Acute myeloid leukemia

Last revised by Dr Yuranga Weerakkody on 30 May 2022

Acute myeloid leukemia (AML), also referred to as acute myelogenous leukemia, is a hematological malignancy characterized by the abnormal clonal proliferation of immature myeloid precursors (myeloblasts) or poorly differentiated cells of the hematopoietic system. It primary infiltrates the bone marrow, but the disease can also extend to blood and other tissues.

It is more common in middle-aged and elderly patients, with a median age of diagnosis at 70 years. The M:F rate varies from 1.1 in the 5th decade to about 1.8 in the 8th decade of life 2,3

Acute myeloid leukemia only accounts for ~20% of all childhood leukaemias, cf. acute lymphoblastic leukemia (ALL), which represents ~80% of leukaemias at this age group 2

There is an ethnic component in the distribution of most types of acute myeloid leukemia, with a strong predominance among the white ethnicity group 2,3.   

Acute myeloid leukemia tends to present with vague and non-specific symptoms such as fatigue and is most commonly revealed on full blood count tests, where anemia, thrombocytopenia, and/or neutropenia are demonstrated 2,4

Described symptoms associated with bone marrow failure include 4:

  • fevers
  • bleeding gums
  • multiple ecchymoses
  • dyspnea on exertion
  • anginal chest pain
  • refractory upper respiratory infection symptoms

Extramedullary leukemic infiltration can lead to organ-involved signs such as hepatosplenomegaly, leukemia cutis, lymphadenopathygingival hyperplasia, and neurological symptoms 4.

The leukemic myeloblasts can commonly be identified either in peripheral blood smears or bone marrow aspirate. Eventually, there is infiltration of other organs and tissues:

The revised 2016 World Health Organizatiοn (WHO) classification of tumors of hematopoietic and lymphoid tissues classifies AML in multiple subtypes 5

Depending on the type of cell lineage involved, AML can be divided into specific morphologic subgroups. 

The leukemic cells are characterized by very little cytoplasm, which holds fine azurophilic granules and Auer bodies or rods. Irregular nuclei and distinct nucleoli are also features of those cells 4.

Acute myeloid leukemia has an overall poor prognosis compared to the other main types of leukemia, having ~30% 5-year survival rate 8. This is most evident among elderly patients over 65 years, where up to 70% die within 1 year of diagnosis 8

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Cases and figures

  • Case 1: adrenal granulocytic sarcoma
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