Hematopathology: Overview
I.
Other
a.
Reactive Lymphadenitis
i.
toxoplasmosis
ii.
infectious mononucleosis
iii.
cat scratch disease
b.
Myelodysplastic Syndrome (MDS)
i.
Low Grade MDS
ii.
High Grade MDS
c.
Chronic Myeloproliferative Disorders
i.
Chronic Myelogenous Leukemia (CML: also see
Leukemia)
ii.
Polycythemia
Vera
iii.
Essential thrombocythemia
iv.
Chronic Idiopathic Myelofibrosis
d.
Leukemoid reaction
II.
Leukemia
a.
Acute Leukemia
i.
Acute Myelogenous Leukemia (AML)
1.
myelodysplasia-related (MDR-AML)
2.
de novo (DN-AML)
-
acute promyelocytic leukemia (APL)
ii.
Acute Lymphoblastic Leukemia (ALL)
1.
Precursor B-Cell ALL
2.
Precursor T-Cell ALL
b.
Chronic Leukemia
i.
Chronic Myelogenous Leukemia (CML)
ii.
Chronic Lymphocytic Leukemia (CLL) / Small
Lymphocytic Lymphoma (SLL)
iii.
Hairy Cell Leukemia
III.
Lymphoma
a.
Non-Hodgkin’s Lymphoma
i.
B-Cell Lymphomas
1.
Burkitt’s Lymphoma
2.
Follicular
3.
Diffuse Large B cell Lymphomas
4.
Multiple Myeloma
5.
Extranodal marginal zone lymphoma of
mucosal associated tissue (MALT lymphoma)
ii.
T-Cell Lymphomas
1.
T-lymphoblastic lymphoma/leukemia
2.
Mycosis Fungoides (MF) and Sézary Syndrome
3.
Peripheral T-cell lymphoma, unspecified
4.
Anaplastic Large Cell (Ki-1+) Lymphoma
(ALCL)
b.
Hodgkin’s Lymphoma
i.
Classical HL
1.
Nodular Sclerosing Hodgkin’s Lymphoma
(NSHL)
2.
Mixed Cellularity Hodgkin’s Lymphoma (MCHL)
3.
Lymphocyte Rich Classical Hodgkin Lymphoma
(LRCHL)
4.
Lymphocyte Depleted Hodgkin's Lymphoma
(LDHL)
ii.
Non-Classical HL
1.
NLPHD
I.
Other
a.
Reactive Lymphadenitis
i.
toxoplasmosis
ii.
infectious mononucleosis
iii.
cat scratch disease
focal abscesses
b.
Myelodysplastic Syndrome (MDS) =
preleukemic syndrome
Marrow-based
A group of clonal stem cell disorders.
Maturation defects à ineffective hematopoiesis
Age > 50
Peripheral cytopenias, Hypercellular marrow
Dysplastic morphology
- Erythroid: multinucleated cells,
dyssynchronous maturation of nucleus and cytoplasm
- Granulocytes: bilobed nuclei (Pelger-Huet
cells), abnormal/absent granules
- Platelets: may lack granules, may be
abnormally large
May have history of exposure to chemotherapy or radiation
10-40% à develop MDR-AML
Treatment: supportive – blood transfusions, antibiotics
(transplantation is only cure)
abnormalities: CD8+,CD7-,CD5-
i.
Low Grade MDS
Normal blast count, refractory anemia, 6-year avg. survival
ii.
High Grade MDS
Excess blasts, refractory anemia, 6-8 month avg. survival
Often have history of chemotherapy or
radiation
c.
Chronic Myeloproliferative Disorders
Neoplastic stem cell proliferation with differentiation
i.
Chronic Myelogenous Leukemia
See leukemia below
ii.
Polycythemia
Vera
increased RBC
production (not secondary to elevated erythropoietin)
hyperviscosity of blood à thrombotic episodes
suspicious: mesenteric, portal, splenic vein
thrombosis
increased GI bleeding
Two phases
1.
polycythemic
phase
2.
spent
phase
iii.
Essential thrombocythemia
megakaryocytic lineage with sustained thrombocytosis (platelet production >
600,000)
first exclude: infection, neoplasm, splenectomy, iron deficiency
thrombosis: splenic, hepatic vein
minimal
fibrosis
iv.
Chronic Idiopathic Myelofibrosis
dysplasia/proliferation: megakaryocytic and granulocytic cells in
bone marrow
Reticulin fibrosis
in marrow (osteosclerosis)
à spleen hematopoiesis (splenomegaly)
Findings: nucleated
RBC’s
median survival: 3-5 years
à acute leukemia (5-30%)
megakaryocytic lineage
d.
Leukemoid reaction
bands, lymphocytes, neutrophils in blood (marrow
is not packed or malignant)
resembles leukemia peripherally (but no bone marrow
involvement)
etiology: infectious disease, intoxication,
neoplasms, acute hemorrhage
may be lymphocytic, monocytic, myelocytic,
plasmocytic
II.
Leukemia
Marrow-based, clonal,
malignant, Hematopoietic.
Diagnosed by finding blasts in peripheral blood and bone marrow
(hypercellular).
a.
Acute Leukemia
Blasts predominate
- Lose ability to differentiate
- High N:C ratio,
fine chromatin, distinct nuclei
- Myeloblasts cannot be morphologically
distinguished from lymphoblasts
-
Auer rods (rare) represent myeloblasts
Signs/Symptoms: marrow failure, cytopenias,
organ infiltration (spleen, lymph nodes, liver, CSF, testis, etc.), leukostasis
i.
Acute Myelogenous Leukemia (AML)
Sudan Black+ (lipid granules: granulocytes), Esterase+ (monocytes),
MPO+
CD13, CD33, CD117
85% of adult acute leukemia
Features: hypercellular marrow, monomorphic blasts (most common:
myeloblastic)
Old classification: FAB classification
1.
Myelodysplasia-Related (MDR-AML)
median age: 62, poor prognosis, not candidates for transplant
poorly responsive to cytotoxic chemotherapy
2.
de novo (DN-AML) = AML with recurrent
cytogenic abnormalities
younger: median age 30’s
t(
organ involvement less frequent than MDR-AML
responds well to chemotherapy
young: therefore transplant candidate
two steps required for de novo AML
1) differentiation
mutation
2) proliferation
mutation
e.g. Flt3: drives proliferation of myeloid
stem cells (15-25% of de novo AML)
a.
Acute Promyelocytic Leukemia (APL)
10% of AML (auer rods more common in)
60-70% survival with ATRA therapy
blasts resemble promyelocytes
* t(15;17) )(PML/RARa)
- RARa = retinoic acid receptor (steroid
hormone family)
- mediates myeloid differentiation
- RA activates normal RARa by releasing a
co-repressor complex containing histone deacetylase
- mutant PML-RARa
is not activated by physiological levels of RA
- mutant PML-RARa
is activated by pharmacologic levels of ATRA (all-trans RA)
à differentiation of Promyelocytic blasts (remission)
*
variant translocation: t(
ii.
Acute Lymphoblastic Leukemia (ALL) /
Lymphoblastic Lymphoma
TdT, CD2,CD3
Surface immunoglobulin negative
most common childhood malignancy
85% of acute leukemia in children (good prognosis: chemo.
successful 70% of children)
15% of adult acute leukemia (poorer prognosis)
Signs/Symptoms: splenomegaly, hepatomegaly, lymphadenopathy
(leukemic infiltrates), hypercellular marrow
1-2%: Burkitt’s Lymphoma’s leukemic
counterpart (CD19, CD10, CD20, surface Ig)
1.
Precursor B-Cell ALL (85%)
TdT, CD19
good risk: t(12;21)
poor risk: t(9;22)
2.
Precursor T-Cell ALL (15%)
TdT, CD2, CD3, CD7
classic presentation: mediastinal mass in
adolescent male (thymus)
average prognosis
b.
Chronic Leukemia
Differentiated cells predominate.
Insidious, with long relatively long survival (years).
Possibility of transformation to acute leukemia exists
i.
Chronic Myelogenous Leukemia (CML)
age 25-60
15-20% of leukemias
most
common myeloproliferative disease
splenomegaly (sense of “fullness”)
megakaryocytes throughout
t(9;22)(ABL-BCR)
Drug that targets: STI571, Gleevec
Distinguish from leukemoid by: WBC>50,000, absence of toxic
neutrophils, blasts, increased platelets, splenomegaly, no fever, karyotype(9;22), abnormal megakaryocytes
Three Phases
1.
chronic
a.
hypercellular marrow (blasts < 10%)
b.
immature myeloids in plasma (but blasts < 2%)
c.
basophilia
2.
accelerated
a.
increased
basophilia
b.
blood/marrow
blasts: 10-20%
3.
blast
crisis
a.
blasts
> 20%
b.
70%
myeloid blast crisis (AML)
c.
30%
lymphoid blast crisis (ALL)
ii.
Chronic Lymphocytic Leukemia (CLL) / Small
Lymphocytic Lymphoma (SLL)
B lymphocyte leukemia
size: small/round
Most common adult leukemia
in Western world
Median age: 65 (most indolent type of leukemia – more likely to
die of other causes - incurable)
Signs/Symptoms: asymptomatic, anemia, infections,
hepatosplenomegaly, lymphadenopathy, lymphocytosis, hypogammaglobulinemia
Pathology: Almost always B-Cells (CD20, CD5,
CD23)
1. blood: small
lymphocytes
2. bone marrow:
small lymphocytes
3. lymph nodes:
small lymphoctes
Transformations
1. Richter’s syndrome (transformation to
large cell lymphoma) 10%
2. Prolymphocytic transformation 13-30%
Associations
1.
Hypogammaglobulinemia à bacterial infection
2.
Hypoproliferative or Autoimmune hemolytic anemia/thrombocytopenia
Genetics
1.
Mutation status of immunoglobulin V genes is important for prognosis (mutated:
better prognosis)
2.
trisomy 12,
iii.
Hairy Cell Leukemia
B lymphocyte leukemia (CD20) with distinctive morphology (rare:
2%)
median age: 55
male:female = 5:1
Clinical presentation: 1) splenomegaly; 2) pancytopenia; 3)
recurrent infections
Hairy cells on peripheral
blood smear
CD20, CD103, CD11c, CD25
Indolent, sensitive to nucleotide analog therapy (2-CDA)
III.
Lymphoma
a.
Non-Hodgkin’s Lymphoma
85% of lymphomas
Older
unpredictable spread
Neoplastic cells predominant
<50% cure overall
large/medium cells: aggressive
small cells: indolent
i.
B-Cell Lymphomas
most common immune malignancy
more common in immunocompromised
patients
pesticide-link
VDJ recombination-induced
1.
SLL
equivalent to CLL (see above)
2.
Burkitt’s Lymphoma
African subtype: jaw mass (EBV+malaria)
Sporadic: GI tract involvement (EBV)
morphology: diffuse, blast-like
Many (non-malignant) macrophages eat the dead tumor cells (diffuse
“starry sky”)
size: medium (aggressive)
Most proliferative
of all the lymphomas
IgM+, CD19+, CD10+, CD20+
non-treated: fatal in 6 months; treated: 90% cure rate
t(8:14)(c-myc:IgH) t(8:2) IgKappa, t(8 :22) IgLambda
3.
Follicular
morphology:
nodular
size: small,
cleaved
follicular growth pattern
painless adenopathy, B-symptoms
B-Cells (CD10+, CD19+, CD20+, CD5-)
t(18:14)(BCL-2:IgH)
don’t proliferate faster, but also don’t die (anti-apoptosis);
resistant to chemotherapy
median survival: 5-8 years
cells become larger over time
4.
Diffuse Large B cell Lymphomas
morphology: diffuse
size:
large
most
common B-cell non-HL
CD10+/-, CD19+, CD20+
t(
aggressive tumor (but aggressive tumors are usually more
sensitive to chemotherapy!)
bcl-6
5.
Multiple Myeloma
monotypic Ig (usually IgG)
destructive bone lesions, renal (tubular) injury, amyloidosis, bacterial infections (may be fatal)
neoplastic cells may induce apoptosis in normal Ig cells
involves marrow but cells are probably of
post follicular B-Cell origin
differentiate from benign monoclonal Ig’s
(common in older patients)
benign do not have:
o
clumps
of monotypic plasma cells in bone marrow
o
bone
lesions,
o
depression
of normal Ig
6.
Extranodal marginal zone lymphoma of
mucosal associated tissue (MALT lymphoma)
extranodal lymphoid tissue (GI, bronchial, etc.: MALT)
size: small to medium
indolent B-Cell lymphoma (CD10-, CD19+, CD20+)
IgG
t(
tend to
remain localized (may à Large cell
lymphoma)
small to medium size
Derivation of lymphoid tissue:
a.
Peyer’s
patches
b.
Hashimoto’s
c.
Sjogren’s
(salivary gland)
d.
infection
(H. pylori)
ii.
T-Cell Lymphomas
10-15% of lymphomas (rare)
divided into precursor (bone/thymus) and
peripheral
tend to be more aggressive than B-Cell lymphomas
paraneoplastic
difficult to diagnose
·
rare
·
extranodal
presentation
·
no
histological or cytological markers
·
no
immunologic markers of clonality
most peripheral T-cell neoplasms show loss of
one or more pan T cell antigens (CD2, CD3, CD5, CD7)
1.
T-lymphoblastic lymphoma/leukemia
precursor
T-Cell neoplasm (TDT+)
size: small T-cells (mostly CD4+)
characteristic
folded, ceribriform nucleus
similar to precursor T-cell acute leukemia
(treated similarly)
classic presentation: mediastinal mass in adolescent
male (thymus)
thymic tissue effaced
2.
Mycosis Fungoides (MF) and Sézary Syndrome
peripheral, Cutaneous
erythematous, pruritic (sun-protected) skin lesions
indolent
PCR demonstration of T-Cell clonality often required for diagnosis
Sézary Syndrome is a subtype of MF
§
circulating
tumor cells
§
generalized
erythroderma
3.
Peripheral T-cell lymphoma, unspecified
peripheral, nodal (lymphadenopathy)
mature
T-cell (TdT-, CD2+, CD3+) may
aberrantly miss a surface marker
paraneoplastic (eosinophilia, pruritis, hemophagocytic
syndromes)
half of all peripheral T-Cell lymphomas
effacement of nodal architecture
size: small,
intermediate, and large mixture
4.
Anaplastic Large Cell (Ki-1+) Lymphoma
(ALCL)
peripheral, nodal
most
common peripheral T cell lymphoma in children
mediastinum spared
bone marrow not involved
good prognosis
strongly
expresses CD30, EMA
t(2;5)(ALK
dysregulation: Anaplastic lymphoma kinase)
b.
Hodgkin’s Lymphoma
Reed-Sternberg cells (CD15+, CD30+, CD45-, CD20-)
15% of all lymphomas
Young adults
Contiguous structures
affected
Localized, painless adenopathy
B-Cells
Rare neoplastic cells
>80% cure
Pain after alcohol consumption
EBV-associated
Diagnosis based on two things:
1.
Reed-Sternberg cells (or variants)
·
neoplastic
·
stop codons render immunoglobulin (V)ariable
regions non-functional
o
would
normally be eliminated by apoptosis (unable à antigen affinity)
·
Forms
of:
a.
classic:
large, binucleate cell with eosinophilic cytoplasm
b.
lacunar:
formalin artifact
c.
L&H
(lymphocyte and histiocytes): popcorn cells, polylobulated nuclei
2.
Reactive
cell background
ii.
Classical HL
1.
Nodular Sclerosing Hodgkin’s Lymphoma
(NSHL)
lacunar RS cells
most common type of HL
younger age: 25
only type that affects females > males
cervical lymphadenopathy, mediastinal mass
B-Symptoms: night sweats, fever, weight
loss (1/3 of patients)
Broad bands of collagen, capsular fibrosis
T-Cell and Eosinophil infiltrate
2.
Mixed Cellularity Hodgkin’s Lymphoma (MCHL)
second-most common
young men
B-Symptoms
Multiple nodes (stage III, IV)
good prognosis
classic RS
cells
EBV virus most closely associated
3.
Lymphocyte Rich Classical Hodgkin Lymphoma
(LRCHL)
Lack B-Symptoms
diffuse, small lymphocytes
L&H RS cells
4.
Lymphocyte Depleted Hodgkin's Lymphoma
(LDHL)
B-symptoms
Most aggressive LDHL
Disseminated
RS Cells predominate
classicàbizarre
RS cells
iii.
Non-Classical HL
1.
NLPHD
L&H RS cells: popcorn cells, polylobulated nuclei (NLPHL)
CD30-, CD45+
Lack B-Symptoms
cervical or axillary
good prognosis if Stage I
à Large B Cell
Lymphomas
small B-lymphocyte reactive background greatly outnumber RS cells
Hematopoietic System
Bone marrow: Hemopoiesis
Four committed
progenitor cell lines
1.
erythroid
(RBC)
2.
megakaryocytic
(megakaryocyte)
3.
granulocytic-monocytic (monocyte, neutrophil, basophil, eosinophils, mast cell)
4.
lymphocytic
(T,B,NK)
Lymphoid System
Lymphoid organs
1.
lymph
nodes
2.
thymus
3.
spleen
4.
adenoids
5.
MALT
(mucosal associated lymphoid tissue); GI, lung, marrow, skin
Lymphopoiesis
Lymphocytes made in bone marrow
Differentiation
·
T-Cells: thymus (à T-helper=CD4+, T-cytotoxic=CD8)
·
B-Cells :
bone marrow (become plasma cells in
lymph tissue)
Migrate to
peripheral lymph tissues
Lymph Nodes
Meeting place for T and B cells
·
Lymphocytes:
through high endothelial venules from blood
·
Antigens:
lymphatic vessels
Compartments
1.
Lymphoid follicles: clonal expansion
B-Cells and plasma cells/memory cells
2.
Marginal zone: immature B-Cells (unchallenged by
antigen)
3.
Parafollicular
cortex: T-Cells
Spleen
Compartments
1.
red pulp: filtering component
2.
white pulp: lymphoid component
a.
B-Cell domains: similar to lymphoid follicles
b.
Periarteriolar
lymphoid sheath:
T-dependent areas
Disorders (General info.)
·
Disorders
can be reactive or neoplastic
·
Marrow-based
reactive disorders
o
Leukocytosis
1.
neutrophilia:
bacteria
2.
eosinophilia:
allergy, parasites
3.
monocytosis:
chronic infections
4.
leukemoid
reaction: severe infection
a.
immature
myeloid precursors can be in circulation
o
Cytopenias
1.
aplastic
anemia (benzene exposure)
·
Lymph
node-based reactive disorders
1.
toxoplasmosis
2.
infectious mononucleosis
3.
cat scratch disease: focal abscesses
·
Neoplasms
1.
Leukemias:
marrow
a.
lymphocytic
or myeloid
b.
acute
or chronic
2.
Lymphomas:
non-marrow (neoplastic cells tend to resemble phenotype)
a.
Hodgkin’s
and Non-Hodgkin’s [NHL: B (80-85%), T, NK (rare) cell types]
3.
Other neoplasms of marrow
a.
Myelodysplastic
Disorders (clonal, hypercellular marrow, dysplastic cytologic features,
peripheral cytopenias, anemia)
b.
Myeloproliferative
Disorders (clonal, hypercellular marrow, no dysplasia, increased peripheral counts)
Lab Test
Procedures
1.
Peripheral
blood draw
2.
Bone
marrow aspirate
3.
Lymph
node fine needle aspiration
4.
Lymph
node biopsy
5.
Other
biopsy
Morphologic examination
1.
Wright’s
stain (number, morphology, types of cells)
2.
H&E:
(architecture of tissue)
Flow Cytometry
·
most
commonly used technique to examine surface antigens
·
separate
out before based on scales of size and complexity (lymphocytes
have smallest size and least complexity)
·
fluorochrome-conjugated
antibodies (lineage/maturation)
Immunohistochemical stains
·
clonality
of B-Cells
·
T-cell
phenotype
Cytochemical studies
·
Myeloid:
·
Lymphoid:
non-specific esterase (NSE)
Cytogenetic studies
·
G-banding
(karyotype) during metaphase (only possible when
sample is large enough and able to divide)
·
FISH
(fluorescent in situ hybridization) picks up small translocations
o
red,
green, yellow (should be two red, two green; translocation: one red, one green,
one yellow)
Molecular studies
·
Reactive:
polyclonal smear
·
Neoplastic:
monoclonal band