Leukemoid Reaction• A leukemoid reaction describes a highWBC count with neutrophilia,usually inresponse to infection.• The WBC count may be as high as 50,000/microL and can easily mimic CML orAML.
• Serum leukocyte alkaline phosphatase isnormal or elevated in leukemoid reaction,but is depressed in chronic myelogenousleukemia.• The bone marrow in a leukemoid reaction,if examined, may be hypercellular but isotherwise typically unremarkable.
Features Suggesting LeukemoidReaction• Toxic granulation.• High LAP score.• Presence of an obvious cause for theneutrophilia.
• As noted above, a leukemoid reaction is typically a response to an underlying medical issue. Causes of leukemoid reactions include:• Hemorrhage• Drugs– Use of Sulfa drugs– Use of Dapsone– Use of glucocorticoids– Use of G-CSF or related growth factors– All-trans retinoic acid (ATRA)• Infections– Clostridium difficile– Tuberculosis– Pertussis– Infectious mononucleosis (lymphocyte predominant)– Visceral Larva Migrans (eosinophil predominant)• Asplenia• Diabetic ketoacidosis• Organ necrosis– Hepatic necrosis– Ischemic colitis• As a feature of Trisomy 21 in infancy (incidence of ~10%)• As a paraneoplastic phenomenon (rare)
What is leukemia?Leukemia is cancer of the white blood cells. Whiteblood cells help your body fight infection. Yourblood cells form in your bone marrow. In leukemia,however, the bone marrow produces abnormalwhite blood cells. These cells crowd out the healthyblood cells, making it hard for blood to do its work.
Myeloid maturationmyeloblastpromyelocytemyelocytemetamyelocyteband neutrophilMATURATIONAdapted and modified from U Va website
Definition• Leukemia: is a cancer of the blood or bone marrowcharacterized by abnormal proliferation of bloodcells,usually WBCs(Leukocytes).• Acute leukemia: rapid increase of immature bloodcells.• Chronic leukemia: excessive build up of relativelymature,but still abnormal blood cells.
About the Disease• Leukemia, lymphoma and myeloma arecancers that originate in the bone marrow(leukemia & myeloma) or in lymphatictissues (lymphoma).
Different Types of BloodCancers• Leukemia• Non-Hodgkin Lymphoma• Hodgkin Lymphoma• Myeloma• Myelodysplastic Syndromes
What is Leukemia• Greek word which means “white blood”• Leukemia is when cells spread rapidly and destroy livingtissue.• It grows/invades the bone marrow which is the factory ofblood and replaces normal blood elements with cancercells.• Cancer cells replace all bone marrow cells which causesinfection and bleeding problems.• Leukemia is basically white blood cells that don‟t workwell and cause trouble.
Signs and Symptoms• Most of the signs and symptoms are due to:1-Anemia.2-Leukopenia.3-Thrombocytopenia.• Bicytopenia,Pancytopenia.• All symptoms associated with leukemiacan be attributed to other diseases,consequently,leukemia is alwaysdiagnosed by laboratory investigations.
Causes• Leukemia,like other malignancies, resultsfrom somatic mutations in the DNA.• Certain mutations produce leukemia byactivating oncogenes or deactivatingtumor suppressor genes.• These mutations may occur spontaneouslyor as a result of exposure to radiationor carcinogenic substances,and likelyto be influenced by genetic factors.
Causes-cont‟d• Ionizing radiation• Viruses: Human T-lymphotropic virus (HTLV-1)• Chemicals: Benzene,chemotherapy.• Smoking: slight increase in leukemiaincidence.• Genetic predisposition toward developingleukemia: Down syn.,Fanconi anemia
Classification• Multiple classification systems.• FAB classification:French-American-British Classification.• FAB Classification relies on morphologic,cytochemical,and immunophenotypingcriteria to define 8 major subtypes(M0-M7)
FAB vs WHO Classification• French-American-British (FAB) Cx– Cellular morphology and cytochemical stain– Acute leukemia as > 30% bone marrow blasts– Widely used• World Health Organization Cx– Cellular morphology and cytochemical stain– Immunologic probes of cell markers, cytogenetics,molecular abnormalities & clinical syndrome– Acute leukemia as > 20% bone marrow blasts– Standard for diagnosis
AML classification - WHOAML not otherwise categorized1. AML minimally differentiated2. AML without maturation3. AML with maturation4. Acute myelomonocytic leukemia5. Acute monocytic leukemia6. Acute erythroid leukemia7. Acute megakaryocytic leukemia8. Acute basophilic leukemia9. Acute panmyelosis with myelofibrosis
Acute vs Chronic LeukemiaAcute ChronicAge Children & youngadultsMiddle age andelderlyOnset Sudden insidiousDuration weeks to months yearsWBC count Variable High
Definition• Acute myeloid leukemia (AML): acutemyelogenous leukemia,acute non-lymphocytic leukemia.• AML consists of a group of relatively well-defined hematopoietic neoplasmsinvolving precursor cells commitedto the myeloid line(WBCs,RBCs,PLTs)
Chracteristics• AML is characterized by a clonal proli-feration of myeloid precursors with areduced capacity to differentiate intomature cellular elements.• As a result,there is an accumulation ofleukemic blasts or other immatureforms in the BM,peripheral blood,andother tissues with a variable reduction inthe production of normal RBCs,platelets,and mature granulocytes.
Specific:• M2 : Chloroma:-presents as a mass lesion „tumorof leukemic cells‟• M3 : DIC• M4/M5 : Infiltration of soft tissues,gum infiltration, skin deposits ,Meningealinvolvement-headache, vomiting, eye symptoms
Bone marrow in acute leukemia• necessary for diagnosis• useful for determining type• useful for prognosis• Acute leukemias are defined by thepresence of > 20% blasts in bone marrow(% of nucleated marrow cells)
• Bone marrow aspirate & trephine:Hypercellular,– blast cells ( > 20%),– presence of Auer rods - AML type• Cytochemistry :Special stains to differentiate AML fromALL ;Positivity with Sudan black &Myeloperoxidase (MPO) in AML
WBC Count in AML• WBC count in AML can be high,normal,orlow.• Median WBC count in AML is 15 000/uL.• 20% of patients have > 100 000/uL• 25-40% of patients have <5000/uL• 95% of patients have blast cells on bloodfilm.
Distinguishing AML from ALL• light microscopy– AML: Auer rods, cytoplasmic granules– ALL: no Auer rods or granules.• flow cytometry• special stains (cytochemistry)
Cytochemical Stains• Since the early 20th century, cytochemical staining ofcells has been a useful tool in differentiatinghematopoietic diseases.• Smears and imprints made from bone marrow, lymphnodes, spleen, or peripheral blood are preferred.– In enzymatic techniques, fresh smears are used toensure optimal enzyme activity• Certain elements may be inhibited during the fixationof smears and imprints
Myeloperoxidase (MPX/MPO)• The proxidase enzyme reacts with H2O2 & release O2,which oxidizes the indicator dye and produce orange-brown granules in the cells (3-amino-9-erythrocarbazol)• Enzyme MPX is found in the 1o granules ofgranulocytes, neutrophils and precursors (from thepromyelocyte stage on) & eosinophils• Monocytes may be weakly pos• Leukemic myeloblasts are usually pos and Auer rodsstain very strongly• Used for differentiating AML (+) from ALL (-)• Normal bone marrow smear <5 days old used for controlslides (promyelocyte - neutrophils)
Myeloperoxidase(MPO)p-Phenylene diamine + Catecol + H2O2MPO > Brown black deposits
Chloracetate (Specific) EsteraseMyeloid Cell LineNaphthol-ASD-chloracetateCAE > Free naphthol compounds+ Stable diazonium salt (eg, Fast Corinth)> Red deposit
Non-Specific Esterase (NSE)• Nonspecific esterase liberates alpha-naphthyl fromthe substrate alpha-naphthyl acetate. Alpha-naphthyl is couples with the dye molecule to formdark reddish-brown granules• Monocytes, monblasts, macrophages, histiocytes,megakaryocytes and some carcinomas are NSE pos• Abnormal erythroblasts are strongly pos• Lymphocytes are neg or may show dot positivity
Non-Specific EsteraseMonocytic LineNaphthyl acetateANAE > Free naphthyl compounds+Stable diazonium salt (eg, Fast blue RR)> Brown deposits
NSE continued• Used for differentiating myelomonocytic andmonocytic leukemia (+) from granulocytic leukemia (-)• Monocyte NSE are fluoride sensitive• Peripheral smear with appreciable # of monocytes or anormal BM smear used for control slideshttp://www.healthsystem.virginia.edu/internet/hematology/hessedd/malignanthematologicdisorders/leukemias/aml-m4.cfm
Double Esterase in M4NSE with Fl inhibitionHistiocyte
Periodic Acid Schiff (PAS)• Periodic acid oxidizes glycogen, mucoproteins, andother high-molecular weight carbohydrates toaldehydes.• Aldehydes react with colorless Schiff reagent,staining them a bright red-pink• Megakaryocytes and platelets stain strongly pos• Normoblasts will stain Pos• Lymphoblasts in ALL show course and granular(block) positivity
PAS Continued• Myeloblasts are Neg• Aids in diagnosis of ALL, erythroleukemia, andmegakaryoblastic leukemia• Normal bone marrow smear used for control slideshttp://www.pathologyoutlines.com/leukemia.html
Periodic Acid SchiffPeriodic acid + Glycogenoxidation > Aldehyde + Schiff reagent(para-rosaniline, Na metabisulfite)> Red deposit
FAB Classification of ALLL1: Small homogeneous blasts; mostly inchildrenL2: Large heterogeneous blasts; mostly inadultsL3: “Burkitt” large basophilic B-cell blastswith vacuoles
WHO Classification ofLymphoproliferative Syndromes Precursor B Lymphoblastic Leukemia/Lymphoma(ALL/LBL) -- ALL in children (80-85% ofchildhood ALL); LBL in young adults and rare;FAB L1 or L2 blast morphology Precursor T ALL/LBL -- 15% of childhood ALLand 25% of adult ALL Burkitt Leukemia/Lymphoma (FAB L3)
Prognostic factors• High WBC – relapse in testis /cns• Infants <1 yr, children >10 yr poor outcome• L1- good prognosis• L2,3- bad prognosis
Prognosis• The response to treatment and overallsurvival of patients with AML areheterogenous.• Prognostic factors are related to patientand tumor characteristics:1-Age2-Performance status3- Karyotype
Adverse Clinical Predictors• Advanced age.• Poor performance status.• History of exposure to cytostatic agents orradiotherapy.(Therapy-related AML).• History of MDS or other hematologicaldiseases