Background. Osteopathy is one of the common initial symptoms of acute lymphocytic leukemia (ALL) in children and adolescents, but multiple osteolysis accompanied by hypercalcemia is rarely observed. Procedure. We treated a 14-year-old female who had multiple osteolytic lesions and hypercalcemia at initial onset of ALL. In this case we examined some humoral factors, which are known to associate with hypercalcemia in malignancies. Results. Parathyroid hormone-related peptide (PTHrP) was elevated in serum, and reverse transcriptase-polymerase chain reaction and immunohistochemistry revealed that the lymphoblasts produced PTHrP directly. Other humoral factors related to hypercalcemia were not detected. ALL relapsed in the bone marrow 3 months after achieving complete remission, and hypercalcemic and elevation of serum PTHrP were also observed. A second remission could not be achieved and hypercalcemia continued. The patient received allogeneic bone marrow transplantation. The serum calcium level became normal after the conditioning therapy. Before engraftment, however, the patient died of infection. Conclusions. The present case suggests that blast-producing PTHrP might be associated with multiple osteolytic lesions and hypercalcemia. PTHrP expressed in the lymphoblasts may, in itself, confer a survival advantage to lymphoblasts and contribute to the refractory nature of the disease.
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