Ultrastructural study of chronic myeloid leukemia in blast crisis using myeloperoxidase and acid phosphatase reactions

Based on the fact that ultrastructural cytochemical techniques sometimes allow a better cytologic classification of acute leukemia cells, peripheral blasts from 10 patients with CML in BC were studied with the electron microscope after the myeloperoxidase and acid phosphatase reactions. In four cases the blasts, according to the optical microscope diagnosis, presented myeloid features and showed cytochemical positivity of the myeloperoxidase and acid phosphatase reactions. In the other six agranular BC, unclassifiable using the optical microscope, the cells showed lymphoblastic-like features with the electron microscope. The myeloperoxidase was constantly negative whereas the acid phosphatase reaction had an ultrastructural distribution similar to that already described in leukemic lymphoblasts. These findings allow the suggestion that electron microscopy of the cells present in the BC of CML could provide additional data to allow a more exact classification of the agranular blasts.