HEMATOLOGY THE HEMATOLOGIC MALIGNANCIES OUTLINE • The Hematologic Malignancies • Acute Leukemias • Acute Myeloid Leukemia o FAB & WHO Classification of AML o General Characteristics of AML o AML: FAB Classification o AML: WHO Classification • Acute Lymphoblastic Leukemia o General Characteristics of ALL o ALL: FAB Classification o Cytochemical Stains • Lymphoid and Plasma Cell Neoplasms o Plasma Cells Neoplasms o Chronic Lymphocytic Leukemia o Hairy Cell leukemia o Prolymphocytic Leukemia o Multiple Myeloma o Waldenstrom Primary Macroglobulinemia • Lymphomas o Lymphomas Classification o Hodgkin Disease o Non-Hodgkin Lymphoma • Myeloproliferative Neoplasms o Chronic Myelogenous Leukemia o Cytochemical Staining o Polycythemia Vera o Primary Myelofibrosis o Essential Thrombocytosis • Myelodysplastic Syndromes & Myelodysplastic / Myeloproliferative Neoplasms o FAB Classification of MDS o WHO Classification of MDS o Features of Selected Types of MDS o Myelodysplastic/ Myeloproliferative Neoplasms THE HEMATOLOGIC MALIGNANCIES • Acute leukemias are characterized by the presence of blasts or immature cell stages in peripheral blood and bone marrow. Most adult patients die of infection in short time after diagnosis. This happens even though there is a high number of leukocytes, the so-called "soldiers of the body ". The leukocytes matured in a very fast pace, and so had not undergone the normal maturational stages. They may skip generation / stages resulting to leukocytosis. • The acute myeloid leukemias under FAB classification are classifies as: M0 Myeloid where undifferentiated blasts, AML-not otherwise categorized, M1 Myeloid where blasts and promyelocytes predominate, M2 Myeloid where myeloid cells demonstrate maturation beyond the blasts and promyelocytic stages, M3 Promyelocytic, promyelocytes predominate in the bone marrow, M4 Myelomonocytic where both myeloid and monocytic cells are present to the extent of at least 20% of the total leukocyte. In M5 Monocytic, most cells are monocytes and composed of two types a & b, a consists of large blasts are seen in the bone marrow and blood, the other one, b is composed of differentiated type of monoblasts, promonocyte and monocyte. In M6 Erythroleukemia, also known as Di Guiglielmo's Syndrome where both erythroid and granulocytic precursors proliferate. In M7 Megakaryocytic Type, large and small megakaryoblasts with high nuclear cytoplasmic ratio; pale and granular cytoplasm. • The acute lymphoblastic leukemia has 3 types as classified in FAB. The L1 is characterized by predominance of small cells, nuclear shape is regular with an occasional cleft, chromatin pattern is homogenous and nucleoli are rarely visible, cytoplasm is moderately basophilic. L2 type has large cells with an irregular nuclear shape, cleft in the nucleus are common, one or more large nucleoli are visible, cytoplasm varies in color. In L3 , Burkitt Lymphoma type, cells are large and heterogenous in size, nuclear shape is round or oval, one to three prominent nucleoli, cytoplasm is deeply basophilic with vacuoles often prominent. • Cytochemistry is a diagnostic tool to differentiate the types of leukemia. This is based on the reaction of intracellular markers being detected (lipid, enzymes) where the cells react with an added substrate in the test system. Examples are, Myeloperoxidase and Sudan Black B stains differentiate acute myeloid from acute lymphoid leukemia; in the former both stains are positive while in the latter both stains are negative. The esterases, alkaline phosphatase, acid phosphatase (tartrate resistant), periodic acid Schiff are more examples of cytochemical stains. These are valuable to the physicians in the diagnosis of leukemia. • In the World Health Organization (WHO) Classification, in addition to the 3 criteria used in FAB, Immunophenotyping by flowcytometry confirms diagnosis of leukemia by identifying the type of antigens or markers on the cells' surface. The surface membrane markers, e.g. cluster of differentiation (CD) and other markers are detected using monoclonal antibodies. It is a supplementary differential testing in the various leukemias and lymphomas. • Myeloproliferative neoplasms (MPNs) are interrelated clonal abnormalities resulting in an excessive proliferation of various phenotypically normal mature cells. The MPNs include Chronic Myeloid Leukemia (CML), Polycythemia Vera (PV), Primary Myelofibrosis (or agrogenic myeloid metaplasia), and Essential Thrombocythemia (ET). No environmental cause of MPN has been identified but genetic susceptibility may exist. • The Myelodysplastic Syndromes (preleukemias) and Myedysplastic/Myeloproliferative Neoplasm are similar in characteristics. The Myelodysplastic Syndromes (MDS) are characterized by the simultaneous proliferation and apoptosis (programmed cell death) of hematopoietic cells that lead to a normal or hypercellular bone marrow biopsy and peripheral blood cytopenias (low cell count) where anemia, thrombocytopenia and leukopenia are common. MDS are classified into; Refractory Anemia (RA), Refractory Anemia with Ring Sideroblasts (RARs), Refractory Anemia with Excess Blasts (RAEB-1 and RAEB-2), the first to demonstarte an overt classic relationship to AML. • The Myelodysplatic/Myeloproliferative Neoplasms is composed of Chronic Myelomonocytic Leukemia (CMML) characterized by feature of both an MPN and MDS. CMML consists of 2 types, CMML-1 and CMML-2. General peripheral blood smear demonstrate a persistent monocyte count, the hallmark of CMML, greater than (1 x 10 9 /L). MDS patients' transformation to AML can happen. MDS and AML patients share certain specific karyotypes. • Nowadays, with advances in diagnostic tools, both physician and patient benefits. The turn -around time for diagnosis is shorter enabling earlier diagnosis, which is of prime importance in the treatment and management of malignancies.
ACUTE LEUKEMIAS • Acute myeloid leukemia (AML) must be distinguished from acute lymphoblastic leukemia (ALL), myelodysplastic syndrome (MDS), or AML arising in the presence of MDS, because therapeutic strategies and the prognosis vary considerably for these diseases. • Acute leukemias are characterized by the presence of blasts and immature leukocytes in the peripheral blood and bone marrow. • Anemia is present. o can be caused by bleeding and the replacement of normal marrow elements by leukemic blasts. • Total leukocyte count is usually elevated, some patients may demonstrate normal or decreased leukocyte count. o Aleukemic ** • AML (also called acute myelogenous leukemia, acute non- lymphocytic leukemia, or ANLL) remains a lethal disorder, which kills the majority of afflicted adults. o More lethal than ALL • 2 Major Divisions : o Acute Myeloid Leukemia (AMLs) ▪ Divided into subtypes: (M0-M7) o Acute Lymphoid Leukemia (ALLs) ▪ Divided into three categories: (L1-L3) ACUTE MYELOID LEUKEMIA FAB & WHO CATEGORIES OF AML FAB CLASSIFICATION • Based on the morphological characteristics of Wright-stained cells in peripheral blood or bone marrow and cytochemical staining of blasts. • This system is based on the type of cell from which the leukemia developed and the maturity of cells. • Classifications are based largely on how the leukemia cells look under the microscope after routine staining. • In a revision of the original criteria, more than 30% blasts in the marrow suffice for the diagnosis of acute leukemia in any of the categories. WHO CLASSIFICATION • Classification is based on: o Morphology o Cytochemistry o Immunophenotype o Genetics o Clinical features • *To define clinically significant disease entities. GENERAL CHARACTERISTICS OF ACUTE MYELOID LEUKEMIA ACUTE MYELOID LEUKEMIA • most common leukemia subtype • recognized as a heterogenous clonal disorder, characterized by: o Maturation block and the accumulation of acquired somatic genetic alterations in hematopoietic progenitor cells that alter normal mechanisms of self- renewal, proliferation, and differentiation. GENETIC DIFFERENCES • FLT3 gene o encodes a type III receptor tyrosine kinase o FLT3 tyrosine kinase - involved in leukemogenesis by a number of different genetic mechanism o FLT3 is known to be mutated in up to 30% of patients with AML • Core-binding Factor (CBF) Complex o Is a transcription factor complex critical for regulation of hematopoiesis and normal myeloid development. o Disruptions of CBF complex: ▪ t(8;21) (q22;q22) or inv (16) (p13q22/t(16,16) (p13;q22), constitute AML subgroups with favorable prognosis. • Micro-RNAs o Associated with cytogenetics, molecular and morphological alterations, & clinical outcomes in AML. o Capable of distinguishing between different leukemias, for example, AML and ALL, and also between cytogenetic subtypes of AML. ACUTE MYELOID LEUKEMIA (FAB CLASSIFICATION) M0 (MYELOID) • Undifferentiated blasts, AML — not otherwise categorized • WHO classification of AML not otherwise categorized M1 (MYELOID) • Blasts and promyelocytes predominate without further maturation of myeloid cells • WHO synonym for this condition is acute myeloblastic leukemia without maturation
• Clinical Signs & Symptoms o Characterized by either a rapid or gradual onset that may resemble an acute infection. o Tumor masses has presence of large quantities of the enzyme MPO produces a green appearance if the tissue is cut. (chloroma) o This type of tumor is referred to as a chloroma. In some cases, the appearance of these tumors is an early sign of AML. • Laboratory Data o Anemia & Thrombocytopenia is present in 85% of all AMLs o Leukocytosis is encountered in more than 1/3 of patients (TL > 100 x 10 9 /L) o Agranular or hypogranular segmented neutrophils may be seen (acquired Pelger-Huët anomaly). o Abnormal eosinophils may also be seen. o Monocytes usually constitute less than 1% of the nucleated cells in the peripheral blood. o Auer rods can be seen ▪ Numerous can be classified as faggot cells M2 (MYELOID) • Myeloid cells demonstrate maturation beyond the blast and promyelocyte stage • WHO synonym for this disease is acute myeloblastic leukemia with maturation • Clinical Signs & Symptoms o Hemorrhagic manifestations such as easy bruising, epistaxis (nose bleed), gingival bleeding, and petechiae are common initial symptoms. o Hepatomegaly, splenomegaly, and lymphadenopathy are seen infrequently. • Laboratory Data o Anemia & thrombocytopenia are present in most cases o Leukocytosis is commonly seen, with rare patients having total leukocyte counts exceeding 300 × 10 9 /L. o Myeloblasts predominate on peripheral blood smears o Auer rods are commonly seen. o Maturation of the granulocytic cell line is also observed. M3 (PROMYELOCYTIC) • Promyelocytes predominate in the bone marrow • Clinical Signs & Symptoms o Fatigue and symptoms of bleeding such as bruising, hematuria, and petechiae are common. o Hepatomegaly, splenomegaly, and lymphadenopathy are seen infrequently. o M3 appears to be the most aggressive of acute leukemia with a severe bleeding tendency and a fatal course, if untreated, of only weeks. o Usually seen in DIC (Disseminated Intravascular Coagulation) ▪ Due to fast paced coagulation, platelets are used as well as procoagulant ▪ Primary fibrinolysis is differentiated because it has normal platelet count & RBC morphology ▪ Has decreased platelet count and abnormal RBC morphology (poikilocytes) ▪ May lead to death • Laboratory Data o Anemia & thrombocytopenia are present in most cases o Total leukocyte counts range from conditions of leukopenia to leukocytosis. ▪ Normal: 4.5 - 11 x 10 9 /L o Leukopenia is seen frequently. o Promyelocytes are the predominating cell type M4 (MYELOMONOCYTIC) • Both myeloid and monocytic cells are present to the extent of at least 20% of the total leukocytes • Referred to as Naegeli type monocytic leukemia. o Includes neutrophil • WHO synonym is acute myelomonocytic leukemia • Usually neutrophil & monocyte
• Clinical Signs & Symptoms o Patients with FAB M4 or FAB M5 leukemia or ALL (predominantly of the T-cell type) with hyperleukocytosis (an excessive increase in the total leukocyte count) are at risk of leukostasis development. o Leukostasis refers to a pathological finding of slightly dilated, thin-walled vessels filled with leukemic cells. The brain and lungs are the most commonly involved organs. • Laboratory Data o Proliferation of granulocytes and monocytes is characteristic. o Anemia and thrombocytopenia are present. o The total leukocyte count varies from leukopenia to leukocytosis. The total leukocyte count rarely exceeds 100 × 10 9 /L. In many patients, the absolute monocyte count reaches or exceeds 5 × 10 9 /L in peripheral blood. M5 (MONOCYTIC) • Most cells are monocytic; two subtypes (a & b) are recognized, o FAB M5a - characterized by large blasts in bone marrow and peripheral blood ▪ common in young adults o FAB M5b - differentiated type by monoblasts, promonocytes, and monocytes ▪ common during middle age • Refered to as Schilling's Type • WHO synonyms are acute monoblastic leukemia (FAB M5a) and acute monocytic leukemia (FAB M5b) • Clinical Signs & Symptoms o The onset of this form of leukemia is dramatic, with headaches and fevers being the chief complaints. o Typical symptoms of monocytic leukemia additionally include fatigue, weight loss, and bleeding from the mouth or nose. • Laboratory Data o Anemia and thrombocytopenia are usually evident. o The total leukocyte count ranges from 15 to 100 × 10 9 /L. o Peripheral blood smears normally exhibit a high proportion of blast forms. o Monocytes and promonocytes constitute 25% to 75% of the nucleated cells. M6 (ERYTHROLEUKEMIA) • Refered to as Erythemic Myelosis or Di Guglielmo syndrome • Abnormal proliferation of both erythroid and granulocytic precursors; may include abnormal megakaryocytic and monocytic proliferations • WHO synonym for FAB M6a and M6b is acute erythroid leukemia. • Clinical Signs & Symptoms o A common presenting symptom is a bleeding manifestation. o Hepatomegaly, splenomegaly, and lymphadenopathy are infrequently observed. • Laboratory Data o Blast cells of erythroid and myeloid origin are found in both the bone marrow and the peripheral blood. o Erythroblasts on blood smears typically have an irregular outline with a high nuclear-cytoplasmic ratio. o Blasts of myeloid origin may have Auer rods. o Promyelocytes may also be present as well as monocytes and promonocytes. M7 (MEGAKARYOCYTIC) • Large and small megakaryoblasts with a high nuclear cytoplasmic ratio; pale, agranular cytoplasm • WHO synonym is acute megakaryoblastic leukemia
• Clinical Signs & Symptoms o Organomegaly is infrequent except in children. o Radiographic evidence of bone lytic lesions has been observed in children. • Laboratory Data o Cytopenia is usually present, particularly thrombocytopenia. ▪ All cell lines are diminished o Immunophenotyping reveals that megakaryoblasts express one or more of the platelet glycoprotein: CD41 or CD61. o Blasts are negative with anti-MPO antibody. ACUTE MYELOID LEUKEMIA (WHO CLASSIFICATION) • Acute Myeloid Leukemia with Certain Genetic Abnormalities o AML with t(8;21) o AML with inv(16)or t(16;16) o AML with t(9;11) o APL with t(15;17) • Acute Myeloid Leukemia, Not Otherwise Specified o AML with minimal differentiation o AML without maturation o AML with maturation o Acute myelomonocytic leukemia o Acute monoblastic/monocytic leukemia o Acute erythroid leukemia o Acute megakaryoblastic leukemia o Acute basophilic leukemia • Acute Leukemias of Ambiguous Lineage o Acute undifferentiated leukemia o Mixed phenotype acute leukemia with t(9;22) o Mixed phenotype acute leukemia with t(v;11q23) o Mixed phenotype acute leukemia, B lymphocytes-myeloid cells o Mixed phenotype acute leukemia, T-myeloid ACUTE LYMPHOBLASTIC LEUKEMIA • ALL is the most common cancer in children, representing 23% of cancer diagnoses among children younger than 15 years of age. • Divided into three subtypes: o L1 (children) o L2 (older children and adults) o L3 (patients with leukemia secondary to Burkitt lymphoma) • Differentiated based on morphology including: o cell size o prominence of nucleoli o amount and appearance of cytoplasm • It is generally accepted that T-cell acute lymphoblastic leukemia (T-ALL) results from the malignant transformation of normal developing T cells in the thymus, the so-called thymocytes. • Morphological Classification & Characteristics FAB Type L1 L2 L3 Size of Blasts Small Large, heterogeneous Large Nuclear Shape Indistinct Indented, prominent Regular oval to round Nucleoli Scant Large, abundant Prominent, basophilic Cytoplasm Invisible Moderately clefted Prominent, vacuoles GENERAL CHARACTERISTICS OF ACUTE LYMPHOBLASTIC LEUKEMIA • The WHO classification that is synonymous with the FAB L1 and L2 classification is: o Precursor B lymphoblastic leukemia/lymphoblastic lymphoma (precursor B- cell ALL) → neoplasm of lymphoblasts committed to the B-cell lineage. o Precursor T lymphoblastic leukemia/lymphoblastic lymphoma (precursor T- cell ALL) → neoplasm of lymphoblasts committed to the T-cell lineage. ACUTE LEUKEMIA (FAB CLASSIFICATION) L1 (HOMOGENEOUS) • One population of cells within the case; small cells predominant; nuclear shape is regular with an occasional cleft; chromatin pattern is homogeneous and nucleoli are rarely visible; cytoplasm is moderately basophilic L2 (HETEROGENEOUS) • Large cells with an irregular nuclear shape; clefts in the nucleus are common; one or more large nucleoli are visible; cytoplasm varies in color
L3 (BURKITT LYMPHOMA TYPE) • Cells are large and homogeneous in size; nuclear shape is round or oval; one to three prominent nucleoli; cytoplasm is deeply basophilic with vacuoles often prominent • Can arise from infectious mononucleosis (Epstein-Barr) ALL: CLINICAL SIGNS & SYMPTOMS • Symptoms can vary from few days to few weeks. • Pain in the extremities, particularly the legs, is produced by an infiltration of leukemic cells into the tissues. • Lymphadenopathy and hepatomegaly are present in 75% of patients. • Leukemic meningitis and cranial nerve palsies caused by nerve infiltration by leukemic blasts are quite common. • Leukemic cells can infiltrate many areas of the body ALL: LABORATORY DATA • Total leukocyte count → elevated in 60% to 70% of patients; ranging from 50 to 100 × 10 9 /L. • < 15% of patients exhibits extreme leukocytosis → TL > 100 × 10 9 /L • Approx. 25% of patients exhibits leukocytopenia • Peripheral Blood Smear : o predominance of blast cells o close to 100% lymphoblasts, lymphocytes & smudge cells CYTOCHEMICAL STAINS FOR ACUTE LEUKEMIAS • Myeloperoxidase o To differentiate AML (+) to ALL (-) o Must be fresh because enzymes are unstable o Marker for Auer Rods due to primary granules o (+) color → black precipitate or reddish brown termed as phi bodies • Sudan Black B (SBB) o To differentiate AML (+) to ALL (-) o Stains lipids & phospholipids o Air dry and Fresh can be both used o (+) color → black color o Done simultaneously with myeloperoxidase o More stable & accurate than myeloperoxidase • Chloroacetate Esterase (Napthol ASD) (SE) o Stains granulocytic lineage o Also known as specific esterase o To differentiate granulocytic leukemia from monocytic leukemia that produces red granules if positive • Non-Specific Esterase (NSE) o Stains monocytic lineage including megakaryocytes and macrophage o To differentiate monocytic leukemia from granulocytic leukemia o α-naphthyl acetate esterase - Monocyte, Plasma Cell & Megakaryocyte ▪ (+) red brown o Sodium Fluoride - added to inhibit monocytic series o α-naphthyl butyrate esterase - monocytic series ▪ (+) dark red precipitate • Periodic Acid Schiff (PAS) o Stains most carbohydrates in all red cells except PRONORMOBLAST o Useful for AML M6 or Erythroleukemia o (+) Color - magenta or purple o Basophils, Lymphocytic Series, plasma cells and erythrocytic cell series
• Acid Phosphatase Stain o Stains ACP found in lysosomes in myelocytic lineage and lymphocytic lineage o Tartaric acid may be used to identify Hairy Cell Leukemia which is resistant to L-tartrate (TRAP) ▪ Presence of Isoenzyme 5 o Heparin must be used (+) → purple to red granules • Terminal Deoxyribonucleotidyl Transferase (TdT) o Can stain ALL due to polymerase immunoperoxidase o To differentiate ALL to AML • Toluidine Blue / Metachromatic Stain o Stains acid mucopolysaccharide of mast cells and basophils AML: CYTOCHEMICAL STAINING LYMPHOID AND PLASMA CELL NEOPLASMS PLASMA CELL NEOPLASMS MATURE B-CELL NEOPLASMS • WHO Classification o Chronic Lymphocytic Leukemia (CLL)/Small Lymphocytic Lymphoma (SLL) o B-Cell Prolymphocytic Leukemia o Hairy Cell Leukemia o Plasma Cell Neoplasms CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) / SMALL LYMPHOCYTIC LYMPHOMA CHRONIC LEUKEMIAS • Generally characterized by the presence of leukocytosis with an increased number of mature lymphocytes, lymphocytosis, on a peripheral blood film. • Example: Malignant lymphoproliferative disorders → characterized by an accumulation of lymphocytes. CHRONIC LYMPHOCYTIC LEUKEMIA / SMALL LYMPHOCYTIC LYMPHOMA • Most common form of leukemia in adults in Western countries but it is very rare in far Eastern countries • Neoplasms composed of small B lymphocytes in the peripheral blood, bone marrow, spleen, and lymph nodes, mixed with prolymphocytes and paraimmunoblasts forming proliferation centers in tissue infiltrates. • Accounts for almost 7% of non-Hodgkin lymphomas (NHLs) in biopsies. • The median age of onset is 65 years. This form of leukemia is rare before age 20 and uncommon before age 50. • Classic CLL is usually a B-cell disorder. o Considered as more benign than T-cell disorder • B-CLL is a biologically and clinically heterogeneous hematologic malignancy characterized by a gradually progressive accumulation of morphologically mature B lymphocytes in the blood, bone marrow, and lymphatic tissues. o These cells are characterized as CD5+, CD19+, CD23+ monoclonal B cells. • Chromosomal alterations : o 13q deletion o 11q deletion o trisomy of chromosome 12 → most consistent finding which is present in approximately 50% of patients o 17p deletion o translocation of chromosomes 8 and 14 → associated with B-CLL o translocation of chromosomes 9 and 22 → observed in non- T and non-B types ▪ Long-arm - Philadelphia chromosome • B-Cells displays the classic surface immunoglobulin (SIg) markers. o CD19 o CD20 o CD24 o CD5 • Clinical Signs & Symptoms o Abnormal findings discovered on a complete blood count (CBC) o Common symptoms include malaise, low-grade fever, and night sweats. o Hepatosplenomegaly is also frequently present. • Laboratory Data : o Total leukocyte counts can range from 30 - 200 × 10 9 /L. o In 1/3 of patients, the total leukocyte count is greater than 100 × 10 9 /L. o Absolute lymphocytosis is a usual finding. o Peripheral blood smears commonly exhibit up to 80% or 90% small lymphocytes.
o Serum electrophoresis studies usually show hypogammaglobulinemia. o Smudge cells are markers for CLL HAIRY CELL LEUKEMIA • Uncommon chronic lymphoproliferative disorder of the B-lymphocyte type. • More common in males than in females. o It has been suggested that a locus on the X chromosome might be involved in HCL • HCL is so named because of the appearance of fine, hair-like, irregular cytoplasmic projections that are characteristic of lymphocytes in this disease. • The cytochemical features of HCL include a strong acid phosphatase reaction that is not inhibited by tartaric acid or tartrate-resistant acid phosphatase (TRAP) stain. o TRAP positivity can vary with disease progression. o Following interferon therapy, enzyme activity in the hairy cell may be TRAP negative. • Immunological Markers : o CD19+, CD20+, CD22+, CD24+, and CD25+ reactivity to the monoclonal antibody that recognizes the interleukin-2 (Tac) receptor. o In addition, the cells display strong Sig (surface immunoglobulin; seen in B-cells). ▪ Cytoplasmic Ig (Cig) - found in plasma cells HPF OIF HAIRY CELL LEUKEMIA VARIANT (vHCL) • More aggressive type of HCL and has different morphological characteristics than typical HCL. • Cells are smaller than the typical HCL cell with a central round nucleus, prominent nucleoli, a larger nuclear:cytoplasmic ratio, and basophilic cytoplasm with occasional cytoplasmic projections. • Differential diagnosis of variant HCL (vHCL) from typical HCL can be made by cytochemical staining (TRAP) and immunophenotyping using flow cytometry. vHCL has a poor prognosis. PROLYMPHOCYTIC LEUKEMIA • Malignancy of B prolymphocytes affecting blood, bone marrow, and spleen. • Characterized by a large number of small lymphocytes with scant cytoplasm and the immature features of prolymphocytes in the peripheral blood. • Leukocytosis can exceed 100 × 10 9 /L. • Prolymphocytes must exceed 55% of lymphoid cells in the peripheral blood • Immunological Markers : o CD19+ o CD20+ o CD24+ o CD22+ o Cells display strong SIg. MULTIPLE MYELOMA (PLASMA CELL MYELOMA) • Multiple myeloma is a malignant bone marrow –based, plasma cell neoplasm associated with abnormal protein production. • Plasma cell leukemia is an increased number of plasma cells in the peripheral blood and should be considered a form of multiple myeloma and not a separate entity. • Usually evolves from an asymptomatic premalignant stage of clonal plasma cell proliferation called “monoclonal gammopathy of undetermined significance (MGUS).” • The onset of this disorder is between the ages of 40 and 70 years, with a peak incidence in the seventh decade of life. • Clinical Signs & Symptoms o Bone pain, weakness, fatigue o Abnormal bleeding - may be a prominent feature o In some patients: major symptoms result from acute infection, renal insuffi ciency, hypercalcemia, or amyloidosis. o Approximately 90% of patients suffer from broadly disseminated destruction of the skeleton. o Multiple myeloma leads to a compensatory decrease in synthesis and increase in catabolism of normal immunoglobulins. o Granulocytopenia may develop as a result of bone marrow failure. o **Bence-Jones protein - light chains in urine
• Laboratory Data : o Increased plasma volume caused by monoclonal protein commonly produces hypervolemia. o Relative lymphocytosis is usually present. o Rouleaux formation on peripheral blood smears is common. ▪ Caused by increased myeloma proteins (gammaglobulins) o Bleeding is common. ▪ Platelet abnormalities, impaired aggregation of platelets, and interference with platelet function by the abnormal monoclonal protein contribute to bleeding. ▪ Inhibitors of coagulation factors and thrombocytopenia from marrow infiltration of plasma cells or chemotherapy may also contribute to bleeding. o Electrophoresis of serum usually demonstrates the overproduction of IgM (19S) antibodies. o A monoclonal serum protein is detected in 91% of patients. ▪ The type of antibody is IgG in the majority of patients. Less frequently IgA is seen, and rarely IgD is demonstrated o Flame cell is observed WALDENSTRÖM PRIMARY MACROGLOBULINEMIA (LYMPHOPLASMACYTIC LYMPHOMA) • It is a B-cell neoplasm characterized by lymphoplasmo-proliferative disorder with infiltration of the bone marrow and a monoclonal immunoglobulin M (IgM) protein. o Associated with the production of abnormally large amounts of gamma globulin of the 19S or IgM type. o Basic abnormality in this macroglobulinemia is uncontrolled proliferation of lymphocyte and plasma cells. • Predominated by gamma globulins (macroglobulins) LYMPHOMAS • Lymphoproliferative disorder → includes the various forms of leukemias and malignant lymphomas that are of lymphoreticular origin. • Lymphomas → group of closely related disorders that are characterized by the overproliferation of one or more types of cells of the lymphoid system such as lymphoreticular stem cells, lymphocytes, reticulum cells, and histiocytes. LYMPHOMAS CLASSIFICATION • Revised European-American Lymphoma Classification (REAL classification) and World Health Organization (WHO) Classification of Tumours of the Haematopoietic and Lymphoid Tissues: o Hodgkin Lymphoma ▪ Preferred because of recent discoveries establishing the origin of the Reed-Sternberg cell in almost all cases of Hodgkin disease as the B lymphocytes. o Non-Hodgkin Lymphoma HODGKIN DISEASE • Characterized by the presence of Reed-Sternberg cells in the lymph nodes. o Reed-Sternberg cells function as: ▪ stimulatory cells in many lymphocyte reactions ▪ accessory cells in mitogen-induced T-cell proliferation ▪ antigen-presenting cells in HLA-DR –restricted, antigen-specific T-cell activation. • Characterized by a persistent defect in the cellular immunity with abnormalities in T lymphocytes, IL-2 production, and increased sensitivity to suppressor monocytes and normal T suppressor cells. o Normal cells are not produced • Aneuploidy , or a deviation from the diploid number of chromosomes, resulting from the gain or loss of chromosomes or from polyploids is a characteristic feature of Hodgkin disease. o A gain of chromosomes 1, 2, 5, 12, and 21 is a recurring numerical abnormality o Structural rearrangements involving chromosome 1 are frequently observed NON-HODGKIN LYMPHOMA • More fatal than Hodgkin’s Disease • Most frequent type of NHL is diffuse large B-cell lymphoma.
• Three different types of diffuse large B-cell lymphomas can be defined based on gene expression subgroups: o Germinal center, B-cell –like lymphoma that expresses high levels of genes characteristic of germinal center, B-cell –like lymal germinal center B cells o Activated B-cell –like lymphoma , which expresses genes characteristic of mitogenically activated blood B cells o New subgroup, type 3 diffuse large B-cell lymphoma , which has a heterogeneous gene expression that suggests it includes more than one subtype of lymphoma OTHER FORMS • Sezary Syndrome → leukemic phase of cutaneous T- cell lymphoma, mycosis fungoides. o In peripheral blood, the disease is characterized by the presence of abnormal circulating lymphocytes, Sézary cells. o Sézary cell → is typically the size of a small lymphocyte and has a dark-staining, clumped, nuclear chromatin pattern. • Mature T-Cell & NK-Cell Neoplasms → derived from mature or postthymic T cells. MYELOPROLIFERATIVE NEOPLASMS • Originated from myeloid precursors CHRONIC MYELOGENOUS LEUKEMIA • Consistently associated with the BCR-ABL 1 fusion gene located in the Philadelphia chromosome (Ph1). o Ph1 chromosome → reciprocal translocation of DNA between chromosomes 9 and 22 (long arms). o Philadelphia chromosome - first discovered aberration CYTOCHEMICAL STAINING • Leukocyte Alkaline Phosphatase Stain (LAP) o Stains ALP present in most neutrophil o To differentiate CML (↓) from leukemoid reaction or polycythemia vera o The degree of reactivity is measured by scoring each of 100 neutrophils according to the amount of precipitated dye present o CAP-LAP count** ▪ Bone marrow smear is used. ▪ Stained using alkaline phosphatase ▪ Examine 100 neutrophils ▪ Individual scoring ▪ NV: 70 -150 o Scored form 0 to 4 (strong) o HEPARIN must be used, EDTA; FALSELY DECREASED o (↑) Leukemoid Reaction, Polycythemia Vera, 3rd Trimester of Preganancy o (↓) CML, IM, PA, PNH
POLYCYTHEMIA VERA • William Osler (1910) (Polycythemia Rubra Vera) o Clinical description was that of a patient with engorged veins, plethora, and an elevated red blood cell count. o Leukocytosis and thrombocythemia were recognized as additional features • Dameshek (1951) o Added PV to the classification of MPNs o Main differential diagnosis is that of reactive erythrocytosis due to hypoxia • Clonal stem cell disorder characterized by hyperproliferation of the erythroid, myeloid, and megakaryocytic lineages • Northern blot analysis showed that PV-1 is highly expressed in normal human bone marrow and to a much lesser degree in fetal liver • Clinical Signs & Symptoms o Plethora - hallmark of PV o Increased in total blood volume o Most serious complications ▪ Arterial & venous complications (vascular accidents) ▪ Transition to acute leukemia o Thrombophlebitis with pulmonary embolism is a common complication of PV and often is unrecognized • Laboratory Data o ↑ erythrocyte count, packed cell volume, hemoglobin o Normal erythrocytic indices o ↓ serum erythropoietin (red cell proliferation is thought to be independent of endogenous erythropoietin) o Peak polycythemic values: ▪ hemoglobin of approximately 20.6 g/dL ▪ microhematocrit of approximately 80% ▪ total leukocyte (white blood cell [WBC]) count of 28,000 × 10 9 /L ▪ platelet count of 1,400 × 10 9 /L PRIMARY MYELOFIBROSIS • Primary Myelofibrosis o characterized by systemic bone marrow fibrosis and extramedullary hematopoiesis. • Secondary Myelofibrosis o caused by infiltrative disorders, including malignancies and infections, or exposure to chemical toxins or irradiation PRIMARY MYELOFIBROSIS • Diagnosis of Primary Myelofibrosis o Major Criteria ▪ Megakaryocytic proliferation with abnormal morphology, usually accompanied by reticulin and/or collagen fi brosis ▪ Not meeting the criteria for other MPNs ▪ Evidence of JAK2V617F or other related mutations o Minor Criteria ▪ Leukoerythroblastosis ▪ Anemia ▪ Increased serum lactic dehydrogenase (LDH) levels ▪ Splenomegaly ESSENTIAL THROMBOCYTOSIS / ESSENTIAL THROMBOCYTHEMIA • Characterized by a significant increase in circulating platelets, usually in excess of 1,000 × 10 9 /L. • Elevated platelet counts may be encountered as a reactive phenomenon, secondary to a variety of systemic conditions, or they may represent essential thrombocythemia, a primary disorder of the bone marrow
• Criteria for Diagnosis of Essential Thrombocytosis/ Essential Thrombocythemia o Persistent elevation of platelets (<450 × 1012 L) in peripheral blood o Significant increase (hyperplasia) of megakaryocytes in the bone marrow o Not meeting criteria of other MPNs o Demonstration of JAK2V617F or related mutation, or in the absence of JAK2V617F, no evidence for reactive thormbocytosis, (e.g., inflammation) MYELODYSPLASTIC SYNDROMES & MYELODYSPLASTIC / MYELOPROLIFERATIVE NEOPLASMS FAB CLASSIFICATION OF MDS WHO CLASSIFICATION OF MDS MDS Subtype Peripheral Blood Bone Marrow Refractory anemia (RA) Anemia <1% blasts Unilineage dysplasia > 10% in one myeloid line <5% blasts <15% ring sideroblasts Refractory anemia with ring sideroblasts (RARS) Anemia No Blasts Erythroid Dysplasia only >15% ring sideroblasts <5% blasts Refractory cytopenias with multilineage dysplasia (RCMD) Cytopenias <5% blasts No Auer Rods <1 x 10 9 /L monocytes Unilineage or multilineage dysplasia 5% to 9% blasts No Auer Rods Refractory anemia with excess blasts, type 2 (RAEB-2) Cytopenias <5% to 19% blasts Auer rods ± <1 × 10 9 /L monocytes Unilineage or multilineage dysplasia 10% –19% blasts Auer rods ± MDS Subtype Peripheral Blood Bone Marrow MDS associated with isolated del (5q) Anemia Normal or elevated platelet count <1% blasts Anemia, hypolobulated megakaryocytic anemia isolated 5q31 chromosome deletion Childhood MDS, including refractory cytopenia of childhood (provisional) Pancytopenia < 5% marrow red blood cell blasts usually hyptocellular marrow MDS, unclassifiable (MDS, U) Cytopenias ≤1% blasts Dysplasia and <5% blasts If no dysplasia, MDS-associated karyotype FEATURES OF SELECTED TYPES OF MYELODYSPLASTIC SYNDROME • Refractory Anemia (RA) • Refractory Anemia with Ring Sideroblasts (RARSs) • Refractory anemia with excess blasts (RAEB-1 and RAEB-2) MYELODYSPLASTIC / MYELOPROLIFERATIVE NEOPLASMS CHRONIC MYELOMONOCYTIC LEUKEMIA (CMML) • FAB classification of CMML Blasts Peripheral Blood Bone Marrow CMML-1 <5% <10% CMML-2 5% –19% 10% –19% Presence of Auer rods irrespective of the percentage of promonocytes and blasts • Other Classification of CMML o Atypical chronic myeloid leukemia (BCR-ABL1negative) ▪ Exhibits features of both myelodysplastic and myeloproliferative disorders at the time of diagnosis. ▪ Characterized by leukocytosis with a majority of neutrophils. ▪ Multilineage dysplasia is common o Juvenile myelomonocytic leukemia (JMML) ▪ Disorder of childhood ▪ Proliferation of granulocytic and monocytic lineages ▪ Blasts and promonocytes account for less than 20% of peripheral blood cells and bone marrow aspirates. ▪ Erythroid and megakaryocytic abnormalities are frequently preset ▪ BCR-ABL1 mutation is absent but mutations of genes of the RAS/MAPK pathway are characteristic. o Myelodysplastic/myeloproliferative neoplasm, unclassifiable ▪ Neoplasm meets the definition of MDS/MPN but does not meet the criteria for CMML or the other classification in this category