Hematopathology Flashcards
What three pathophysiological processes can lead to anemia?
Blood loss
Impaired RBC production
Increased RBC consumption or destruction
What are the two broad categories of RBC disorders?
Erythrocytosis - increased RBC mass
Anemia - decreased RBC mass resulting in decreased capacity to deliver oxygen
What six ways does the body use to compensate for tissue hypoxia in the face of anemia?
Increase RBC production by increasing epo
Increasing efficiency of oxygen delivery by increasing 2,3 DPG
shunt blood to vital areas –> pallor
Increase cardiac function –> increased hr
Increase or restore blood volume
Increase pulmonary function –> increased rr
How long do RBCs normally last in circulation?
100-120 days
How can CBC be used to test for anemia?
Includes RBC count, RBC indices, WBC count and platelet count
Anemia confirmed by low hb concentration and/or low hematocrit
Once anemia is diagnosed, what is the next broad categories they can be grouped into?
Microcytic
Normalcytic
Macrocytic
Based on mean corpuscular volume
After sorting according to mcv, what sorting step comes next for anemia?
Mean corpuscular hemoglobin concentration (MCHC) separates into hyperchromic, normochromic, or hypochromic
Central pallor should be about 1/3 diameter of cell
After mcv and mhch parameters have been established, what other measures can be used to categorize anemias?
RBC distribution width (RDW)
RBC count
Reticulocyte count
What is the RDW?
Coefficient of variation of RBC volume
Higher RDW means more variation in size
Can categorize anisocytotic vs. non-anisocytotic
Which anemia is associated with a high RBC count and which with low?
Thalassemia
Iron deficiency
Under normal conditions what should the reticulocyte percentage be?
0.5-1.5%
If there is normal RBC proliferation and maturation, how long after a blood loss should an increase in reticulocytes be seen in the peripheral blood?
2-3 days
Why must the reticulocytes count be adjusted using the corrected reticulocyte count?
Because if an anemia is due to RBC depletion, the percentage of reticulocytes will be proportionally higher
How can reticulocytes be seen in the peripheral blood?
Special stain can stain for basophilic matrix of rRNA still present
How many days do reticulocytes spend in the bone marrow and then the periphery before being fully mature?
3 days
1 day
Why is the reticulocyte count further modified to the reticulocyte production index?
Because in anemia, they are released into the periphery at an earlier stage of maturation and thus spend less time in the bone marrow and more time there
How are the results of the RPI used?
Not anemic - RPI should be 1-2%
Anemic - RPI3 means adequate bone marrow response, suggests anemia secondary to RBC destruction, etc.
How does anemia from acute blood loss happen?
CBC will not recognize anemia until intravascular volume replenished either by transmigration of tissue fluid or therapy
After compensatory shift can identify cytopenias due to dilution
Normocytic and normochromic
How does anemia in chronic blood loss happen?
Initial stages - bone marrow increases RBC production and compensates –> CBC might be normal but reticulocyte count up
Over time, iron will become depleted –> type of anemia of iron deficiency
What is important about iron deficiency in the elderly?
Should be regarded as right sided colon cancer until proven otherwise as this is common etiology of chronic blood loss in that demographic
What type of anemia is that due to proliferation defects?
Normocytic, normochromic
What is aplastic anemia?
Stem cell defects lead to failure of production of hematopoietic lineages
Bone marrow becomes hypo cellular and peripheral blood becomes pancytopenic
Has adequate epo
What is myelophthisic anemia?
Bone marrow is replaced by nonhematopoietic tissue
Body shifts production of blood cells to liver and spleen - not normal regulatory environment –> release of immature cells
Teardrop cells (dacrocytes) in peripheral blood
Only proliferation anemia with that may have increased reticulocyte count
What are the basic feature of maturation defect anemias?
Bone marrow hyper cellular with increased RBC precursors
Peripheral blood has too few mature RBC
Also called ineffective erythropoiesis
What kind of anemia is iron deficiency anemia?
Microcytic, hypochromic
What happens during the development of iron deficient anemia?
Body mobilizes iron stores then
Plasma ferritin decreases as storage iron decreases, plasma iron falls, plasma transferrin rises - can be seen before cell changes
Anemia develops once stores exhausted
Early normochromic and normocytic, then microcytic, then hypochromic
What other changes are seen with cells in iron deficiency anemia?
Anisocytosis
Poikilocytosis
Low RBC count
Low reticulocyte count
What is the gold standard for diagnosis of iron deficiency?
Prussian blue reaction on bone marrow aspirate
Both iron stores in histiocytes and sideroblastic iron in erythrocytes will be absent
What is the cause of megaloblastic anemia?
Folate or cobalamin deficiency
Cofactors needed for dTMP which is needed for DNA
Impaired nuclear synthesis with intact cytoplasmic synthesis - opposite of iron deficiency anemia
What are the features of megaloblastic anemia?
Macrocytosis (MCV>100)
High RDW
Low reticulocyte count
Maybe leukocytopenia or thrombocytopenia
Nucleated RBCs, basophilic stippling, RBC fragments, teardrop cells and lack of polychromasia in periphery
Hyper segmented neutrophils
Serum lactate dehydrogenase and bilirubin increased
What five additional tests should be ordered in megaloblastic anemia after initial findings?
Serum cobalamin
Serum folate
RBC folate
Serum methylmalonic acid - only increases with cobalamin deficiency
Serum homocysteine - accumulates with both cobalamin and folate deficiency
What is the probable cause of b12 deficiency as opposed to folate?
Lots of b12 stores in body - probs an absorption problem
Folate usually due to decreased intake
What are changes on bone marrow exam associated with megaloblastic anemia?
Hypercellularity
Shift toward immaturity = left shift
Megaloblastic features in precursor cells
What are some features seen in myelodysplastic syndromes but not megaloblastic anemia?
hyposegmented neutrophils
Hypo granulated granulocytes
What are features seen in megaloblastic anemia but not myelodysplastic syndromes?
Hypersegmented neutrophils
Giant metamyelocytes
Giant band neutrophils
Abnormal ancillary studies
What is anemia of chronic disease?
Associated with inflammatory states like infection or malignancy
Related to release of inflammatory cytokines that act to decrease iron absorption, induce macrophage sequestration of iron, and decrease epo
What do lab tests of anemia of chronic disease show?
Decreased serum iron
Increased serum ferritin
Decreased iron binding capacity
What does bone marrow exam of anemia of chronic disease show?
Normal numbers of RBC precursors
Increased iron stores with absent sideroblastic iron
Hb levels rarely fall below 9
80% are normocytic and normochromic, ret are microcytic and hypochromic
What are lab findings in hemolytic anemia?
Signs of bone marrow compensation/increased RBC production
Signs of increased RBC destruction (increased lactate dehydrogenase, increased serum unconjugated bilirubin, increased urobilinogen, decreased haptoglobin)
What kinds of intrinsic defects can cause hemolytic anemia?
Abnormalities in hemoglobin, membrane or enzymatic machinery
What is paroxysmal nocturnal hemoglobinuria (PNH)?
Defect in PIG-A gene leads to dysfunctional GPI anchors on RBC membranes
Normally anchor cd55 and cd59 which regulate complement lysis
What is sickle cell disease?
Valine sub for glutamic acid in beta globin
Manifestations of vaso-occlusive episodes include pain crisis, acute chest syndrome, renal dysfunction, priapism, and retinal pathology
Baseline hb between 6-10
What kind of anemia is that which results from sickle cell?
Normocytic and normochromic
Marked anisopoikilocytosis
What do peripheral blood smears of sickle cell anemia show?
Sickle cells and variants - blister cells, spherocytes, evidence of hyposplenism (uncleared RBCs, target cells, Howell-jolly bodies, and pappenheimer bodies)
Might have some fetal hemoglobin
How does thalassemia lead to hemolysis?
Defect in synthesis of either alpha or beta chain increases synthesis of the other - then excess precipitates within RBC
What kind of anemia is thalassemia?
Microcytic and hypochromic
What kinds of mutations are usually in alpha thalassemia and what kind in beta?
Gene deletions - one gene deletion typically silent
Point mutations in regulatory regions
What is seen in the peripheral blood smear of less severe thalassemias?
Small RBCs with mild anisocytosis and poikilocytosis
What is seen in the peripheral blood smear of more severe thalassemias?
Pronounced and bizarre anisopoikilocytosis with target cells, teardrop cells, schistocytes, and nucleated RBCs
What is hereditary spherocytosis?
Mutations lead to defective interactions between RBC membrane and cytoskeleton which causes loss of membrane during circulation
Rigid spheres can’t pass through splenic cords and are removed
What kind of anemia is seen with hereditary spherocytosis?
Normocytic and hyperchromic
What test can differentiate between hereditary spherocytosis and warm antibody type immunohemolytic anemia?
Direct anti globulin test - negative for spherocytosis and positive for the other
How does G6PD deficiency cause anemia?
Glutathione protects RBCs from oxidant stress but can’t be reduced without this enzyme
Oxidant stress leads to precipitation of denatured hb which forms intracellular inclusions (Heinz bodies) that damage membrane
What is seen in peripheral blood in g6pd deficient anemia?
Heinz bodies can be removed by spleen resulting in bite and nibble cells
Reticulocyte count may not be elevated
What are immunohemolytic anemias?
Antibodies to RBC membranes
IgG in warm antibody type, IgM in cold
Blood smear sees aggregates of RBCs from multimeric IgMs
What is the hallmark of anemias associated with mechanical trauma or of microangiopathic anemias?
Large numbers of RBC fragments (schistocytes)
What three conditions have microangiopathic hemolysis?
Thrombotic thrombocytopenic purpura
Hemolytic uremic syndrome
Disseminated intravascular coagulation
What are normal B cell markers?
CD 19, 20, 22, 79a
Pax-5
Ig light chains
What are typical T cell markers?
CD1a, 2, 3, 4, 5, 7, 8
What are typical NK cell markers?
CD2, 7, 8, 16, 56
Which marker is seen on all normal leukocyte populations?
CD45
What markers are important for differentiating between classical and nodular lymphocytic predominant Hodgkin’s lymphoma?
CD30, 15, 45, 20, 3
What are markers of immaturity in lymphoid populations?
CD34 and TdT
What is Ki-67 (Mib-1)?
A marker of cell proliferation used to determine percentage of neoplastic cells actively proliferating
Which markers can help subcategorize b lineage lymphomas and leukemia?
CD10 and CD5
What are the two broad types of acute lymphoblastic leukemia/lymphoblastic lymphoma (ALL/LBL)?
B-ALL/LBL - lymphoblasts resemble normal immature B cells known as hematogones
T-ALL/LBL - lymphoblasts resemble normal immature T cells known as thymocytes
85% in US are B cell lineage
Since cells in ALL/LBL have the same markers as their normal counterparts, how can you differentiate normal from neoplastic populations?
Intensity and pattern of expression
What are clinical features of ALL/LBL?
Secondary to cytopenias:
Fatigue
Hemorrhage infection
Bone or joint pain, lymphadenopathy, skin lesions, organomegaly
What is the prognosis of ALL/LBL?
Highly aggressive - require intensive chemotherapy
High cure rate in children but requires prolonged treatment
Grim survival rates in elderly
CSF involved in both types - negative implications
T type generally less favorable prognosis
What are the different ways NHL may arise?
Out of reactive polyclonal lymphoid proliferation with emergence of dominant clone (MALT)
Secondary to translocation of oncogenes
Genetic rearrangements produce novel hybrid proteins
What are b symptoms?
Weight loss
Pruritus
Fever
Night sweats
What does clinical staging of follicular lymphoma involve?
Splenic involvement
Liver involvement
Bone marrow involvement
What cell types is follicular lymphoma composed of?
Various proportions of neoplastic centrocytes and centroblasts
Express CD10 typical of germinal center cells
Higher grade means more centroblasts present
What is the translocation involved in follicular lymphoma?
Chromosomes 14, 18
Involves Ig heavy chain and bcl2
What characteristic surface markers do cells in MALT lymphoma not express and where do they tend to spread?
Both CD10 and CD5 negative
Tend to spread to extra nodal sites rather than lymph nodes
What are the translocations and gene involved in MALT lymphoma?
T 11,18 involving API2 and MALT1 genes
T 14,18 involving IGH and MALT1 genes
T 1,14 involving Bcl-10 and IGH genes
How does diffuse large B cell lymphoma typically infiltrate?
Diffusely infiltrates into tissues to create sheets of large atypical cells
How does Ki-67 typically stain diffuse large B cell lymphoma?
Between 20-80 but can be up to 100
What is endemic burkitts associated with?
Seen in equatorial Africa mostly in kids
Associated with Epstein Barr virus
Where is sporadic burkitts seen and what is its association with EBV?
Everywhere
Children and young adults
Less than 30% associated with EBV
Where does immunodeficiency related burkitts occur and what is its association with EBV?
With HIV and cd4 above 200
Between 30-50% associated with EBV
What are the morphological features of burkitts lymphoma?
Diffuse infiltrates Uniformly medium sized lymphoma cells with round nuclei, peripheral nucleoli, and deep basophilic cytoplasm Often has lipid containing vacuoles 100% stain by Ki-67 Mitotic bodies CD10 and CD38 positive
What are the translocations and genes involved in burkitts lymphoma?
C-MYC gene from ch 8 involved in translocation with either Ig heavy chain on 14 or one of light chains on 2 or 22
Why is chemotherapy and remission more effective in aggressive lymphomas rather than indolent?
Because our chemotherapy is targeted at proliferating cells and aggressive lymphomas proliferate much more and more rapidly than indolent lymphomas that are slow growing
Where does classical Hodgkin lymphoma typically arise?
Lymph nodes of cervical region or mediastinum
Spreads orderly to contiguous lymph node groups or lymphoid structures
Typically B cell lineage
Why can Hodgkin lymphoma easily be overlooked?
Only half present with b symptoms and these are associated with various infectious disease
Lymphadenopathy may not always be apparent
What are the features involved in NLPHL?
Typically only a single lymph node in cervical, axillary, or inguinal region
Mediastinal involvement rare
B symptoms uncommon
B cell lineage
What is the unique morphological characteristic common to all types of Hodgkin lymphoma?
Tissue enlargement due primarily to infiltration by benign reactive inflammatory cells amid paucity of lymphoma cells
What five markers are stained for in Hodgkin lymphoma and what are the results in classical vs. NLPHL?
CD45 Negative, positive CD30 Positive, negative CD15 Positive, negative CD20 Negative, positive CD3 Negative, negative
What are the characteristics of CLL/ALL?
Small, mature neoplastic lymphoid cells indistinguishable from normal mature lymphocytes - diffuse monotonous infiltration
Lymphocytosis
Fatigue from anemia, bleeding from thrombocytopenia, or swollen glands from lymphadenopathy
Maybe hepatosplenomegaly
*this and mantle cell are only ones that express CD5
What is an m spike?
The monoclonal immunoglobulin detected with a plasma cell neoplasm
What is AML?
Neoplastic proliferation of immature cell forms of myeloid series tag replaces normal bone marrow elements, suppresses normal hematopoiesis, and has circulating neoplastic cells in blood
What are the classes of mutations responsible for AML in the second hit theory?
Class 1 = activating factors, like FLT3 tyrosine receptor
Class 2 = impair differentiation (usually at blast phase), usually transcription factors
What is the clinical presentation of AML?
Anemia and thrombocytopenia
Many have leukocytosis
Possible infections and fever secondary to neutropenia
DIC especially in APL
Myeloid sarcoma if blasts form lesions in tissues
What is a myelopathy and what are its histological features?
Blast with granulocytic differentiation
High n/c ratio, finely dispersed nuclear chromatin, one to multiple nuclei
Cytoplasm may have fine granules or crystallized granular material
MPO positive
What are monoblasts and what are their histological features?
Blasts of monocytic lineage
Pale gray cytoplasm more abundant than myeloblasts
Fine chromatin and round or folded nucleus
MPO negative, but esterase positive
What are the histological features of megakaryoblasts?
Round nuclei with one to three nucleoli
Cytoplasmic blebs
What are myeloblast markers?
CD117, CD13, CD33, MPO
What is a monocytic marker?
CD14
What are erythroid markers?
CD71, glycophorin-A
What are megakaryocytic markers?
CD41, CD61
What is seen in t(8,21) AML?
Large myeloblasts with granules
Auer rods
Spectrum of maturation in neutrophilic series with dysplastic features (hyposegmented, no cytoplasmic granules)
What is the pathogenesis of APL?
Fusion protein is PML with retinoic acid receptor alpha (RARA)
Blocks normal differentiation and maturation is stuck at promyelocytic phase
Treated with ATRA
What drugs are implicated in therapy related AML?
*Alkylating agents
*Topoisomerase II inhibitors
Antimetabolites
Antitubulin agents
What are myelodysplastic syndromes?
Encompass group of clonal stem cell disorders that are characterized by ineffective hematopoiesis resulting in hyper plastic bone marrow and peripheral cytopenias
What are the clinical features of mds?
Symptoms related to cytopenias
Not typically organomegaly
Cells display dysplasia
RBCs have anisopoikilocytosis and basophilic stippling
What is the prognosis of MDS?
Higher percentage of blasts is higher grade
Lower grade has better prognosis
Therapy related has especially poor prognosis
Median survival is few months to 2 years
Can easily progress to AML
What are chronic myeloproliferative neoplasms?
Clonal stem cell disorders characterized by unregulated sustained myeloid cell proliferation in bone marrow with little disturbance in cell maturation leading to neoplastic cells in peripheral blood
Hyperplastic bone marrow and elevated blood cell counts
What is clonal evolution?
The on going accumulation of mutations that can result in the progression or transformation of a chronic myeloproliferative neoplasm
What is the “spent phase”?
Phase of CMPN where bone marrow elements replaced by fibrosis (myelofibrosis) as well as transformation to AML
What are the clinical feature of CMPNs?
Fatigue, malaise, weight loss
Hepatosplenomegaly
Many patients present asymptomatic
What are the three phases of CML?
Chronic phase - myelocyte bulge, blasts <2% of peripheral WBCs, absolute basophilia, thrombocytosis, hyper cellular bone marrow
Accelerated phase - more than 10% blasts in blood or bone marrow
Blast phase - more than 20% blasts in blood or bone marrow
What is polycythemia Vera?
Increased RBC production independent of mechanisms normally regulating erythropoiesis
Usually also an increase megakaryocytic and myeloid elements
What are clinical features of PV?
Hypertension or thrombotic episodes secondary to increased RBC and sluggish flow Hematocrit 60% or higher WBCs and platelets elevated Often basophilia Low epo levels Indolent disease treated with phlebotomy
What are the morphological findings in the bone marrow during the polycythemic phase of PV?
Proliferation of maturing erythroid precursors
Increase in granulocytes and megakaryocytes
Hyper cellular bone marrow
Frequent absence of storage iron
What is primary myelofibrosis?
Increase in all myeloid cells which drives proliferation of fibroblasts
What are the two phases of PM and what symptoms do patients present with in each?
Early/prefibrotic stage - 40% of patients asymptomatic, rest have symptoms related to hypermetabolism
Fibrotic stage - symptoms related to bone marrow fibrosis and extra medullary hematopoiesis with massive splenomegaly
What is a typical peripheral blood finding in fibrotic stage of PM? Typical bone marrow finding?
Tear drop RBCs + circulating nucleated erythrocytes + left shifted granulocytes = leukoerythroblastic reaction
Dry tap - can see megakaryocytic proliferation in fibrotic background
What is essential thrombocythemia?
Involves megakaryocytic lineage
Sustained thrombocytosis
Indolent disorder with symptom free intervals interrupted by thromboembolic or hemorrhagic episodes
What are the common symptoms of ET?
Transient cerebral ischemia
Paresthesias Related to microvascular occlusion
Digital ischemia
What are the findings in the bone marrow in ET?
Bone marrow normocellular or mildly hyper cellular
Marked proliferation of enlarged megakaryocytes
Minimal to no increase in reticulin fibers
