Hypercalcemia and diffuse osteolytic lesions in the acute phase of chronic myelogenous leukemia. A possible relation between lymphoid transformation and hypercalcemia.

A patient with blastic crisis of chronic myelogenous leukemia (CML) is presented. The acute phase was localized in the lymph nodes and bones, causing severe osteolytic lesions and hypercalcemia. The blast cells were undifferentiated in light microscopy and by histochemical stains. As viewed under electron microscopy, a considerable proportion of the blast cells were of myeloid origin, while immunologic markers and cytogenetics indicated a lymphoid origin. It seems plausible that the patient had a mixed myeloid-lymphoid blast crisis, but that the lymphoid blasts were responsible for the severe osteolytic lesions and the hypercalcemia.