Leukemia Flashcards by pattie o.

Leukemias vs. Lymphomas: Overproduction of cells

Leukemias: Overproduction of various types of immature or mature cells in the bone marrow and/or peripheral blood. Lymphomas: Solid malignant tumors of the lymph nodes and related WBCs in bone tissue.

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Leukemias vs. Lymphomas: Cell Types

Leukemias: Frequently involves WBCs of the myelogenous or lymphocytic cell types. Lymphomas: The distinctive cell type is the lymphocyte.

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Leukemias vs. Lymphomas: Blood-brain barrier

Leukemias: Malignant cells easily trespass the blood-brain barrier. Lymphomas: Malignant cells are initially confined to lymph nodes, spleen, liver, and bone marrow, though they can spill into the circulating blood.

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Leukemias vs. Lymphomas: Tumor location and spread

Leukemias: Malignant cells primarily in bone marrow and peripheral blood. Lymphomas: Solid tumors in lymph nodes and organs containing mononuclear phagocytic cells, may spill over into circulating blood.

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Leukemia: Definition

Overproduction of immature or mature WBCs in the bone marrow or peripheral blood.

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Leukemia: Disease course and WBC count

More blasts = shorter, fatal course; ↑ WBC with left shift.

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Leukemia: M:E ratio

10:1.

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Anemia type in acute leukemia

Normocytic, normochromic.

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Acute Leukemias: Duration and cell forms

Short duration; numerous immature cells in bone marrow/peripheral blood; ↑ WBC count.

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Chronic Leukemias: Duration and cell forms

Long duration; mostly mature cells in bone marrow/peripheral blood; WBC count varies (elevated or lower than normal).

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FAB Classification of Leukemias

Based on morphology in Romanowsky-stained smear and cytologic/histochemical characteristics of cells.

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Myeloperoxidase (MPO): Function

Used to differentiate AML blasts from ALL blasts.; found in primary granules of neutrophils, eosinophils, and monocytes

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MPO Positive Cells

Neutrophilic granulocytes, Auer rods, leukemic blasts in FAB M1, M2, M3, eosinophils.

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MPO Weakly Positive or Negative Cells

Monocytes.

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MPO Negative Cells

Myeloblasts, basophils, lymphocytic and erythrocytic cell series.

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Peroxidase Stain Reminders

May produce red-brown, dark brown, or black color; RBCs may turn brown due to pseudoperoxidase activity in hemoglobin.

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Precautions for DAB Handling

Wear protective clothing, use mechanical pipetting aids, clean up spills instantly, wash hands after use, weigh benzidine in hood.

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Peroxidase Enzyme Sensitivity

Sensitive to light; stain immediately or keep in dark. Older smears or those exposed to light should not be peroxidase negative.

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Cyanide-resistant Peroxidase Stain

Detects eosinophilic leukemia; eosinophil peroxidase differs due to enzyme activity with sodium cyanide.

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Sudan Black B (SBB): Function

Stains sterols, neutral fats, phospholipids in primary and secondary granules of neutrophils and lysosomal granules of monocytes.

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SBB Positive Cells

Promyelocyte, myelocyte, metamyelocytes, bands, segmented neutrophils (strongly positive), leukemic blasts, Auer rods, eosinophils.

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SBB Weakly Positive or Negative Cells

Myeloblasts, monocytic cells.

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SBB Negative Cells

Lymphocytes and precursors, megakaryocytes, platelets, erythrocytes.

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SBB Staining Reminders

Brownish-black granules in myelocytic precursors, few granules in monocytes, eosinophilic granules with central pallor.

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SBB Staining Properties

Can be performed on specimens months old; reagents not carcinogenic.

SBB Disadvantages

Time-consuming (1-2 hours), possible false positives in lipid vacuole disorders, increased background in bone marrow specimens.

Lymphocytic Leukemias: Myeloperoxidase and Sudan Black B

Myeloperoxidase: negative, Sudan Black B: negative.

Most Common Childhood Leukemia

Acute Lymphocytic Leukemia (ALL).

FAB Classification: L1

70% of childhood ALL; markers: CALLA (CD10), TdT, CD19, CD20.

FAB Classification: L2

70% of adult ALL; markers: TdT.

FAB Classification: L3

Rare in children/adults; markers: sIg, CD19, CD20, CD22, CD24.

FAB Classification: Cell Size L1

Homogeneous population of small blasts.

FAB Classification: Cell Size L2

Heterogeneous population of large blasts.

FAB Classification: Cell Size L3

Homogeneous population of large blasts with nuclear and cytoplasmic vacuoles.

Nucleus L1

Uniformly round, small.

Nucleus L2

Irregular.

Nucleus L3

Round to oval.

Nucleolus L1

Single.

Nucleolus L2

Single to several.

Nucleolus L3

Two to five.

Chromatin L1

Slightly reticulated with perinucleolar clumping.

Chromatin L2

Fine.

Chromatin L3

Coarse with clear parachromatin.

Cytoplasm L1

Scant, blue.

Cytoplasm L2

Moderate, pale.

Cytoplasm L3

Moderate, blue, prominently vacuolated.

Cyto-chemistry L1

PAS+: Positive, Methyl Green Pyronin: Negative, ORO: Positive (sometimes).

Cyto-chemistry L2

PAS+: Positive, Methyl Green Pyronin: Negative, ORO: Positive (sometimes).

Cyto-chemistry L3

PAS: Negative, Methyl Green Pyronin: Positive, ORO: Positive.

Immunologic Markers: E Rosettes

T-ALL: Positive.

Immunologic Markers: Surface Ig

B-ALL: Positive.

Immunologic Markers: Serum Anti-ALL

Common ALL: Positive.

Most common type of leukemia in elderly, characterized by persistent lymphocytes

Chronic Lymphocytic Leukemia (CLL).

Chronic Lymphocytic Leukemia (CLL) cells present

Increased smudge cells, Rieder cells in peripheral blood smear.

Clinical Variations of CLL

Hairy-cell leukemia, Lymphosarcoma cell leukemia, Prolymphocytic leukemia.

Acute lymphoblastic leukemia (ALL) Solid tumor counterpart

Lymphoma, poorly differentiated; lymphocytic.

Chronic lymphocytic leukemia (CLL) Solid tumor counterpart

Lymphoma, well-differentiated; lymphocytic.

Monocytic leukemia Solid tumor counterpart

Reticulum cell sarcoma.

Acute myelogenous granulocytic leukemia Solid tumor counterpart

Chloroma.

Plasma cell leukemia Solid tumor counterpart

Myeloma.

Stem cell leukemia Solid tumor counterpart

Lymphoma, undifferentiated.

Non-lymphocytic leukemias/myelogenous leukemias (granulocytes, monocytic progenitor) Initial stains: Myeloperoxidase and Sudan Black reaction

Positive.

Acute Myelogenous Leukemia (AML) M0 - Myelocytic

AML, minimally differentiated/undifferentiated. MPO and SBB negative.

Acute Myelogenous Leukemia (AML) M1 - Myelocytic

AML, without maturation. May demonstrate Auer rods.

Acute Myelogenous Leukemia (AML) M2 - Myelocytic

AML, with maturation. Most common subtype of AML. May demonstrate Auer rods.

Acute Myelogenous Leukemia (AML) M3 - Myelocytic

Acute Promyelocytic Leukemia (APL), associated with DIC and Faggot cells. Demonstrates Auer rods.

Acute Myelogenous Leukemia (AML) M3V - APL, microgranular variant

Cells have characteristic ‘butterfly’, ‘bowtie’, ‘coin-on-coin’, or ‘apple core’ nuclei.

2nd most common subtype of AML. May demonstrate Auer rods.

Acute Myelomonocytic Leukemia (AMML) M4 - Myelocytic Monocytic

AMML with increased marrow eosinophils.

Acute Myelomonocytic Leukemia (AMML) M4E

Schilling Leukemia.

Acute Monocytic Leukemia (AMOL) M5 - Monocytic

AML poorly differentiated. Seen in children; >80% monoblasts in BM.

Acute Monocytic Leukemia (AMOL) M5A

Well differentiated. Seen in middle-aged adults; <80% monoblasts in BM.

Acute Monocytic Leukemia (AMOL) M5B

Di Guglielmo's Syndrome. Demonstrates Auer rods.

Acute Erythroleukemia M6 - Erythrocytic Myelocytic

AML M6 reaction with PAS. Strongly positive (L1, L2, M6).

Acute Erythroleukemia M6

Di Guglielmo's Syndrome anemia type: macrocytic, normochromic.

Anemia Type: Di Guglielmo's Syndrome

Acute Megakaryocytic Leukemia requires immunocytochem staining for accurate diagnosis.

M7 - Megakaryocytic, Factor VIII stains positive.

Acute basophilic leukemia.

AML 8 - Acute Basophilic Leukemia.

M1, M2, M3 leukemia positive cytochemical stains.

Positive for MPO, SBB, Naphthol AS-D, Chloroacetate (SE).

M4 (AMML) leukemia positive cytochemical stains.

Positive for MPO, SBB, Naphthol AS-D, Chloroacetate (SE), α-Naphthyl Butyrate Esterase (NSE), α-Naphthyl Acetate Esterase (NSE).

M5 (AMoL) leukemia cytochemical stains.

Positive or negative for SBB, positive for α-Naphthyl Butyrate Esterase (NSE), α-Naphthyl Acetate Esterase (NSE).

M6 leukemia cytochemical stains.

Positive or negative for MPO, SBB, Naphthol AS-D, Chloroacetate (SE).

M7 leukemia cytochemical stains.

Localized positivity for α-Naphthyl Acetate Esterase (NSE) and positive for Factor VIII stain.

Myelocytic leukemia positive cytochemical stains.

Positive for MPO, SBB, SE, Naphthol AS-D.

Monocytic leukemia positive cytochemical stains.

Positive for NSE, Butyrate Esterase.

ICC Classification AML subtypes with ≥10% blasts

Includes t(15;17)/PML::RARA, t(8;21)/RUNX1::RUNX1T1, inv(16)/CBFB::MYH11, t(9;11)/MLLT3::KMT2A, t(6;9)/DEK::NUP214, t(3;3)/GATA2::MECOM, mutated NPM1.

ICC Classification AML subtypes with ≥20% blasts

t(9;22)/BCR::ABL1, myelodysplasia-related gene mutations, myelodysplasia-related cytogenetic abnormalities.

WHO 2022 Classification usually represents

No blast threshold for classification.

WHO 2022 Classification AML subtypes with ≥20% blasts

BCR::ABL1 fusion, CEBPA mutation, myelodysplasia-related, defined by differentiation.

Chronic Myelogenous Leukemia (CML) AKA,

Chronic granulocytic leukemia

Chromosome Associated with CML,

Philadelphia Chromosome (Ph1)

First description of Philadelphia Chromosome,

Peter C. Nowell, 1960

Cause of Philadelphia Chromosome,

Reciprocal translocation between chromosomes 9 and 22

Result of translocation in CML,

Formation of BCR-ABL1 fusion gene

Three clinical phases of CML,

Chronic phase, Accelerated phase, Blast crisis

Percentage of CML patients with Philadelphia Chromosome,

0.9

Significance of Philadelphia Chromosome in CML,

Indicates good prognosis

Chromosomes involved in CML translocation,

Chromosome 9 and 22

Parts of chromosomes involved in translocation,

Long arms of chromosomes 9 and 22

Must be differentiated from Chronic Myelogenous Leukemia (CML) because it may cause confusion,

LEUKEMOID REACTION (LR)

LEUKEMOID REACTION (LR) is characterized by,

Excessive leukocytic response in peripheral blood

WBC count in LEUKEMOID REACTION (LR),

Greater than 50 X 10⁹ /L (with neutrophilia and marked left shift)

Marked left shift in LEUKEMOID REACTION (LR),

Presence of immature neutrophilic forms

Most frequent WBC increase in LEUKEMOID REACTION (LR),

Neutrophils

Generally used to distinguish LR from CML,

LEUKOCYTE (NEUTROPHIL) ALKALINE PHOSPHATASE (LAP/NAP) TEST

Principle of LAP/NAP Test,

↑ LAP activity observed in neutrophils that have undergone normal growth

KAPLOW'S METHOD Principle,

Hydrolysis of sodium alpha naphthyl phosphate by alkaline phosphatase produces a colored precipitate with a diazotised amine

Fixative used in KAPLOW'S METHOD,

Methanol and formalin

Buffer used in KAPLOW'S METHOD,

Propanediole

Substrate in KAPLOW'S METHOD,

Sodium alpha naphthyl phosphate

Initial stain used in KAPLOW'S METHOD,

Brentamine fast game salt

Counterstain used in KAPLOW'S METHOD,

Aqueous Mayer's hematoxylin

Procedure for LAP Test (Kaplow's Method),

Immerse dry blood smear in fixative for 30 seconds, then dry

Working substrate for LAP test,

Made up of buffer, substrate, and initial stain

After applying working substrate in KAPLOW's LAP,

Allow to stand for at least 10 minutes

Counterstaining time for KAPLOW's LAP,

10 to 15 minutes

After counterstaining in KAPLOW, where is it mounted,

Glycerol

Examination of KAPLOW's LAP under the microscope,

Look for reddish-brown to black precipitate in neutrophil cytoplasm

Scoring of neutrophils in LAP test,

Count 100 segmented neutrophils and bands, score based on precipitate

Score for no precipitate,

Score for slightly diffused precipitate,

Score for moderately diffused precipitate,

Score for heavily diffused precipitate,

Score for very heavily diffused precipitate,

Normal LAP score range,

15 to 100

Interpretation of normal LAP score,

Leukomoid reaction

Interpretation of decreased LAP score,

CML

Examples of cases with INCREASED KAPLOW’S (LAP) SCORE,

Third trimester pregnancy, PCV, Infections, Intoxication

Examples of cases with DECREASED KAPLOW’S (LAP) SCORE,

CML, Paroxysmal nocturnal hemoglobinuria, Sideroblastic anemia, Myelodysplastic syndrome

Leukocyte types in CML vs. LEUKEMOID REACTION,

CML: Blasts/promyelocytes, LEUKEMOID REACTION: Myelocytes

Toxic granulation in CML vs. LEUKEMOID REACTION,

CML: Absent, LEUKEMOID REACTION: Present

Eosinophils/Basophils in CML vs. LEUKEMOID REACTION,

CML: Decreased (↓), LEUKEMOID REACTION: Increased (↑)

LAP score in CML vs. LEUKEMOID REACTION,

CML: Decreased (↓), LEUKEMOID REACTION: Increased (↑)

Philadelphia chromosome in CML vs. LEUKEMOID REACTION,

CML: Usually present, LEUKEMOID REACTION: Absent

Splenomegaly in CML vs. LEUKEMOID REACTION,

CML: Usually prominent, LEUKEMOID REACTION: Mild (if present)

Platelet count in CML vs. LEUKEMOID REACTION,

CML: >600 or <50 X 10⁹/L, LEUKEMOID REACTION: Normal