Acute myeloid leukemia

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).

Morphology

Peripheral blood:

Blasts with some maturation

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

Bone marrow:

Blasts, some with large azurophilic granules, perinuclear hof

<90% of nonerythroid cells are blasts

≥10% neutrophilic component

<20% monocytic component

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).

Morphology

Peripheral blood:

White blood cell count may be low or only slightly elevated

Blasts, hypergranular promyelocytes, cytoplasm gray to blue, nucleus may be folded or bilobed

Multiple Auer rods possible, may be in bundles (Faggot cells), schistocytes

Bone marrow:

Blasts, hypergranular promyelocytes, nuclei often bilobed or kidney shaped

± Multiple Auer rods

Cytochemistry

Myeloperoxidase:

strongly positive (see Figure 15-2, E)

Sudan black B:

strongly positive (see Figure 15-2, F)

Genetics

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Tags: Clinical Hematology Atlas

Jun 12, 2016 | Posted by admin in HEMATOLOGY | Comments Off

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