (LN, spleen, etc)

Leukemia: neoplasms originating in Blood and Bone marrow - include BOTH myeloid and lymphoid origin

Myeloid Sarcoma: myeloid neoplasms involving the tissue

• NO STRICT CRITERIA

Question 4

What is the difference between Acute and Chronic Heme Malignancy?

What cell markers are used for immature cells?

How is Acute Leukemia defined (myeloid or lymphoid)?

Answer 4

Acute: Precursor/Blasts
Chronic: Mature Cells

Blasts: CD34+

AL: >20% blasts in peripheral bone or marrow (or <20% with certain genes)

Question 5

What is the difference between Myelodysplastic Syndromes and Myeloproliferative Neoplasms?

Answer 5

Both: neoplastic mature myeloid cells

MDS: dysplasia in myeloid lineage resulting in peripheral blood cytoPENIAs

MPN: cause ELEVATED peripheral blood cell counts