Extramedullary manifestation of the blastic phase of chronic myelocytic leukemia: A chromosome study

Two patients with extramedullary manifestation of the blastic phase of chronic myelocytic leukemia (CML) are reported. 100% of the metaphases derived from extranedullary sites were aneuploid. Despite the absence of blastic changes in the bone marrow and the peripheral blood, a significant proportion of the metaphases derived from these tissues also showed aneuploidy. It is suggested that maturation and differentiation of aneuploid myeloblasts are influenced by their environment.