Blastic crisis in previously clinically silent chronic myelogenous leukemia

A patient is described in whom CML fist presented as blastic crisis. The diagnosis of CML was based upon the findings of Ph¹ chromosome in the bone marrow, basophilia in the peripheral blood, absence of neutrophil alkaline phosphatase (NAP) activity in the leukocytes, elevated serum vitamin B₁₂ and an enlarged firm spleen. CML with blastic crisis as its first expression is relatively rare, as compared to CML in which blastic crisis appears as a phase of prolonged clinically manifest disease.