Chronic myeloid leukemia
Chronic myeloid leukemia, also known as chronic myelogenous leukemia, is a myeloproliferative neoplasm characterized by the overproduction of differentiated granulocytes.
The annual incidence is about 1 per 100,000 1. The typical age at presentation is 50-60 years 1.
Constitutional symptoms are common, such as fatigue, weight loss, and sweats 2. Some patients are asymptomatic, with the diagnosis being first suspected based upon routine blood work finding leukocytosis with a predominance of the neutrophil lineage.
Chronic myeloid leukemia is caused by a chromosomal abnormality in hematopoietic stem cells in which reciprocal translocation between chromosomes 9 and 22 creates the fusion gene BCR-ABL1. The shortened chromosome 22 containing the fusion gene is called the Philadelphia chromosome. The diagnosis is established by karyotype (to detect the Philadelphia chromosome), fluorescence in situ hybridization (to detect the BCR-ABL1 fusion gene), or reverse transcription polymerase chain reaction (to detect the BCR-ABL1 mRNA product).
Patients commonly have splenomegaly and diffuse marrow infiltration (manifest as abnormally low signal on T1-weighted MRI).