Shadow - low white and m3

Preamble

Acute promyelocytic leukemia with PML-RARA corresponds to AML-M3
in FAB typing.
It accounts for 5% to 8% of AML, and is more common in middle-aged adults, often with disseminated intravascular coagulation (DIC).

Typical APL (coarse-granular) leukocytes are often not elevated or decreased, and fine-granular leukocyte counts are often high
.

Case history

01 Case 1

The patient is a middle-aged man presenting to the Department of
Cardiology with arrhythmias.
Blood routine shows that the number of white blood cells is significantly reduced, the proportion of neutrophils is reduced, and the proportion of lymphocytes is relatively increased.
Macrocytic anemia, with different
red blood cell sizes.

Because the number of white blood cells is too small, the scatter plot does not show obvious abnormalities
.

Push the film for reexamination, a type of cells can be seen under the microscope: large cell body, butterfly shape visible nucleus, fine chromatin, more cell quality, increased granules, visible internal and external plasma, and some cells can see Auer bodies
.

Query the Lis system, coagulation experiments showed that D-dimer increased
.

Combined with blood routine, blood coagulation results and re-examination microscopic findings, a reminder report
is issued.

Sent for bone marrow, hyperplasia is extremely active, and a large number of abnormal cells
can be seen.
Such cells are large and have more particles, and "bundle-like" Auer bodies are easy to see
.
Typical bone marrow image of
acute promyelocytic leukemia.

Morphologic considerations are acute promyelocytic leukemia
.

Flow cytometry is consistent with acute promyelocytic leukemia immunophenotype
.

Biopsy combined with immunohistochemistry, consistent with acute myeloid leukemia (predisposition to APL).

The karyotyping of chromosomes was 46,XY,t(15;17)(q24; q21)
。

02 Case 2

The patient is an older man presenting with leukopenia
.
CBC suggests marked leukocytes and other normal
.

There are no obvious anomalies
in the scatterplot.

Coagulation tests show a decrease in fibrinogen and an increase in
D-dimer.

Push re-examination, no abnormal cells
were seen.
Patients with isolated leukopenia, no other obvious relevant history and signs, and abnormal coagulation should be considered for further re-microscopy
.
Do centrifugal smear, a small number of abnormal cells can be seen: the cell body is large, the nucleus can be seen butterfly-shaped, the cell mass is large, the internal and external plasma is visible, the granules are increased, and some cells can be seen Auer bodies
.

Bone marrow was sent for examination, and 12% of abnormal cells
were visible.
Such cells: large cell body, irregular nucleus, fine chromatin, cell mass, increased particles, some cells can be seen "wood bundle" Auer bodies
.
Consider acute promyelocytic leukemia, which is later confirmed by genetic and chromosomal examination as APL
.

Case studies

The first symptoms of both cases of APL were leukopenia, and doubts were found, and the examination was perfected, and the final diagnosis was confirmed
.
There are two difficulties in the re-examination of leukopenia in blood routine
.

First, the scatter plot is extremely difficult to
display.
The number of white blood cells is small, the scatter points shown in the figure are few, and when there are fewer abnormal cells, it cannot be prompted
in time.

The solution is to use the "low-value white blood cell" mode during retesting, increasing the volume of blood injected, and doubling the number of white blood cells passing through the channel
.
Scattering increases, and the detection of abnormal white blood cells reaches the level
of normal white blood cell detection.

Second, it is difficult to find abnormal cells by
push-film microscopic examination.
The number of white blood cells is small, the number of cells in the whole blood film is limited, and sometimes the complete film can not count less than 200 cells, and the target cells
cannot be found.
The distance between white blood cells increases with each other, low-magnification lenses are afraid of missed detection, and oil microscopes take too much
time.

The solution is to centrifuge and push the slide microscopy
.
There are two ways to do this:

1.
EDTA anticoagulant whole blood 2200 centrifugation for 10 minutes, discard plasma, aspirate leukocyte layer push, and stain microscopy
.

2.
Wait for the blood sample to sink naturally, aspirate the plasma, centrifuge, discard the supernatant, mix well and push the tablet
.

After centrifugation, the detection rate of abnormal cells was greatly improved
.

Case summary

Hematologic diseases with markedly elevated white blood cells are not easy to miss due
to the large number of cells, scatter plots, and microscopic findings.
The blood routine of leukopenia is normal due to the small amount of cells, and the scatter plot is often normal, which is relatively easy to miss
.
Of particular concern is promyelocytic leukemia
with leukopenia.
Early detection and diagnosis may be curative, but when the clinical presentation is typical, it can be life-threatening
.
Master the re-examination technology of leukopenia, do not easily let go of a specimen, and protect the life and health
of patients to the greatest extent.

【References】

[1] Clinical Hematology Testing/Xu Wenrong Wang Jianzhong, ed.
5th ed.
Beijing: People's Medical Publishing House, 2012

[2] Clinical Laboratory Diagnostic Atlas/edited by Wang Jianzhong.
Beijing: People's Medical Publishing House, 2012

[3] Criteria for diagnosis and efficacy of blood diseases/Shen Ti Zhao Yongqiang, editor.
4th ed.
Beijing: People's Medical Publishing House, 2018

[4] Hematology/Zhang Zhinan, Hao Yushu, editor-in-chief.
2nd ed.
Beijing: People's Medical Publishing House, 2011