Faculty/ Presenter Disclosure
Faculty: Will Chen
Relationships with commercial interests:
Grants/Research Support: None
Speakers Bureau/Honoraria: None
Consulting Fees: None
Other: Consulting services to DynaLIFEDx Laboratories
Disclosure of Commercial Support
This program has received financial support from DynaLIFEDx in the form of an Educational Program.
This program has received in-kind support from DynaLIFEDx in the form of logistical support
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Potential for conflict(s) of interest:
Will Chen has received no honorarium, and provides consulting services to DynaLIFEDx.
DynaLIFEDx provides laboratory services which will be discussed in this program.
Mitigating Potential Bias
DynaLIFEDx operates in accordance with Alberta Health Services, testing and solutions are a direct result of provincial standards.
Leukocytosis on a CBC What to do? Will Chen, MDCM, FRCPC, DABPath Hematopathologist, DynaLIFEDx & Cross Cancer Institute Clinical Lecturer, Dept. of Laboratory Medicine and Pathology, University of Alberta
Objectives
Review common causes of leukocytosis in the peripheral blood (PB).
Discuss appropriate utilization of flow cytometry in investigation of leukocytosis.
Determine which cases need urgent hematology/oncology referral.
Leukocytes in peripheral blood
Neutrophils and precursors
Lymphocytes
Eosinophils
Basophils
Monocytes
Normal WBC count: 4.5-11 x 109/L
Order peripheral smear evaluation for further investigation, lab will often reflex.
Neutrophilia
ANC: > 7.0 x 109/L
Most common cause: infection
Toxic changes:
toxic granulation
cytoplasmic vacuolation
Dohle bodies (rough endoplasmic reticulum remnant)
Left shift
Immature granulocytic precursors in peripheral blood (+/- myeloblasts).
http://www.medical-labs.net/neutrophil-maturation-diagram758/granulocytes-series-in-a-smear/
Other benign causes of neutrophilia
Inflammatory states: burns, postoperative, asthma, MI, gout attack, collage vascular diseases, etc.
Acute hemorrhage
Corticosteroids
Chronic idiopathic neutrophilia
Neoplastic causes of neutrophilia
Often associated with presence of myeloblasts in PB.
Bone marrow blast %:
50 x 109/L
Marked left shift with “myelocyte bulge” – myelocytes outnumber more mature forms
Often associated with thrombocytosis.
Often with absolute basophilia (very helpful in distinguishing from benign leukocytosis).
http://imagebank.hematology.org/Content%5C901%5C1022%5C1022_full.JPG
Acute Myeloid Leukemia
Typically ≥20% blasts in bone marrow or specific cytogenetic abnormalities.
Blast % in PB can vary!
Many subtypes based on morphologic/cytogenetic findings
Median age in 60s, rarer in children
Urgent referral to hematology/ER for bone marrow.
http://drugline.org/img/term/leukemia-acute-myelogenous-8659_0.jpg
Special subtype: Acute promyelocytic leukemia
t(15;17) PML-RARA translocation
10-15% of AML cases.
Can present with coagulopathy/DIC.
Hemorrhage is major cause of early death.
Often leukopenic with rare blasts (only 1 blast in one case!).
ATRA should be administered at first morphologic/clinical suspicion.
Confirm with FISH studies.
Excellent prognosis/cure rate if treated appropriately.
How I treat acute promyelocytic leukemia. 2009; Blood: 114 (25)
Bone marrow: APL with prominent Auer rods 2009 Blood 114 (25)
Bone marrow: Hypogranular variant with “butterfly” cells 2009 Blood 114 (25)
Other causes of increased blasts
Blasts in PB are never “normal”, regardless of neutrophil count.
Benign: GCSF therapy (can mimic CML with prominent left shift)
Leukoerythroblastic reaction/picture: presence of circulating nucleated RBCs and myeloid precursors (often blasts) in PB.
Broad ddx: marrow infiltrative (myelophthisic) process, severe infection, trauma, acute hemorrhage, hemolysis, hypoxia, megaloblastic anemia.
www.cpsa.ab.ca/FLibraries/FPro_QofC_ALQEP_Critiques/FCritique_04-03-S.pdf
Bottom Line
Consider bone marrow in cases with unexplained circulating blasts in PB.
Be on the lookout for APL and refer immediately for ATRA
Flow cytometry typically not performed on PB in AML/MPN cases. Will be performed on BM.
Other myeloid cells
Basophilia: Associated with myeloproliferative neoplasms. Also allergic/inflammatory conditions, infection, iron deficiency.
Eosinophilia: drugs, parasitic infection, autoimmune disease, malignancies, hypereosinophilic syndromes
Monocytosis: infection, inflammatory disorders, often associated with neutrophilia. Also seen in CMML.
Lymphocytes
Normal range: 0.8-4.8 x 109/L
Include T-cells, B-cell and natural killer cells.
Morphologic types of lymphocytes in PB:
“Mature-appearing”: includes normal and neoplastic
Reactive/large granular lymphocytes
Lymphoblasts (normally never present)
“Mature” lymphocytes
Increased in infectious/inflammatory conditions.
Persistent lymphocytosis in absence of underlying condition
consider lymphoproliferative disorder
order flow cytometry
Flow Cytometry
Living cells stained with fluorescently-labeled antibodies to various lymphocyte antigens
Cells passed through suspension in single file and fluorescent signals detected
Data collected on each cell and examined in aggregate as dot plots
Expensive! ($ hundreds)
Test Utilization
When to order flow cytometry on lymphocytosis cases?
No guidelines available.
Some studies suggest optimal “cutoff” = 7.0 x 109/L and PB smear showing “malignant” features (J Clin Pathol. 2014 Dec;67(12)).
My approach Absolute lymphocytosis on CBC/diff Order blood smear evaluation if not reflexed Smear suggestive of malignancy? Not definite
Yes
Unexplained lymphocytosis persistent for 3-6 months Yes Order flow cytometry (lymphoid flow at CCI)
No Repeat CBC/diff + smear in 3-6 months
Most common “mature” LPD in PB
Chronic lymphocytic leukemia.
Most common in men > age 50.
Indolent B-cell lymphoma.
Many smudge cells on PB with “soccer ball” cells.
B-cell count non-urgent referral to heme/onc.
http://www.clevelandclinicmeded.com/medicalpubs/diseasemanagement/ hematology-oncology/chronic-leukemias/images/figure-5.jpg
Other common B-cell LPDs
Follicular lymphoma
Hairy cell leukemia:
Often pancytopenia
Monocytopenia is a “classic” feature
Splenomegaly very common
Villous cytoplasmic projections (“hairs”)
Mantle cell lymphoma
Marginal zone lymphoma
Lymphoplasmacytic lymphoma
Reactive lymphocytes/Large granular lymphocytes
Large, reactive lymphocytes seen in viral infections, esp. mononucleosis.
LGLs are normal component of PB, representing NK/Tcells. Can be increased in infectious/immune conditions
Also seen in LGL leukemia
Infectious mononucleosis: Reactive lymphocytes
https://classconnection.s3.amazonaws.com/595/flashcards/15 00595/png/picture11351649570766.png
http://imagebank.hematology.org/Content%5C908%5C1050%5C1050_full. JPG
Downey cells: blue cytoplasm with “skirting” around other cells
Large granular lymphocyte
http://imagebank.hematology.org/Content%5C381%5C2785%5C2785_ful G
LGL Leukemia
Rare indolent T-cell lymphoma.
Incidental finding, often in rheumatoid arthritis patients (Felty syndrome: RA, splenomegaly, neutropenia).
Requires lymphocyte count ≥ 2.0 x 109/L.
Typically involves blood, marrow, spleen and liver; nodal involvement rare.
Lymphoblasts
Never normal: urgent referral to hematology for bone marrow.
Flow cytometry can be performed on marrow.
Acute lymphoblastic leukemia:
B-cell or T-cell: morphologically indistinguishable
Most common childhood cancer (highest incidence age range 2-5). In adults AML > ALL.
https://s3.amazonaws.com/classconnection/632/flashcards/2652632/jpg/l2149E3E6EF0B58C945D8.jpg
“L3” lymphoblast = Burkitt lymphoma
Aggressive mature B-cell lymphoma, not ALL
http://atlasgeneticsoncology.org/Anomalies/Images/FlandrinBurkitt.jpg
Take Home Message
Immediate hematology referral/ER visit:
Acute myeloid leukemia
Particularly APL which requires immediate ATRA therapy
Cases of unexplained pancytopenia with rare blasts should also have bone marrow to exclude acute leukemia
Acute lymphoblastic leukemia
Burkitt lymphoma/other aggressive lymphomas
Semi-urgent referral:
Chronic myelogenous leukemia/other MPNs
Lymphomas
Non-urgent referral (3-6 months):
Monoclonal B-cell lymphocytosis
Use of flow cytometry
Expensive test
Order for investigation of lymphocytosis
Consider only after smear review
Highest yield in cases with unexplained, persistent lymphocytosis
Unnecessary on PB for myeloid neoplasms
Questions? Email:
[email protected]
Thank You!