Abstract
We report a 25 year-old male of CML, who repeated lymphoid blast crises twice and finally experienced a myelomonocytoid blast crisis. In the first and the second crises, after 2 years of chronic phase, the blasts were only weakly positive or negative for terminal deoxynucleotidyl transferase. Based on other morphological features of the blasts, however, lymphoid blast crisis was strongly suspected. Actually, he responded well to the vincristine and prednisolone therapy. In the third crisis, the blasts showed myelomonocytoid features. He did not respond to the same regimen, and died of intracranial infiltration during daunorubicin and cytosine arabinoside therapy after one year from the first crisis.
Chromosomal analysis showed the karyotypes of 46, XY, t(9:22) (q34:q11) in the chronic phase, 45, XY, -7, -9, +der(9) t(7;9) (q11;p11), t(9:22) (q34:q11) in the lymphoid blast crisis, and 46, XY, t(9:22) (q34:q11), t(11:17) (q23:q25) in the myelomonocytoid blast crisis.
