Acute myeloid leukaemia

Acute myeloid leukaemia (AML) is a life-threatening haematological malignancy that predominantly occurs in older adults.

Many subtypes exist; the acute promyelocytic leukaemia (APL) subtype is particularly aggressive and may be associated with life-threatening coagulopathy.

Characteristically, abnormal myeloid blasts are present in the bone marrow (and in some cases the peripheral blood and extramedullary tissue) and normal haematopoiesis is reduced.

Diagnosis requires bone marrow aspirate and trephine biopsy analysis. Cytogenetic analysis and molecular genetic testing can inform diagnosis, prognosis, and treatment.

Treatment includes chemotherapy and/or targeted therapies in two main phases: induction and consolidation. Haematopoietic stem cell transplantation and/or maintenance therapy may be used in select patients.

AML is a life-threatening haematological malignancy caused by clonal expansion of myeloid blasts in the bone marrow, peripheral blood, and/or extramedullary tissues.

AML is a highly heterogeneous disease that can be classified into subtypes based on blast count (in the bone marrow or peripheral blood) and the presence of genetic abnormalities.[1]Khoury JD, Solary E, Abla O, et al. The 5th edition of the World Health Organization Classification of Haematolymphoid Tumours: myeloid and histiocytic/dendritic neoplasms. Leukemia. 2022 Jul;36(7):1703-19. https://www.nature.com/articles/s41375-022-01613-1 http://www.ncbi.nlm.nih.gov/pubmed/35732831?tool=bestpractice.com [2]Arber DA, Orazi A, Hasserjian RP, et al. International Consensus Classification of Myeloid Neoplasms and Acute Leukemias: integrating morphologic, clinical, and genomic data. Blood. 2022 Sep 15;140(11):1200-28. https://www.doi.org/10.1182/blood.2022015850 http://www.ncbi.nlm.nih.gov/pubmed/35767897?tool=bestpractice.com See Classification. 

AML may arise de novo, or secondary to a prior treatment, pre-existing heamatological disorder (e.g., myelodysplastic syndrome), or germline predisposition.[1]Khoury JD, Solary E, Abla O, et al. The 5th edition of the World Health Organization Classification of Haematolymphoid Tumours: myeloid and histiocytic/dendritic neoplasms. Leukemia. 2022 Jul;36(7):1703-19. https://www.nature.com/articles/s41375-022-01613-1 http://www.ncbi.nlm.nih.gov/pubmed/35732831?tool=bestpractice.com [2]Arber DA, Orazi A, Hasserjian RP, et al. International Consensus Classification of Myeloid Neoplasms and Acute Leukemias: integrating morphologic, clinical, and genomic data. Blood. 2022 Sep 15;140(11):1200-28. https://www.doi.org/10.1182/blood.2022015850 http://www.ncbi.nlm.nih.gov/pubmed/35767897?tool=bestpractice.com

APL is an aggressive subtype of AML that is characterised by a distinctive cytomorphology (hypergranular promyelocytes with bilobed nuclei and bundles of Auer rods), a tendency for coagulopathy (due to thrombocytopenia and disseminated intravascular coagulation), and a specific t(15;17)(q22;q12) cytogenetic abnormality resulting in the PML::RARA fusion gene.[Figure caption and citation for the preceding image starts]: Peripheral blood film of a patient with acute promyelocytic leukaemia showing hypergranular promyelocytes, some with bundles of Auer rodsFrom the collection of Drs K. Raj and P. Mehta; used with patient consent [Citation ends].[Figure caption and citation for the preceding image starts]: Peripheral blood film of a patient with acute promyelocytic leukaemia showing hypergranular promyelocytes with bi-lobed nuclei and bundles of Auer rodsFrom the collection of Drs K. Raj and P. Mehta; used with patient consent [Citation ends].