WBCs Disorders Dr. Nabila Hamdi MD, PhD
ILOs Compare and contrast ALL, AML, CLL, CML in terms of age distribution, cytogenetics, morphology, immunophenotyping, laboratory diagnosis clinical features and prognosis. Differentiate between the most common types of Non Hodgkin Lymphomas in terms of age distribution, cytogenetics, morphology, immunophenotyping, laboratory diagnosis, clinical features and prognosis. Differentiate between types of leukemia of both Lymphoid and Myeloid origin 2
Outline I. OVERVIEW II. Acute Leukemia 1. Acute Lymphoblastic Leukemia/Lymphoblastic Lymphoma 2. Acute Myeloid Leukemia III. Chronic Leukemia 1. Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma 2. Chronic Myelogenous Leukemia IV. Lymphoma 1. Diffuse Large B Cell Lymphoma 2. Burkitt Lymphoma 3
Overview AML ALL CML CLL http://encyclopedia.lubopitko-bg.com/blood_cells.html 4
Pathogenesis of Acute Leukemia Acquired mutations in transcription factors that regulate the differentiation of immature lymphoid or myeloid progenitors. Maturation arrest at blast stage Acquired mutations that allow the tumor cells to proliferate in a growth factor independent fashion Uncontrolled proliferation of blasts 5
Morphology of Acute Leukemia ALL Lymphoblasts have condensed nuclear chromatin, small nucleoli, and scant agranular cytoplasm. Lymphoblasts are TdT-positive. AML (Courtesy of Dr. Robert W. McKenna, Department of Pathology, University of Texas Southwestern Medical School, Dallas, Texas.) Myeloblasts have delicate nuclear chromatin, prominent nucleoli, and fine cytoplasmic granules. Myeloblasts are often peroxidase-positive. 6
Stages of B- and T-cell differentiation from which specific lymphoid and tumors emerge are shown. CD, cluster of differentiation; DR, human lymphocyte antigen-class II antigens; Ig, immunoglobulin; TCR, T-cell receptor; TdT, terminal deoxyribonucleotidyl transferase. 7
Acute Lymphoblastic Leukemia/Lymphoblastic Lymphoma ALL and lymphoblastic lymphoma are aggressive tumors, composed of immature lymphocytes (lymphoblasts), that occur predominantly in children and young adults. ALLs constitute 80% of childhood leukemia, peaking in incidence at age 4, with most cases being of pre-b cell origin. The pre-t cell tumors are most common in males between 15 and 20 years of age. 8
ALL/Lymphoblastic Lymphoma Clinical Features: Abrupt, stormy onset. Most patients present for medical attention within 3 months of the onset of symptoms. Blasts accumulating in the marrow suppress the growth of normal hematopoietic cells: fatigue (anemia), fever (neutropenia), and bleeding (petechiae, ecchymoses, epistaxis, gum bleeding) secondary to thrombocytopenia. Bone pain and tenderness, resulting from marrow expansion. Generalized lymphadenopathy, splenomegaly, and hepatomegaly due to dissemination of the leukemic cells (more pronounced in ALL than in AML). CNS manifestations, including headache, vomiting, and nerve palsies resulting from meningeal spread (more common in children than in adults and in ALL than in AML) 9
ALL/Lymphoblastic Lymphoma Laboratory Findings: Peripheral blood: Identification of blasts WBC count is variable; it may be greater than 100,000 cells/μl but in about half of the patients is less than 10,000 cells/μl. Anemia is almost always present. Platelet count usually is below 100,000/μL. Neutropenia is a common finding. Pancytopenia Bone marrow examination: (in aleukemic leukemia) Identification of blasts 10
ALL/Lymphoblastic Lymphoma Genetic Features: Pre-B cell tumors: Children: hyperdiploidy (more than 50 chromosomes/cell) (12;21) translocation involving TEL1 and AML1 genes Adults (25%): (9;22) translocation Pre-T cell tumors: frequent translocations involving the T cell receptor and transcription factor genes. Immunophenotypic Features: TdT is specifically expressed in pre-b and pre-t cells, is present in more than 95% of cases. CD19 (B cell) CD3 (T cell). 11
ALL/Lymphoblastic Lymphoma Prognosis: Best prognosis: Children 2 to 10 years of age have; with intensive chemotherapy up to 80% are cured. Correlated with good prognosis chromosomal aberrations (t[12;21] and hyperdiploidy) Worse outcomes: Male gender Age younger than 2 or older than 10 years, correlated with the presence of a BCR-ABL fusion gene t(9;22). A high leukocyte count at diagnosis. Molecular evidence of persistent disease on day 28 of treatment. 12
AML Acute Myeloid Leukemia AML primarily affects older adults; the median age is 50 years. The clinical signs and symptoms closely resemble those produced by ALL and usually are related to the replacement of normal marrow elements by leukemic blasts. Typically patients present within a few weeks of the onset of symptoms (Fatigue, pallor, abnormal bleeding, and infections) Splenomegaly and lymphadenopathy generally are less prominent than in ALL. 13
Pathogenesis: AML Mutations in genes encoding transcription factors that are required for normal myeloid cell differentiation. Accumulation of myeloid precursors (blasts) in the marrow. Acute promyelocytic leukemia (M3): (15;17) translocation results in the fusion of retinoic acid receptor α (RARA) gene on chromosome 17 and the PML gene on chromosome 15. The chimeric gene produces a PML/RARA fusion protein that blocks myeloid differentiation at the promyelocytic stage. 14
Morphology: AML Granules Bilobed nuclei-cells Needle-like Auer rods (specific for neoplastic myeloblasts) Acute promyelocytic leukemia Bone marrow aspirate: The neoplastic promyelocytes have numerous granules. Other characteristic findings include the presence of several cells with bilobed nuclei and a cell in the center of the field that contains multiple needle-like Auer rods. 15
AML Immunophenotype: The expression of immunologic markers is heterogeneous in AML. Most tumors express some combination of myeloid-associated antigens, such as CD13, CD14, CD15, CD64 CD33 is expressed on pluripotent stem cells but is retained on myeloid progenitor cells. Prognosis: AML is a devastating disease with an overall survival of only 15% to 30% with conventional chemotherapy. A bright spot is the improvement in outcomes in acute promyelocytic leukemia brought about by targeted treatment with ATRA (all-trans retinoic acid) and arsenic salts. 16
Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma CLL and SLL are essentially identical, differing only in the extent of peripheral blood involvement. If the peripheral blood lymphocyte count exceeds 4000 cells/μl, the patient is diagnosed with CLL. CLL is the most common leukemia of adults in the Western world. For unclear reasons, CLL/SLL is much less common in Asia. 17
CLL/SLL Pathogenesis: CLL/SLL is an indolent, slowly growing tumor, (cell survival is more important than cell proliferation). Tumor cells contain high levels of BCL2, a protein that inhibits apoptosis. Immune dysregulation: CLL/SLL cells suppress normal B cell function resulting in hypogammaglobulinemia and autoimmune hemolytic anemia. As time passes, tumor cells tend to displace the normal marrow elements, leading to anemia, neutropenia, and eventually thrombocytopenia. 18
CLL/SLL Morphology: Low-power view shows diffuse effacement of nodal architecture. At high power, a majority of the tumor cells have the appearance of small, round lymphocytes. In addition to the lymph nodes, the bone marrow, spleen, and liver are involved in almost all cases. In most patients there is an absolute lymphocytosis featuring small, maturelooking 19 lymphocytes.
CLL/SLL Immunophenotypic and Genetic Features: The pan-b cell markers of mature B cells CD19, CD20, and CD23 and surface Ig heavy and light chains. The tumor cells also express CD5 Karyotypic abnormalities (50%) : Trisomy 12 Chromosomal deletions (11, 13, and 17) Unlike in other B cell neoplasms, chromosomal translocations are rare. 20
Clinical Features: CLL/SLL When first detected, CLL/SLL is often asymptomatic. Easy fatigability, weight loss, and anorexia Generalized lymphadenopathy and HSMG (50%-60%) The leukocyte count may be increased only slightly (in SLL) or may exceed 200,000 cells/μl with absolute lymphocytosis. Hypogammaglobulinemia (in more than 50%) Prognosis: The course and prognosis are extremely variable. The median survival is 4 to 6 years, however CLL/SLL tends to transform to more aggressive tumors that resemble diffuse large B cell lymphoma: recent onset of weight loss and enlargement of lymph nodes (Richter syndrome). Once transformation occurs, the median survival is less than 1 year. 21
Chronic Myelogenous Leukemia CML is marked by the hyperproliferation of neoplastic myeloid progenitors that retain the capacity for terminal differentiation. CML principally affects adults between 25 and 60 years of age. The peak incidence is in the fourth and fifth decades of life. 22
Pathogenesis: CML CML is always associated with the presence of a BCR-ABL fusion gene. A balanced t(9;22) translocation moves ABL from chromosome 9 to a position on chromosome 22 adjacent to BCR. Although the Ph chromosome is highly characteristic of CML, it also is present in 25% of adult B cell ALLs. BCR-ABL generates signals that mimic the effects of growth factor receptor activation in myeloid progenitors. Although the BCR-ABL fusion gene is present in multiple lineages, for unclear reasons the pro-growth effects of BCR-ABL are confined mainly to the granulocyte and megakaryocyte lineages. Because BCR-ABL does not inhibit differentiation, the early disease course is marked by excessive hematopoiesis. 23
Morphology: CML Chronic myelogenous leukemia peripheral blood smear. Granulocytic forms at various stages of differentiation are present. 24
CML Morphology: The peripheral blood findings are highly characteristic. The leukocyte count is elevated, often exceeding 100,000 cells/μl. The circulating cells are predominantly neutrophils, metamyelocytes, and myelocytes but basophils and eosinophils are also prominent and platelets are usually increased. A small proportion of myeloblasts, usually less than 5%, are often seen in the peripheral blood. The BM is hypercellular owing to increased numbers of granulocytic and megakaryocytic precursors. The red pulp of the enlarged spleen resembles bone marrow because of the presence of extensive extramedullary hematopoiesis. 25
CML Clinical Features: The onset of CML often is insidious with nonspecific symptoms (easy fatigability, weakness, weight loss). Sometimes the first symptom is a dragging sensation in the abdomen caused by SMG. The natural history of CML initially is one of slow progression. Even without treatment, the median survival is 3 years. After a variable period, blast crisis might occur. It is marked by increasing anemia, new thrombocytopenia, and additional cytogenetic abnormalities. in 30% of cases the blast crisis resembles B-ALL and in the remaining 70% of cases, the blast crisis resembles AML. BCR-ABL tyrosine kinase inhibitors, such as imatinib and nilotinib, induce complete remission in a high fraction of patients. 26
features type Age Clinical picture Lab Immuno pheno type Genetics Prognosis ALL B & T Child (B) Young adult (T) -Stormy (Weeks) -Fatigue -Fever -Bleeding -Bone pain -Lymphadenopathy -SMG -HMG -CNS: Headache, vomiting Smear: Blasts (TdT+ve) CBC: variable WBC count Pancytopenia BM: Blasts (hypercellular) condensed nuclear chromatin, small nucleoli, and scant agranular cytoplasm TdT (+ve) CD 19 B CD 3 T Pre-B ALL Children: (good prognosis) -Hyperdiplody -t(12, 21) Adults: (bad prognosis) t(9, 22) 25% Best: (2 10 years old) t[12;21]&hyperdiploidy Worse: -Male -<2 years old ->10 years old - WBC at diagnosis -Persistent >28 day - treatment AML CLL/SLL CML Adult (50 years old) Adult Adult From 20 to 60 -Few weeks -Indolent, slowly growing -Insidious, slow -Fatigue -Fatigue, weight loss, - -Fatigue -Infections, fever anorexia -Weakness -Bleeding -At diagnosis, often no -Weight loss -Pale symptoms -SMG (extramedullary -Lymphadenopathy -Lymphadenopathy hematopoiesis) -SMG -SMG -Bleeding -HMG Smear: Blasts (Peroxidase +ve) CBC: WBC Pancytopenia BM: Blasts (hypercellular) delicate nuclear chromatin,prominent nucleoli, and fine cytoplasmic granules Needle-like Auer Rods CD 13, 14, 15 & 64 M3: Acute promyelocytic leukemia t(15,17) (PML RARα) fusion protein(differentiation blocked at promyelocytic stage Poor, but Acute Promyelocytic has better prognosis upon treatment with ATRA -Ig (bacterial infect.) -AI. Hemolytic anemia -WBC (lymphocytosis) -Small lymphocytes, mature-looking -Biopsy: diffuse effacement of lymph node structure -BM hypercellular -Later: Pancytopenia -Mature B cells -CD 19, 20, 23 & CD5 -Surface Ig rearrangement -BCl 2 (no apoptosis) -Trisomy 12 -del 11, 13, 17 ** -No translocations! -Variable -Richter Syndrome: Transformation to "diffuse B cell lymphoma" (more aggressive/poor prognosis): weight loss and enlargement of lymph nodes -WBC >100,000/µL -Neutrophils -Metamyelocytes -Myelocytes -Basophils -Eosinophils -Platelets (Thrombocytosis) -Myeloblasts < 5% -Anemia -BM hypercellular -Blast crises: More blasts Anemia Thrombocytopenia Like AML (70%) Like B-ALL (30%) Variable Philadelphia t(9, 22) BCR ABL fusion protein in myeloid stem cells Granulocytes & Megakaryocytes are mainly affected Tyrosine kinase Inhibitors Complete remission possible 27
BLB,pre-B lymphoblast; CLP, common lymphoid progenitor DN, CD4 /CD8 (double-negative) pro-t cell; DP, CD4+/CD8+ (double-positive) pre-t cell GC, germinal center B cell; MC, mantle zone B cell; MZ, marginal zone B cell; NBC, naive B cell PC, plasma cell; PTC, peripheral T cell. 28
Diffuse Large B Cell Lymphoma Pathogenesis: The most common type of lymphoma in adults, accounting for approximately 50% of adult non-hodgkin lymphoma (NHLs) and about 15% of childhood lymphomas. Increased levels of BCL6 protein, an important transcriptional regulator of gene expression in germinal center B cells. Overexpression of BCL2 protein due to t(14;18) translocation. Morphology: The neoplastic B cells are large (at least three to four times the size of resting lymphocytes) and vary in appearance from tumor to tumor. Immunophenotyping: Mature B cell tumors express pan-b cell antigens, such as CD19 and CD20. Many also express surface Ig. CD10 is variably expressed. 29
Diffuse Large B Cell Lymphoma Subtypes : EBV-associated diffuse large B cell lymphomas arise in the setting of: AIDS Transplant recipients The elderly Kaposi sarcoma herpesvirus (KSHV) or human herpesvirus type 8 (HHV- 8): encodes proteins homologous to several known oncoproteins, including cyclin D1. Mediastinal large B cell lymphoma occurs most often in young women and shows a predilection for spread to abdominal organs and CNS. 30
Diffuse Large B Cell Lymphoma Clinical Features: Patients typically present with a rapidly enlarging, often symptomatic mass at one or several sites. Extranodal presentations are common: tumors can appear in virtually any organ or tissue (commonly in brain and GIT) Involvement of the liver, spleen, and bone marrow is not common at diagnosis. Without treatment, diffuse large cell B cell lymphomas are aggressive and rapidly fatal. 31
Pathogenesis: Burkitt Lymphoma Burkitt lymphoma is endemic in parts of Africa and occurs sporadically in other geographic areas. Burkitt lymphoma is highly associated with translocations involving the MYC gene on chromosome 8 leading to the dysregulation and overexpression of MYC protein: t(8,14), t(8,2) or t(8,22). In most endemic cases and about 20% of sporadic cases, the tumor cells are latently infected with EBV, but the role of EBV in the genesis of this tumor remains uncertain. 32
Morphology: Burkitt Lymphoma Very high rates of proliferation and apoptosis are characteristic. Apoptosis accounts for the presence of numerous tissue macrophages containing ingested nuclear debris. Immunophenotyping: Surface IgM, the pan-b cell markers CD19 and CD20, CD10 and BCL6+. 33
Burkitt Lymphoma Clinical Features : Both the endemic and nonendemic sporadic forms affect mainly children and young adults. Burkitt lymphoma accounts for approximately 30% of childhood NHLs in the US. The disease usually arises at extranodal sites: Endemic tumors often manifest as maxillary or mandibular masses. Whereas abdominal tumors involving the bowel, retroperitoneum, and ovaries are more common in North America. Burkitt lymphoma is among the fastest-growing human neoplasms; however, with very aggressive chemotherapy regimens, a majority of patients can be cured. 34
Burkitt Lymphoma Burkitt lymphoma lymph node. The tumor cells and their nuclei are fairly uniform, giving a monotonous appearance. Note the high level of mitotic activity (arrowheads) and prominent nucleoli. http://manbir-online.com/diseases/eb-virus.htm 35
References ROBBINS Basic Pathology 9 th Edition Source of the cover: http://home.kku.ac.th/acamed/kanchana/bsi.html 36
Thank you 37