1

Morfologia normale e patologica

Gina Zini Centro di

Ricerca

ReCAMHDpt

. Ematologia

Università

Cattolica

S. Cuore

-

Roma

EMATOLOGIA DI LABORATORIO:percorsi diagnostici e obiettivi clinici.Milano 11-12 Novembre 2010

Prerequisites for classification of myeloid neoplasms

by WHO 2008 criteria (I)

Morphologic, cytochemical

and immunophenotypic

features

of

the neoplastic cell

- to establish

lineage

and degree of maturation

-

to

decide

whether

cellular proliferation

is

cytologically

normal

or dysplastic, effective

or ineffective

Criteria should be applied to initial specimens prior to any therapy including GFs

Prerequisites for classification of myeloid neoplasms

by WHO 2008 criteria (II)

•

Blast

percentage

on PB and BM remains

fundamental

for categorizing

and for

evaluating

disease

progression

• Cytogenetic

and molecular

genetic

are required

at diagnosis

-

to

identify

specific

genetically

defined

entities-

to

establish

a baseline

to

assess

disease

progression

Morphological quantitative rules (I)

Peripheral Blood

Manual

differential

on 200 cells, WBC RBC and Plt

qualitative evaluation,

? Neutrophil

granularity? ► Well

controlled

staining

Bone Marrow aspirate

Manual

differential

on 500 nucleated

cells

► guidelines

(undiluted

samples, areas close

to

particles, multiple smears)

Cell

count

includes:- blasts

and promonocytes

- promyelocytes, myelocytes, metamyelocyes, band neutrophils, segmentedneutrophils

-

eosinophils, basophils, monocytes, mast

cells- lymphocytes- erythroid

precursors

Megakaryocytes

are not

included

BMF cell count: PB diluition

effects on cell count at different volumes

Dresch et al. J Clin Pathol 1974.

particles ?

MGKsor other

precursors ?

acceptable quality ?

BMF

•

qualitative evaluation (blasts,dysplasia,

cancer

cells…)

•

quantitative (myelogram)

and qualitative evaluation

cellularity

?

PB

highly reduced

Y Y

Y

N

increased, normal or

slightly reduced

N

N

•

From the FAB 1976 to

the WHO 2008 the blast

percentage

remains

a major factor

in diagnosis, subclassification

and prognosis

•

The definition

of a blast

cell

is

still

based

on that

one

proposed

in 1976 by

the FAB group.

• It

is

unclear

whether

it

has

been

applied

in the same

manner

worldwide.

•

Since

the WHO has

changed

the definition

of AML (minimum criterion

is 20% blasts) and since

RAEB has

been

diveded

into

2 groups

(5 to

9%

and 10 to

19% of blasts, respectiely) it

has

become

clear

that

the definition

of blasts

of granulocyte

lineage

should

be

more precise.

Flow cytometry determination should not be used as substitute (diluition, not all blasts are CD34+)

Morphological quantitative rules (II)

Bl

≥

20% Bl

≥

20%

Bl

< 20%

Blasts

ANC and NEC

Myelogram

1

Granulocytic

series 50%

Blasts

20%Erythroid

series

25%

Lymphocytes

5%

L/E=

2,8

Blasts/ ANC: 20%

DGN: AML

Myelogram

2

Granulocytic

series

25%Blasts

5%

Erythroid

series

65%Lymphocytes

5%

L/E=

0,46

Blasts

/NEC: 5 x100/30= 16,6%

DGN: AREB II

* ANC: all nucleated cells* NEC: non erythroid cells. Lymphocytes and plasmacells are excluded too

Myelogram

3

Granulocytic

series

10%Blasts

4%

Erythroid

series

80%Lymphocytes

6%

L/E=

0,17

Blasts

/NEC: 4 x100/14= 28,57%

DGN: AML

WHO 2008 Diagnostic

algorythm

WHO 2008 MDS Classification

-

Adults

WHO 2008 MDS Classification

-

Childhood

Simultaneous

proliferation

and apoptosis

of hematopoietic

cells

Additional

category: Refractory Cytopenia

of Childhood

(RCC)

ChildrenUsually

hypocellular

BM

<2% blasts

in PB<5% blasts

in BM

Persisten

cytopenia(s) with

dysplasia

WHO 2008: Acute Leukemia and Related Precursors Neoplasms

AML with

myelodisplasia-related

changes

Dysplasia must be present in

at least

50% of the cells

at

least

in 2 BM cell

lines.

What is a Ring Sideroblast?•

An erythroblast with siderotic

granules

–

5 or more [Juneja

1983] –

10 or more [Cazzola

1988, Brunning

(WHO) 2001]

•

Covering a certain proportion of the nuclear outline–

A third or more [Juneja

1983, Cazzola

1988, Brunning

2001]•

What the 2008 WHO

classification will advise

–

5 or more siderotic

granules–

Covering a third or more of the nuclear circumference

•

Myeloblasts, monoblasts

and megacaryoblasts

should

be included.

•

Erythroblats

should

be

considered

“blast

equivalent

“

only

in the Pure acute erythroid

leukemia.

•

Promonocytes

are considered

“monoblast

equivalent

“

when the requisite percentage

is

tallied

for

the diagnosis

of acute

monoblastic, acute monocytic

and acute myelomonocytic leukemia.

•

In acute promyelocytic

leukemia the “blast equivalent “

is the abnormal promyelocyte.

• Small dysplastic MGK and microMGK

are not blasts.

WHO 2008: What is a Blast Cell?

Myeloblasts

recamh@rm.unicatt.it