M a l i g n a n t H e m a t o p a t h o l o g y
Types of Hematopoietic Malignancies
Leukemias
• Acute leukemias
• Acute myeloid leukemia
• Acute lymphoblastic leukemia
• Chronic leukemias
• Chronic myeloproliferative disorders
• Chronic lymphoproliferative disorders
• Myelodysplastic syndromes
Lymphomas 
• Non-Hodgkin's lymphoma
• Hodgkin's disease
Plasma cell disorders
• Myeloma
Myeloid vs. Lymphoid
Myeloid malignancies
• Acute myeloid leukemia
• Chronic myeloproliferative disorders
• Myelodysplastic syndromes
Lymphoid malignancies
• B-cell malignancies
• Acute lymphoblastic leukemia, B-cell type
• Non-Hodgkin’s lymphoma, B-cell types
• Myeloma
• T-cell malignancies
• Acute lymphoblastic leukemia, T-cell type
• Non-Hodgkin’s lymphoma, T-cell types
• Hodgkin’s disease
Acute vs. Chronic Leukemia
How to Think About a Patient With Leukemia
Age
• Kids - almost always acute; almost always lymphoid.
• Adults - more often chronic; if acute, more likely to be myeloid.
Acute vs. chronic
• Clinical setting (abrupt or insidious onset?).
• Morphology (lots of blasts or lots of maturing cells?).
Myeloid vs. lymphoid
• Clinical setting may be helpful.
• Morphologic clues (eg, Auer rods).
• Often need to do special stains or markers (see below).
How to Diagnose a Leukemia
Morphology (Wright-Giemsa stain)
• Blood smear
• Bone marrow biopsy
Cytochemistry (special stains)
• Most important stains:
• Myeloperoxidase (MPO) - stains neutrophilic cells (and sometimes
monocytic cells).
• Sudan black B (SBB) - same pattern as MPO.
• Non-specific esterase (NSE) - stains monocytic cells.
• Usually negative in lymphoid leukemias.
• Frequently positive in myeloid leukemias.
• See reference section for a more detailed list of cytochemical stains.
Immunophenotyping (looking for antigens or “markers” on the cell surface)
• Some useful markers:
• CD5 - Expressed on all T cells
• CD10 - Expressed on developing B cells
• CD19 - Expressed on mature B cells
• CD20 - Expressed on mature B cells
• CD33 - Expressed on myeloid precursors and monocytes
• Immunophenotyping is most helpful in lymphoid leukemias.
• See reference section for a more detailed list of cell markers.
Cytogenetics (examination of chromosomes under a microscope)
• Gives a rough overall look at ALL the patient's chromosomes - but can only
detect abnormalities that cause big chunks of the chromosomes to move
around or disappear.
• Sometimes confirms diagnosis; often more useful for prognosis.
• See reference section for a list of some cytogenetic abnormalities.
Molecular studies (examination of DNA using PCR, Southern blotting, etc.)
• Very sensitive way of looking for a specific chromosomal abnormality (but
you have to know the exact DNA sequence of the abnormality you are
looking for!).
• Can often detect abnormalities that don't show up on cytogenetics; but can
only look for specific abnormalities (no information about the rest of the
patient's chromosomes).
Electron microscopy
• Not routinely used for diagnosis - but on rare occasions can be very helpful.
