Acute Myeloblastic Leukemia (AML)
Introduction
The defining criterion for the diagnosis of acute leukemia, both lymphoblastic and myeloblastic, is the finding of 20% or more blasts on a differential count of nucleated hematopoietic cells on a bone marrow aspirate. In acute myeloblastic leukemia, the blasts may be agranular (type I) or granular (type II) or a combination.
In the FAB classification, the AMLs are divided into 8 major types, designated MO through M7. M2 AML is further subdivided to include an M2Eo subtype, M3 AML to include a hypergranular and a hypogranular (microgranular) subtype, M4 AML to include an M4Eo subtype, M5 AML to include an M5a and M5b subtype, and M7 AML to include a micromegakaryoblastic and a megakaryoblastic subtype. The criteria used to define these subtypes are based mainly on morphology, but cytochemical and immunophenotypic profiles are often necessary. As with the acute lymphoblastic leukemias, the various profiles obtained from these studies are not absolute. Some lineage markers such as the T cell markers, CD7 and CD2, show frequent lineage infidelity.
In the WHO classification, cytogenetic profiles, and the presence of a myelodysplastic phase preceeding the development of AML or at time of diagnosis of AML are factored into the classification. Also considered is whether AML development in the setting of prior exposure to leukemogenic drugs such as alkalyating agents, topoisomerase II ingibitors and other drugs, or ionizing radiation.
FAB subtypes of Acute Leukemia
For all publication requests, please complete the image permission form and we will respond to your request shortly.
 |
Charles
E.
Hess,
M.D.,FACP [more information]
Professor of Internal Medicine
|
||||