The median age when AML is diagnosed ranges between 63 and 71 years in the UK, Canada, Australia and Sweden, compared with 40 to 45 years in India, Brazil and Algeria.AML accounts for about 90% of all acute leukemias in adults, but is rare in children. The rate of therapy-related AML (AML caused by previous chemotherapy) is expected to rise with an increase in the use of chemotherapy, an ageing population and more patients surviving their initial chemotherapy treatment; therapy-related disease accounts for just under 10% of all cases of AML. AML is slightly more common in men, with a male-to-female ratio of 1.3:1 to 1.4:1. Incidence is also seen to differ by ethnicity, with caucasians having higher recorded incidences and the lowest recorded incidences being in Pacific Islanders and native Alaksans.In the UK, AML accounts for 31% of all leukemia cases, and around 3,100 people were diagnosed with the disease each year in 2016–2018. History
The first published description of a case of leukemia in medical literature dates to 1827 when French physician Alfred-Armand-Louis-Marie Velpeau described a 63-year-old florist who developed an illness characterized by fever, weakness, urinary stones, and substantial enlargement of the liver and spleen. Velpeau noted the blood of this person had a consistency "like gruel", and speculated the appearance of the blood was due to white corpuscles. In 1845, a series of people who died with enlarged spleens and changes in the "colors and consistencies of their blood" was reported by the Edinburgh-based pathologist J.H.
Each of the WHO categories contains numerous descriptive subcategories of interest to the hematopathologist and oncologist; however, most of the clinically significant information in the WHO schema is communicated via categorization into one of the subtypes listed below. The revised fourth edition of the WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues was released in 2016. This classification, which is based on a combination of genetic and immunophenotypic markers and morphology, defines the subtypes of AML and related neoplasms as: In 2022 a new classification has been published. Acute leukemias of ambiguous lineage (also known as mixed phenotype or biphenotypic acute leukemia) occur when the leukemic cells can not be classified as either myeloid or lymphoid cells, or where both types of cells are present. French-American-British
The French-American-British (FAB) classification system provides terminology that is still sometimes used, and it remains a valuable diagnostic tool in areas without access to genetic testing, this system has largely become obsolete in favor of the WHO classification, which correlates more strongly with treatment outcomes.The FAB system divides AML into eight subtypes, M0 through to M7, based on the type of cell from which the leukemia developed and its degree of maturity. AML of types M0 to M2 may be called acute myeloblastic leukemia. Classification is done by examining the appearance of the malignant cells with light microscopy and/or by using cytogenetics to characterize any underlying chromosomal abnormalities. The subtypes have varying prognoses and responses to therapy.