Acute myeloid leukemia

Published on 04/03/2015 by admin

Filed under Hematology, Oncology and Palliative Medicine

Last modified 22/04/2025

Print this page

This article have been viewed 5084 times

15 Acute myeloid leukemia

Approach to acute myeloid leukemia

The World Health Organization (WHO) Classification of Tumours and Haematopoietic and Lymphoid Tissues is based on morphology; immunophenotyping; genetic features, including karyotype and molecular testing; and clinical features. WHO lists the characteristic features of acute myeloid leukemia (AML) as increased bone marrow cellularity with ≥20% blasts, variable white blood cell count, anemia, and thrombocytopenia in the peripheral blood.

AML is separated into four categories:

1. Acute myeloid leukemia with recurrent genetic abnormalities

2. Acute myeloid leukemia with myelodysplasia-related changes *

3. Therapy-related myeloid neoplasms *

4. Acute myeloid leukemia, not otherwise specified

This atlas presents characteristic peripheral blood and bone marrow morphology for each of the AMLs with recurrent genetic abnormalities and those not otherwise specified together with the associated cytochemical reactions, genetic abnormalities, and immunophenotypes.

Acute myeloid leukemia without maturation

Fab M1

FIGURE 15–2A Peripheral blood (×1000).

FIGURE 15–2B Peripheral blood: Auer rods in myeloblast (×1000). Auer rods are composed of fused primary granules usually rod shaped but may be round in appearance. Single or multiple Auer rods may be seen in malignant myeloblasts and malignant promyelocytes.

FIGURE 15–2C Bone marrow (×500).

FIGURE 15–2D Bone marrow (×1000).

FIGURE 15–2E Positive myeloperoxidase stain.

FIGURE 15–2F Positive Sudan Black B stain.

Morphology

Peripheral blood:

± Auer rods (see Figure 15-2, A and B)

Bone marrow:

≥90% of nonerythroid cells are blasts

Cytochemistry

Myeloperoxidase:

positive (see Figure 15-2, E)

Sudan black B:

positive (see Figure 15-2, F)

Nonspecific esterase:

Genetics

Recurrent genetic abnormalities: not defined

Immunophenotype

CD13⁺, CD33⁺, CD34^±, HLA-DR^±, CD117⁺

Acute myeloid leukemia with maturation

Fab M2

FIGURE 15–3A Peripheral blood Type I myeloblast (×1000).

FIGURE 15–3B Peripheral blood Type II myeloblast (×1000).

FIGURE 15–3C Bone marrow (×500).

FIGURE 15–3D Bone Marrow (×1000).

Cytochemistry

Myeloperoxidase:

positive (see Figure 15-2, E)

Sudan black B:

positive (see Figure 15-2, F)

Genetics

Subset with t(8;21) is designated as AML with recurrent genetic abnormalities. In this subset, blasts are large with abundant basophilic cytoplasm, azurophilic granules, and possible perinuclear hofs.

Immunophenotype

CD13⁺, CD33⁺, CD65⁺, CD11b⁺, CD15⁺, HLA-DR^±

Acute promyelocytic leukemia

FIGURE 15–4A Peripheral blood. A, Hypergranular promyelocyte (×1000); B, Faggot cells.

FIGURE 15–4B Bone marrow (×500).

FIGURE 15–4C Bone marrow (×1000).

Acute promyelocytic leukemia—microgranular variant

FIGURE 15–5A Peripheral blood (×1000).

FIGURE 15–5B Bone marrow (×500).

FIGURE 15–5C Bone marrow (×1000).

Acute myelomonocytic leukemia

Fab M4

FIGURE 15–6A Peripheral blood (×1000).

FIGURE 15–6B Bone marrow (×500).

FIGURE 15–6C Bone marrow (×1000).

FIGURE 15–6D Positive naphthol-AS-D chloroacetate esterase (specific) stain.

FIGURE 15–6E Positive α-naphthyl esterase (nonspecific) esterase stain in monocytes (left). Naphthyl esterase stain inhibited by NaFl (right).

Genetics

Recurrent genetic abnormalities: not defined

inv(16) or t(16;16) and abnormal eosinophils are excluded from this category.

Immunophenotype

CD13⁺, CD33⁺, CD14⁺ CD4⁺, CD11b⁺, CD64⁺, CD15⁺, CD36⁺

Acute myeloid leukemia with inv(16) (p13.1q22) or t(16;16)(p13.1;q22)^; CBFB-MYH11

Acute myeloid leukemia with abnormal marrow eosinophils

Fab M4EO

FIGURE 15–7A Peripheral blood (×1000).

FIGURE 15–7B Bone marrow (×500).

FIGURE 15–7C Bone marrow (×1000).

Cytochemistry

Myeloperoxidase:

positive (see Figure 15-2, E)

Nonspecific esterase:

positive (see Figure 15-6, E)

Specific esterase:

weakly positive in abnormal eosinophils

Genetics

Recurrent genetic abnormality: inv(16) (p13.1q22) or t(16;16)(p13.1;q22); CBFB-MYH11

These genetic abnormalities are diagnostic of AML and do not require a ≥20% blast count.

Immunophenotype

CD34⁺, CD117⁺, CD13⁺, CD33⁺, CD15⁺, CD4⁺, CD11b⁺, CD11c⁺, CD14⁺, CD64⁺, CD36⁺, CD65⁺

Acute monoblastic and monocytic leukemia

FIGURE 15–8A Peripheral blood—monoblasts predominate (×1000).

FIGURE 15–8B Peripheral blood—promonocytes predominate (×1000).

FIGURE 15–8C Bone marrow showing monoblast predominance (×500).

FIGURE 15–8D Positive α-naphthyl butyrate esterase (nonspecific) esterase stain.

Acute erythroid leukemia

Fab m6a

(erythroid/myeloid leukemia)

FIGURE 15–9A Peripheral blood (×1000).

FIGURE 15–9B Bone marrow erythroleukemia (×500).

FIGURE 15–9C Bone marrow —pure erythroid leukemia (×500).

FIGURE 15–9D Positive periodic acid–Schiff stain.

Genetics

Recurrent genetic abnormalities: not defined

Immunophenotype

Hemoglobin +, glycophorin +, CD13⁺, CD33⁺, CD117^±

Fab M6b

Acute megakaryocytic leukemia

Fab M7

FIGURE 15–10A Peripheral blood (×500).

FIGURE 15–10B Peripheral blood (×500).

FIGURE 15–10C Micromegakaryocyte. Peripheral blood (×1000).

Cytochemistry

Myeloperoxidase:

Sudan black B:

Specific esterase:

Periodic acid–schiff:

positive or negative

Nonspecific esterase:

focal positivity

Genetics

Recurrent genetic abnormalities: not defined

Note:

In infants may be associated with t(1:22)(p13;q13).

Immunophenotype

CD41⁺, CD61⁺, CD36⁺

^* Diagnosis is, in part, based on patient presentation and as such will not be addressed in this atlas.

^† French-American-British classification of acute leukemia.

^‡ 1. Abnormal promyelocytes are considered blast equivalents for the purpose of diagnosis.
2. May be associated with disseminated intravascular coagulopathy.

Related

Clinical Hematology Atlas