What type of leukemia is characterized by the presence of promyelocytes with heavy granulation?

Acute promyelocytic leukemia (APL) is characterized specifically by the presence of promyelocytes that exhibit heavy granulation. This type of leukemia is a subtype of acute myeloid leukemia (AML) and is particularly noted for its distinct morphological features, including the presence of the promyelocyte cells that have abundant cytoplasmic granules and often multiple Auer rods.

In APL, these promyelocytes can also sometimes be found in bundles known as "faggot cells," which further helps in identifying this leukemia. The heavy granulation is a hallmark finding in cytogenetic and morphological examinations, which is critical for diagnosis. Additionally, APL is commonly associated with specific genetic abnormalities, particularly the translocation t(15;17), which leads to the fusion of the promyelocytic leukemia (PML) gene and the retinoic acid receptor alpha (RARA) gene, confirming its identity as a distinct clinical entity within the broader category of acute myeloid leukaemias.

Understanding these features is important for hematopathologists and medical professionals in order to provide appropriate treatment strategies, including the use of all-trans retinoic acid (ATRA), which has dramatically improved outcomes for patients with this specific type