a rare presentation of chronic myeloid leukemia blast crisis

Chronic myeloid leukemia (CML), as the name suggests, is a chronic disorder in which granulocytes undergo dysregulated production and uncontrolled proliferation. Majority of CML patients present during the chronic phase (CP) of the disease. The interval from CP to onset of blastic transformation and acute leukemia can vary from days to several years. The biological basis of blast phase is poorly understood. Most common blast crisis is myeloid type and less frequently lymphoid or promyelocytic. The transformation of CML to promyelocytic blast crisis is a rare form. These findings suggest that BCR-ABL1 gene arises from leukemic stem cell (LSC) which is still not committed to myeloid or lymphoid differentiation. The blastic clone may originate either at the multipotent LSC or at committed leukemia progenitor cell. Here, we report a case of promyelocytic blast crisis with t(15;17) in addition to t(9;22).