CML in Chronic Phase

Chronic myeloid leukemia is a proliferative disorder characterized by the dysregulated production and uncontrolled proliferation of mature and maturing granulocytes. It is characterized by the chromosomal translocation t(9;22)(q34.1;q11.2), which results in the formation of the Philadel­phia (Ph) chromosome and the BCR-ABL1 fusion gene.

Diagnostic Criteria (WHO 2016)

• Peripheral and/or bone marrow blast less than 10%
• Demonstration of the Philadelphia chromosome or the underlying t(9;22) translocation by conventional cytogenetic techniques 

Blood Film Features:

• Leucocytosis involving various stages of granulocytic maturation
• Peaks in myelocytes & neutrophia
• Blast less then 10% (Usually less than 2%)
• Platelets may be normal or increased
• Eosinophilia and Basophilia
• No significant dysplasia
• Cytochemistry:  neutrophil alkaline phosphate score low

Bone Marrow Features:

• Hypercellular bone marrow
• Myeloid:Erythroid (M:E) ratio increased
• Granulocytic hyperplasia involving various stages of maturation
• Blast less than 10% (Usually less than 5%)
• Small megakaryocytes with hypolobulated nuclei

Other features to look for:

• Pseudo-Gaucher cells
• Sea blue histiocytes

Other Resources

• ASH image bank:  CML
• Youtube: Medicosis Perfectionalis – CML