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.
It has been reported a solid ethnic component in the distribution of most types of AML, with a strong predominance among the white ethnicity group 2,3.
therapy-related acute myeloid leukemia (t-AML)
- immunosuppression for solid organ transplant
- prior radiation therapy or chemotherapy
- trisomy 21 8
AML tends to present with vague and nonspecific 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:
- bleeding gums
- multiple ecchymoses
- dyspnea on exertion
- anginal chest pain
- refractory upper respiratory infection symptoms
Extramedullary leukemic infiltration can lead to organ-involved symptoms such as hepatosplenomegaly, leukemia cutis, lymphadenopathy, gingival 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:
- CNS manifestations
- pulmonary complications tend to be observed more frequently at presentation in neutropenic AML patients of advanced age 7.
- testicular manifestations
The revised 2016 World Health Organization (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.
Treatment and prognosis
AML has 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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- 6. Stefanski M, Jamis-Dow C, Bayerl M, Desai RJ, Claxton DF, Van de Louw A. Chest radiographic and CT findings in hyperleukocytic acute myeloid leukemia: A retrospective cohort study of 73 patients. (2016) Medicine. 95 (44): e5285. doi:10.1097/MD.0000000000005285 - Pubmed
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- 8. Girish S. Shroff, Mylene T. Truong, Brett W. Carter, Marcelo F. Benveniste, Rashmi Kanagal-Shamanna, Greg Rauch, Chitra Viswanathan, Prajwal C. Boddu, Naval Daver, Carol C. Wu. Leukemic Involvement in the Thorax. (2019) RadioGraphics. 39 (1): 44-61. doi:10.1148/rg.2019180069 - Pubmed