■■■【1】 FAB classification of leukemias Background Organized in 1976 in an attempt to provide a uniform means of discussing the leukemias worldwide. The classifications were based on morphology and cytochemistry Laboratory Features Peripheral Blood 90%of patients have moderate to severe neutropenia 50%of patients have a leukocytosis 30%of patients have a leukopenia The blasts are of variable size 70-80%of the patients have normochromic, normocytic anemia 60%of the patients have hematocrits of <30% Thrombocytopenia is usually present Bone Marrow Blast count of ≥30% is diagnostic of acute leukemia Cytochemistry Type I, II, and III myeloblasts show ≥3% positivity of blasts for myeloperoxidase, Sudan black B, or specific esterase Monoblasts and promonocytes are positive with the nonspecific esterase Erythroblasts and megakaryoblasts are positive with the periodic acid-Schiff Type I Myeloblast Size: 10-18 μ : Nucleus Shape: Oval or round N/C Ratio: high Color: Dark purple Chromatin: Fine Nucleoli: 1-3 : Cytoplasm Color: Light to medium blue Contents Without azurophilic granules Clinical Conditions Acute myelocytic leukemia minimally differentiated (MO) Acute myelocytic leukemia without maturation (M1) Acute myelocytic leukemia with maturation (M2) Acute myelomonocytic leukemia (M4) Erythroleukemia (M6a) Myeloproliferative neoplasms-chronic myelogenous leukemia, primary myelofibrosis Type II Myeloblast Size: 10-18 μ : Nucleus Shape: Oval or round N/C Ratio: Slightly lower than type I Color: Dark purple Chromatin: Slightly more condensed than type I Nucleoli: 2-5 : Cytoplasm Color: Medium blue Contents: <20 azurophilic granules and may have Auer rods Clinical Conditions Acute myelocytic leukemia without maturation (M1) Acute myelocytic leukemia with maturation (M2) Acute myelomonocytic leukemia (M4) Erythroleukemia (M6a) Myeloproliferative neoplasms-chronic myelogenous leukemia, primary myelofibrosis Type III Myeloblast Size: 10-18 μ : Nucleus Shape: Oval or round N/C Ratio: Lower than type I Location: Centrally located Color: Dark purple Chromatin: Slightly more condensed than type II Nucleoli: Less visible : Cytoplasm Color: Medium blue Contents: >20 azurophilic granules but don't obscure the nucleus Clinical Conditions Acute myelocytic leukemia with maturation (M2) Abnormal promyelocyte Size: 18-25 μ : Nucleus Shape: Round or, more commonly, reniform or bilobed 2/N/C Ratio: 1 Color: Purple Chromatin: Relatively fine, becoming coarser Nucleoli: 2-3 varying from visible to indistinct : Cytoplasm Hypergranular type Color: Intensely basophilic Contents: Large red to purple granules; Auer rods may be numerous and intertwined, giving haystack appearance (faggot cells); may obscure the nucleus Microgranular type Color: Moderately basophilic Contents: Small, indistinct granules that are difficult to see with the light microscope; Auer rods are often found but not as abundant as those found in the hypergranular type Clinical Conditions Acute promyelocytic leukemia (M3, M3v) L1 Lymphoblast Size: 14-22 μ : Nucleus shape is regular or small cleaved and indented Purple nucleus has a homogeneous and condensed chromatin pattern Nucleoli are inconspicuous or not visible : Cytoplasm is scanty moderately basophilic and rarely vacuolated Clinical Conditions Precursor lymphoblastic leukemia L2 Lymphoblast Size: 14-22 μ : Nucleus has an irregular or indented shape N/C ratio: high Nucleus is purplish-red with variable heterogeneous chromatin One to two nucleoli are often prominent : Cytoplasm is variable but occasionally intensely basophilic and rarely vacuolated Clinical Conditions Precursor lymphoblastic leukemia L3 Lymphoblast Size: 14–18 μ : Nucleus is oval to round, is purple, and has a finely stippled and homogeneous chromatin pattern N/C ratio : slightly lower than type 2 One to two nucleoli are often prominent : Cytoplasm is intensely basophilic with prominent vacuolization Clinical Conditions Burkitt lymphoma Acute lymphoblastic leukemia (L3) Burkitt leukemia/lymphoma ■■■【2】WHO classification of leukemias Background First published in 2001, revised in 2008, and again in 2016/2017 to stratify neoplasms according to lineage using clinical features, morphology including myeloid, lymphoid, and histiocytic/dendritic cells immunophenotypes, and genetic features Laboratory features Peripheral Blood Well-stained blood smears should be examined for white blood cell, red blood cell, and platelet abnormalities Manual 200-cell leukocyte differentials are recommended Bone Marrow Aspiration and Bone Marrow Trephine Biopsy 500 nucleated bone marrow cells should be counted Cytochemistry Usually performed on peripheral blood and bone marrow aspirate smears Immunophenotype Analysis should be performed by flow cytometry on each case Differentiation antigens appear at various stages of hematopoietic development and in various myeloid and lymphoid neoplasms Genetics Specific gene abnormalities including rearrangements due to translocations, deletions, and mutations are of primary importance Performance of a cytogenetic analysis of bone marrow by conventional karyotyping should be conducted at initial evaluation and at regular intervals Molecular genetic features may be utilized for diagnosis, prognosis, and treatment purposes Definitions Agranular Blast Size: 10-18 μ : Nucleus Shape: Oval or round N/C Ratio: 6:1-7:1 Color: Dark purple Chromatin: Fine Nucleoli: 1-3 : Cytoplasm Color: Light to medium blue Contents: Without azurophilic granules Granular Blast Size: 10-18 μ : Nucleus Shape: Oval or round N/C Ratio: Slightly lower than an agranular Color: Dark purple Chromatin: Slightly more condensed than an agranular Nucleoli: 2-5 : Cytoplasm Color: Medium blue Contents: Azurophilic granules present and may have Auer rods ■■■【3】 AML (FAB classification) ■■■【3-1】 M0 (Acute Myeloid Leukemia With Minimal Differentiation) Laboratory Features Peripheral Blood Blasts are agranular Platelets are decreased Bone Marrow >30% blasts ≥20% blasts are reactive for myeloid associated antigen Myeloblasts are type I No Auer rods Blasts are negative for lymphoid-associated antigens Blasts are positive for myeloid-associated antigens Cytochemistry <3% blasts are myeloperoxidase, Sudan black B, and specific esterase (chloroacetate) positive ■■■【3-2】 M1 (Acute Myeloid Leukemia Without Maturation) Laboratory Features Peripheral Blood The predominant cell is usually a type I myeloblast Auer rods are rare Bone Marrow >30% blasts ≥90% or more of the nonerythroid cells are myeloblasts <10% promyelocytes or more mature cells of the granulocytic series Cytochemistry Myeloperoxidase and Sudan black B are positive in >3% of the blasts Naphthol AS-D chloroacetate (specific esterase) may be positive Nonspecific esterases are negative ■■■【3-3】M2 (Acute Myeloid Leukemia With Maturation) Laboratory Features Peripheral Blood Type II myeloblasts may be the predominant cell Auer rods typically present Bone Marrow >30% blasts 30-89% or more of the nonerythroid cells are myeloblasts ≥10% are promyelocytes or more mature granulocytes Blasts are predominantly type II or type III Cytochemistry ≥3% blasts are myeloperoxidase and Sudan black B positive Naphthol AS-D chloroacetate (specific esterase) positive ■■■【3-4】M3 (Acute Promyelocytic Leukemia Hypergranular Variant) 70-80% hypergranular cases are about Laboratory Features Peripheral Blood Blasts and promyelocytes show heavy granulation and multiple Auer rods White blood cell count is usually decreased <5.0 × 10⁹/L, but the range is 3.0-15.0 × 10⁹/L Auer rods range from 10 to 20 per cell (faggot cells) and the rods may be intertwined or single. Few Auer rods are possible Bone Marrow Most of the cells are abnormal promyelocytes with heavy azurophilic granulation Multiple Auer rods found in promyelocytes (faggot cells) ■■■【3-5】M3v Acute Promyelocytic Leukemia) (Microgranular Variant 20-30%of cases are microgranular Laboratory Features Peripheral Blood White blood cells are markedly increased Promyelocytes are usually bilobed and the cytoplasm contains only a few granules Bone Marrow Azurophilic granules are small and difficult to see with light microscopy (<250 nm) Promyelocytes are large with a lower N/C ratio The nucleus is usually lobulated, irregular, folded, bilobed, or monocytoid in appearance Cytochemistry Myeloperoxidase, Sudan black B, and specific esterase positive ■■■【3-6】M4 (Acute Myelomonocytic Leukemia) Laboratory Features Peripheral Blood White count is usually increased Both myelocytic and monocytic differentiations are found and ≥5 x 10⁹/L monocytes and precursors are seen Auer rods may be present Bone Marrow >30% myeloblasts, monoblasts, and promonocytes ≥20% granulocytic precursors ≥20% monocytic precursors If the bone marrow has <20% monocytic component, then it must have a peripheral blood monocytosis of ≥5 x 10⁹/L (monocytes and precursors) Blast percentage includes type I and type II myeloblasts, monoblasts, and promonocytes Cytochemistry Myeloblasts are positive for myeloperoxidase, Sudan black B, and specific esterase and negative with nonspecific esterases Monoblasts and promonocytes are negative or only slightly positive with myeloperoxidase and negative with Sudan black B Nonspecific esterase is positive and inhibited by sodium fluoride ■■■【3-7】M4eo Acute Myelomonocytic Leukemia) (With Increased BoneMarrow Eosinophila Laboratory Features Peripheral Blood WBC is usually increased (range 30 x 10⁹/L to 100 ×10⁹/L) Abnormal eosinophils are not found Myeloblasts and monoblasts present Bone Marrow ≥5% , <30% abnormal eosinophils Atypical eosinophils with possible pseudo-Pelger-Huët features in the nuclei and abnormal basophilic granules Cytochemistry Abnormal eosinophils are specific esterase and periodic acid-Schiff positive ■■■【3-8】M5a (Acute Monoblastic Leukemia) Acute leukemia with almost total monocytic dominance Laboratory Features Peripheral Blood White blood cells are usually increased Blast morphology is variable Auer rods are usually absent Bone Marrow <20% granulocytic precursors ≥80% are typically monoblasts Auer rods are usually absent Cytochemistry <20% are myeloperoxidase positive ≥80% are nonspecific esterase positive Naphthol AS-D chloroacetate negative Naphthol AS-D acetate esterase is ++++ (strong positivity) and inhibited by sodium fluoride (1+ or negative) 【3-9】M5b (Acute Monocytic Leukemia) Laboratory Features Peripheral Blood Monocytosis with the promonocyte as the predominant cell Bone Marrow ≥80% immature monocytic component with the promonocyte as the predominant cell■<20% are the granulocytic component Cytochemistry <20% are myeloperoxidase positive cells■Promonocytes may show some weak positivity with myeloperoxidase and are Sudan black B negative■ ≥80% of the cells are nonspecific esterase positive ■ ≥80% of the cells are nonspecific esterase negative with sodium fluoride inhibition ■■■【3-10】M6a (Erythroleukemia) Usually exhibits three phases and there is more myeloid involvement as the disease progresses Laboratory Features Peripheral Blood Normocytic normochromic to macrocytic/normochromic anemia Anisocytosis, poikilocytosis, basophilic stippling, and nucleated red blood cells Bone Marrow Acute and abnormal proliferation of erythroid and myeloid precursors >50% erythroblasts (all nucleated cells) ≥30% myeloblasts (nonerythroid cells) type I and type II Trilineage dysplasia common-dyserythropoiesis, dysmegakaryopoiesis, and dysgranulopoiesis Cytochemistry Periodic acid-Schiff positive in early erythrocytic precursor Myeloperoxidase and Sudan black B show >3% positive in myeloblasts ■■■【3-11】M6b (Pure Erythroid Leukemia) Erythroid cell line malignancy with no myeloid involvement Laboratory Features Peripheral Blood Usually a macrocytic anemia Platelets are decreased Bone Marrow ≥80% of the cell are of erythroid lineage (≥30% must be proerythroblastic) Cytochemistry Myeloperoxidase, nonspecific esterase, and Sudan black B negative Block positivity with the periodic acid-Schiff ■■■【3-12】M7 (Acute Megakaryoblastic Leukemia) Laboratory Features Peripheral Blood Variable white blood cell count but usually decreased Normocytic/normochromic anemia Platelets are variable, bizarre, and atypical Bone Marrow >30% blasts (usually hard to get an aspirate for quantitation of blasts) ≥50% megakaryocytic cells (megakaryoblasts, promegakaryocytes, and megakaryocytes) Megakaryoblasts are highly pleomorphic Small round cells with scant cytoplasm and dense heavy chromatin or larger vacuolated blasts Cytochemistry Myeloperoxidase and Sudan black B negative Periodic acid-Schiff positive Nonspecific esterase (acetate) positive Nonspecific esterase (butyrate) negative ■■■【4】 AML (WHO classification) Criteria Do not fit the criteria for acute myeloid leukemias with recurrent genetic abnormalities, myelodysplastic-related changes, or therapy-related acute myeloid leukemias Define criteria for the diagnosis of acute myeloid leukemias across a diverse morphologic spectrum Include the specific diagnostic criteria for pure erythroid leukemia Mutation analysis and cytogenetic studies are required before a case can be placed into this category Cytochemical studies are used to subtype the acute myeloid leukemias, not otherwise specified Subclassification is based on morphologic and cytochemical/immunophenotypic features of the leukemic cells Presence of ≥20% blasts in peripheral blood or bone marrow-bone marrow blast percentage should be determined from a 500-cell differential Peripheral blood differential should include 200 leukocytes If leukopenia is present, a buffy coat can be used Acute Myeloid Leukemia with Minimal Differentiation ■■■【4-1】 Clinical Features Pallor, fatigue, and weakness from anemia Bleeding, bruising, and petechial hemorrhages caused by thrombocytopenia Infections that fail to respond to appropriate therapy Pathology Makes up <5% of acute myeloid leukemias Patients are usually infants or older adults Laboratory Features Peripheral Blood White Blood Cells Increased in 50% of patients but may be normal or decreased Predominant cell in peripheral blood is the myeloblast Red Blood Cells Normocytic/normochromic anemia Nucleated red blood cells may be seen Platelets decreased Bone Marrow Hypercellular >20% blasts Blasts are usually of medium size with dispersed nuclear chromatin Round or slightly indented nuclei with one or two nucleoli Cytoplasm is agranular with a varying degree of basophilia Auer rods are absent Cytochemistry Myeloperoxidase, Sudan black B, and naphthol AS-D chloroacetate esterase are negative (<3% of blasts are positive) Alpha-naphthyl acetate and butyrate esterases are negative Immunophenotype Most cases express CD34, CD38, and HLA-DR CD11b, CD15, CD14, CD64, and CD65 are usually negative Negative for B- or T-cell-associated antigens Blast cells exhibit at least two myeloid markers (CD13, CD117, CD33) Genetics No specific chromosomal abnormality has been identified Acute Myeloid Leukemia without Maturation ■■■【4-2】 Clinical Features Pallor, fatigue, and weakness from anemia Bleeding, bruising, and petechial hemorrhages caused by thrombocytopenia Infections that fail to respond to appropriate therapy Pathology 5-10% of cases of acute myeloid leukemias Majority of patients are adults but it may occur at any age Laboratory Features Peripheral Blood White Blood Cells Usually increased but may be normal or decreased Predominant cell in peripheral blood is a myeloblast Red Blood Cells Normocytic/normochromic anemia Nucleated red blood cells may be seen Platelets decreased Bone Marrow Hypercellular ≥20% blasts >90% are myeloblasts Myeloblasts may have azurophilic granules and/or Auer rods Cytochemistry Myeloperoxidase and Sudan black B are positive in a variable number of blasts but more than 3% Nonspecific esterases are negative Immunophenotype Cells express one or more of the following: CD13, CD33, and CD117 CD34 and HLA-DR may be positive; CD15, CD65, CD14, and CD64 are negative Genetics There are no specific associated abnormalities Acute Myeloid Leukemia with ■■■Maturation 【4-3】 Clinical Features Pallor, fatigue, and weakness from anemia Bleeding, bruising, and petechial hemorrhages caused by thrombocytopenia Infections that fail to respond to appropriate therapy Pathology Accounts for about 10% of cases of acute myeloid leukemias Occurs at any age but about 20% are <25 years of age and 40% ≥60 years of age Laboratory Features Peripheral Blood White Blood Cells count is variable ≥20% blasts in peripheral blood and 10% or more of the cells show granulocyte maturation <20% are of the monocyte lineage Red Blood Cells Normocytic/normochromic anemia Platelets usually decreased Bone Marrow Hypercellular >20% blasts with or without azurophilic granulation and Auer rods are common Maturation indicated by promyelocytes and more mature granulocytic forms present in ≥10% of nucleated cells Dysplasia if often present but ≤50% of cells in two lineages Eosinophil precursors may be present but do not have the cytologic abnormalities Basophils or mast cells may be slightly increased Cytochemistry Myeloperoxidase and Sudan black B positive Specific esterase positive Immunophenotype Expression of one or more of the following: CD13, CD33, CD65, CD11b, and CD15 CD14 and CD64 are usually absent Genetics No association with recurrent genetic abnormalities ■■■【4-4】Acute Myelomonocytic Leukemia Clinical Features Pallor, fatigue, and weakness from anemia Bleeding bruising, and petechial hemorrhages caused by thrombocytopenia Infections that fail to respond to appropriate therapy Bone tenderness, hepatosplenomegaly, and lymphadenopathy Infiltration of leukemia cells in extramedullary sites Gingival hyperplasia is found in some cases Pathology Accounts for about 5-10% of cases of acute myeloid leukemias Occurs in all age groups but is more common in individuals over 50 years of age Male to female ratio is about 1.4:1 Laboratory Features Peripheral Blood White Blood Cells Count is usually increased Both myelocytic and monocytic differentiation occurs High number of monocytic cells may be present Red Blood Cells Normocytic/normochromic anemia Platelets Decreased but may be normal Bone Marrow ≥20% blasts (including promonocytes) ≥20% neutrophils and precursors Scattered fine azurophil granules, vacuoles, and Auer rods may be present >20% monocytes and precursors Monoblasts are large cells with abundant cytoplasm that is moderately to intensely basophilic and may have pseudopod formation Promonocytes have irregular and delicately convoluted nuclear configuration; cytoplasm is usually less basophilic and more granulated with occasional large azurophilic granules and vacuoles Cytochemistry Myeloblasts are positive for myeloperoxidase (at least 3%), Sudan black B, and specific esterase and negative with nonspecific esterases Monoblasts are negative for myeloperoxidase and Sudan black B Monoblasts are positive for nonspecific esterases Immunophenotype Positive for myeloid antigen-CD13 and CD33 Positive for monocytic markers-CD14, CD4, CD11b, CD64, and CD36 Genetics Nonspecific cytogenetic abnormality but +8 is present in the majority of cases Acute Monoblastic Monocytic Leukemia ■■■【4-5】 Clinical Features Bleeding disorders are the most common presentation Gum hyperplasia Splenomegaly Infections Extramedullary involvement: lymph nodes, liver, skin, spleen, central nervous system Pathology Accounts for <5% of acute myeloid leukemias More common in young individuals The male to female ratio is 1.8:1 Laboratory Features Peripheral Blood White Blood Cells Usually increased • ≥20% blasts (including promonocytes) Blast morphology is variable Monoblasts are the predominant cells in the monoblastic type Promonocytes are the predominant cells in the monocytic type Red Blood Cells Normocytic/normochromic anemia Platelets Decreased Bone Marrow Hypercellular ≥20% blasts ≥80% of the cells are of the monocytic lineage including monoblasts, promonocytes, and monocytes • <20% are of the neutrophilic origin • In acute monoblastic leukemia, the majority of the cells are monoblasts • In acute monocytic leukemia, the majority of the cells are promonocytes Cytochemistry • Myeloperoxidase is typically negative or very weakly positive Nonspecific esterase is typically positive Immunophenotype • Variable expression of CD13, CD33, CD15, and CD65 • At least two of the following markers are present: CD14, CD4, CD11b, CD11c, CD64, CD68, CD36, and lysozyme Genetics • Nonspecific cytogenetic abnormalities are present in most cases ■■■【4-6】Pure Erythroid Leukemia Clinical Features Weakness, fatigue, weight loss, fever • Hepatosplenomegaly Petechiae, purpura Pathology Neoplastic proliferation of immature cells committed to erythroid lineage • Pure erythroid leukemia is very rare and can occur at any age Laboratory Features Peripheral Blood White Blood Cells Count is variable Red Blood Cells • Normocytic/normochromic to macrocytic/normochromic anemia Anisocytosis and poikilocytosis Basophilic stippling Nucleated red blood cells Platelets Variable Bone Marrow >80% of cells are erythroid with ≥30% proerythroblasts • If the neoplastic erythroblasts occur in sheets, erythroblasts may constitute <80% of the cells, but proerythroblasts should constitute ≥30% of the cells • No significant myeloblastic component • Dysmegakaryopoiesis is common Ring sideroblasts may be present • Presence of medium- to large-sized erythroblasts containing round nuclei, fine chromatin, and one or more nucleoli • Cytoplasm is deeply basophilic Cytochemistry Negative for myeloperoxidase and Sudan black B Periodic acid-Schiff, alpha-naphthyl acetate esterase, and acid phosphatase positive Immunophenotype • Erythroid precursors are for hemoglobin A, glycophorin, and CD117 HLA-DR and CD34 are negative Genetics No specific chromosomal abnormalities are described • Multiple structural abnormalities are commonly found such as -5/del(5q) and -7/del(7q) Acute Megakaryoblastic ■■■【4-7】Leukemia Clinical Features Pale, fatigue, and weakness from anemia Bleeding, bruising, and petechial hemorrhages caused by thrombocytopenia • Infections that fail to respond to appropriate therapy Pathology Accounts for <5% cases of the acute myeloid leukemias Occurs in both adults and children Laboratory Features Peripheral Blood White Blood Cells Variable but usually decreased Red Blood Cells • Normocytic/normochromic anemia Platelets Count is variable and may be normal or increased Bizarre and atypical forms Bone Marrow Megakaryoblasts are highly pleomorphic • Medium-sized to large blasts with a round, slightly irregular or indented nucleus with fine reticular chromatin and 1-3 nucleoli Cytoplasm is basophilic and mostly agranular with distinct blebs or pseudopods Increased reticulum fibrosis may result in a dry tap • >20% blasts in which ≥50% are of the megakaryocytic lineage Cytochemistry • Myeloperoxidase and Sudan black B negative Periodic acid-Schiff positive Nonspecific esterase (acetate) positive Nonspecific esterase (butyrate) negative Immunophenotype Expression of one or more of the following: CD41 or CD61 or CD42b Genetics No specific chromosomal abnormalities are associated Acute Panmyelosis witb Myelofibrosis (APMF) ■■■【4-8】 Clinical Features • Weakness, fatigue, fever, and bone pain Rapidly progressive • Pancytopenia is present Pathology Very rare form of acute myeloid leukemias Occurs de novo • Primarily affects adults Laboratory Features Peripheral Blood White Blood Cells Count is decreased Dysplasia is common Red Blood Cells Normocytic/normochromic anemia-variable macrocytosis Platelets Count is decreased Abnormal forms are observed Bone Marrow >20% blasts Hypercellular • Increased fibrotic stroma, resulting in inadequate sample Increased erythroid, granulocyte, and megakaryocyte precursors Megakaryocytes are typically dysplastic Cytochemistry Myeloperoxidase is negative Immunophenotype Blasts are usually positive for CD34 and one or more of the following: CD13, CD33, and CD117 Genetics Usually abnormal involving chromosome 5 and/or 7 ■■■【 4-9 】Myeloid Sarcoma Criteria Tumor mass consisting of myeloid blasts with or without maturation Occurring at sites other than bone marrow Clinical Features Tumors that occur in any site in the body such as skin, lymph nodes, gastrointestinal tract, bone, soft tissue, and testes Pathology Most tumors occur as de novo neoplasms 1/4 of cases occur in the absence of an underlying acute myeloid leukemia or other myeloid neoplasms 8-20% of cases have undergone allogeneic stem cell transplantation May be the initial manifestation of relapse in a patient with previously diagnosed acute myeloid leukemias • Can be associated with simultaneous or previously treated non-Hodgkin lymphoma Laboratory Features Peripheral Blood White Blood Cells Normal to increased Blasts may be present Red Blood Cells Normal to decreased Platelets Normal to decreased Bone Marrow Blasts may be present Biopsy Consists of myeloblasts with or without maturation • In some cases, it displays myelomonocytic or pure monoblastic morphology • Rare tumors consist of erythroid precursors or megakaryoblasts but can be seen in blast transformation of myeloproliferative neoplasm Cytochemistry • Granulocytic lineage shows myeloperoxidase and naphthol AS-D chloroacetate esterase (CAE) positivity • Monoblastic forms show nonspecific esterase positivity Immunophenotype • Immature myeloid profiles express CD33, CD34, CD68, and CD11 • Myelomonocytic tumors are positive for CD66/KP1 with MPO and CD68/PGM1 in populations that are CD34 negative Monoblastic tumors are positive for CD66/PGM1 and CD163 and lack MPO and CD34, CD14, and KLF4 Genetics 55% of cases have chromosome aberrations • Monosomy 7; trisomy 8; KMT2A rearrangement; inv(16); trisomy 4; monosomy 16; loss of 16q, 5q, or 20q; and trisomy 11 16% of cases carry NPM1 mutations With Recurrent Genetic Abnormalites ■■■【4-10】 Criteria Clonal hematopoietic neoplasms When there is an associated t(8;21)(q22;q22.1), inv(16)(p13.1q22) or t(16;16)(p13.1;q22) chromosomal abnormality or t(15;17)(q22;q11-12); PML-RARA fusion, the blast count in peripheral blood and/or bone marrow may be <20% for the diagnosis of acute leukemia >20% blasts Classification Acute Myeloid Leukemia With Balanced Translocations/Inversions Most commonly identified are balanced abnormalities These structural chromosomal rearrangements create a fusion gene A# : Acute myeloid leukemia with t(8;21)(q22;q22.1); RUNX1-RUNX1T1 B# :Acute myeloid leukemia with inv(16)(p13.1q22) or t(16;16)(p13.1;q22); CBFB-MYH11 C# :Acute promyelocytic leukemia with t(15;17) (q22;q11-12); PML-RARA D# :Acute myeloid leukemia with t(9;11)(p21.3;q23.3); KMT2A-MLLT3 E# :Acute myeloid leukemia with t(6;9)(p23;q34.1); DEK-NUP214 F# :Acute myeloid leukemia with inv(3) OR t(3;3) (q21.3;q26.2); GATA2, (q21.3q26.2) MECOM G# :Acute Myeloid Leukemia(Megakaryoblastic) With t(1;22) p(13.3;q13.1);RBM15-MKL1 Acute Myeloid Leukemia With Gene Mutations Translocations and inversion mutations are common in acute myeloid leukemias H# :NPM1 I# :Biallelic CEBPA RUNX1 (provisional) A# :Acute Myeloid Leukemia With t(8;21)(q22;q22.1); RUNX1-RUNX1T1 Clinical Features Myeloid sarcomas may be present at the time of diagnosis Weakness and pallor associated with anemia Bleeding due to decreased platelet count • Infection if neutropenia exists Pathology Translocations result in a fusion of RUNX1-RUNX1T1 Found in 10-15% or pediatric cases of acute myeloid leukemias Found in about 7% of adult cases of acute myeloid leukemias Occurs predominantly in younger people Shows maturation in the neutrophilic lineage Down-regulates normal transcriptional activity Laboratory Features Peripheral Blood White Blood Cells Large blasts with abundant basophilic cytoplasm Smaller blasts may be present Auer rods are common with abnormally long pointed ends Granular myeloblasts may be the predominant cell Dysplasia in granulocytes Red Blood Cells Anemia may be present Platelets May be decreased Bone Marrow Typically hypercellular >20% blasts If the 8;21 translocation is present, may have <20% blasts for a diagnosis Some blasts may show pseudo-Chediak-Higashi granules Large salmon-colored granules in some blasts Auer rods are frequently found with long pointed ends • Blasts may show a hof next to the nucleus Granulocytic series show variable dysplasia Eosinophil precursors are frequently increased but don't have cytoplasmic granule abnormalities Cytochemistry Myeloblasts myeloperoxidase positive Immunophenotype Weak expression of CD33 Will also show CD34, MPO, HLA-DR, CD13, and CD15 • If CD56 is present, it indicates a poorer prognosis Genetics Balanced abnormalities of t(8;21)(q22;q22.1) Additional chromosomal abnormalities can be seen in approximately 70% of the cases ASXL1 mutations occur in approximately 10% patient, mostly adults ASXL2 mutations occur in 20-25% of patients of all ages B# :Acute Myeloid Leukemia With inv(16)(p13.1q22) or t(16;16) (p13.1;q22); CBFB-MYH11 Clinical Features Occurs at all age groups but more likely in younger patients Myeloid sarcomas may be present Pallor, fatigues, and weakness from anemia Bleeding, bruising, and petechial hemorrhages caused by thrombocytopenia Bone tenderness, hepatosplenomegaly, and lymphadenopathy Pathology Found in about 5-8% of all patients with acute myeloid leukemias Shows acute myelomonocytic leukemia Exhibits an abnormal eosinophilic component in the bone marrow CBFB-MYH11 molecular fusion Laboratory Features Peripheral Blood White Blood Cells Variable white blood cell count Neutropenia Variable blast count Monoblasts, promonocytes, and myeloblasts are present Absolute monocytosis common Red Blood Cells Normocytic/normochromic anemia Platelets Decreased Bone Marrow ≥20% blasts If inv(16) or t(16:16) translocation is present, may have <20% blasts for a diagnosis Predominant myelomonocytic and abnormal eosinophilic component Decreased number of mature neutrophils Variable number of eosinophils but usually increased and at all stages of maturation Eosinophilic granules are larger than normal and have an intense basophilic purple-violet color in eosinophilic precursors (Harlequin cell) Auer rods may be seen in myeloblasts Cytochemistry Naphthol AS-D chloroacetate esterase is positive in the abnormal eosinophils Periodic acid-Schiff is positive in the abnormal eosinophils Myeloblasts are myeloperoxidase positive Monoblasts and promonocytes usually show nonspecific esterase positive Immunophenotype Complex with the presence of multiple blast populations • Increased myeloblasts show CD34, CD117, and CD33 • Monocytic cells show CD36, CD64, CD33, HLA-DR, CD14, and CD45 Genetics Inv(16)(p13.1q22) found in the majority of cases t(16;16)(p13.1;q22) found less commonly Abnormal genetics rearrangements result in the fusion of the CBFB gene to the MYH11 gene C# : Acute Promyelocytic Leukemia (APL) With t(15;17)(q22;q11-12); PML-RARA Clinical Features Associated with disseminated intravascular coagulation (DIC) and increased fibrinolysis Pallor, fatigue, and weakness Pathology Occurs in about 5-8% of the acute myeloid leukemia cases in younger patients Occurs at any age but most cases are young to middle- aged adults Hypergranular and microgranular (hypogranular) forms exist Laboratory Features-Hypergranular Type Peripheral Blood White Blood Cells Low count in hypergranular type ≥20% blasts (promyelocytes included in blast count) If the 15;17 translocation is present, may have <20% blasts for a diagnosis Count markedly elevated with numerous abnormal microgranular promyelocytes showing reniform, irregular, or bilobed nuclei in hypogranular type Red Blood Cells Normocytic/normochromic anemia Platelets Decreased Bone Marrow >20% blasts The nucleus in the abnormal promyelocytes is irregular and often kidney-shaped or bilobed Large granules in the cytoplasm of the promyelocytes are dense and stain a deep blue or purple Promyelocytes may have bundles of Auer rods randomly distributed in the cytoplasm (faggot cells) Laboratory Features-Microgranular (Hypogranular) Type Peripheral Blood White Blood Cells Count markedly elevated with numerous abnormal microgranular promyelocytes showing reniform, irregular, or bilobed nuclei Red Blood Cells Normocytic/normochromic anemia Platelets Decreased Bone Marrow ≥20% blasts (promyelocytes included in blast count) • If the 15;17 translocation is present, may have <20% blasts for a diagnosis Predominantly bilobed and irregular nucleus in promyelocytes Cytoplasmic granules are present but smaller than the resolution of the microscope and so appear absent or decreased in number A small number of promyelocytes will demonstrate clearly visible granules and bundles of Auer rods (faggot cells) Cytochemistry Myeloperoxidase is strongly positive in promyelocytes Specific esterase is strongly positive in 75% of cases Nonspecific esterase is typically negative but may be weakly positive Immunophenotype Hypergranular type shows bright expression of CD13, CD33, and CD17 in most cases Absence of CD34, HLA-DR, and CD117 is a typical finding CD15 and CD65 are weak or negative If CD56 is present, it is a worse prognosis • In the microgranular type, there is a frequent expression of CD34 and CD2 Genetics t(15;17)(q24.1;q21.2) Translocation results in the fusion of the RARA gene and the PML gene D# : Acute Myeloid Leukemia With t(9;11)(p21.3;q23.3); KMT2A-MLLT3 Clinical Features Patients may present with disseminated intravascular coagulation May have extramedullary myeloid sarcomas and/or tissue infiltration in gingiva and/or skin Pathology Occurs at any age but is more common in children Constitutes about 9-12% of pediatric and 2% of adult leukemias Laboratory Features White Blood Cells Count may be low or high ≥20% circulating monoblasts and promonocytes Variable % of myeloblasts Auer rods are usually absent Red Blood Cells • Normocytic/normochromic anemia Platelets Decreased Bone Marrow Hypercellular >20% blasts • Monoblasts and promonocytes typically predominate (>80% nucleated cells) Monoblasts are large with abundant intensely basophilic cytoplasm and may have pseudopod formation Monoblasts may have fine azurophilic granules and vacuoles Monoblasts usually contain round nuclei with delicate chromatin Promonocytes have a less basophilic cytoplasm but the nuclei are more irregular Cytochemistry Nonspecific esterase reaction is strongly positive for monocytic lineage • Monoblasts are myeloperoxidase negative Immunophenotype Strong expression of CD33, CD65, CD4, and HLA-DR • Monocytic markers, CD14, CD11b, CD11c, CD64, and CD36, may be present Genetics • t(9;11)(p21.3;q23.3) • Translocations cause fusion genes of MLLT3 and KMT2A E# :Acute Myeloid Leukemia With t(6;9) (p23;q34.1); DEK-NUP214 Clinical Features Patients may present with a pancytopenia but usually present with anemia and thrombocytopenia Pathology • DEK-NUP214 fusion causes altered nuclear transportation and aberrant transcription factor • Occurs in both children and adults • Associated with any subtype of acute myeloid leukemia except promyelocytic and megakaryocytic leukemias • The most common are myelomonocytic leukemia and leukemia with maturation Laboratory Features White Blood Cells ≥20% peripheral or bone marrow blasts • Count is usually lower than other acute myeloid leukemias (about 12 x 109/L) • ≥2% basophilia • Granulocytic dysplasia Red Blood Cells • Normocytic/normochromic anemia Platelets Decreased Bone Marrow >20% blasts • Auer rods may be present Granulocytic and erythrocytic dysplasia • ≥2% basophilia Ring sideroblasts are present in some cases Cytochemistry • Myeloperoxidase reaction is strong Nonspecific esterase is positive if a monocytic component is present in the leukemia Immunophenotype • Expression of CD9, CD13, CD33, CD38, CD123, and HLA-DR • May have the CD64 monocytic marker Genetics ⚫t(6;9)(p23;q34.1) • Translocation results in the fusion of DEK and NUP214(CAN) F# : Acute Myeloid Leukemia With inv(3) (q21.3q26.2) OR t(3;3) (q21.3;q26.2); GATA2, MECOM Clinical Features Most patients present with anemia and a normal platelet count Normal platelet count but 7-22% have thrombocythemia • Some patients have hepatosplenomegaly Pathology Occurs most commonly in adults Laboratory Features White Blood Cells ≥20% peripheral blood blasts Hypogranular neutrophils with pseudo-Pelger-Huët anomaly Red Blood Cells • Normocytic/normochromic anemia. Platelets Count may be normal or elevated ⚫ Giant and hypogranular Bone Marrow >20% blasts • Increased megakaryocytes but atypical or dysplastic Megakaryocytes may be small and mono- or bilobed Basophils, eosinophils, and mast cells may be increased • Multilineage dysplasia is seen Immunophenotype ⚫ Blasts cells usually express CD13, CD33, HLA-DR, CD34, and CD38 Megakaryocytic markers of CD41 and CD61 may be expressed Genetics A variety of abnormalities of the long arm of chromosome 3 but inv(3)(q21.3q26.2) and t(3;3) (q21.3;q26.2) are the most common • The abnormalities involve the oncogene MECOM • GATA2 enhances the activation of MECOM G# :Acute Myeloid Leukemia (Megakaryoblastic) With t(1;22) (p13.3;q13.1); RBM15-MKL1 Clinical Features Cases usually restricted to infants and children <3 years of age • Marked hepatosplenomegaly Often presents with anemia and thrombocytopenia Pathology Represents <1% of cases of acute myeloid leukemias Commonly in infants without Down syndrome with a female predominance Laboratory Features White Blood Cells Moderately elevated Red Blood Cells Normocytic/normochromic anemia Platelets Variable Bizarre and atypical forms Bone Marrow >20% blasts • Small and large megakaryoblasts may be present but are usually of medium to large size Megakaryocytes have basophilic, agranular cytoplasm showing pseudopod formation Megakaryocyte nuclei are irregular or indented Cytochemistry • Sudan black B and myeloperoxidase reactions are negative Periodic acid-Schiff may be positive Immunophenotype Expression of CD41, CD42b, and/or CD61 CD13 and CD33 may be positive CD34, CD45, and HLA-DR are often negative Genetics ⚫ In most cases, t(1;22)(p13.3;q13.1) is the sole. karyotypic abnormality ⚫ A fusion gene is produced (RBM15-MKL1) H# :Acute Myeloid Leukemia With Mutated NPM1 Clinical Features Patients usually have no history of myelodysplastic syndromes or myeloproliferative neoplasms • May present with anemia and thrombocytopenia May have infiltration of gingiva, lymph nodes, and skin Pathology Accounts for 2-8% of childhood and 27-35% of adult acute myeloid leukemia cases About 80-90% of acute monocytic leukemias show NPM1 mutation Laboratory Features White Blood Cells Count is usually high Red Blood Cells Normocytic/normochromic anemia Platelets Higher platelet count than other acute myeloid leukemias without NPM1 mutation Bone Marrow >20% blasts Multilineage involvement but monocytic or myelomonocytic is common Cytochemistry Specific to the cell lines involved Immunophenotype • Expression of CD13, CD33, and possibly CD14, CD11b, and CD68 Genetics Mutated NPM1 Usually associated with a normal karyotype I# :Acute Myeloid Leukemia With Biallelic Mutation of CEBPA Clinical Features Usually presents de novo Pathology • Occurs in about 6-15% of de novo acute myeloid leukemias Occurs in about 15-18% of acute myeloid leukemias with normal karyotypes Laboratory Features White Blood Cells Count is typically increased Red Blood Cells • Normocytic/normochromic anemia but hemoglobin is higher than in most leukemias Platelets Numbers decreased Bone Marrow >20% blasts • Most are associated with acute myeloid leukemias with or without maturation Some cases have monocytic or myelomonocytic features Cytochemistry Myeloperoxidase or Sudan black B is positive if a myeloblast component is present Nonspecific esterase is positive when a monocytic population is present Immunophenotype • Blasts usually express one or more of the following: CD13, CD33, CD65, CD11b, and CD15 • The majority of blasts express HLA-DR and CD34 Genetics • Biallelic mutation of CEBPA Approximately 70% of the cases have a normal karyotype • ACUTE MYELOID LEUKEMIAS WITH MYELODYSPLASIA-RELATED CHANGES Criteria ≥20% blasts in peripheral blood or bone marrow • Morphologic features of multilineage dysplasia Occurring in patients with a prior history of myelodysplastic syndrome or myelodysplastic/myeloproliferative neoplasm, with myelodysplastic-related cytogenic abnormalities Specific genetic abnormalities characteristic of acute myeloid leukemia with recurrent genetic abnormalities absent • No history of prior cytotoxic or radiation therapy Clinical Features Often presents with severe pancytopenia Pathology • Makes up about 24-35% of all cases of acute myeloid leukemias ⚫ Occurs mainly in elderly patients Dysplasia in ≥50% of the cells in at least two hematopoietic cell lines Laboratory Features White Blood Cells Dysgranulopoiesis in peripheral blood and bone marrow • Neutrophils with hypogranular cytoplasms and hyposegmented or bizarrely segmented nuclei Red Blood Cells • Decreased Platelets • Decreased Bone Marrow • >20% blasts • Dyserythropoiesis • Megaloblastosis, karyorrhexis and clear irregularity, fragmentation, or multinucleation Ring sideroblasts, cytoplasmic vacuoles Dysmegakaryopoiesis Micromegakaryocytes and normal-sized or large megakaryocytes with nonlobulated or multiple nuclei Cytochemistry Periodic acid-Schiff may be positive in dysplastic erythroid precursors Prussian blue demonstrates ring sideroblasts Immunophenotype Variable results due to the heterogeneity of the underlying genetic changes • Increase in CD14 expressions on blasts is related to a poor prognosis Genetics Gain or loss of major segments of certain chromosomes with complex karyotype (≥3 abnormalities) ⚫ THERAPY-RELATED MYELOID NEOPLASMS Criteria • Therapy-related cases of acute myeloid leukemia (t- AML), myelodysplastic syndromes (t-MDS), and myelodysplastic/myeloproliferative neoplasms (t- MDS/MPN) that occur as a late complication of cytotoxic chemotherapy and/or radiation therapy applied to prior disorders Clinical Features Commonly occurs 5-10 years after exposure to alkylating agents and/or ionizing radiation • Presents with an MDS with marrow failure and one or more cytopenias Pathology • Accounts for 10-20% of all cases of acute myeloid leukemias, myelodysplastic syndromes, and myelodysplastic/myeloproliferative neoplasms • About 70% of cases have been treated for solid tumors About 30% of cases have been treated for hematologic tumors Laboratory Features White Blood Cells • Dysplastic changes in neutrophils with abnormal nuclear segmentation and hypogranular cytoplasm • Basophilia is frequently present Red Blood Cells Decreased Macrocytosis and poikilocytosis Platelets May be decreased Bone Marrow • >20% blasts Hypercellular, normocellular, or hypocellular • Reticulin fibrosis is common • Multilineage dysplasia Immunophenotype No specific immunophenotypic findings Genetics The leukemic cells of >90% of patients show an abnormal karyotype that correlates with the latent period between the initial therapy and the onset of the leukemic disorder and the cytotoxic agent • About 70% of cases harbor unbalance chromosomal aberrations—partial loss of 5q, loss of chromosome 7, or deletion of 7q associated with one or more additional chromosomal abnormalities MYELOID PROLIFERATIONS ASSOCIATED WITH DOWN SYNDROME Criteria • Ratio of lymphoblastic leukemia to acute myeloid leukemia in children aged >4 years with Down syndrome is 1.0:1.2 There is a 150-fold increase in acute myeloid leukemias in children aged >5 years with Down syndrome 70% of cases are acute megakaryoblastic leukemia TRANSIENT ABNORMAL MYELOPOIESIS ASSOCIATED WITH DOWN SYNDROME Clinical Features Symptoms are usually the same as those of acute myeloid leukemias and usually diagnosed at age 3-7 days May have jaundice, ascites, respiratory distress, bleeding, and pericardial or pleural effusions Hepatosplenomegaly is often present Pathology Unique disorder of newborns with Down syndrome • Diagnosed in approximately 10% of newborns with Down syndrome • Undergoes spontaneous remission within the first 3 months of life 20-30% of children develop acute myeloid leukemias 1-3 years later Laboratory Features White Blood Cells • May be marked leukocytosis Increased basophils % of blasts may exceed the blast % in bone marrow Red Blood Cells Anemia Platelets Decreased Bone Marrow >20% blasts Blasts often have basophilic cytoplasm with coarse basophilic granules and cytoplasmic blebbing suggestive of megakaryoblasts • Erythroid and megakaryocytic dysplasia Cytochemistry Granules in blasts are myeloperoxidase negative Immunophenotype ⚫ Blasts are positive for CD34, CD117, CD13, CD33, HLA- DR, CD41, CD42, CD110 (TPOR), IL3R, CD36, CD61, and CD71 Negative for CD15, CD14, CD11a, and glycophorin A • 50% are negative for CD34 Genetics Trisomy 21 and acquired mutations of the gene encoding GATA1 in blast cells • MYELOID LEUKEMIA ASSOCIATED WITH DOWN SYNDROME Clinical Features • Manifests predominantly in the first 3 years of life If <20% blast cells in the bone marrow appears to be relatively indolent present with complications due to thrombocytopenia Pathology Occurs in 20-30% of children with a history of transient abnormal myelopoiesis (TAM) and the leukemia usually occurs 1-3 years after TAM • About 1-2% of children with Down syndrome develop acute myeloid leukemia during first 5 years of birth Down syndrome patients account for 20% of all pediatric patients with acute myeloid leukemias/myelodysplastic syndromes Laboratory Features White Blood Cells Decreased ⚫ Blasts may be present Red Blood Cells Macrocytic anemia • Anisopoikilocytosis Erythroid precursors may be seen Dacryocytes Platelets Decreased Giant platelets may be seen Bone Marrow >20% blasts ⚫ Blasts have slightly irregular to round nucleus A variable number of blasts contain coarse granules Cytoplasm of blasts is basophilic and blebs are usually present Erythroid precursors may show megaloblastic and dysplastic changes Dysgranulopoiesis may also be present Megakaryocytic series is extremely dysplastic Cytochemistry • Granules in blasts are myeloperoxidase positive Immunophenotype • Blasts are positive for CD117, CD13, CD33, CD7, CD4, CD42, TPO-R, IL-3R, CD36, CD41, CD61, and CD71 Negative for CD15, CD14, and glycophorin A 50% are negative for CD34 Genetics Trisomy 21 and somatic mutations of the gene encoding GATA1 13-44% of cases have trisomy 8 ACUTE LYMPHOBLASTIC LEUKEMIA NOS FAB CLASSIFICATION L1 (Precursor Lymphoblastic Leukemia) Mutation of a single lymphoid stem cell causing proliferation of malignant lymphoblasts Laboratory Features Peripheral Smear : White blood cells may be increased decreased or normal■Normocytic/normochromic anemia■Decreased platelets Bone Marrow : Hypercellular■≥25% blasts that are predominantly small blasts, up to twice the size of a normal small lymphocyte, nucleoli are not present and the cytoplasm is scant and only slightly or moderately basophilic Cytochemistry : Sudan black B, peroxidase, specific esterase, and nonspecific esterase are negative■Large block positivity with the periodic acid-Schiff ■Focal positivity with acid phosphatase in T-cell blasts ■ Terminal deoxynucleotidyl transferase is positive in 90- 95% in L1 and L2 and negative in L3 =========================== L2 (Precursor Lymphoblastic Leukemia) Mutation of a single lymphoid stem cell causing proliferation of malignant lymphoblasts Laboratory Features Peripheral Blood : White blood cells may be increase decreased or normal■Normocytic/normochromic anemia■Platelets are often decreased Bone Marrow : The blasts are larger than L1, heterogeneous in size, the nucleus is irregular with clefting, and nucleoli are present Cytochemistry : Sudan black B, peroxidase, specific esterase, and nonspecific esterase negative■Large block positivity with the periodic acid-Schiff■Focal positivity with acid phosphatase in T-cell blasts■ Terminal deoxynucleotidyl transferase is positive in 90- 95% in L1 and L2 and negative in L3 =========================== L3 (Burkitt Type) The lymphoblasts are similar in appearance to those found in Burkitt lymphoma.Constitutes about 3-4% of precursor lymphoblastic leukemias in children and adults Laboratory Features Peripheral Blood : White blood cells may be increased decreased or normal■ Normocytic/normochromic anemia■Decreased platelets are often seen■ Blasts are larger than L1 and have round to oval nucleoli with fine, homogenous chromatin, and one or more nucleoli may be seen■Cytoplasm of the blasts is deeply basophilic and vacuolated Bone Marrow : Hypercellular with blasts that are larger than L1, have a round-to oval-shaped nucleus with fine, homogenous chromatin, and one or more nucleoli present■Cytoplasm of the blasts is deeply basophilic and vacuolated Cytochemistry : Sudan black B, peroxidase, specific esterase, and nonspecific esterase negative■Periodic acid-Schiff negative■ Terminal deoxynucleotidyl transferase negative ■Oil red O positive ============================== ACUTE LYMPHOBLASTIC LEUKEMIA WHO CLASSIFICATION Criteria • ≥20% or 25% (WHO) bone marrow blast countMorphology and immunophenotype are sufficient for the diagnosis of most lymphoid neoplasms • No one antigenic marker is specific for any neoplasm, and a combination of morphologic features and a panel of antigenic markers are necessary for correct diagnosis Most B-cell lymphomas have characteristic immunophenotypic profiles that are very helpful in diagnosis Immunophenotypic profiling is somewhat less helpful in the subclassification of T-cell lymphomas • Genetic features are playing an increasingly important role in the classification of lymphoid malignancies. They are valuable tools to determine the clonality in B- cell and T-cell proliferations. • Precursor lymphoid neoplasms are primarily diseases of children • Infectious agents have been shown to contribute to the development of several types of mature B-cell, T-cell, and NK-cell lymphomas B-Lymphoblastic leukemia NOS Clinical Features Patients usually present with anemia, thrombocytopenia, and/or infections • Lymphadenopathy, hepatomegaly, and splenomegaly are common • Bone pain is a prominent feature Pathology • Acute lymphoblastic leukemia is primarily a disease of children under 6 years of age but also can occur at any age • 80-85% are B-cell precursor types B-lymphoblastic leukemia/lymphoma accounts for about 10% of lymphoblastic lymphomas, and the rest are of T lineage Laboratory Features White Blood Cells • May be decreased, normal, or increased Red Blood Cells • Normocytic/normochromic anemia Platelets • Decreased Bone Marrow • Small to medium-sized blasts with scanty cytoplasm to larger blasts with a lower N/C ratio and irregular nuclear outline • Nuclei are moderately condensed to dispersed and nucleoli are inconspicuous Cytochemistry Myeloperoxidase negative • Periodic acid-Schiff and TdT positive Immunophenotype • Positive for CD19, CD10, CD24, CD79a, CD22, PAX5, and nuclear TdT Genetics Most cases have a rearrangement of IGH Nonspecific genetic abnormalities Diagnostic Scheme T-Lymphoblastic leukemia Clinical Features Presents with high white count and may have mediastinal mass Skin, tonsils, liver, spleen, central nervous system, and testes may be involved Pathology Neoplasm of lymphoblasts committed to the T-cell lineage Makes up about 15% of childhood acute lymphoblastic leukemia Is more common in adolescents than younger children Laboratory Features White Blood Cells Usually high count Red Blood Cells Normocytic/normochromic anemia Platelets Decreased Bone Marrow Medium-sized blast cells with a high N/C ratio, a scant cytoplasm, and usually an irregular nuclear outline Chromatin in the nucleus is condensed to dispersed and nucleoli are inconspicuous Lymphoblasts are indistinguishable from those of the B-lymphoblastic leukemia/lymphoma type The number of mitotic figures is higher than in B- lymphoblastic leukemia/lymphoma Cytochemistry • Show focal acid phosphatase positivity Immunophenotype Usually TdT positive and may express CD1a, CD2, CD3, CD4, CD5, CD7, and CD8 CD7 and CCD3 are expressed the strongest Genetics • Most cases show rearrangements of the TR gene About 20% of cases also show the presence of IGH gene rearrangements • 50-70% of cases have an abnormal karyotype involving the alpha and delta TR loci at 14q11.2, the beta locus at 7q35, and the gamma locus at 7p14-15 WITH RECURRENT GENETIC AABNORMALITIES Laboratory Features : Peripheral Blood White blood cells May be decreased, normal, or increased■KMT2A rearrangement patients have very high white counts of >100x 109/L■Translocation between IL3 and IGH genes result in variable eosinophilia and blasts may be absent in peripheral blood■Red Blood Cells Normocytic/normochromic anemia■Platelets Decreased : Bone Marrow Small to medium sized blasts with scanty cytoplasm to larger blastswith a lower N/C ratio and irregular nuclear outline■Nuclei are moderately condensed to dispersed and nucleoli are inconspicuous : Cytochemistry Myeloperoxidase negative■ Periodic acid-Schiff and TdT positive Immunophenotype B-ALL with BCR-ABL1 is positive for CD 10, CD19, CD15 and TdT■ KMT2A rearrangements, especially t(4;11) are CD19 positive but CD10 and CD24 are negative■ ETV6-RUNX1 translocations have CD19, CD10, and CD34 and CD9, CD20 and CD66c are negative : Genetics Cytogenetic abnormalities are seen in most cases and define specific entities with unique phenotypic and prognostic features ■ t(9;22)(q34.1;q11.2); BCR-ABL1■t(v;11q23.3); KMT2A -rearranged t(12;21)(p13.2;q22.1); ETV6-RUNX1■Hyperdiploidy■ Hypodiploidy■t(5;14)(q31.1;q32.1); IGH/IL3■t(1;19)(q23;p13.3); TCF3-PBX1■BCR-ABL1 -like■¡AMP21 MYELOPROLIFERATIVE NEOPLASMS Chronic Myeloid Leukemia, BCR ABL1 Positive Laboratory Features-Chronic Phase Peripheral Blood :White Blood Cells, Granulocytic leukocytosis with shift to the left (entire maturation series of granulocytes is seen)■<5% blasts■Basophilia and often eosinophilia■ No granulocytic dysplasia or toxic changes■Red Blood Cells, No or mild anemia■ Rare nucleated red blood cells■Platelets, Normal to elevated count■ Atypical large platelets, megakaryocytic cytoplasmic fragments, or megakaryocytic nuclei Bone Marrow : ≥95% cellularity■Myeloid:erythroid ratio ≥10:1■<5% blasts■Minimal or no granulocytic dysplasia■Increased small and monolobulated megakaryocytes ■Pseudo-Gaucher cells and sea-blue histiocytes can be observed if there is increased cell turnover Cytochemistry : Neutrophils in the chronic phase have markedly decreased leukocyte alkaline phosphatase score (score is usually ≤10) Laboratory Features-Accelerated Phase Peripheral Blood : White Blood Cells ,Persistent and increasing white blood cell count■ 10-19% myeloid blasts■ Entire maturation series of granulocytes is seen but notoxic changes■Basophilia ≥20%■Red Blood Cells, Normocytic/normochromic anemia■Occasional nucleated red blood cells■Platelets, Persistent thrombocytosis (>1000 x 10⁹/L) or persistent thrombocytopenia (<100 x 10⁹/L) Bone Marrow : 90-100% cellularity■Myeloid:erythroid ratio 10:1-50:1■ Increased small abnormal megakaryocytes■Pseudo-Gaucher cells and sea-blue histiocytes can be observed if there is increased cell turnover Laboratory Features-Blast Phase Peripheral Blood/Bone Marrow : >20% blasts■Extramedullary proliferation of blasts(hepatosplenomegaly)■Presence of large clusters of blasts in the bone marrow ■ In the blast phase, the blasts may have strong, weak, or no myeloperoxidase activity, but express antigen associated with granulocytic, monocytic, megakaryoblastic, and/or erythroid differentiation ■ 20% of blast phase leukemias are lymphoblastic (typically B cell) Genetics : Translocation of material from the long arm of 22 to the long arm of 9 and from 9 to 22■Fuses the BCR gene from chromosome 22 with regions of the ABL gene on chromosome 9 (BCR-ABL1 fusion protein) ================================= POLYCYTHEMIA VERA Laboratory Features Peripheral Blood :White Blood Cells, Increased in about two-thirds of patients■ Immature forms usually not seen■Basophils may be increased■Leukocyte alkaline phosphatase increased in three quarters of cases■Red Blood Cells ,Hemoglobin level increased■ Hematocrit level increased■ Red blood cell mass increased■Platlets, Normal to increased Bone Marrow : Hyperplastic■Erythroid hyperplasia■ Increased megakaryocytes ■ Granulocytic hyperplasia■ Increased reticulin in postpolycythemic myelofibrosis and myeloid metaplasia■ Iron stores are often depleted WHO Criteria Meet all three major criteria or the first two major and minor criteria Major Criteria Major:■Hemoglobin >16.5 g/dL in men and 16.0 g/dL in women or hematocrit >49% in men and >48% in women or increased red cell mass(>25% above mean normal predicted value)■Bone marrow showing panmyelosis with pleomorphic megakaryocytes■Presence of JAK2 V617F or JAK2 exon 12 mutation Minor Criteria Minor:■ Decreased serum erythropoietin level ================================= ESSENTIAL THROMBOCYTHEMIA Laboratory Features Peripheral Blood :White Blood Cells,Usually normal or mildly increased■Basophilia absent or minimal■Red Blood Cells Normocytic/normochromic anemia Microcytic, hypochromic anemia if there is gastrointestinal tract blood loss■Red blood cell mass not elevated■ No dacryocytes or leukoerythroblastosis■Platelets Thrombocytosis with counts ≥450 x 10⁹/L but typically higher■Platelets vary in size■Bizarre shapes with agranular forms are not uncommon Bone Marrow : Normocellular or moderately hypercellular■Increased numbers of large to giant megakaryocytes Megakaryocytes mass increased■ Increased megakaryocytes arranged in clusters or evenly dispersed■Blasts <5%■Absent or minimal reticulin fibrosis■Normal iron stores Immunophenotype : No abnormal phenotypes Genetics : 60% of cases harbor JAK2 V617F (exon 14) mutation■20-25% of cases have CALR mutations■3-5% of cases have MPL mutations■JAK2 exon 12 mutations absent WHO Criteria Diagnosis of ET requires meeting all four major criteria or the first three major and minor criteria Major Criteria Major: ■Persistant platelet count ≥450 × 10⁹/L■Bone marrow biopsy findings: Megakaryocytic proliferation with loose cluster formation,Enlarged, hyperlobulated megakaryocytes, No significant granulocytic or erythroid proliferation or granulocytic shift to the left, No significantgranulocytic or erythroid dysplasia,No significant reticulin fibrosis■Exclusion of other myeloproliferative neoplasms t(9;22)(q34.1;q11.2); BCR-ABL1 negative■Presence of JAK2, CALR, or MPL mutation Minor Criteria Minor:■Another clonal abnormality or exclusion of reactive =================================== Myeloifibrosis Laboratory Features Peripheral Blood : White Blood Cells,Count is usually <30.0 x 10⁹/L Immature cells in the myeloid series■Red Blood Cells,Nucleated red blood cells■Normocytic/normochromic anemia■ Dacryocytes (tear-shaped red blood cells) are present■Platelets ,Normal, decreased, or increased Morphology may be abnormal Bone Marrow : In the early/prefibrotic phase, the aspirate is hypercellular, trilineage hematopoiesis present, and megakaryocytic atypia■Blasts <5%■During the fibrotic phase, it is inaspirable or results in a dry tap Cytochemistry : Reticulin stain is increased Immunophenotype : No abnormal phenotypic features Genetics : 60% of patients have the JAK2 V617F mutation■CALR mutations in 25% of cases■MPL mutations in 6-7% of cases■May have additional mutations but no Philadelphia chromosome or BCR-ABL1 fusion gene WHO Criteria for Early/Prefibrotic Primary Myelofibrosis Diagnosis requires meeting all three major criteria and at least one minor criterion Major Criteria Major:■Hypercellular bone marrow with megakaryocytic hyperplasia and atypia, granulocytic hyperplasia, and normal or decreased erythropoiesis with grade 0 or 1 (of 3) reticulin fibrosis■Exclusion of other WHO-defined myeloid neoplasms ■Presence of a JAK2, CALR, or MPL mutation or presence of other clonal marker and absence of other causes of reactive reticulin fibrosis Minor Criteria Minor:■Leukocytosis ≥11 x 10⁹/L■ Increased serum lactate dehydrogenase ■Anemia (not attributable to other underlying condition) ■ Palpable splenomegaly WHO Criteria for Overt Primary Myelofibrosis Major Criteria Major:■ Megakaryocytic proliferation and atypia with grade 2 or 3 (of 3) reticulin fibrosis or collagen fibrosis■ Exclusion of other WHO-defined myeloid neoplasms ■Presence of JAK2, CALR, or MPL mutation or presence of other clonal marker and absence of other causes of reactive reticulin fibrosis Minor Criteria Minor:■Leukocytosis ≥11 × 10⁹/L■Increased serum lactic dehydrogenase■ Anemia (not attributable to other underlying condition)■ Palpable splenomegaly■ Leukoerythroblastosis ================================= • CHRONIC EOSINOPHILIC LEUKEMIA, NOT OTHERWISE SPECIFIED Clinical Features Many patients are asymptomatic Hepatosplenomegaly Skin involvement Fever, night sweats, cough, and weight loss Central nervous system irregularities, congestive heart failure, and pulmonary fibrosis Pathology Rare ⚫ Usually middle-aged males are affected Tissue eosinophil infiltration causes organ damage ⚫ Clonal abnormality Laboratory Features White Blood Cells • Persistent absolute eosinophilia (≥1.5 x 109/L) • 30-70% eosinophils • Count is usually ≥30.0 x 109/L <20% blasts Eosinophils exhibit sparse granulation with clear areas of cytoplasm and vacuoles and may be increased in size Red Blood Cells • Normocytic/normochromic anemia Platelets Decreased Bone Marrow Eosinophilia with increasing myeloid immaturity <20% blasts • Charcot-Leyden crystals are often present • Increased number of eosinophilic myelocytes Immunophenotype • No specific abnormalities Genetics • No single or specific cytogenetic or molecular genetic abnormalities • Cases with rearrangement of PDGFRA, PDGFRB, or FGFR1, or with PCM1-JAK2 are specifically excluded • MASTOCYTOSIS Criteria Classified as a separate disease category because of its unique clinical and pathologic features Ranges from indolent cutaneous disease to aggressive systemic disease Classification • Cutaneous mastocytosis • Systemic mastocytosis • Indolent systemic mastocytosis • Systemic mastocytosis with an associated hematologic neoplasm; at least one extracutaneous organ is involved Aggressive systemic mastocytosis Mast cell leukemia Mast cell sarcoma Clinical Features • Fever, fatigue, and weight loss Skin manifestations such as pruritus, urticaria, and flushing • Abdominal pain, gastrointestinal distress, headache, and hypotension • Bone pain, fractures, arthralgias, and myalgias Splenomegaly, lymphadenopathy, and hepatomegaly MastocytosisPathology • A clonal, neoplastic proliferation of mast cells that accumulate in one or more organ systems • Presence of clusters of abnormal mast cells Laboratory Features White Blood Cells May have 10% or more mast cells • Mast cells are morphologically abnormal Eosinophilia is a common finding Red Blood Cells Mild to moderate normocytic/normochromic anemia Platelets Decreased Bone Marrow ≥20% mast cells Diffuse, compact infiltrate with reduction in fat cells and normal hematopoietic cells • Mast cells are atypical with hypogranular cytoplasm and irregularly shaped monocytoid or bilobulated nuclei Cytochemistry • Toluidine blue may be positive Immunophenotype Expresses CD9, CD33, CD45, CD68, and CD117 • Lacks CD14, CD15, and CD16 • Reacts with antibodies against tryptase Genetics ≥90% of cases associated with point mutations within KIT TET2 mutations seen in about 30% of cases but not specific to mastocytosis • ASXL1 and CBL mutations may be predictive of survival in advanced systemic mastocytosis SRSF2 and RUNX1 may be associated with higher-risk disease in advanced systemic mastocytosis MATURE B-CELL NEOPLASMS CHRONIC LYMPHOCYTIC LEUKEMIA/SMALL LYMPHOCYTIC LYMPHOMA Laboratory Features Peripheral Blood : White Blood Cells count is increased to 20-200 × 10⁹/L■ Absolute lymphocytosis■Typical, small lymphocytes, with a hypermature- appearing nucleus■Smudge cells present■ <10% prolymphocytes■Red Blood Cells, Normocytic/normochromic anemia■Platelets ,Normal ,Often decreased with disease progression Bone Marrow : >30% lymphocytes ■ <10% prolymphocytes Immunophenotype : CD5, CD19, CD23, and CD79b positive■CD20 and sIg weak Genetics : 13q14.3 deletion, which is the most common chromosomal abnormality■Most common mutated genes are NOTCH1, SF3B1,TP53, ATM, BIRC3, POT1, and MYD88 ===================================== B-CELL PROLYMPHOCYTIC LEUKEMIA Laboratory Features Pripheral Blood : White Blood Cells,Typically> 100 x 10⁹/L■>55% prolymphocytes and usually >90% (WHO)■ Medium-sized cells that contain a large, vesicular nucleolus and condensed nuclear chromatin and have lower N/C ratio■Red Blood Cells Normocytic/normochromic anemia■Platelets Decreased Bone Marrow : Same types of prolymphocytes seen in the peripheral blood Immunophenotype : CD19, CD20, CD22, CD79a, CD79b, FMC7, and sig positive■CD5 and CD23 positive in less than one-third of cases Genetics : Exhibit heavy- and light-chain Ig gene rearrangements■Cells express much more sIg than do chronic lymphocytic leukemia cells■ MYC abnormalities are common■ May see TP53 deletions■ Must lack t(11;14)(q13;q32), which is found in mantle cell lymphoma ============================ HAIRY CELL LEUKEMIA Laboratory Features Peripheral Blood : White Blood Cells Usually decreased■ Presence of hairy cells■ Monocytopenia Neutropenia■Red Blood Cells, Moderate normocytic/normochromic anemia■Platelets, Thrombocytosis in 80% of patients Bone Marrow : Cannot be aspirated in more than half of the cases because of reticulin fibers■Small to medium-sized lymphoid cells with oval or bean-shaped nucleus■ The pale blue cytoplasm is abundant and has “hairy” projections Cytochemistry : Tartrate-resistant acid phosphatase positive■Specific esterase (naphthol AS-D chloroacetate esterase) and myeloperoxidase reactions are negative Immunophenotype : CD103, CD20, CD19, CD22, CD11c, CD25, CD200, and annexin A1 positive Genetics : About 85% of cases demonstrate IGHV genes with somatic hypermutation■BRAF V600E mutations ============================== MATURE T-CELL NEOPLASMS T-CELL LARGE GRANULAR LYMPHOCYTIC LEUKEMIA Laboratory Features Peripheral Bood : White Blood Cells,Persistent neutropenia■Lymphocytosis in the range of 4.0-10.0 x 10⁹/L■ Presence of large granular lymphocytes, generally >2.0 × 10⁹/L■ Predominant lymphocytes have moderate to abundant cytoplasm and fine or course azurophilic granules■Red Blood Cells,May have a macrocytic anemia■Platelets Normal to decreased Bone Marrow : Lymphocytic infiltration is variable■Left-shifted granulocytic maturation is common Immunophenotype : CD2, CD3, CD8, CD16, and CD57 positive Genetics : T-cell receptor gene clonally rearranged■STAT3 mutation is present in about one-third of cases =============================== ADULT T-CELL LEUKEMIA/LYMPHOMA Laboratory Features Peripheral Blood : White Blood Cells,May be only a few abnormal cells in the peripheral blood■Cells have highly convoluted nuclei with deep multilobulated indentation■Cell size and N/C ratio are larger than that of normal lymphocytes■Red Blood Cells,Normocytic/normochromic anemia■Platelets,Normal to decreased Bone Marrow : Presence of infiltrates and evidence of bony remodeling and fibrosis Immunophenotype : CD2, CD3, and CD5 are positive■CD7 is negative Genetics : Rearrangement of TR genes ============================== SéZARY SYNDROME Laboratory Features Peripheral Blood: White Blood Cells ,Hyperconvoluted lymphoid cells in peripheral blood■Red Blood Cells ,May have a normocytic/normochromic anemia■Platelets, Normal to decreased Bone Marrow : Eosinophilia, Monocytosis, Plasmacytosis Rare infiltrates of Sézary cells Cytochemistry : Focal positivity with acid phosphatase■Myeloperoxidase, alkaline phosphatase, and specific esterase (chloroacetate esterase) negative Immunophenotype : CD3 and CD4 positive■CD8, CD7, and CD26 negative■Flowcytometry:CD4+/CD7-in >30% of cases or CD4+/CD26- in >40% or T-cell population Genetics : T-cell receptor genes are clonally rearranged■Overexpression of PLS3, DNM3, TWIST1, and EPHA4 ================================ MYELODYSPLASTIC SYNDROMES Criteria Group of clonal hematopoietic stem cell diseases characterized by ■Ineffective hematopoiesis ■<20% blasts in peripheral blood and bone marrow ■Dysplasia in ≥10% of cells in one or more myeloid lineages■Cytopenia in at least one hematopoietic lineage■ Persistent cytopenias: The increased degree of apoptosis within the bone marrow progenitors contributes to the cytopenias Definitions: Dyserythropoiesis Dysgranulopoiesis Dysmegakariopoiesis : Dyserythropoiesis Peripheral blood Dimorphic pattern Basophilic stippling Pappenheimer bodies Bone marrow Megaloblastic change Abnormal mitotic figure Karyorrhexis Multinodularity Vacuolated erythroblast Ring sideroblast(prussian blue stain) Defective hemoglobin Irregular nuclear outline(nuclear budding) Irregular cytoplasmic cleft Erythroid shift to left : Dysgranulopoiesis Peripheral Blood Pseudo pelger huet Pseudo chediak higashi Hyperclumped nucleus Monocytosis Ring nucleus Abnormal segmentation Aur rod Bone marrow Myeloid shift to left Hypogranular neutrophil : Dysmegakaryopoiesis Dysplasia (≥10% based on evaluation of ≥30 megakaryocytes) Peripheral Blood Micromegakaryocyte Large atypical platelet Degranulated platlet Bone marrow Mononuclear megakaryocyte Abnormal granulation Vacuolated ctyoplasm Abnormal nuclear change Bilobed nucleus Hypersegmented nuclei Separated nuclear lobe MYELODYSPLASTIC SYNDROME WITH SINGLE-LINEAGE DYSPLASIA (MDS-SLD) Criteria if≥10% dysplastic cells in affected cell lineage■ Red blood cells-hemoglobin concentration <10 g/dL ■White blood cells-absolute neutrophil count <1.8 × 10⁹/L■Platelets-platelet count <100 × 10⁹/L■Erythroid precursors contain <15% ring sideroblasts if no SF3B1 mutation and <5% if SF3B1 mutation Laboratory Features Peripheral Blood : White blood cells if affected neutropenia(<1.8×10⁹/L),<1% blasts■Red Blood Cells Normocytic/normochromic or macrocytic/normochromic anemia(<10 g/dL),Anisochromasia or dimorphic population■Platelets, If affected , thrombocytopenia (<100 × 10⁹/L) Bone Marrow : <5% blasts■no Auer rods■Markedly decreased to markedly increased erythroid precursors■Dysplasia present in ≥10% of single lineage■ Hypercellular or normocellular■Ring sideroblasts may be present but account for■<15% of the erythroid precursors or <5% if SF3B1 mutation is present■ Iron stores may be increased Genetics : 50% have cytogenetic abnormalities but they are not specific■Del(20q), gain of 8, and abnormalities of 5 and 7■60-70% of cases have somatic driver mutations that affect the stem cell■ Most commonly mutated genes are TET2 and ASXL1 ========================= MYELODYSPLASTIC SYNDROME WITH RING SIDEROBLASTS AND SINGLE LINEAGE DYSPLASIA (MDS- RS-SLD) Laboratory Features Peripheral Blood : White Blood Cells,<1% blasts■Red Blood Cells Normochromic, macrocytic or normochromic,normocytic anemia Dimorphic pattern with hypochromic microcytes and normocytic or macrocytic cells Bone Marrow : Increase in erythroid precursors with dyserythropoiesis ■ No significant dysplasia in nonerythroid lineages■<5% myeloblasts in nucleated bone marrow cells ■no Auer rods Cytochemistry : Prussian blue stain,≥15% ringed sideroblasts as defined by ≥5 iron granules encircling one-third or more of the nucleus (≥5% if SF3B1 mutation is present) Immunophenotype : Aberrance in the immature erythroid progenitor compartment■ CD34+ cells (blasts) are typically <5% Genetics : SF3B1 mutation detected in 64-83% of cases =========================== MYELODYSPLASTIC SYNDROME WITH MULTILINEAGE DYSPLASIA (MDS-MLD) Criteria One or more cytopenias■Dysplasia of ≥10% of cells in two or more lineages■<1% blasts in peripheral blood and <5% in bone marrow■ No Auer rods■No monocytosis■Erythroid precursors contain <15% ring sideroblasts if no SF3B1 mutation and <5% if SF3B1 mutation Laboratory Features Peripheral Blood : White Blood Cells,Dysgranulopoiesis,Absolute neutrophil count <1.8 × 109/L,<1% blasts,No Auer rods, <1 x 10⁹/L monocytes■Red Blood Cells,Hemoglobin <10 g/dL,Dimorphic population■Platelet count <100 x 10⁹/L,May have abnormal morphology Bone Marrow : Normocellular or hypercellular but hypocellular can be seen■Dysplasia in ≥10% of the cells in two or more myeloid cell lines (erythroid, granulocytic, and megakaryocytic) ■<5% blasts■No Auer rods■Megakaryocyte abnormalities may be seen : Cytochemistry : Prussian blue stain to evaluate presence of ring sideroblasts and increased iron stores Immunophenotype: CD34+ cells (blasts) are typically <5% Genetics :Abnormalities include trisomy 8, monosomy 7, del(7q) monosomy 5, del(5q), and del(20q)■ Several gene mutations can be present ============================= MYELODYSPLASTIC SYNDROME WITH RING SIDEROBLASTS AND MULTILINEAGE DYSPLASIA (MDS- RS-MLD) Laboratory Features Peripheral Blood : White Blood Cells , <1% blasts, Dysgranulopoiesis■Red Blood Cells, Normochromic, macrocytic or normochromic normocytic anemia, Dimorphic pattern with hypochromic microcytes and normocytic or macrocytic cells■Platelets Abnormal platelet morphology Bone Marrow : Increase in erythroid precursors with dyserythropoiesis■ Granulocytes or megakaryocytes show ≥10% dysplastic forms■<5% myeloblasts in nucleated bone marrow cells and■ no Auer rods Cytochemistry : Prussian blue stain ≥15% ringed sideroblasts as defined by ≥5 iron granules encircling one-third or more of the nucleus (≥5% if SF3B1 mutation is present) Immunophenotype : Aberrance in the immature progenitor compartment■Abnormal maturation in granulopoiesis, the monocytic compartment, and erythropoiesis CD34+ cells (blasts) are typically <5% Genetics : SF3B1 mutation detected in 57-76% of cases MYELODYSPLASTIC SYNDROME WITH EXCESS BLASTS (MDS-EB) Criteria Characterized by 2–19% blasts in the peripheral blood or 5-19% myeloblasts in the bone marrow Subcategories■MDS-EB-1: 2-4% blasts in peripheral blood or 5-9% blasts in bone marrow■MDS-EB-2: 5-19% blasts in peripheral blood , or 10-19% blasts in bone marrow, If Auer rods are present it is MDS EB-2 regardless of blast numbers Laboratory Features Peripheral Blood : White Blood Cells ,Neutropenia,Dysgranulopoiesis■Red Blood Cells Anisopoikilocytosis with macrocytes, Dimorphic population, Decreased reticulocytes■Platelets Decreased, Large, giant, or hypogranular Bone Marrow : Usually hypercellular; may be hypocellular or normocellular■Clusters or aggregates of blasts■ Erythropoiesis, granulopoiesis, and megakaryopoiesis may be increased with variable dysplasia Cytochemistry : Peroxidase stain is positive Immunophenotype : CD34, CD117, or CD33 positive Genetics : 30-50% of cases have clonal cytogenetic abnormalities and can include +8, −5, del(5q), -7, del(7q), and del(20q)■ Splicing gene mutations are common (SRSF2) MYELODYSPLASTIC SYNDROME WITH ISOLATED DEL(5Q) Criteria Anemia with or without other cytopenias■Del(5q) occurs either in isolation or with one other cytogenetic abnormality other than monosomy 7/del(7q)■<1% of the peripheral blood leukocytes and <5% blasts of nucleated cells in bone marrow■ Auer rods are absent Laboratory Features Peripheral Blood : White Blood Cells Normal■Red Blood Cells Macrocytic anemia ,Hemoglobin level often <8.0 g/dL■Platelets Normal or elevated count Bone Marrow : <5% blasts of nucleated cells■ No Auer rods■ Increased megakaryocytes, which are normal to slightly decreased in size■ Dysmegakaryopoiesis Monolobated or hypolobated nuclei in megakaryocytes ■Hypercellular or normocellular■May have dysplastic erythroid precursors but less pronounced Cytochemisty : Prussian blue stain revealing ring sideroblasts may be present Genetics : Deletion of bands q31-q33 on the long arm of chromosome 5■ Cases with one additional cytogenetic abnormality except monosomy 7 or del (7q) have similar outcome ================================= /MYELODYSPLASTIC MYELOPROLIFERATIVE NEOPLASMS Criteria Clonal chronic myeloid neoplasm characterized by myelodysplastic and myeloproliferative features manifested by at least one dysplasia and at least one cytosis in blood Blasts are ≤20% in blood and bone marrow • Mature cells predominate CHRONIC MYELOMONOCYTIC LEUKEMIA (CMML) Criteria Persistent peripheral blood monocytosis defined as >1.0 × 10⁹/L and >10% monocytes■ Absence of Philadelphia chromosome, BCR-ABL1 fusion, or myeloproliferative neoplasm■Absence of PDGFRA, PDGFRB, FGFR1, or PCM1-JAK2■<20% blasts or blast equivalents in peripheral blood or bone marrow■Dysplasia in one or more of the myeloid lineages .Subcategories: ■CMML-0,Blasts <2% in peripheral blood and <5% in bone marrow and no Auer rods■CMML-1, Blasts 2-4% in peripheral blood or 5-9% in bone marrow and no Auer rods■CMML-2, Blasts between 5% and 19% in peripheral blood or 10-19% in bone marrow or Auer rods are present Laboratory Features Peripheral Blood : White Blood Cells Usually normal to decreased■ Monocytes range from 2 to 5 x 10⁹/L but may be above 80 x 10⁹/L■Monocytes are >10% of the leukocytes■Monocytes are mature but can exhibit abnormal granulation or nuclear lobulation■ Blasts and promonocytes are <20% of the white blood cell count■ There are <10% neutrophil precursors■Dysgranulopoiesis is common■ Basophilia is typically mild but rare cases of increased eosinophils have been described■Red Blood Cells ,Anemia is usually normocytic but sometimes macrocytic, Dimorphic population■Platelets, Decreased count, Abnormal forms may be found Bone Marrow : Usually hypercellular■ Granulocytic proliferation■Slight dysgranulopoiesis■<20% blasts and promonocytes■ Dyserythropoiesis■ Slight dysmegakaryopoiesis■Increased monocytic precursors Cytochemistry : Nonspecific esterase positive for monocytic cells ■Myeloperoxidase and Sudan black B positive in granulocytic cells■ Periodic acid-Schiff negative Immunophenotype :Expresses the myelomonocytic antigen such as CD33 and CD13■Variable expression of CD14, CD68, and CD64 Genetics : 60% of cases show TET2 mutations ■ 50% of cases have SRSF2 mutations■ 40% of cases have ASXL1 mutations ============================== Atypical Chronic Myeloid Leukemia (aCML) BCR-ABL1 Negative Laboratory Features Peripheral Blood : Leukocytosis with counts ≥13.0 x 10⁹/L but most have counts from 24.0 to 96.0 x 10⁹/L■ Immature and dysplastic 10-20% immature cells (promyelocytes, myelocytes, and metamyelocytes)■ Blasts are usually <5% but must be <20%■Monocytes are usually <10%■Basophilia <2%■Dysgranulopoiesis is pronounced with pseudo Pelger- Huët cells, abnormally clumped chromatin, or bizarre segmentation■Red Blood Cells, Anemia ,Dyserythropoiesis ,Macro-ovalocytosis may be present■Platelets Count is variable but decreased numbers are common Bone Marrow : Hypercellular due to increased neutrophils and their precursors■ Increased myeloid to erythroid ratio with >10:1 common■Blasts are typically <5% but always <20%■ Dysgranulopoiesis, dyserythropoiesis, and dysmegakaryopoiesis■ Some cases have over 30% erythroid precursors Cytochemistry :No diagnostic abnormalities Immunophenotype : Neutrophils and precursors are positive for CD33, CD13, and CD15 Genetics : SETBP1 and ETNK1 mutations are relatively common ■ The CSF3R mutation is present in <10% of cases ■ Common cytogenetic abnormalities are inv(17q),trisomy 8, and deletion of long arm of chromosome 20 ========================== JUVENILE MYELOMONOCYTIC LEUKEMIA (JMML) Laboratory Features Peripheral Blood : White blood cell count varies from 25.0 to 30.0 × 10⁹/L■Mainly neutrophils with some immature cells such as promyelocytes and myelocytes■Monocytes are increased (1.0 x 10⁹/L)■Blasts and promonocytes usually account for <5% and always <20%■Red blood cells,Nucleated red blood cells are frequent■Marked increased in hemoglobin F■Platelets variable but may be decreased and may be severe Bone Marrow : Hypercellularity Granulocytic proliferation but rarely erythroid precursors can predominate■Monocytes account for about 5-10% or cells Blasts and promonocytes are <20%■No Auer rods■ Dysplasias are minimal but pseudo Pelger-Huët cells or hypogranular forms may be seen■Megakaryocytes are often decreased Cytochemistry : Nonspecific esterase stain is positive in monocytic precursors■Myeloperoxidase and Sudan black B positive in granulocytic cells Immunophenotype : No specific immunophenotypic abnormalities have been reported Genetics : 25% of cases have monosomy 7■65% of cases have a normal karyotype
