Other 13 Flashcards
CD34
Antigen/marker of HSC cells
CD45
leukocyte common antigen – found on all white cells
Hematopoietic stem cells
Pluripotent == can generate all mature blood cells
mature blood elements are terminally differentiated cells with finite life spans
One cell → all lineages
Capacity for self-renewal
Common origin of all formed blood elements
Myeloid: erythrocytes, granulocytes, monocytes, platelets
MMEG == Monocytes, megakaryocytes, erythrocytes, and granulocytes
this is how Putthoff refers to Myeloid derived cells
MPO (peroxidase) positive
Lymphoid: lymphocytes
TdT positive (pre-B and pre-T cell marker
HSC location
3rd week of development: transient in the yolk sac; definitive hematopoiesis in the mesoderm of the intraembryonic aorta/gonad/mesonephros region
3rd month of development: Migration to liver (also seen in placenta)
liver == chief sit of blood cell formation until shortly before birth
4th month of development: Migration to bone marrow (entire skeleton)
Puberty: Restricted to axial skeleton
Bone marrow sinusoids
Network of thin-walled sinusoids lined by a single layer of endothelial cells on top of a discontinuous basement membrane and adventitial cells
There are clusters of HSC and fat cells that sendoff differentiated cells via transcellular migration
Megakaryocytes lie next to sinusoids and extend out cytoplasmic processes that bud off into the blood stream to release platelets
RBC precursors surround macrophages (nurse cells) that provide the iron to make the hemoglobin
Extramedullary hematopoiesis
Extramedullary Hematopoiesis
In stress conditions, HSC migration occurs and tissues other than the bone marrow can provide adequate environment to allow hematopoiesis to occur
Liver and spleen
Erythropoietin
Regulates RBC progenitor cells Produced by peritubular capillary lining cells in the kidney Relative to the PO2 Released constantly at Hb > 10 Released logarithmically at Hb < 20
Leukoerythroblastosis
processes that distort the marrow architecture, such as deposition of metastatic cancer or granulomatous disorders, can cause the abnormal release of immature precursors into the peripheral blood
Marrow aspirate
Allows for the best assessment of the morphology of hematopoietic cells
immature precursors (-blasts) forms are identified with lineage-specific antibodies and histochemical markers
Mature marrow precursors are identified based on morphology alone
Normal adults: fat:hematopoietic elements = 1:1
Hypoplastic states: proportion of fat cells is greatly increased
Hyperplastic states: fat cells disappear
Normal % of T cells of lymphocytes in peripheral blood
80% are T cells
WBC disorders
Proliferative: expansion of leukocytes
Reactive (infection, inflammation) – fairly common
Neoplastic – much more important to recognize
Leukopenia: deficiency of leukocytes
Leukopenia
Abnormally low WBC count
Often a result of reduced neutrophils (so leukopenia is usually a neutropenia/granulocytopenia)
Lymphopenia is less common
If present, often due to HIV infection, after glucocorticoid or cytotoxic therapy, with autoimmune disorders, malnutrition, acute viral infections (redistribution of lymphocytes because type I IFNs lead to the sequestration of activated T cells in lymph nodes and increased adherence to endothelial cells
Neutropenia
Neutropenia: reduction in the number of neutrophils in the blood
Most common cause of agranulocytopenia is drug toxicity
Agranulocytosis
Agranulocytosis: clinically significant reduction in neutrophils
patients have increased susceptibility to bacterial and fungal infections
Most commonly due to drug toxicity: idiosyncratic and unpredictable due to metabolic polymorphisms or auto-antibodies (chloramphenicol, sulfa, chlorpromazine, thiouracil, phenylbutazone)
chloramphenicol == aplastic anemia and gray baby syndrome
Pathogenesis neutrophils
Pathogenesis
Inadequate or ineffective granulopoiesis
Suppression of HSC’s (aplastic anemia, infiltrative marrow disorders)
granulocytopenia, anemia, and thrombocytopenia
Suppression of committed granulocytic precursors due to drugs – most common cause
Disease states → ineffective hematopoiesis (megaloblastic anemia, myelodysplastic syndromes)
Congenital conditions (Kostmann syndrome: inherited defects in specific genes impair granulocytic differentiation)
Increased destruction or sequestration of neutrophils in the periphery
Immunologically mediated injury (idiopathic, related to autoimmune disorder, drug-related)
Splenomegaly → splenic enlargement leads to sequestration of neutrophils and modest neutropenia
associated with anemia and thrombocytopenia
Increased peripheral utilization (Overwhelming bacterial, fungal, or rickettsial infection)
Agranulocytosis morphology : hypocellularity in the bone marrow
Hypo- or hypercellularity in the bone marrow
Hyper: excessive destruction of the cells in the periphery, neutropenias caused by ineffective granulopoiesis (i.e. megaloblastic anemias and myelodysplastic syndromes)
Hypo: agents that suppress or destroy granulocytic precursors
Agranulocytosis morphology infections
Leads to infections with ulcerating necrotizing lesions of the oral cavity – agranulocytic angina
Deep lesions covered by dark necrotic membranes from which bacteria or fungi can be isolated
Infection can also occur in other locations
Increased risk of infection by Candida and Aspergillus
Clinical agranulocytosis
Signs and symptoms related to infection: Malaise, chills, fever followed by marked weakness and fatigability
Overwhelming infections can cause death within hours to days
Serious infections occur with a count < 500/mm3
Treatment agranulocytosis
Broad spectrum antibiotics
GCSF administration to stimulate production of granulocytes from marrow precursors
Leukocytosis
Increase in the number of WBCs in the blood
Common in inflammatory states
leukemoid reaction == elevated LAP
leukemia == normal LAP
Driven by production of cytokines (TNF, IL1), growth factors and adhesion molecules
May include d, eosinophilia, basophilia, monocytosis, lymphocytosis
Peripheral leukocyte count influences
Related to size of precursor in marrow pool, circulation and peripheral tissues
Rate of release of cells from the storage pools into the circulation
Proportion of cells adherent to the blood vessel walls (marginal pool)
Rate of extravasation of cells from the blood into tissues
Role of infection on leukocytosis
TNF and IL-1, if sustained, can cause there to be an egress of mature granulocytes out of the bone marrow and for there to be increased production of growth factors
IL5: Stimulates production of eosinophils
G-CSF: Stimulates production of granulocytes (neutrophils
Sepsis of severe inflammatory disease on leukocytosis
In sepsis or severe inflammatory diseases, can be accompanied by morphologic changes in neutrophils
Toxic granulations: coarser and darker, abnormal azurophilic (primary) neutrophilic granules
due to strong response to infection
Dohle bodies: patches of dilated endoplasmic reticulum seen as sky-blue cytoplasmic “puddles”
seen in neutrophils
due to strong response to infection
Leukomoid rection : many immature granulocytes
Leukemoid Reaction: many immature granulocytes appear in the blood due to an infection; looks like myeloid leukemia
LAP will be elevated in leukemoid reaction
LAP will be normal in leukemia
Lymphopenia causes
Decreased number of circulating lymphocytes
Immunodeficiency (Di George syndrome [chromosome 22q11 deletion])
High cortisol state (Cushing syndrome)
Autoimmune destruction (SLE)
Whole body radiation
Neutrophilic leukocyteis causes
Increased circulating neutrophils
Bacterial infection or tissue necrosis (left shift) with Decreased CD16 and Fc receptors
High cortisol state
Eosinophilic leukocytosis causes
Increased circulating eosinophils Allergic reactions (type I hypersensitivity) Parasitic infections Hodgkin lymphoma Drug reactions Some vasculitides *increased IL5 --> eosinophils
Basophils leukocytosis
Increased circulating basophils
CML (chronic myeloid leukemia)
Rare, except in CML ^^
Monocytosis causes
Increased circulating monocytes Chronic inflammatory states (autoimmune or infectious) TB, bacterial endocarditis, malaria Malignancy Collagen vascular disorders (SLE) Inflammatory bowel diseases
Lymphocytic lymphocytosis causes
Increased circulating lymphocytes Viral infections (HAV, CMV, EBV) Bordetella pertussis infection Chronic immunologic stimulation (TB, brucellosis) Often accompanies monocytosis
Germinal centers
Develop in lymph nodes within several days of antigenic stimulation
due to enlargement of primary follicles; pale staining
Highly dynamic structures where B cells acquire the capacity to make high-affinity antibodies against specific Antigens
Dark zone of proliferating centroblasts (blast like B cells)
Light zone of centrocytes (B cells with irregular or cleaved nuclear contours
Acute nonspecific lymphadenitis : localized
Localized: Direct microbiologic drainage (i.e. cervical region due to dental or tonsillar infection; axillary or inguinal regions due to infections in the extremities
Acute nonspecific lymphadenitis systemic
Systemic: Associated with bacteremia and viral infections (particularly in children
Mesenteric acute nonspecific lymphadenitis
Mesenteric: An infection that causes mesenteric lymph nodes to enlarge and become tender
Can look like appendicitis
Morphology acute nonspecific lymphadenitis
Large germinal centers with numerous mitotic figures
Nodes are swollen, gray-red and engorged
Presence of macrophages with particulate debris
In severe infections the entire lymph node can become necrotic or a bag of pus
Less severe infections have scattered infiltrates of neutrophils that accumulate in the lymphoid sinuses
Endothelial cell hyperplasia (lining the sinus
Calinical acute nonspecific lymphadenitis
Clinical
Affected nodes are enlarged and tender; may become fluctuant (moveable) when abscess formations is extensive; overlying skin is red
suppurative infections that penetrate the lymph node capsule & track to the skin –> draining sinuses –> scar
Chronic nonspecific lymphadenitis
Nontender lymph nodes without acute inflammation or tissue damage
Tender LAD == acute process (infection)
nontender LAD == chronic process (cancer)
Common in inguinal and axillary lymph nodes as they drain large areas of the body and are stimulated by trivial injury/infections of extremities
Tertiary lymphoid organs
chronic immune reactions can promote the appearance of organized collections of immune cells in nonlymphoid tissues
chronic gastritis caused by Helicobacter pylori infection –> peyer’s patch hyperplasia
can lead to MALToma (marginal cell lymphoma)
rheumatoid arthritis –> B-cell follicles appear in the inflamed synovium
can lead to MALToma (marginal cell lymphoma)
lymphotoxin is probably involved
Follicular hyperplasia
due to stimuli activating the humoral immune response
Presence of large oblong germinal centers (2° follicles) surrounded by a collar of small resting naive B cells (mantle zone)
Germinal centers contain centroblasts (dark) and centrocytes (light)
Dendritic cells and tingible-body macrophages are interspersed
tingible-body macrophages == macrophages that have phagocytosed the apoptotic B-cells
May be due to rheumatoid arthritis, toxoplasmosis, or early HIV – B cell responses
Tangible body macrophages
Tingible-body macrophages
Contain the nuclear debris of B cells
B cells undergo apoptosis if they fail to produce an antibody with a high affinity for antigen
Seen in ALL and Burkitt Lymphoma
tingible body == apoptotic B cells in a macrophage
Reactive follicular hyperplasia
Preservation of lymph node architecture – neoplastic means things are going awry
Marked variation in follicular shape and size
Frequent mitotic figures, phagocytic macrophages and recognizable light (-cyte) and dark (-blast) zones
Paracortical hyperplasia
due to stimuli triggering the T-cell mediated immune response (e.g. acute viral infection)
infectious mononucleosis (EBV)
In exuberant reactions, the T-cell zones (containing immunoblasts) may encroach on the B-cell follicles
Hypertrophy of sinusoidal and vascular endothelial cells
May be accompanied by infiltrating macrophages and eosinophils
Imunoblasts (dark staining)
Activated T cells 3-4 times the size of resting lymphocytes
Round nuclei, open chromatin, several prominent nucleoli, moderate amounts of pale cytoplasm
If numerous, exclude lymphoid neoplasm from differential diagnoses
Sinus histiocytosis
inus Histiocytes (aka reticular hyperplasia)
Increase in the number and size of cells that line lymphatic sinusoids
Nonspecific, but can be prominent in lymph nodes draining cancers such as carcinoma of the breast
lymphatic endothelial cells are markedly hypertrophied and significant increases in macrophages occurs
Expansion and distension of the sinuses
sinus histiocytosis does not mean metastatic cancer; these lymph nodes are reactive; sinus histiocytosis is a reactive phenomenon in a lymph node draining cancer
histiocytosis X is dendritic cell proliferation – what does the X stand for??
Hemophagocytic lymphohistiocytosis
Definition: macrophage activating syndrome
Reactive condition with cytopenias and signs and symptoms of systemic inflammation due to macrophage activation
Familial (early onset) and sporadic (any age
Pathogenesis hemophagocytic lymphohistiocytosis
Systemic activation of macrophage and CD8+ cytotoxic T-cells
macrophages phagocytose blood cell progenitors in the marrow and formed elements in peripheral tissues
Mediators released from macrophage and lymphocytes suppress hematopoiesis and produce signs and symptoms of systemic inflammation
“Cytokine storm” or SIRS can occur due to the cytopenias
SIRS criteria
Hyper/Hypo-thermia
Tachycardia
Tachypnea
Leukocytosis/leukopenia
Appear shock-like
unbridled HLH is associated with extremely high levels of inflammatory mediators such as IFNγ, TNFα, IL-6, and IL-12, as well as soluble IL-2 receptor
infection is the most common trigger for HLH, especially Epstein-Barr virus (EBV
Clinical hemophagocytic lymphohistiocytosis
patients present with acute febrile illness and hepatosplenomegaly
Hemophagocytosis may be seen on bone marrow exam – neither sufficient nor required to make diagnosis
Anemia, thrombocytopenia,
increased plasma ferritin and soluble IL-2 receptor (indicators of severe inflammation)
Elevated LFT’s and TGs (related to hepatitis)
coagulation studies may show evidence of DIC
Untreated = rapid progression to multiorgan failure, shock, death
Treatment HLH
Immunosuppressive drugs and “mild” chemotherapy
Germline mutations or persistent/resistant disease? HSC transplantation
Treated: 50% survive
May have significant sequelae (renal damage in adults, growth and mental retardation in children)
Untreated: grim prognosis, < 2 months survival if familial
Familial hemophagocytic lymphohistiocytosis
Mutations impact the ability of cytotoxic T cells and NK to properly form or deploy cytotoxic granules
Uncontrolled disease
Greatly increased IFNγ, TNFα, IL6, IL12 and soluble IL2 receptor
familial form is more severe
Leukocyte alkaline phosphatase (LAP)
Elevated in reactive WBC disorders
LAP will be high in reactive states, e.g. infection
Low in myeloproliferative and neoplastic WBC disorders
WBC neoplasma
WBC Neoplasms
Lymphoid
Myeloid
Histiocytoses
Lymphoid neoplasma
Neoplasm of B-cell, T-cell and NK-cell origin
Phenotype may resemble a particular stage of normal maturation – useful for diagnosis and classification
Myeloid neoplasma
Neoplasm of early hematopoietic progenitors
Tend to evolve over time to more aggressive forms of disease – clinically important
Acute myeloid leukemia
Immature progenitor cells (blasts) accumulate in the bone marrow suppressing normal hematopoiesis
Both myelodysplastic syndromes and myeloproliferative disorders can “transform” to this disease
Myelodysplastic syndromes
Ineffective hematopoiesis due to defective maturation of myeloid progenitors
Resultant peripheral blood cytopenias
more severe than myeloproliferative disorders
Chronic. Myeloproliferative disease
hronic Myeloproliferative Disease
Increased production of one or more terminally differentiated myeloid elements leads to elevated peripheral blood counts
Polycythemia Vera, Essential Thrombocytopenia, Primary Myelofibrosis, and CML
Histiocytosis
Uncommon proliferative lesions of macrophage and dendritic cells
Langerhans cell (special type of immature dendritic cell) gives rise to a spectrum of neoplastic disorders referred to as the Langerhans cell histiocytoses
look for cutaneous involvement; all are CD4 +ve
Factors influencing WBC neoplasia
Chromosomal translocations and other acquired mutations
Inherited genetic factors
acute leukemias: dominant negative oncogenic mutations involving transcription factors are often present that interfere with early stages of lymphoid or myeloid cell differentiation
Viruses
Chronic inflammation (i.e. Helicobacter Pylori)
Iatrogenic factors (radiation and some chemotherapy)
Smoking
oncogenic mutations occur most frequently in germinal center B cells during attempted antibody diversification
class switching == intragenic recombination event in which the IgM heavy-chain constant gene segment is replaced with a different constant gene
somatic hypermutation == point mutations within Ig genes that may increase antibody affinity for antigen
Translocations in WBC neoplasma
Translocations in WBC neoplasms
Most common nonrandom chromosomal abnormality seen in WBC neoplasms
WBC mutations
Play crucial roles in the development, growth or survival of the normal counterpart to the malignant cell (gain or loss of function)
Oncoproteins can block normal maturation, activate pro-growth signals or inhibit apoptosis
Protooncogenes may be activated during gene rearrangement and diversification
Activation induced cytosine deaminase and its role in neoplasia
This enzyme is upregulated after Antigen stimulation in germinal center B cells
Allows Ig class switching and somatic hypermutation to increased antibody affinity
May induce MYC/Ig translocations – AID creates lesions in DNA that lead to chromosomal breaks
Can activate protooncogenes (i.e. BCL6
V(D)J recombinant and its role in neoplasia
This enzyme cuts DNA at specific sites within the Ig and T-cell receptor loci
May go awry, leading to the joining of portions of other genes to Ag receptor gene regulatory elements
Unique to B and T cells
Leukemia and lymphoma can be influenced by
Leukemia & Lymphoma can be influenced by: Inherited genetic factors: Down syndrome (trisomy 21) associated with an increased risk of Acute Lymphoblastic Leukemia (ALL) in children < 5 years Bloom syndrome Fanconi anemia ataxia telangiectasia Type I neurofibromatosis
HTLV1
HTLV1: adult T-cell leukemia/lymphoma (ATLL
EBV
EBV: Burkitt lymphoma, Hodgkin lymphoma, other B-cell Lymphoma
EBV infects B cells in the cortex; response to EBV infection is a paracortical hyperplasia of T-cells
KSHV/HHV8
KSHV/HHV8: B-cell Lymphoma that presents as a malignant effusion in the pleural cavity
HIV
HIV: B-cell Lymphoma
Chronic inflammation leading to WBC neoplasia
Helicobacter pylori: Gastric B-cell Lymphomas
Gluten sensitive enteropathy: intestinal T-cell Lymphomas
Breast implants: T-cell Lymphoma
Iatrogenic factors leading to blood neoplasia
Iatrogenic factors leading to blood neoplasia
Radiation and chemo can affect the myeloid and lymphoid precursors to cause neoplasia
Smoking on blood neoplasia
Acute Myeloid Leukemia increased, especially due to benzene
Lymphocytic leukemia
(Lymphocytic) Leukemia: neoplasms that have wide spread involvement of the bone marrow and often (not always) the peripheral blood
signs and symptoms related to the suppression of normal hematopoiesis by tumor cells in the bone marrow
“acute” leukemia == most common leukemia of childhood (ALL)
infections –> thrombocytosis; leukemia –> thrombocytopenia
generally: acute means kids and are -blasts; chronic means adults and are -cytes
Lymphoma
Lymphoma: proliferations of lymphoid cells that arise as discrete tissue masses – involvement of the tissue makes it an “-oma” (“-oma” means mass)
2/3 of non-Hodgkin’s lymphomas and virtually all Hodgkin’s lymphomas present as enlarged, nontender lymph nodes; 1/3 of remaining non-Hodgkin’s lymphomas present with symptoms related to tissue/organ involvement
Leukemia vs lymphoma
Leukemia vs. Lymphoma
Lymphomas more commonly exhibit tissue involvement (“-oma” means mass)
leukemia and lymphoma reflect the usual tissue distribution of each disease at presentation
Immature B cells
Precursor B cell (-blasts) neoplasms
Mature B cells
Peripheral B cells (-cystes) neoplasma
Immature T cells
Precursor T cell neoplasma
Mature T cells and NK cells
Peripheral T cell neoplasms
Mature T cells and NK cells
Peripheral T cell and NK cell neoplasma
Reed sternberg cells and variants
Hodgkin lymphoma
Lymphoid neoplasms
Histological examination is required for diagnosis
Antigen receptor gene rearrangement precedes transformation of cells – all daughter cells derived from the malignant progenitor share the same antigen receptor gene configuration and sequence
Monoclonal: all daughter cells express the same configuration and sequence, synthesizing identical proteins (immunoglobulins or TCRs) – monoclonal means cancer, malignant
Polyclonal: means that they are immature and are reactive
Most resemble a recognizable stage of B or T cell differentiation (most are B cell neoplasms)
even though 80% of circulating lymphocytes are T-cells
Often associated with immune problems
Behavior resembles normal B and T-cells
most lymphoid tumors are widely disseminated at the time of diagnosis
Hodgkin lymphoma: sometimes restricted to one group of lymph nodes
marginal zone B-cell lymphomas: often restricted to sites of chronic inflammation
MALTomas that arise in the setting of chronic inflammation
t(11;18), t(14;18) or t(1;14)
HOdgkin
Hodgkin’s: spreads in an orderly fashion and staging is useful
distinctive pathologic features and is treated in a unique fashion
Non Hodgkin
Non-Hodgkin’s: spreads widely, and less predictably
Acute lymphoblastic
Neoplasm of immature lymphoblasts (most are B-ALL)
There is a lot of clinical overlap between B and T-ALL
Kids with a very low platelet count have ALL until proven otherwise – most common leukemia of childhood
Population ALL
Increased risk in Hispanics»whites > African Americans
Slight male predominance
Most common cancer of children (usually patients <15)
*Most common cancer of children
Pathogenesis ALL
Dysregulation of expression and function of transcription factors for normal B and T cell development
Disturb differentiation and promote arrest of maturation, inducing self-renewal
Mutations that drive cell growth (i.e. TK) are common
70% of T-ALLs have gain-of-function mutations in NOTCH1
majority of B-ALLs have loss-of-function mutations in PAX5, E2A, and RBF or a balanced t(12;21) involving the genes ETV6 and RUNX1
Numerical or structural chromosomal change: 90% (Translocations, altered ploidy)
Caused by relatively few mutations as compared to solid tumors
ALL morphology
Leukemic presentation: marrow is hypercellular and packed with lymphoblasts that replace the normal marrow elements
Scant basophilic cytoplasm with nuclei larger than small lymphocytes
Delicate, finely stippled nucleoli with a rim of condensed chromatin
Subdivided nuclear membrane (convoluted)
High mitotic rate
“Starry sky” due to macrophage ingestion of tumor cells
A bone marrow biopsy is performed and on microscopic examination shows nearly 100% cellularity with replacement by primitive cells that have large nuclei with delicate chromatin and indistinct nucleoli with scanty cytoplasm. These cells mark for CD10 (CALLA) antigen
Lymphoblasts (different features than myeloblasts
must differentiate ALL from AML because they differ in their response to chemotherapy
Acute lymphoblastic leukemia/lymphoma
More condensed chromatin
Less conspicuous nuclei
Smaller amounts of cytoplasm whihc lacks granules
MPO(-), PAS (+), TdT (+)
Abrupt; stormy onset”, within days to few weeks of first symptoms
Related to depression of marrow function; fatigue due to anemia; fever due to infection from neutropenia; bleeding due to thrombocytopenia;
More common in all; bone pain
More common in ALL ; HA, vomiting, nerve palsies from meningeal spread
Acute myeloid leukemia
MPO (+)
No nerve palsies
B and T cell antibody stain are required for definitive diagnosis of ALL or AML
Clinical
most common translocation == t(4;11) – ??? (Hubbard)
Normal hematopoiesis is suppressed due to physical crowding, growth factor competition, etc.
Abrupt, “stormy” onset in days to weeks of first signs and symptoms
Signs and symptoms related to depression of marrow function
Fatigue (anemia), fever (neutropenia → infection), bleeding (thrombocytopenia)
Mass effects due to neoplastic infiltration
Bone pain from marrow expansion and infiltration, LAD, HSM, testicular enlargement
neurological manifestations due to meningeal spread: headache, vomiting, nerve palsies; diplopia
With aggressive chemotherapy, 95% of children with ALL achieve complete remission, and 75-85% are cured
still leading cause of cancer deaths in children (most common cancer)
only 35-40% of adults are cured due to different molecular pathogenesis and inability to tolerate the necessary chemo regimen effective in children
Poor prognosis
Age < 2 (strong association of infantile ALL with translocation of MLL gene)
t(9:22) Philadelphia chromosome
Presentation in adolescence or adulthood
Peripheral blood blast count > 100,000 (high tumor burden likely)
Detection of residual disease after therapy
Favorable prognosis
Age between 2 and 10 years old Low white cell count Hyper-diploidy trisomy of chromosome 4, 7, 10 Presence of t(12:21) -- involves ETV6 and RUNX1 genes
B cell ALL
Acute childhood leukemia
Peak incidence at age 3
Extensive marrow and peripheral blood involvement
B-cell tumors present with cyclic tumors
Morphology B cell ALL
Marrow is hypercellular and packed with lymphoblasts
Pancytopenia
Genetics B cell ALL
loss-of-function mutations in PAX5, E2A, EBF or *t(12:21) ETV6/RUNX1
Hyperdiploidy and hypodiploidy may be present and are exclusive in B-ALL
Immunophenotype B cell all
TdT (+) (pre-B-cell marker) CD10, 19, 20 (+) Very immature neoplasm: CD10 (-) Mature neoplasm: IgM heavy chain (+) (μ chain) PAX5 (+) t(9:22) BCR/ABL protein
Treatment B cell all
Effectively treatment in children with chemotherapy
Prophylax scrotum and CSF
T cell all
Presents in adolescent male (teenagers) as thymic mass (mediastinal) “lymphomas”; and T-cells (thymocytes) – mnemonic == 3 T’s
May evolve to a leukemia
lymphadenopathy and splenomegaly
Signs and symptoms may include complications related to compression of vessels or airways in the mediastinum
Genetics T cell all
NOTCH1 gain-of-function mutations – T-cells are NOTCH1 GOF
Immunophenotype T cell ALL
TdT (+) – precursor lymphocyte (i.e. lymphoblast) markers
CD1 and CD8 positive
Immature: CD3, CD4, and CD8 negative
Chronic lymphocytic leukemia (CLL) & small lymphocytic lymphoma
only difference between CLL and SLL is the degree of peripheral blood lymphocytosis
Follicular lymphoma
lar lymphoma == efface the normal architecture of the lymph nodes
follicular hyperplasia does not
t(14;18
DLBCL
BCL6
Burkitt lymphoam
T(8;14)
Mantle cell lymphoma
T(11;14)
Marginal zone lymphoma MALToma
t(11;18), t(14;18), or t(1;14
Hairy cell leukemia
TRAP, BRAF
Chronic lymphocytic leukemia
Most common leukemia of adults in the Western world
*Morphologically, phenotypically and genotypically indistinguishable from SLL, differ only in the degree of peripheral blood lymphocytosis (absolute WBC count > 5000/mm3
Populations at risk CLL
Male 2:1
Age: 60yrs
More common in the West than Asian countries
Chromosomal anomalies CLL
Chromosomal translocations are rare
Deletions: 13q14.3(microRNAs 15a & 16-1), 11q, 17p
Trisomy 12q – “tr-elve,” and the mnemonic becomes “11, 12/trelve, 13, 14, 15, 16, and 17
Genetics CLL
Somatic hypermutation of immunoglobulin genes can occur indicating cell of origin may be post-germinal center memory B cell or naive B cell
Unmutated Ig segments = increased aggressive course
NOTCH1 receptor gain of function mutations – this is a poor prognostic factor
RNA splicing mutations
Tell growth CLL
Confined to proliferation centers
NFκB is stimulated by stromal cells = promotion of growth and survival
BCRs produce signals required for growth and survival via BTK (Bruton TK)
*BTK inhibitors have produced sustained response in many patients
Morphology CLL
Proliferation centers (pathognomonic): Larger lymphocytes gathered in loose aggregates that contain mitotically active cells
Smudge cells: Small round lymphocytes in the peripheral blood with scant cytoplasm, disrupted when making the smear
smudge cells are not characteristic of anything (non-specific)
lymph node architecture is effaced by small lymphocytes (6-12um) with round or slightly irregular nuclei, condensed chromatin and scant cytoplasm
Infiltrates seen in bone marrow, splenic pulp (white + red) and hepatic portal tracts
Immunophenotype CLL
CD 5, 19, 20, 23 (+)
B cell proliferation that is positive for CD5, think CLL
Low levels of surface Ig (IgM +/ IgD) are also seen
When lymph node involvement occurs this becomes known as Small Lymphocytic Lymphoma
only difference between CLL and SLL is the degree of peripheral blood lymphocytosis
Prolymphocytes are seen in lymph nodes
Clincial CLL
patients are often asymptomatic at diagnosis
Signs and symptoms appear as nonspecific: easy fatigability, weight loss, anorexia, generalized lymphadenopathy, hepatosplenomegaly
Variable leukocyte count
Leukopenia in SLL with marrow involvement
Leukocytosis in CLL with heavy tumor burden
Monoclonal Ig “spike” may be present in the blood – more indicative of multiple myeloma?
patients with monoclonal B cells < # than required for diagnosis can have similar genetic defects but only 1% progress to symptomatic disease
Median survival 4-6 years, 10 years in patients with decreased tumor burden at diagnosis
CLL effect on immune function
Hypogammaglobulinemia = bacterial infection
Neoplastic B cell auto-antibodies = hemolytic anemia or thrombocytopenia
Poor prognosis cll
11q, 17p deletions
Lack of somatic hypermutation
ZAP70 (+): augments immunoglobulin receptor signaling
NOTCH1 mutations
Richter syndrome: tendency of CLL/SLL to transform to a more aggressive tumor in the form of diffuse large B-cell lymphoma; transformation of CLL/SLL to an aggressive B-cell lymphoma
Rapidly enlarging mass within a lymph node or the spleen, likely due to additional acquired mutations
large cell transformation is BAD; survival < 1 yea
Treatment CLL symptomatic
Gentle chemotherapy
Immunotherapy with antibodies to surface proteins (CD20)
hematopoietic stem cell transplant is offered to young patients
BTK inhibitors
Follicular lymphoma
Tumor of lymph nodes that causes obliteration of the lymph node and loss of architecture
lymphoma (neoplastic) will efface lymph node architecture; hyperplasia (reactive) won’t
Most common form of indolent non-Hodgkin’s lymphoma in the US
Who gets follicular lymphoma
Less common in Europe
Rare in Asian population
Pathogenesis follicular lymphoma
Arises from germinal center cells
strongly associated with chromosomal translocations involving BCL2
t(14:18) BCL2/Ig heavy chain – seen in >90% of follicular lymphomas (characteristic translocation of follicular lymphoma)
IGH locus on chromosome 14
BCL2 locus on chromosome 18
BCL2 antagonizes apoptosis (promotes cell survival)
Overexpression of BCL2 inhibits apoptosis of B cells that fail somatic hypermutation
Devoid of apoptotic cells because BCL2 is anti-apoptotic
MLL2: histone methyltransferase (epigenetics!); mutated in >90% of follicular lymphomas
Neoplastic cells grown in lymph nodes in a network of reactive follicular dendritic cells, macrophages and T cells and their microenvironment determines treatment response
Morphology follicular lymphoma
Follicular (nodular) and diffuse proliferation of centrocytes (predominant) and centroblasts
Lymphocytosis in 10%, makes it more aggressive
Para-trabecular lymphoid aggregates in bone marrow (also seen in splenic white pulp and hepatic portal triads
Centrocytes follicular
Small cells with irregular or cleaved nuclear contours
Scant cytoplasm
Centroblasts cll
Large cells with open nuclear chromatin
Several nucleoli
Modest amounts of cytoplasm
Immunophenotype
CD 10, 19, 20 (+) CD5 (-) BCL6 (+) -- anti-apoptotic BCL2 (+) normal follicular cells are normally devoid of this marker Surface Ig (+)
Clinical follicular
Presents in middle age as painless, generalized lymphadenopathy
Extra-nodal site involvement is uncommon
Incurable with waxing-waning course; survival is 7-9 years not improved by aggressive therapy
palliate the patient with low dose chemotherapy or immunotherapy (anti-CD20 antibody)
Transformation in 30-50% to diffuse large B-cell Lymphoma (usually) or Burkitt Lymphoma
Diffuse large B cell lymphoma BAD: patient at risk
Most common form of non-Hodgkin’s lymphoma
Median age: 60 years old (may also occur in young adults and children
Pathogenesis DLBCL
3q27 mutation (translocation or acquired) involving BCL6
BCL6 is required for formation of normal germinal centers – dysregulation of BCL6 == DLBCL
Overexpression of BCL6 inhibits germinal center B-cell differentiation, growth arrest and apoptosis
Other potential mutations
t(14;18) involving BCL2 (anti-apoptotic)
tumors with BCL2 rearrangements usually lack BCL6 rearrangements
this translocation is characteristic/pathognomonic for follicular lymphoma
MYC mutation
myc dysregulation == Burkitt Lymphoma
Histone acetyltransferase mutations (p300, CREBP)
large, destructive masses; extranodal involvement
this is a mature B cell neoplasm
Morphology DLBCL
Large cells (4-5X > normal lymphocytes)
Diffuse pattern of growth
Substantial morphologic variation
Commonly has a round-oval nucleus (vesicular in appearance)
Multiple (2-3) nucleoli (or single and centrally placed)
Cytoplasm: moderately abundant and pale or basophilic
More anaplastic tumors may contain multinucleated cells with inclusion-like nucleoli
DLBCL immunophenotype
CD 19, 20 (+)
Variable expression of CD10 and BCL6
Most have surface immunoglobulin
DLBCL location
Rapidly enlarging mass at nodal or extranodal site
May arise anywhere in the body
commonly Waldeyer ring (oropharyngeal lymphoid tissue including the tonsils and adenoids)
DLBCL == Waldeyer ring
Liver and spleen involvement leads to destructive masses
Extranodal is common: GI, skin, bone, brain
Bone marrow involvement is rare (late course
DLBCL clincial
aggressive tumors that are rapidly fatal without treatment
Treated: 60-80% complete remission, 40-50% cured
Adjuvant treatment with anti-CD20 antibody –> improved initial response and improved outcomes
Limited disease has better outcome than widespread disease or those with bulky tumor masses
Inhibition of NFκB and B cell receptor pathways is beneficial
MYC translocations have worse outcome and may be best treated similar to Burkitt lymphoma
myc dyregulation == Burkitt Lymphoma
Immunodeficiency associated large B cell lymphoma
Occurs with severe T-cell immunodeficiency (HIV or allogenic bone marrow transplant)
EBV infection of neoplastic B cells
May regress with restoration of T cell immunity
Primary effusion lymphoma DLBCL
Malignant pleural or ascitic effusion
Most common in patients with advanced HIV or who are elderly
Tumor cells infected with KSHV/HHV8 which appears to have a causal role – always associated with Kaposi’s
Anaplastic tumor cells that do not express B or T cell markers
Possess clonal immunoglobulin heavy chain gene rearrangements
Burkitt lymphoma
Burkitt Lymphoma == “Burkitt is Burk-EIGHT” [t(8;14)]
Definition
Most commonly affect kids and young adults
Highly associated with MYC translocations on chromosome 8 that leads to high MYC protein levels
MYC increases genes for aerobic glycolysis (Warburg effect) allowing cells to biosynthesize building blocks for growth and cell division, if glucose and glutamine are available – this is important
Burkitt Lymphoma == dysregulation of c-MYC
Three variants: African (endemic), sporadic (nonendemic), HIV associated
histologically identical, but different in some clinical, genotypic, and virologic characteristics
not ALL Burkitt lymphomas are EBV positive; All African (endemic) Burkitt lymphomas are though
aka Diffuse Small Non-Cleaved Lymphoma (Hubbard)
Pathogenesis burkitt
t(8:14) MYC/Ig heavy chain
May also be t(2:8) or t(8:22) for the light chains
chromosome 2 == kappa
chromosome 22 == lambda
chromosome 8 == MYC
chromosome 14 == IgH
Induced by AID in germinal center B cells
MYC overexpression, increased activity
Fastest growing human tumor – doubles in size every 36 hours
Infection with EBV precedes transformation
Morphology burkitt
Diffuse infiltrate of intermediate sized lymphoid cells
Round/oval nuclei, coarse chromatin, several nucleoli, moderate amount of cytoplasm
High mitotic index
Numerous apoptotic B cells – tingible body macrophage
“Starry sky” pattern due to phagocytosis of nuclear remnants by macrophages
If bone marrow is involved, tumor cells exhibit clumped nuclear chromatin, 2-5 nucleoli and royal blue cytoplasm with clear cytoplasmic vacuoles
Immunophenotype burkitt
CD 10, 19, 20 (+) BCL6 (+) Surface IgM (+) BCL2 (-) MYC (+) -- Burkitt Lymphoma is dysregulation of c-MYC
Burkitt clincial
30% of childhood non-Hodgkin’s lymphoma in the USA
Aggressive lymphoma
Responds well to chemotherapy
Children and young adults are usually cured
Older adults have more guarded outcome
Burkitt sporadic
Burkitt Lymphoma: Sporadic (nonendemic)
t(8:14)
Breakpoint on IgH locus is in the class switch region
15-20% of patients are latently infected with EBV
Mass of ileocecum and peritoneum – just GI
Burkitt african endemic
Burkitt Lymphoma: African (endemic)
t(8:14)
Breakpoint on IgH locus is in the 5’ V(D)J sequence
All patients are latently infected with EBV
Mass of mandible/face and/or abdominal viscera (kidneys, ovaries, adrenals)
Bone marrow or peripheral blood involvement is rare
Burkitt lymphoma HIV
t(8;14)
25% of patients are latently infected with EBV
Plasma cell neoplasma(dyscrasias)
Most common plasma cell dyscrasia == Monoclonal Gammopathy of Uncertain Significance (MGUS)
most common plasma cell malignancy == multiple myeloma
Cells secrete monoclonal Ig (serve as tumor markers)
Will commonly see plasma cell clusters, they don’t normally present in clusters
M component: a monoclonal Ig in the blood
Restricted to plasma due to high molecular weight
not seen in urine unless glomerular damage has occurred
neoplastic plasma cells often synthesize excess light chains along with complete immunoglobulins
light chains are small in size and excreted in the urine (Bence-Jones proteins)
One light chain is increased others are low
15% of deaths due to lymphoid neoplasms
Monoclonal gammopathy
Monocolonal gammopathy
Heavy chain disease == rare monoclonal gammopathy that is seen in association with a diverse group of disorders including lymphoplasmacytic lymphoma and an unusual small bowel marginal zone lymphoma that occurs in malnourished populations (so-called Mediterranean lymphoma)
common feature == synthesis and secretion of free heavy chain fragments
Multiple myeloma
Multiple Myeloma (plasma cell myeloma) == the most common plasma cell neoplasm
Definition
causes bony destruction of the skeleton and often presents with pain due to pathologic fractures
Plasma cell neoplasm that commonly causes tumorous masses throughout the skeletal system
“moth eaten”
lytic bone lesions, hypercalcemia, renal failure, and acquired immune problems
Multiple myeloma patients
Male
African descent
Peak incidence: 65-70 years old – disease of older adults
Multiple myeloma variants
Solitary myeloma: single mass in bone or soft tissue
Smoldering myeloma: lack of signs and symptoms with high plasma M component
does not exhibit lytic bone lesions
Multiple myeloma pathogenesis
athogenesis Frequent IgH (heavy chain) rearrangements Translocated with cyclin D1 and D3: good prognosis Poorer prognosis Deletion of chromosome 13q Deletion of chromosome 17p (TP53) t(4;14) MYC acquisition NFκB promoting B-cell survival high levels of IL-6
Growth and survival multiple myeloma
Growth and survival
IL-6 is important for growth of plasma cells, produced by neoplastic plasma cells and resident marrow stromal cells (higher levels = poor prognosis)
Bone destruction is mediated by factors produced by neoplastic cells
MIP1α upregulates NFκB ligand (RANKL) activating osteoclasts
Osteoblasts are inhibited via Wnt pathway
increased bone resorption → hypercalcemia and pathologic fractures
Morphology multiple myeloma
Destructive plasma cell tumors (plasmacytomas) involving the axial skeleton
Vertebral column, ribs, skull, pelvis, femur, clavicle, scapula
Appear as 1-4cm punched-out defects radiographically
Soft, gelatinous, red tumor masses
Can also present as widespread myelomatous bone disease that causes diffuse demineralization (osteopenia) instead of focal defects (i.e. pathologic fractures
Morphology neoplastic plasma cells
Increased number of plasma cells in the marrow with perinuclear clearing due to large Golgi apparatus and odd placed nucleus
Rouleaux formation: high level of M proteins causes RBCs in blood smears to stick together linearly
characteristic/indicative but not specific – seen whenever immunoglobulin levels are elevated
Flame cells: intracellular accumulation of degraded protein with fiery red cytoplasm
Mott cells: multiple grapelike cytoplasmic droplets
Cells containing inclusions of fibrils, crystalline rods and globules
Globular inclusions: Russell bodies (cytoplasmic) or Dutcher bodies (nuclear)
Dutch == nuclear families
Immunophenotype multiple myeloma
CD138 (+) (aka syndecan-1)
May be CD56 (+)
Signs ANS symptoms multiple myeloma
Effects of plasma cell growth in tissues (bones)
Production of excess immunoglobulin
Suppression of normal humoral immunity
Clincial sequelae multiple myeloma
Pathologic fracture and chronic pain due to resorption
Hypercalcemia –> Neurologic signs and symptoms (confusion, weakness, lethargy)
stones, bones, groans, and psychiatric moans + shortened QT
Renal failure (second biggest cause of death after infections)
myeloma kidney
Acquired immune abnormalities
Recurrent bacterial infection (most common cause of death)
Cellular immunity is unaffected
Bence jones proteinuria
Excreted light chains are toxic to renal tubular epithelial cells –> myeloma kidney –> renal failure/insufficiency (second most common cause of death in multiple myeloma, after infection)
Some (λ3, λ6) may be prone to amyloidosis of the AL type
primary or immunocyte-associated amyloidosis results from a monoclonal proliferation of plasma cells secreting light chains (usually of the λ isotype) that are deposited as amyloid
Increased immunoglobulins (especially IgG) and/or light chains in the plasma & urine
most multiple myelomas are IgG with kappa light chains - ???
Monoclonal immunoglobulins M proteins: IgG (55%), IgA (25%)
Excessive production and aggregation of M proteins, especially IgA or IgG3 –> hyperviscosity
Waldenström macroglobulinemia == a syndrome in which high levels of IgM lead to symptoms related to hyperviscosity of the blood; occurs in older adults; associated with lymphoplasmacytic lymphoma
IgA or IgG3->hyperviscosity
Waldenström macroglobulinemia == a syndrome in which high levels of IgM lead to symptoms related to hyperviscosity of the blood; occurs in older adults; associated with lymphoplasmacytic lymphoma
Marrow involvement
Diagnosis requires bone marrow examination
Marrow involvement often gives rise to a normocytic, normochromic anemia +/- moderate leukopenia and thrombocytopenia
