Acute myeloid leukemia:
morphology and beyond
Nancy Rosenthal, MD
Clinical Professor of Pathology
Objectives
 Review clinical, morphologic, immunophenotypic, and
cytogenetic abnormalities that allow us to classify AML
 Introduce new cytogenetic and mutational
abnormalities that may be leukemia defining in the
future
 Discuss upcoming updates to the WHO classification
that will be utilized starting in 2016 (?)
 No conflicts to disclose
Diagnosing and following adult patients with acute myeloid leukaemia in the genomic
age
British Journal of Haematology
Volume 167, Issue 2, pages 162-176, 7 AUG 2014 DOI: 10.1111/bjh.13048
http://onlinelibrary.wiley.com/doi/10.1111/bjh.13048/full#bjh13048-fig-0001
Diagnosing and following adult patients with acute myeloid leukaemia in the genomic
age
British Journal of Haematology
Volume 167, Issue 2, pages 162-176, 7 AUG 2014 DOI: 10.1111/bjh.13048
http://onlinelibrary.wiley.com/doi/10.1111/bjh.13048/full#bjh13048-fig-0003
Is there still a role for morphology in
the diagnosis of AML?
 May allow establishment of a diagnosis quickly
 Especially important in the diagnosis of acute
promyelocytic leukemia so ATRA can be started
 Leads to the ability to review all of hematopoiesis
 Exclude relevant differential diagnoses
Do we need to do an aspirate and
bone marrow biopsy?
 Only in the setting of >20% blasts in the peripheral
blood
 Depends on how the patient will be treated
 Does give information about cellularity, maturation
patterns, stromal changes
 Helpful baseline for comparison purposes during
evaluation of treatment efficacy
Diagnosis of AML – WHO
2008
 Algorithmic approach
 Previous therapy
 Therapy related myeloid neoplasm
 Recurrent cytogenetic abnormalities
 t(9;22), t(8;21), inv16, etc.
 AML with myelodysplasia related changes
 AML
 Not otherwise specified
AML with recurrent genetic
abnormalities
 Clues to the diagnoses can be obtained by evaluating
morphology
 Blasts may be less than 20%
 Blasts (in all cases) should be counted the old fashion
way, not based on flow cytometry
Clues from flow cytometry
 t(8;21) – strong CD34, CD13+, weak CD33, CD19+,
PAX5+, cytoplasmic CD79a+, weak TdT
 t(9;22) – CD34 -, HLADR -, CD117+
 Inv16 – myeloid and monocytic markers and CD2+
For a definitive diagnosis - need
cytogenetic studies and/or FISH
Mutations in AML - 2008
 Provisional entities
 NPM1
 CEPBA
 Prognostic markers
 FLT3
 KIT
AML with recurrent cytogenetic
abnormalities – new categories
 New mutation subgroups are being proposed
 AML with RUNX 1 mutation – older men, poor prognosis
 AML with NPM1 – good prognosis
 AML with CEBPADM – only changes prognosis (good) if
present as a double mutant
Kaplan-Meier curves for overall survival stratified by (A) CEBPA–wild-type (WT) or CEBPAmutant status, (B) CEBPA-WT, CEBPA-single, or CEBPA-double mutant status, (C) CEBPA-WT,
single N-terminal (term), single C-term, or double N-term plus C-term mutant sta...
Claire L. Green et al. JCO 2010;28:2739-2747
©2010 by American Society of Clinical Oncology
(A) Disease-free survival, (B) overall survival, and (C) event-free survival of patients younger
than age 60 years with cytogenetically normal acute myeloid leukemia according to RUNX1
mutation status.
Jason H. Mendler et al. JCO 2012;30:3109-3118
©2012 by American Society of Clinical Oncology
AML with myelodysplasia related
changes
 Previous MDS
 Dyspoiesis – 50% of the cells in 2
cell lines
 Cytogenetic abnormalities
AML with myelodysplasia-related
changes
Survival data.
Olga K. Weinberg et al. Blood 2009;113:1906-1908
©2009 by American Society of Hematology
Characteristics of acute myeloid leukemia with myelodysplasia‐related changes: A
retrospective analysis in a cohort of Chinese patients
American Journal of Hematology
Volume 89, Issue 9, pages 874-881, 19 JUN 2014 DOI: 10.1002/ajh.23772
http://onlinelibrary.wiley.com/doi/10.1002/ajh.23772/full#ajh23772-fig-0002
Revised criteria for AML with
MRC
 Remove de novo cases with no MDS related cytogenetic
abnormality if there is an NPM1 or CEBPAdm
 Revise cytogenetic abnormalities
 Del9q is an MDS related entity only in the absence of
NPM1 mutations
 NPM1 commonly associated with del9q and is likely not
adverse in this setting
Case
Flow cytometry, cytogenetics and
molecular studies
 14% myeloid blasts positive for CD117, CD13, CD33,
CD34, CD38, HLA-DR and partial expression of CD7.
 42~44,XY,add(2)(p11.2), del3, del 5,
del(6)(q21),7,add(8)(q24),add(9)(p2,2),
add(13)(q22),17,der(19)add(19)(p13)add(19)(q13.1),ad
d(22)(p11.2)
+mar[cp19]/46,XY[1]
 FLT3, NPM1 and CEBPA negative
Acute erythroid leukemia 2008
 2 subtypes recognized
 Acute erythroid/myeloid leukemia
 > 50% erythroid precursors
 >20% of the non-erythroid cells are blasts
 Acute erythroleukemia
 First one is controversial as the diagnosis of acute
leukemia can be made with a very small number of
blasts.
 Altered erythroid percentages can changed based on
therapy, metabolic defects, use of erythropoietin
Comparison of 40 patients who had MDS with erythroid hyperplasia (MDS-E), 41 patients who
had AML with myelodysplasia-related changes and erythroid hyperplasia (AML-MRC), and
124 patients with acute erythroid leukemia (AEL).
Robert P. Hasserjian et al. Blood 2010;115:1985-1992
©2010 by American Society of Hematology
Figure 1. Effects of the presence of erythroid predominance (EP) and diagnostic categories on
overall survival.
Zuo Z, Medeiros LJ, Chen Z, Liu D, Bueso-Ramos CE, et al. (2012) Acute Myeloid Leukemia (AML) with Erythroid Predominance
Exhibits Clinical and Molecular Characteristics that Differ from Other Types of AML. PLoS ONE 7(7): e41485.
doi:10.1371/journal.pone.0041485
http://127.0.0.1:8081/plosone/article?id=info:doi/10.1371/journal.pone.0041485
Acute erythroleukemia
 New update of WHO
 >50% erythroid precursors and 5-19% blasts would be
considered RAEB (actually myelodysplasia with excess
blasts)
 > 50% erythroid and >20% blasts would be acute myeloid
leukemia (often AML with myelodysplasia related
changes)
 Pure erythroleukemia will remain in AML
 Erythroleukemia will become an extremely rare
disorder.
Case
Flow cytometry, cytogenetics and
molecular studies
 90% monocytic cells which express CD38, CD64,
bright CD33, and partial CD36,HLA-DR, CD56, CD13
and CD14
 Cytogenetics showed t(11;17)
 FISH showed an MLL rearrangement but no RARA
break-apart probe abnormality
 NPM1, CEBPA and FLT3 were negative
Acute monocytic/monoblastic
leukemia
 Need a careful monocyte, promonocyte, monocyte
count to make the diagnosis of AML
 Presence of NPM1 mutation or 11q23 rearrangement is
not leukemia defining
 May herald rapid progression from CMML to AML is
present and these patients should be watched closely
Promonocytes
Differentiation of types of monocytic
cells can be problematic
 Morphological evaluation of monocytes and their
precursors
 Haematologica 2009;94:994
 Authors included Barbara Bain, Richard Brunning, etc.
monoblast
Round/oval
Delicate/lacelike prominent
nucleolus
Basophilic,
rare
azurophilic
granules
Large 20-30
um
promonocyte
Convoluted
indented
Delicate/lacelike prominent
nucleolus
Variably
basophilic
Variable
azurophilic
granules
Except for
nuclear shape
similar to
monoblast
Immature
monocyte
Convoluted
indented
More
Less
condensed
basophilic than
Rare nucleolus blast but more
than
monocytes
monocyte
Lobulated
indented
Condensed
Gray, occ
Large 20-25
No nucleolus granules, occ um
vacuoles
Resemble
monocytes but
less mature
and smaller
Monocyte
immature monocyte
promonocyte
monoblast
Classification
 90 digital images of monocytic cells circulated among 5
experts
 All experts made the same identification on 25 of the
cells, 4/5 made the same identification on 44 cells
 Percentage of good concordance (4/5 experts) was
76%
 For 21 cells the concordance rate was 3/5 or 2/5
 6 cells had only 2/5 concordance – were sent back for a
2nd reading
 These cells were confirmed as immature monocytes
 Highest concordance was for monoblasts and lowest
was for immature monocytes
 Proposed using their classification scheme and correlate
with flow cytometric findings
Use of flow cytometry to detect
abnormal monocytes
 May lack CD13, CD33, or CD14
 Express aberrant antigens such as CD56, CD19, CD7
or CD5
 May be difficult to distinguish immature monocytes from
promonocytes
My conclusion
 Differentiating these cells is difficult for even those most
expert in morphology
 Making the diagnosis of acute monocytic leukemia
based on counting promonocytes is problematic in
some cases
Summary
 The diagnosis of AML is ever changing and will
continue to evolve based on increased understanding
of molecular mechanisms.
 Targeted therapy may further influence diagnostics in
the future.
 At the moment there is still a role for morphology !!!