Neoplastic Proliferation of WBC

White blood cells

·         Myeloid

–        Myeloblast

–        Promyelocyte

–        Myelocyte

–        Metamyelocyte

–        Band

–        Neutrophil,eosinophil, basophil

•          Lymphoid

–        Lymphocyte (B and T) and plasma cells

–        Neoplastic proliferation of white cells

Classification according to the origin of tumor cells:

–        Lymphoid neoplasms

•          Lymphocytic Leukemia

•          Lymphoma (Hodgkin and non Hodgkin)

•          Plasma cell dyscrasia

–        Myeloid neoplasms

•          Acute myelogenous leukemia

•          Myelodysplastic syndromes

•          Chronic myeloproliferative disorders

–        Histiocytoses: proliferative lesion of macrophages and dendritic cells

•          Langerhans cell histiocytoses

Lymphoid Neoplasms

•          Leukemia: lymphoid neoplasm characterized by a malignant neoplastic proliferation and accumulation of immature

hematopoietic cells in the bone marrow with spillage of neoplastic cells in peripheral blood

•          Lymphoma : proliferations arising as discrete tissue masses within either lymph node or other organs

–        Hodgkin lymphoma

–        Non- Hodgkin lymphoma

•          Plasma cell neoplasms (Plasma cell dyscrasias)

–        Tumors composed of terminally differentiated B cells

–        Usually present within the bones as discrete masses

–        Secretion of whole antibodies or immunoglobulin fragments by the tumor cells and cause systemic symptoms

Leukemia : Malignant tumors that primarily involve the bone marrow with spillage of neoplastic cells into the peripheral blood

Classification

•          On the basis of cell types predominantly involved: i. Myeloid         ii. Lymphoid

•          On the basis of natural history of the disease: i. Acute           ii. Chronic

•          Thus the main types are:

–        Acute myelogenous leukemia (AML)

–        Acute lymphoblastic leukemia (ALL)

–        Chronic myeloid leukemia (CML)

–        Chronic lymphocytic leukemia (CLL)

•          Acute leukemia- Rapidly downhill course

•          Chronic leukemia- Indolent behaviour

•          ALL- Children

•          AML- Adults (peak age 15-39 years)

•          CLL- Elderly

•          CML- Adults (25-60 yrs; peak incidence 4^th & 5^th decades)

•          ALL- more common in children, good prognosis. Less in adult, bad prognosis

•          CLL- Insidious onset. Prolonged clinical course. Poor response to treatment

•          AML- more common in adults

•          CML- both young and old adults. Prolonged course. May turn into acute leukemia

Etiology of white cell neoplasia

1)      Genetic factors

–        Bloom syndrome

–        Fanconi anemia

–        Ataxia telangiectasia

–        Down syndrome

2) Environmental factors

–        Ionising radiation

–        Chemical- Benzene

–        Drugs- Alkylating drugs

3)   Infection

o   Human T-cell leukemia virus-1: Adult T-cell leukemia/lymphoma

o   Epstein-Barr virus: Burkitt lymphoma, Hodgkin lymphoma

o   Kaposi sarcoma herpesvirus: B cell lymphoma

o   HIV: B cell lymphoma

o   Helicobacter pylori: Gastric B cell lymphoma

Acute leukemia

•          Characterised by predominance of undifferentiated leucocyte precursors or leukemic blasts

•          AML- Derived from myeloid stem cells

•          ALL- Lymphoid stem cell

•          Acute leukemia: Blasts >20% in the marrow

Pathophysiology of Acute Leukemias

•          Block in differentiation à accumulation of immature leukemic blasts in the bone marrow àsuppression of the function of normal hematopoietic stem cells by physical displacement à bone marrow failure à clinical signs and symptoms

Clinical Features of Acute Leukemias

•          Abrupt onset. Most patients present within 3 months of the onset of symptoms

•          Symptoms related to depression of normal marrow function

–        Fatigue (due to anemia)

–        Fever (reflecting infections resulting from the absence of mature leukocytes)

–         Bleeding (petechiae, ecchymoses, epistaxis, gum bleeding) secondary to thrombocytopenia

•          Bone pain and tenderness due to marrow expansion and infiltration of the subperiosteum

•          Generalized lymphadenopathy, splenomegaly, and hepatomegaly

–        due to organ infiltration by leukemic cells

–        more pronounced in ALL than in AML

–        Central nervous system manifestations

–        Headache, vomiting, and nerve palsies resulting from meningeal spread

–        More common in children than in adults

–        More common in ALL than AML.

WHO classification of Acute myelogenous leukemia

•          AML with recurrent chromosomal rearrangements

•          AML with multilineage dysplasia

•          AML, therapy related

•          AML, not otherwise specified

WHO classification of lymphoid neoplasms

•          Precursor B-cell neoplasms (neoplasms of immature B cells)

•          Peripheral B-cell neoplasms (neoplasms of mature B cells)

•          Precursor T-cell neoplasms (neoplasms of immature T cells)

•          Peripheral T-cell and NK cell neoplasms (neoplasms of mature B cells)

•          Hodgkin lymphoma

French-American – British (FAB) classification

AML: Mo – M7

Revised FAB Classification of Acute Myelogenous Leukemias (AML)

•          M0: Minimally differentiated AML

•          M1: AML without maturation

•          M2: AML with maturation

•          M3: Acute promyelocytic leukemia

•          M4: Acute myelomonocytic leukemia

•          M5: Acute monocytic leukemia

•          M6: Acute erythroleukemia

•          M7: Acute megakaryocytic leukemia

Diagnosis

•          Blood picture

AML- Myeloblast

               ALL- Lymphoblast

–        Anemia

–        WBC count variable: increased

–        Neutropenia

–        Low or high  platelets

–        Aleukemic leukemia: Pancytopenia but no blasts in peripheral blood

•          Bone marrow examination

•          Cellularity- Hypercellular

•          Leukemic cells- Blasts > 20%

•           Erythropoiesis, megakaryocytes reduced

Cytochemistry

                MPO, SB + in myeloid

                                PAS +

Difference between myeloblast and lymphoblast

                               

	Lymphoblast	Myeloblast
Nuclear Chromatin	Coarse and clumped	Fine
Nucleoli	1-2	3-5
Cytoplasm	Less	More and may contain granules
Auer rod	-ve	+ve
Accompanying cells	Lymphocytes	Promyelo, myelo, meta and neutriphils
MPO	-ve	+ve
Sudan Black B	-ve	+ve
Periodic Acid-Schiff	Block positivity immunomarker	Often positive

Management

•          Supportive care

–        Blood transfusion

–        Control of infection

–        Nutritional support

•          Chemotherapy

 Chronic leukemia

•          Divided into two types:

                  1. Chronic myelogenous leukemia (CML)

                  2. Chronic lymphocytic leukemia (CLL)

Chronic myelogenous leukemia (CML)

•          Stem cell disease characterized by granulocytic immaturity, basophilia, splenomegaly and distinct chromosomal abnormality – Philadelphia chromosome

•          Peak incidence: 4^th  and 5^th decade

Pathogenesis

–        BCR-ABL fusion gene is the product of a (9;22) translocation that moves the ABL gene from chromosome 9 to a position on chromosome 22 adjacent to the BCR gene. The derivative chromosome 22 is often referred to as the Philadelphia (Ph) chromosome, because it was discovered in Philadelphia

–         t (9;22)---- Philadelphia chromosome

–        A piece of the long arm of one chromosome #9 and a piece of the long arm of one chromosome #22 have translocated (exchanged places): t(9;22)(q34;q11.2). The hybrid chromosome #22 has been termed the Philadelphia chromosome

–        Encodes for tyrosine kinase activity

–        Uncontrolled proliferation of myeloid cells

–        proliferating CML progenitors retain the capacity for terminal differentiation

Clinical features

1. Insidious onset
2. Anemia
3. Anorexia, weight loss, weakness
4. Dragging sensation in abdomen due to massive spleenomegaly

Lab investigation

1. Blood picture
1. Anemia
2. WBC: Leukocytosis-  exceeding 100,000 cells/μL  neutrophils, metamyelocytes, and myelocytes,  basophils and eosinophils. Myeloblasts, usually less than 5%
3. Platelets : Thrombocytosis
2. Bone marrow examination: Hypercellular due to hyperplasia of granulocytic and megakaryocytic precursors. Myeloblasts are usually only slightly increased. Reduction in erythropoietic cells

               

D/D: Leukemoid reaction

–          Presence of the Ph chromosome in CML

–          Measurement of leukocyte alkaline phosphatase

•           Granulocytes in CML are almost completely devoid of this enzyme, whereas it is increased in leukemoid reactions and other myeloproliferative disorders (such as PCV)

Phases of CML

•          Chronic phase

•          Accelerated phase

•          Blast crisis (> 20% blasts)

Chronic lymphocytic leukemia (CLL)

v  Peripheral blood lymphocytosis exceeds 4000 cells/mm³

v  Disease of elderly (> 50 years) with male preponderance

v  Lymphoid malignancy of mature B cells

v  Insidious onset

Pathophysiology

•          The neoplastic B cells suppress normal B-cell function resulting in hypogammaglobulinemia

•           Autoantibodies against autologous red cells; other autoantibodies can also be detected

•           Tumor cells displace the normal marrow elements, leading to anemia, neutropenia, and eventual thromobocytopenia

Clinical features

1. Easy fatigability, wt. loss, anorexia
2. Lymphadenopathy
3. Hepatospleenomegaly
4. Increased susceptibility to infection (deranged immune function with hypogammaglobulinemia)
5. Autoimmune hemolytic anemia or thrombocytopenia (auto Ab against RBC and platelets)

Lab investigation

1. Blood picture
1. Anemia
2. WBC- Marked leukocytosis (absolute lymphocyte count >4000 per cumm) , smudge cells
3. Platelets- Normal or moderately reduced
2. Bone marrow examination
1. Increased lymphocyte count
2. Reduced myeloid precursors
3. Reduced erythroid precursors

Lymphoma

•          Malignant tumours of lymphoreticular origin arising as discrete tissue mass

•          Two distinct clinicopathologic groups:

1.       Hodgkin lymphoma

2.       Non-Hodgkin  lymphoma

Non-Hodgkin Lymphoma (WHO classification)

3.       Precursor B cell neoplasms

•          Precursor B  lymphoblastic leukemia/lymphoma

4.       Peripheral B cell neoplasms

•          Small lymphocytic lymphoma

•          Follicular lymphoma

•          Burkitt lymphoma

•          Diffuse large B-cell lymphoma

•          Extranodal marginal zone lymphoma

•          Mantle cell lymphoma

5.       Precursor T cell neoplasms

•          Precursor T lymphoblastic leukemia/lymphoma

6.       Peripheral T cell  and NK-cell neoplasms

•          Anaplastic large cell lymphoma

•          Angioimmunoblastic T-cell lymphoma

•          Adult T-cell lymphoma

•          NK/T-cell lymphoma

Hodgkin lymphoma (WHO classification)

•          Classical  subtypes

1.       Nodular sclerosis

2.       Mixed cellularity

3.       Lymphocyte rich

4.       Lymphocyte depletion

•          Lymphocyte predominance

Lymphoma

•          Clinical presentation of various lymphoid neoplasm

1.       2/3 of NHL and all cases of Hodgkin lymphoma: Non tender nodal enlargement (often >2 cm), localised or generalized

2.       1/3 NHL arise at extranodal sites (eg- Skin, Stomach, Brain)

•          Vast majority of lymphoid neoplasms (80-85%) are of B cell origin, most of the remainder being T cell tumours

Hodgkin Lymphoma

•          Tumor of B-cell origin

•          Characterized morphologically by the presence of distinctive neoplastic giant cells called Reed-Sternberg (RS) cells, which are admixed with reactive, nonmalignant inflammatory cells

•          Arise almost invariably in a single lymph node or chain of lymph nodes and spread characteristically in a stepwise fashion to the anatomically contiguous nodes

Reed-Sternberg cell

•          Large (15 -45 um in diameter)

•          Multiple nuclei or a single nucleus with multiple nuclear lobes

•          Prominent nucleoli

•          Abundant  slightly eosinophilic cytoplasm

•          CD15+, CD30+

Diagnostic Reed-Sternberg cell

•           Cells with two mirror-image nuclei or nuclear lobes, each containing a large (inclusion-like) acidophilic nucleolus surrounded by a distinctive clear zone

•          Owl-eye appearance

•          Nuclear membrane is distinct

•          Mixed cellularity

•          Lymphocyte rich

•          Lymphocyte depletion

Variants of RS cells

1.       Mononuclear variant: single round or oblong nucleus with a large inclusion like nucleolus

2.       Lymphocyte rich

3.       Mixed cellularity

4.       Lacunar cells: folded or multilobate nuclei  with abundant pale cytoplasm

5.       Nodular sclerosis

6.       Lymphohistiocytic variant: polypoid nuclei resembling popcorn, inconspicuous nucleoli and moderately abundant cytoplasm

7.       Lymphocyte predominance

Nodular sclerosis

•          Most common

•          Both men and women. Adolescents or young adults

•          Involve lower cervical, supraclavicular, and mediastinal lymph nodes

•          Prognosis is excellent

•          Lacunar cells

•          Background- L, M, E, P

•          Fibrous band

•          Cells express CD15 and CD30

Mixed cellularity

•          Most common form of Hodgkin lymphoma in patients older than the age of 50

•          Males

•          Classic RS cells

•          Background- L, M, E, P

•          More patients have disseminated disease and systemic manifestations.

Lymphocyte rich

•          Males

•          Lymphadenopathy

•          Mononuclear and diagnostic R-S cells

•          CD 15+, CD 30+

•          Reactive lymphocyte

•          Associated with EBV

•          Good to excellent prognosis

Lymphocyte depletion

•          Least common

•          Elderly and HIV +VE; EBV

•          Paucity of lymphocytes and abundance of  R-S cells

•          Prognosis less favourable

Lymphocyte predominance

•          Uncommon

•          Young to middle aged males

•          Cervical or axillary lymphadenopathy

•          L and H cell (popcorn cell); CD 20+

•          large number of small resting lymphocytes admixed with a variable number of benign histiocytes

•          Excellent prognosis

Spread of Hodgkin Lymphoma

•          Nodal disease

•          Splenic disease

•          Hepatic disease

•          Marrow involvement

•          Extranodal disease

Clinical staging: Ann Arbor classification

Clinical Course

•          Painless enlargement of lymph node

•          Tumor stage important prognostic variable

•          Stage I and IIA : cure rate 90%

•          Advanced disease (stages IVA and IVB): 60-70% 5 year disease free survival

Non Hodgkin lymphoma

•          Children and adolescent

1.       Precursor B –cell acute  lymphoblastic leukemia/lymphoma

2.       Precursor T –cell acute  lymphoblastic leukemia/lymphoma

3.       Burkitt lymphoma

4.       Anaplastic large cell lymphoma

•          Adults

1.       Diffuse large B-cell lymphoma

2.       Extranodal marginal zone lymphoma

3.       Burkitt lymphoma

4.       Adult T-cell leukemia/lymphoma

5.       Anaplastic large cell lymphoma

6.       Extranodal NK/T-cell  lymphoma

•          Older adults

1.       Follicular lymphoma

2.       Small lymphocytic lymphoma

3.       Mantle cell lymphoma

Follicular lymphoma

•          Common tumors

•          Middle age

•          Both male and female

•          Nodular aggregates of lymphoma cells

Morphology

–        Lymph node effaced

–        Nodular appearance

–        Neoplastic cells are "centrocyte-like" cells s that have angular "cleaved" nuclear contours, coarse nuclear chromatin and indistinct nucleoli

–         These small, cleaved cells are mixed with variable numbers of larger "centroblast-like" cells that have vesicular chromatin, several nucleoli, and modest amounts of cytoplasm

–        Mitoses are infrequent, and single necrotic cells (cells undergoing apoptosis) are not seen (vs. reactive follicles)

Immunophenotype

–        Tumors express the pan-B-cell markers CD19 and CD20, CD10, and BCL6, a transcription factor that is required for follicular center formation

–        The neoplastic cells characteristically express BCL2, a protein that is absent from normal follicular B cells

Mantle Cell Lymphoma

•          Composed of B cells that resemble cells in the mantle zone of normal lymphoid follicles

•          Occur mainly in older males

•          Fatigue, lymphadenopathy and  generalized disease involving the bone marrow, spleen, liver, and (often) the gastrointestinal tract

•           These tumors are aggressive and incurable

Morphology

•          Diffuse or vaguely nodular pattern

•           The tumor cells are usually slightly larger than normal lymphocytes and have an irregular nucleus and inconspicuous nucleoli

•          The bone marrow is involved in the majority of cases, and about 20% of patients have peripheral blood involvement

•          Frequent involvement of the gastrointestinal tract, sometimes in the form of multifocal submucosal nodules that grossly resemble polyps (lymphomatoid polyposis)

Diffuse Large B-Cell Lymphoma

•          Approximately 50% of adult NHL

•           B-cell phenotype

•          Diffuse growth pattern

•          Aggressive clinical history

•          EBV : AIDS or transplant patients

•          Kaposi sarcoma herpesivirus (KSHV), also called human herpesvirus type 8 (HHV-8) : primary effusion lymphomas within the pleura, pericardium, or peritoneum

•          Mediastinal large B-cell

–        young females

–         spread to abdominal viscera and the central nervous system.

•          Arise at any age

–        Median age at presentation is about 60 years

–        15% of childhood lymphomas

–        Patients typically present with a rapidly enlarging, often symptomatic mass at one or several sites

–        Extranodal presentations are common: gastrointestinal tract and the brain

–        Involvement of the liver, spleen, and bone marrow is not common at the time of diagnosis

Morphology

•           Large nuclei (at least three to four times the size of resting lymphocytes)

Different forms

–         In many tumors, cells with round, irregular, or cleaved nuclear contours, dispersed chromatin, several distinct nucleoli, and modest amounts of pale cytoplasm predominate (Fig. 12-17). Such cells resemble centroblasts

–         In other tumors, the cells have a large round or multilobulated vesicular nucleus, one or two centrally placed prominent nucleoli, and abundant cytoplasm that can be either pale or intensely staining. These cells resemble an immunoblast

•          Immunophenotype

–        CD19 and CD20 +ve

–         Express surface IgM and/or IgG.

Burkitt Lymphoma

•          Endemic/ sporadic

•          EBV

•          Children and young adults

•          usually arises at extranodal sites: maxilla or mandible,abdominal tumors involving the bowel, retroperitoneum

•          High grade tumor

•          Distinguish from ALL

Morphology

•          The tumor cells are uniform and intermediate in size and have round or oval nuclei containing two to five prominent nucleoli

•           Moderate amount of cytoplasm containing small, lipid-filled vacuoles

•           A high mitotic rate is very characteristic of this tumor, as is cell death, accounting for the presence of numerous tissue macrophages containing ingested nuclear debris. Because these benign macrophages are often surrounded by a clear space, they create a "starry sky" pattern

•          Immunophenotype

–        Express surface IgM, κ or λ light chain

–         CD19, CD20 and CD10

Small Lymphocytic Lymphoma/Chronic Lymphocytic Leukemia

•          These two disorders are morphologically, phenotypically, and genotypically identical, differing only in the extent of peripheral blood involvement

•           If the peripheral blood lymphocytosis exceeds 4000 cells/mm³, the patient is diagnosed with chronic lymphocytic leukemia (CLL); if not, a diagnosis of small lymphocytic lymphoma (SLL) is made

Morphology

•           Sheets of small round lymphocytes and scattered ill-defined foci of larger, actively dividing cells diffusely efface involved lymph nodes

•          The predominant cells are compact, small, resting lymphocytes with dark-staining round nuclei, scanty cytoplasm, and little variation in size

•           The foci of mitotically active cells are called proliferation centers; their presence is pathognomonic for CLL/SLL

•           In addition to the lymph nodes, the bone marrow, spleen, and liver are involved in almost all cases

Plasma cell dyscrasias

•          Six variants

1.       Multiple myeloma

2.       localized plasmacytoma (solitary myeloma)

3.       lymphoplasmacytic lymphoma

4.       heavy-chain disease

5.       primary or immunocyte-associated amyloidosis

6.       monoclonal gammopathy of undetermined significance

•          All originate from a clone of B cells that differentiates into plasma cells and secretes a single complete or partial immunoglobulin

•          These disorders are also called monoclonal gammopathies as the serum contains excess amount of immunoglobulins

•          M component: associated immunoglobulin

Multiple myeloma

•          Plasma cell neoplasm

Ø  Clonal proliferation of neoplastic plasma cells in the bone marrow

Ø  Neoplastic plasma cells are called myeloma cells and associated immunoglobulin is called M component

Ø  Associated with multifocal lytic lesions throughout the skeletal system

Ø  vertebral column, 66%; ribs, 44%; skull, 41%; pelvis, 28%; femur, 24%; clavicle, 10%; and scapula, 10%

Ø  Elderly (5^th to 6^th decades

Pathogenesis

Ø   Interleukin 6 (IL-6) produced by fibroblasts and macrophages in the bone marrow stroma à proliferation of myeloma cells

Ø  Secretion of IgG (60%), followed by IgA (20% to 25%): M component

Ø  κ or λ light chains

Ø  Bence-Jones proteins:

Ø   Free light chains that are rapidly excreted in the urine

Ø  Affect renal function

•          Malignant plasma cells secrete complete immunoglobulin molecules and free light chains and thus produce both serum M components and Bence-Jones proteins

•          Plasma cells grow within marrow, diffusely replacing normal hematopoietic tissue

•          The bone resorption results from the secretion of certain cytokines (e.g., IL-1β, tumor necrosis factor, IL-6) by myeloma cells. These cytokines stimulate production of another cytokine called RANK-ligand, which promotes the differentiation and activation of osteoclasts

•          Bone destruction may cause hypercalcemia and pathological which occur most frequently in the vertebral column.

•          Increased protein concentration in the blood is responsible for an elevated ESR as a result of rouleaux formation.

•          In some cases the light chains form amyloid, which is deposited in tissues, particularly the renal glomeruli and heart.

•          Renal dysfunction is common as a result of light chain casts, with secondary damage to tubules and amyloid.

Clinical features

1)      Bone pain (infiltration by neoplastic plasma cells)

2)      Susceptibility to infections (suppression of normal immunoglobulin secretion)

3)      Renal failure (toxic effects of Bence-Jones proteins on cells lining the tubules, recurrent bacterial infections and hypercalcemia)

4)      Anemia (marrow replacement as well as from inhibition of hematopoiesis by tumor cells)

5)      Pathologic fracture (bone destruction and diffuse resorption)

6)      Neurologic manifestation such as confusion and lethargy (hypercalcemia)

Morphology

 Bone marrow lesions

•          Hypercellular

•          Plasma cells – >30% of marrow cellularity

•          Plasma cells may show prominent nucleoli

•          Immunoglobulin inclusions (Russel bodies) in cytoplasm

•           Myeloma nephrosis

–        Renal involvement by multiple myeloma

–         Proteinaceous casts in the distal convoluted tubules and collecting ductSS Most of these casts are made up of Bence-Jones proteins, but they may also contain complete immunoglobulins, Tamm-Horsfall protein, and albumin

–         Epithelial cells lining the cast-filled tubules become necrotic or atrophic because of the toxic actions of the Bence-Jones proteins

–        Metastatic calcification

–         When complicated by systemic amyloidosis, nodular glomerular lesions are present

–        Pyelonephritis can also occur as a result of the increased susceptibility to bacterial infections

Diagnosis

1.       Blood

o   Rouleaux formation due to high level of serum M  protein

o   Elevated ESR

o   Anemia

o    Serum calcium, urea, creatinine increased

2.       Bone marrow examination

3.       Electrophoretic studies on serum and urine monoclonal spike of complete immunoglobulin or immunoglobulin light chain

4.       Imaging

o   Pathologic fracture of vertebra

o   Punched out lesion on x-ray

5.       Bence jones protein in urine

Prognosis: Poor

Progressive disease, with median survival ranging from 4 to 5 years